Enhancing Soil Conditions and Maize Yield Efficiency through Rational Conservation Tillage in Aeolian Semi-Arid Regions: A TOPSIS Analysis

Abstract

Conservation tillage technology possesses substantial potential to enhance agricultural production efficiency and tackle issues such as wind erosion and land degradation in semi-arid regions. The integration of no-tillage and straw mulching technologies in the conventional aeolian semi-arid agricultural zones of western Liaoning, China, has led to notable improvements in crop yield and soil quality. However, a comprehensive assessment of the mechanisms and kinetics involved in soil nutrient variations is yet to be conducted. During a two-year study period, we assessed four tillage systems in the aeolian semi-arid regions of Northern China: no-tillage with full straw mulching (NTFS), no-tillage with half straw mulching (NTHS), no-tillage without straw mulching (NT), and conventional tillage (CT). The investigation focused on examining nutrient conditions, enhancing photosynthetic activity, and increasing maize yield while improving water use efficiency (WUE). Our findings emphasize the beneficial impact of combining no-tillage and straw mulching on enhancing soil water retention, resulting in a notable rise in soil moisture levels during the crucial growth phases of maize. This approach also positively influenced soil nutrient levels, particularly in the 0–20 cm layer, fostering an environment conducive to maize cultivation. In terms of ecological benefits, no-tillage with straw mulching curtailed soil sediment transport and wind erosion, notably at 30–40 cm heights, aiding in the ecological protection of the region. The yield and WUE were substantially higher under NTFS and NTHS than under CT, with NTHS demonstrating the most significant gains in yield (14.5% to 16.6%) and WUE (18.3% to 21.7%) throughout the study period. A TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) analysis confirmed NTHS as the optimal treatment, achieving the highest scores for soil water, nutrient availability, wind erosion control, maize photosynthesis, yield, and WUE, thus emerging as the most effective conservation tillage strategy for sustainable agriculture in aeolian semi-arid regions.

1. Introduction

The aeolian semi-arid region, a quintessential dry-farming zone in China, is predominantly situated in the western reaches of three northeastern provinces, the northern part of Hebei Province, the Dongsi League of the Inner Mongolia Autonomous Region, and the central and western regions. Spanning approximately 800,000 km², this region is a critical grain-producing area in China and, at the same time, represents one of the country’s most environmentally vulnerable regions [1]. The region grapples with a series of challenges, including scarce and erratic rainfall [2], intermittent droughts, intense soil wind erosion [3], and suboptimal farmland productivity [3]. Beyond these natural impediments, recent unsustainable tillage practices and excessive development have led to the degradation of soil profiles, with thinning soil layers and a dearth of water and nutrients. These factors have intensified the difficulties surrounding crop production efficiency and the pursuit of sustainable agricultural development in the region [4]. Addressing these multifaceted issues—shaped by a confluence of factors such as drought, wind erosion, subpar soil structure, and nutrient deficiency—is essential for bolstering agricultural production in the aeolian semi-arid region [5]. Improving crop production efficiency and addressing substantial land degradation challenges in the aeolian semi-arid region are crucial for enhancing agricultural productivity. These challenges arise from various factors such as drought, wind erosion, inadequate soil structure, and nutrient scarcity.

Conservation tillage techniques, including reduced tillage, no-tillage, and surface cover, offer a suite of benefits for agricultural systems. They enhance soil structure, elevate soil organic matter content, curtail soil erodibility, and improve overall soil quality, thereby bolstering the soil’s capacity for environmental regulation [6,7]. These techniques represent a strategic array of measures designed to boost crop yields while simultaneously curbing soil degradation. In a pivotal study, Blanco et al. (2016) conducted a controlled experiment in a region of Central America plagued by severe erosion. Their research revealed that the implementation of no-tillage practices, in comparison with traditional tillage methods, significantly mitigated soil erosion, leading to a noteworthy reduction of 28.7% in the area of eroded land [8]. Moreover, the erosion rate within the no-tillage plots was found to have a significantly negative correlation with the degree of vegetation cover in the tropical rainforest region [8]. Conservation tillage not only fortifies soil stability and porosity but also aids in water infiltration and curtailing soil loss while preserving elevated levels of soil organic matter [9,10]. Furthermore, conservation tillage initiates the formation of a natural protective surface layer, which, in turn, reduces soil erodibility and augments the water use efficiency of crops. Conservation tillage, particularly when integrated with intercropping and no-tillage techniques, has the potential to markedly decrease water loss, improve water use efficiency, and boost crop yields in a subtropical monsoon region [10].

A plethora of studies have substantiated the potential for the significant mitigation of soil wind erosion through the application of straw mulch in a warm temperate monsoon region [11]. In an examination of suburban farmlands, Chen et al. (2022) illustrated that the implementation of both maize stalk mulching and maize stubble resulted in a pronounced diminution in the sediment transport of farmland when compared with conventional tillage methods [12]. Additional research has indicated that straw coverage of 20% is amply sufficient to achieve a notable reduction in wind erosion rates at wind speeds below 12 m·s⁻¹, while an optimal coverage of 40% is imperative for forestalling wind erosion at speeds surpassing 16 m·s⁻¹ [13]. In further studies, Cong et al. (2016) revealed that both stubble height and straw mulching significantly influence wind erosion, with straw mulching having a more profound effect than stubble height in a semi-arid region [14]. A multitude of studies have revealed that the application of straw mulch can precipitate a staggering 90.4% reduction in sediment transport on farmland in contrast to scenarios devoid of mulch in semi-arid regions [15].

Empirical research has shown that the application of straw mulch can reduce the soil’s bulk density and increase its porosity in semi-arid regions [16]. Acting as a physical buffer between the soil surface and the atmosphere, straw mulching reduces the impact of direct solar radiation on the ground. As a result, it substantially curbs soil water evaporation and promotes water infiltration, offering clear advantages over the absence of mulching in semi-arid regions [17,18]. Furthermore, straw mulching exerts a beneficial influence on water storage and the conservation of soil moisture in different climatic regions [19,20,21]. Under no-tillage conditions, the soil moisture content in the upper layer (0–20 cm) has been found to surpass that achieved with traditional tillage methods, a difference particularly pronounced in areas and during seasons characterized by scant precipitation in a semi-arid region [22]. Enform et al. observed that, within the 0–5 cm layer, no-tillage resulted in higher soil moisture levels than traditional tillage in a subtropical Mediterranean zone [23]. Additional studies have corroborated these findings, highlighting that, throughout the various growth stages of crops, the soil water content in the 0–90 cm layer under no-tillage is greater than that under traditional tillage in a temperate continental climate zone [24]. The practice of no-tillage markedly influences soil water storage dynamics within the field. In the same type of region, Xu et al. (2021) demonstrated that no-tillage leads to higher soil water storage levels than traditional tillage, with a notable increase of 5.67% [25].

Conservation tillage plays a pivotal role in enhancing soil nutrient input, increasing available nutrient levels, and expediting material transformation and nutrient cycling. This enhancement improves the overall utilization of soil nutrients by both plants and microorganisms [26]. Furthermore, straw mulching boosts soil enzymatic activity through the modulation of soil temperature, moisture, and aeration, which are factors conducive to substance transformation and nutrient decomposition within the soil in semi-arid regions [27]. Camarotto et al. (2018) demonstrated that the practice of no-tillage can lead to a significant increase in the total nitrogen content in various crop organs. This method promotes the translocation of a greater amount of nitrogen to the grains, thereby elevating the nitrogen harvest index in Mediterranean climate regions [28]. When it comes to the total nitrogen content in wheat plants and the enduring impact of soil nitrogen transfer, no-tillage has been found to be more effective than sub-tillage.

In arid and semi-arid regions, enhancing crop WUE has perennially been a focal point of research [29]. Research has highlighted that the surface application of straw mulch could effectively curtail soil evaporation and augment rainwater infiltration [30], thereby significantly enhancing the water use efficiency of winter wheat [31]. When contrasted with traditional tillage, straw mulching has been shown to amplify WUE by 9–60% [32], attributable to its ability to effectively reduce soil water evaporation while increasing the water reserves available for crop transpiration [18]. Li et al. (2018) corroborated these benefits, indicating that straw mulching could increase the water use efficiency of potatoes by 5.6% in comparison with traditional tillage methods in the north China plain [33].

Historically, research has predominantly focused on assessing the individual impacts of either straw mulching or no-tillage practices in different climatic regions, with scant focus on the synergistic effects of straw mulching and no-tillage techniques in semi-arid zones. Moreover, a large number of studies have narrowed their scope to investigating the impacts of conservation tillage on isolated or a limited set of parameters, such as soil moisture, nutrient levels, wind erosion, crop photosynthesis, yield, and water use efficiency. Nonetheless, practical agricultural production necessitates a holistic approach that accounts for a multitude of objectives and factors.

Accordingly, the objectives of this study are as follows: firstly, to examine the viability of integrating straw mulching with no-tillage practices within an aeolian semi-arid region; secondly, to conduct a thorough assessment of the diverse impacts that various tillage methods exert on soil moisture, nutrient content, wind erosion, crop photosynthetic activity, yield, and water use efficiency; and, thirdly, to formulate the most effective combination of conservation tillage strategies tailored for aeolian semi-arid areas. This research aims to provide a robust scientific foundation for the optimization of maize cultivation management in the aeolian semi-arid regions of northern China.

2. Materials and Methods

2.1. Site Description

Field trials were conducted at the Experimental Station for Dry Farming and Water-saving Agriculture of the Chinese Academy of Sciences, situated in the Fuxin Mongolian Autonomous County, Fuxin City, Liaoning Province (Figure 1, 42°7′ N, 121°43′ E). These trials spanned from May to October across two consecutive years, 2021 and 2022. Under the northern temperate semi-arid monsoon continental climate, the station is located at an average elevation of 210 m. It experiences an average annual temperature that fluctuates between 7.1 and 7.6 °C, with an average annual precipitation of 493.1 mm. A significant portion of this precipitation, specifically 68%, is concentrated within the months of June to August, while the average annual evaporation rate stands at 1847.6 mm. According to relevant data, the wind speed showed a clear “bimodal” pattern on a monthly scale, with the highest wind speed in April, gradually decreasing, and reaching the lowest value of the year in August. Spring (March–May) is a period of high wind speed, with an average wind speed of about 3.66 m per second, while summer (June–August) has lower wind speeds, with an average wind speed of 2.54 m per second. These data reflect the seasonal variation of wind speed, with higher wind speeds in spring due to the rapid temperature rise and monsoon activity, and lower wind speeds in summer due to widespread high temperatures and weakened airflow activity.

The soil at the experimental site is classified as brown soil, with a sandy loam texture. The bulk density of the topsoil is 1.42 g·cm⁻³, and the field’s water-holding capacity is 23.00%. Chemically, the soil has a pH of 6.15, a total nitrogen content of 0.76 g·kg⁻¹, and an alkali hydrolyzed nitrogen content of 119.50 mg·kg⁻¹. The available phosphorus content is 8.12 mg·kg⁻¹, while the total potassium content is 17.73 g·kg⁻¹, with an available potassium content of 104.66 mg·kg⁻¹. The organic matter content is substantial, at 15.67 g·kg⁻¹. The principal crops cultivated in this soil include maize, peanuts, and soybeans.

2.2. Experimental Design

The experimental design incorporated a randomized block layout, encompassing four distinct treatments: no-tillage with full straw mulching (NTFS), no-tillage with half straw mulching (NTHS), no-tillage without straw mulching (NT), and conventional tillage serving as the control (CK). Each treatment was meticulously replicated thrice within the field to ensure the reliability of the results.

Table 1. Test treatment and code description.

Code	Treatment	Specific Operation
NTFS	No-tillage with full straw mulching	After the autumn harvest, all straw is retained in the experimental field. In the subsequent year, the crop is sown directly without tillage, following a single pass of straw crushing.
NTHS	No-tillage with half straw mulching	During the autumn harvest, only half of the straw row is removed to achieve a half straw mulching effect. The remaining straw residue is then incorporated into the soil, and the crop is sown without tillage in the following year.
NT	No-tillage with no straw mulching	After the autumn harvest, the stubble is entirely removed. The crop is sown without tillage in the next year, leaving the soil bare of straw mulch.
CT	Conventional tillage with no straw mulching	Upon completion of the autumn harvest, all stubble and straw are removed. The soil is then subjected to conventional tillage practices, including rotation and ridging, in preparation for the next year’s planting.

provides a detailed overview of the specific measures implemented for each treatment, with the dimensions of the plots standardized to 6 m by 8 m.

Prior to the experiment, a uniform variety of maize had been cultivated in the designated plot using the prevailing local methods for a period exceeding three years, which yielded consistently robust soil productivity. The maize variety selected for this study was Yufeng 303. The developmental phases of spring maize are delineated into six distinct stages: the sowing stage (SOS), seedling stage (SES), jointing stage (JS), tasseling stage (TS), filling stage (FS), and mature stage (MS). The maize was planted at a density of 60,000 plants per hectare, utilizing a mechanized seeding process that involved the use of sophisticated seeding equipment. This method established a plant spacing of 30 cm and a ridge spacing of 50 cm to optimize growth and yield. The sowing of the maize took place on 14 May 2021, with the harvest concluding on the 29th of September. For the year 2022, the planting occurred slightly earlier, on the 12th of May, with the harvest being gathered on the 27th of September. A balanced compound fertilizer with a ratio of N–P₂O₅–K₂O = 26:10:12 was applied at a rate of 750 kg per hectare during the sowing operation, ensuring nutrient delivery through the fertilization equipment. Beyond these specific procedures, all other cultivation and management techniques adhered to the conventional and time-tested local agricultural practices.

2.3. Measurement and Methods

2.3.1. Rainfall during Growth Period

Daily precipitation at the experimental site was determined using a rain gauge, which was installed about 1 m above the ground to avoid splash back and ensure accurate measurements. The level of water collected was then measured using the scale on the measuring tube, which is usually marked in millimeters.

2.3.2. Soil Bulk Density

Throughout the maize planting season, the ring knife method was used to assess soil bulk density across the 0–100 cm depth stratum, with measurements taken at intervals of 20 cm, thereby delineating a total of five distinct layers [34]. This metric of soil bulk density serves as a crucial tool for estimating soil water retention and consumption.

2.3.3. Soil Water Content

Soil moisture content was determined at 20 cm intervals of five soil layers spanning 0–100 cm in depth, corresponding to both the sowing and ripening phases of the spring maize cultivation. Supplementary measurements were taken for the 0–20 cm and 20–40 cm strata during the critical jointing and filling stages of maize development. Within the confines of each plot, a designated measuring station was established for the collection of soil samples. These samples were extracted using a soil auger of 5 cm in diameter, followed by a drying process in an oven set to 105 °C for a duration of 8 h, until a consistent weight was achieved. The soil moisture indicators were subsequently calculated by employing the following methodology:

(1)

Soil weight moisture content = (fresh soil quality-dried soil quality)/dried soil quality × 100%.

(2)

Soil water storage (mm) = soil depth (cm) × soil bulk density (g·cm⁻³)× soil weight moisture content (%) × 10.

(3)

Soil water consumption (mm) = soil water storage at sowing stage (mm) − soil water storage at maturity stage (mm) + effective precipitation greater than 5 mm at growth stage (mm).

(4)

Water use efficiency (WUE, kg·ha⁻¹·mm⁻¹) = grain yield (kg·ha⁻¹)/total soil water consumption (mm).

2.3.4. Soil Nitrate Nitrogen and Ammonium Nitrogen

During the 2021–2022 seasons, the soil nitrate nitrogen and ammonium nitrogen concentrations in the 0–20 cm and 20–40 cm strata were quantified at the jointing and maturing stages of spring maize. For each plot, soil samples were collected using a soil corer with a 5 cm diameter. The extraction process involved taking a 5 g aliquot of fresh soil and combining it with a potassium chloride solution at a concentration of 2 mol·L⁻¹, maintaining a mass ratio of 10:1 for the potassium chloride solution to the soil. After oscillating at an ambient temperature for 1 h with a mechanical shaker, the supernatant was decanted and filtered through qualitative filter paper. The soil nitrate and ammonium nitrogen contents were then determined using an AA3 flow analyzer (Bran Luebbe, Hamburg, Germany).

2.3.5. Soil Dissolved Organic Carbon (DOC)

During the 2021–2022 agricultural seasons, the concentration of soluble organic carbon (SOC) in the 0–20 cm and 20–40 cm soil layers was measured at both the jointing and maturing stages of spring maize. The soil sampling procedure followed the guidelines detailed in Section 2.3.4. Fresh soil samples were extracted using distilled water at a soil-to-water ratio of 5:1. The filtrate was then passed through a 0.45 µm filter membrane to ensure clarity. The soluble organic carbon content was quantified using a total organic carbon analyzer (Shimadzu, TOC-Vwp, Kyoto, Japan).

2.3.6. Soil Wind Erosion

For the assessment of soil wind erosion, a wind erosion ring, measuring 25 cm in diameter and 3 cm in height, was utilized [14]. Prior to the planting period, a quantity of soil was carefully monitored to determine its moisture content before being positioned within the wind erosion ring. The upper surface of the ring was leveled with the surrounding soil, and the lower surface was in full contact with the soil beneath, integrating the wind erosion ring with the natural soil profile both above and below ground. This ensured a seamless integration of the ring with the existing soil structure. During the autumn harvest, the wet weight and moisture content of the soil contained within the ring were meticulously measured.

To accurately assess the impact of wind erosion within each experimental plot, we placed three wind erosion rings. These were located at the front, center, and rear of every plot to ensure comprehensive coverage. By calculating the average wind erosion from these positions, we were able to obtain a representative measure of the erosion occurring within the plot. To determine the soil moisture content within the wind erosion zone, we employed a soil drill to collect samples. Importantly, these samples were not taken directly from the wind ring itself. Instead, we extracted the soil from the vicinity of the wind ring, ensuring that the sampling points were at the same elevation as the wind ring. This method ensures that the soil moisture data are relevant and reflective of the conditions in the wind ring, thereby providing a more precise evaluation of the environmental conditions affecting erosion. During the autumn harvest, the wet weight and moisture content of the soil contained within the ring were meticulously measured.

The calculation formula is as follows:

$$W_f=W/(S\times {10}^{-4})$$

(1)

$$W=W_1\times \left(1-{\theta }_{g1}\right)-W_2\times \left(1-{\theta }_{g2}\right)$$

(2)

$$S={\displaystyle \frac{\pi d^2}{4}}$$

(3)

Here, $W_f$ is the amount of wind erosion per unit area (kg·m⁻²), $W$ is the amount of wind erosion during the entire wind erosion period (kg), $S$ is the area of the wind erosion circle (cm²), $W_1$ is the weight of the soil in the wind erosion circle during the spring planting period (kg), $W_2$ is the weight of the soil in the wind erosion circle during the autumn harvesting period (kg), ${\theta }_{g1}$ is the weight of the soil in the wind erosion circle during the spring planting period (%), ${\theta }_{g2}$ is the weight and moisture content of the soil in the wind erosion circle during the autumn harvest period (%), d is the inner diameter of the wind erosion circle, and $\pi$ is PI.

2.3.7. Sediment Discharge

To monitor sediment transport at various heights—specifically, 30, 40, 50, 60, and 70 cm above the farmland surface—a self-fabricated cloth bag sand collector was used. Upon the occurrence of each wind erosion event, the collector’s inlet, which measured 15 cm in length, 5 cm in width, and 5 cm in height, was strategically positioned to face the direction of the wind, facilitated by the action of its tail. This design allowed for the efficient capture of airborne dust at the outlet, where it was then collected by the cloth bags.

2.3.8. Net Photosynthetic Rate and Stomatal Conductance of Maize

At the maize jointing, tasseling, and filling stages, to determine whether the absorption of light by plants was consistent, in the morning of sunny days from 9:00 to 12:00, the photosynthesis function of the LI-6400 portable measurement system (LI-COR, Superior St, Lincoln, NE, USA) was used to measure the leaf net photosynthetic rate (Pn, mol·m⁻²·s⁻¹) and stomatal conductance (C, mol·m⁻²·s⁻¹). An artificial light source was used for the determination, and the light intensity was set to 1500 mol·m⁻²·s⁻¹. To ensure reliability, each measurement was independently repeated three times for each treatment.

2.3.9. Grain Yield

The grain yield was determined within an 18 m² area at the center of the experimental plot during the maturity phase. By utilizing a grain moisture meter (model PM8188), the water content of the grain was precisely determined and then adjusted to represent the yield per hectare at a standard moisture content of 14% (kg·ha⁻¹).

2.4. Multi-Objective Decision Making and Evaluation Based on TOPSIS

The TOPSIS entropy weight model evaluates decisions by establishing ideal and anti-ideal solutions through the construction of a weighted, standardized decision matrix of evaluative indices. Subsequently, this model calculates the Euclidean distances between each alternative scheme and both the ideal and anti-ideal solutions to measure the relative proximity of each scheme to the ideal. The alternative scheme with the shortest distance to the ideal, demonstrating the greatest alignment with the optimal criteria, is chosen as the preferred decision.

Employing the TOPSIS approach, this study conducted a holistic assessment of various parameters under different tillage practices. The assessment included maize yield, water use efficiency (WUE), net photosynthetic rate, stomatal conductance, soil ammonium and nitrate nitrogen levels, soluble organic carbon, water content, water storage, wind erosion, sediment transport, and additional indicators. The optimal treatment was identified as the one where multiple factor indicators collectively achieved the highest performance level.

(1)

The raw data exhibit a discernible trend. For a comprehensive assessment of multi-objective optimal farming methods, it is essential to categorize and analyze the evaluative indicators, which include those that are extremely large, extremely small, intermediate, and interval-based. In this study, a positive processing approach is adopted for these indicators, where a higher value signifies a more favorable outcome. Consequently, it is imperative to normalize the extremely small, intermediate, and interval-based indicators. Given that this study primarily involves indicators of very large and very small magnitudes, only minor adjustments are required to co-trend these indicators. The specific formula for this transformation is presented as follows:

$$x^{\prime }=M-x$$

(4)

Here, $x^{\prime }$ is the post-assimilation index, $M$ is the maximum value of this index, and $x$ is the pre-assimilation index.

(2)

Construct a standardized evaluation matrix to systematically organize the data for analyses. Let us consider a scenario with m distinct evaluation schemes and n evaluative indicators, as depicted in the matrix below.

$$X=\left[\begin{array}{cccc}{x}_{11}& x_{12}& \cdots & x_{1n}\\ x_{21}& x_{22}& \cdots & x_{2n}\\ ⋮& ⋮& \ddots & ⋮\\ x_{m1}& x_{m2}& \cdots & x_{mn}\end{array}\right]$$

(5)

where $x_{ij}$ represents the evaluation index $j$ in scheme $i$.

Matrix (5) is normalized using Equation (6), and a normalized matrix, Matrix (7), is obtained.

$$z_{ij}={\displaystyle \frac{x_{ij}-\min (x_i)}{\max (x_j)-\min (x_i)}}$$

(6)

$$Z=\left[\begin{array}{cccc}{z}_{11}& z_{12}& \cdots & z_{1n}\\ z_{21}& z_{22}& \cdots & z_{2n}\\ ⋮& ⋮& \ddots & ⋮\\ z_{m1}& z_{m2}& \cdots & z_{mn}\end{array}\right]$$

(7)

where $z_{ij}$ represents the standardized value of evaluation index $j$ in scheme $i$.

(3)

Determine the weight indicator. The entropy weight method is used to determine the weight of the indicators. The specific methods are as follows:

$$p_{ij}={\displaystyle \frac{z_{ij}}{{\displaystyle \sum _{i=1}^m{z}_{ij}}}}$$

(8)

$$E_j=-{\displaystyle \frac{1}{\ln m}}{\displaystyle \sum _{i=1}^m{p}_{ij}\ln p_{ij}}$$

(9)

Here, if $p_{ij}=0$, then define $\underset{p_{ij}\to 0}{{\displaystyle \lim }}{p}_{ij}\ln p_{ij}=0$.

$$H_j=1-E_j$$

(10)

$$W_j={\displaystyle \frac{H_j}{n-{\displaystyle \sum _{j=1}^n{E}_j}}}$$

(11)

where $p_{ij}$ is the characteristic proportion of the index; $E_j$, $H_j$, and $W_j$ are the information entropy, difference coefficient, and entropy weight of the $j$ index, respectively.

Through the above calculation formula, the weighting matrix Y can be obtained.

$$Y=\left[\begin{array}{cccc}{z}_{11w1}& z_{12w2}& \cdots & z_{1nwn}\\ z_{12w1}& z_{22w2}& \cdots & z_{2nwn}\\ ⋮& ⋮& \ddots & ⋮\\ z_{m1w1}& z_{m2w2}& \cdots & z_{mnwn}\end{array}\right]$$

(12)

(4)

Calculate the comprehensive evaluation index. The maximum (small) value of each column element of matrix Y is taken to form the optimal (inferior) vector $Y^{+}$ ($Y^{-}$), and the distance between each column element and $Y^{+}$ ($Y^{-}$) is calculated to obtain a comprehensive evaluation index for each treatment. The calculation process is as follows:

$$Y^{+}=(Y_1^{+},Y_2^{+},\dots ,Y_n^{+},)=(\max \{y_{11},y_{21},\dots ,y_{m1}\},\dots \max \{y_{1n},y_{2n},\dots ,y_{mn}\})$$

(13)

$$Y^{+}=(Y_1^{+},Y_2^{+},\dots ,Y_n^{+},)=(\min \{y_{11},y_{21},\dots ,y_{m1}\},\dots \min \{y_{1n},y_{2n},\dots ,y_{mn}\})$$

(14)

$$D^{+}=\sqrt{{\displaystyle \sum _{j=1}^n{(Y^{+}-y_{ij})}^2}}$$

(15)

$$D^{-}=\sqrt{{\displaystyle \sum _{j=1}^n{(Y^{-}-y_{ij})}^2}}$$

(16)

$$S_i={\displaystyle \frac{D_i^{-}}{D_i^{+}+D_i^{-}}}$$

(17)

where $y_{ij}$ is the standardized value of index $j$ in scheme $i$ after the weighted calculation; $D{i}^{+}$ and $D_i^{-}$ are the distances between scheme $i$ and the maximum value and the minimum value, respectively; and $S_i$ represents the comprehensive evaluation index of option $i$.

2.5. Data Analysis

Data and graphical representations depicting soil water content, soil water storage, soil nitrate nitrogen, ammonium nitrogen, soluble organic carbon, wind erosion, sediment transport, crop net photosynthetic rate, stomatal conductance, yield, and water use efficiency were generated utilizing Microsoft Excel 2020 (Microsoft Corporation, Redmond, WA, USA), IBM SPSS Statistical Analysis 20.0 (IBM Corporation, New York, NY, USA), and Origin 2022 (OriginLab Corporation, Northampton, MA, USA). A one-way analysis of variance (ANOVA) was used to examine the differences between each treatment and the control group (CK). Subsequently, the least significant difference (LSD) test was applied to compare the average differences among the treatments and the control (p < 0.05). The data are presented as the mean ± standard error (SE).

3. Results

3.1. Characteristics of Precipitation Distribution in the Test Area

As delineated in

Table 2. Precipitation distribution characteristics at different growth stages of spring maize (mm).

Year	Seedling Stage	Jointing Stage	Tasseling Stage	Filling Stage	Mature Stage	Growth Stage
2021	55.9	108.9	56.8	98.4	70.1	390.1
2022	57.9	118.9	91.8	103.8	26.0	398.4
Average	38.2	81.4	128.6	110.3	47.4	406.0

, the 2021 rainfall totaled 390.1 mm, which is 15.9 mm less than the average annual precipitation. Similarly, in 2022, the rainfall amounted to 398.4 mm, which is 7.6 mm less than the average annual level. Consequently, both years were characterized as drought years. A detailed analysis of the precipitation across the various growth stages of spring maize revealed significant fluctuations. During the seedling and jointing stages, the precipitation for both years surpassed the average, creating conditions conducive to crop development. However, the precipitation patterns during the maturity stage were divergent—2021 experienced above-average rainfall, while 2022 saw a shortfall.

3.2. Soil Water

3.2.1. Soil Moisture Content

Using soil moisture data from 2021 and 2022, it was found that the content in the 0–40 cm soil layer was higher with the conservation tillage methods (NTFS, NTHS, and NT) than with conventional tillage (CT) during both the jointing and tasseling stages. Notably, soil moisture was higher during the jointing stage than during the tasseling stage, as detailed in

Table 3. Soil moisture content of different treatments at jointing and filling stages. Different letters represent significant differences at 5% probability level.

Year	Treatment	Jointing Stage		Filling Stage
		0–20 cm (%)	20–40 cm (%)	0–20 cm (%)	20–40 cm (%)
2021	NTFS	18.60 ± 0.08 b	19.37 ± 0.72 b	14.37 ± 0.38 b	17.81 ± 0.83 b
	NTHS	19.61 ± 0.68 b	20.62 ± 0.58 b	14.28 ± 0.93 b	17.28 ± 0.16 b
	NT	17.09 ± 1.20 ab	18.21 ± 0.38 ab	12.39 ± 0.85 ab	15.73 ± 1.15 a
	CT	16.91 ± 0.35 a	17.28 ± 1.21 a	11.68 ± 0.18 a	16.38 ± 0.29 a
2022	NTFS	17.74 ± 0.36 b	17.63 ± 0.83 b	11.13 ± 0.63 b	12.20 ± 0.70 a
	NTHS	18.51 ± 0.06 b	18.73 ± 0.60 b	12.05 ± 0.46 b	12.63 ± 0.18 a
	NT	15.53 ± 1.40 a	16.14 ± 0.63 a	10.21 ± 0.08 a	11.54 ± 1.10 a
	CT	16.21 ± 0.92 a	16.43 ± 1.22 a	10.07 ± 0.15 a	11.45 ± 0.62 a

. In 2021, the soil moisture content in both the 0–20 cm and 20–40 cm layers under the NTHS and NTFS treatments significantly surpassed that under CT, with no significant differences among the conservation treatments themselves (p < 0.05). During the filling stage, the 0–20 cm soil layer exhibited a moisture content ranking of NTFS > NTHS > NT > CT, with no-tillage combined with straw mulching showing a marked increase over CT. For the 20–40 cm layer, the trend was NTHS > NTFS > CT > NT, highlighting that the no-tillage with straw mulching was significantly more effective in retaining moisture than CT and NT. In 2022, the 0–20 cm soil layer’s moisture content during both the jointing and tasseling stages followed the sequence NTHS > NTFS > NT, with both the NTHS and NTFS treatments significantly outperforming CT and NT. There was no significant difference between the moisture content of NT and that of CT, NTHS, and NTFS. The 20–40 cm soil layer’s moisture content varied; during the jointing and filling stages, it adhered to the pattern NTHS > NTFS > NT, with no-tillage with straw mulching during the jointing stage being significantly higher than both NT and CT. Although the moisture trend of the filling stage paralleled that of the jointing stage, the difference was not statistically significant.

3.2.2. Soil Water Storage

Soil water storage was influenced by the tillage practices employed and the timing of measurement (

Table 4. Effects of 0–100 cm soil water storage during sowing and maturity stages. Different letters represent significant differences at 5% probability level.

Year	Treatment	Sowing Stage (mm)	Maturity Stage (mm)
2021	NTFS	321.2 ± 25.9 a	273.4 ± 12.8 a
	NTHS	311.6 ± 42.6 a	275.8 ± 13.1 a
	NT	291.3 ± 12.8 ab	281.5 ± 16.2 a
	CT	279.5 ± 23.7 b	289.0 ± 19.3 a
2022	NTFS	362.2 ± 18.9 a	310.3 ± 22.5 a
	NTHS	338.7 ± 12.8 a	296.8 ± 12.3 a
	NT	311.0 ± 28.7 b	291.5 ± 19.1 a
	CT	311.8 ± 33.5 b	285.1 ± 22.8 a

). During the 2021–2022 growing seasons, the conservation tillage methods, when compared with conventional tillage (CT), led to an increase in soil water storage during the planting phase, with the order of effectiveness being no-tillage with full straw mulching (NTFS) > no-tillage with half straw mulching (NTHS) > no-tillage without straw mulching (NT) > CT. However, while conservation tillage enhanced soil water storage at the maturity stage, the differences among the treatments were not statistically significant. Consequently, it was concluded that both NTFS and NTHS notably increased soil water storage during the planting period.

3.3. Soil Available Nutrient Content

3.3.1. Soil Nitrate Nitrogen

Figure 2 presents the variations in the nitrate nitrogen levels within the 0–40 cm soil depth under varying treatment conditions during the jointing and maturity stages for the years 2021 and 2022. The data clearly demonstrate that tillage practices have a significant impact on nitrate nitrogen content. At the jointing stage, in both the 0–20 cm and 20–40 cm soil layers, the conservation tillage methods resulted in substantially higher nitrate nitrogen levels than traditional tillage. This increase was measured at 13.8–29.1% in 2021 and 19.8–48.2% in 2022. With the exception of the NTHS treatment in 2022, the nitrate nitrogen content, over the two-year period, adhered to the ranking of NTFS > NTHS > NT > CT, showing no significant differences among the three conservation tillage practices. In contrast, at the maturity stage, the nitrate nitrogen levels under conservation tillage were considerably lower than those under traditional tillage for both soil layers, with reductions ranging from 15.2% to 38.8% in 2021 and from 17.9% to 31.4% in 2022. The order of nitrate nitrogen content was NTFS < NTHS < NT < CT for both years, again, without significant differences among the conservation tillage treatments.

3.3.2. Soil Ammonium Nitrogen

Figure 3 illustrates the fluctuations in the ammonium nitrogen levels within the 0–40 cm soil layer under the various treatments during the jointing and maturity stages for the years 2021 and 2022. It is apparent that the ammonium nitrogen content was influenced by the treatment methods at both growth stages. During the jointing stage, in both the 0–20 cm and 20–40 cm soil layers, the ammonium nitrogen levels were ranked as NTHS > CT > NTFS > NT. In 2021, these levels showed a significant increase in the 0–20 cm soil layer under NTHS compared with under NT, and they were markedly higher in the 20–40 cm layer under NTHS than under both NT and NTFS. In 2022, the 0–20 cm layer under NTHS continued to exhibit significantly higher levels than under NT, with no significant variation observed in the 20–40 cm layer. At the maturity stage, the 0–20 cm soil layer exhibited a different trend: in 2021, the order was NTHS > CT > NT > NTFS, while in 2022, it was NTFS > NTHS > NT > CT, with no significant differences among the treatments. Similarly, for the 20–40 cm soil layer, the pattern in 2021 was CT > NTHS > NTFS > NT, and, in 2022, it reversed to NTFS > NTHS > NT > CT, again, without significant differences among the treatments.

3.3.3. Soil DOC

Figure 4 displays the variations in the soil dissolved organic carbon (DOC) within the 0–40 cm soil layer under the different treatments during the jointing and maturity stages for the years 2021 and 2022. At the jointing stage, in the 0–20 cm soil layer, the DOC content was ranked as NTFS > NTHS > NT > CT, being significantly higher in the NTFS treatment than in the CT treatment. This resulted in increases of 10.2% in 2021 and 18.6% in 2022. In the 20–40 cm soil layer, the DOC content increased with the increased application of straw mulch, peaking under the NTFS treatment and being the lowest under the CT treatment, with respective increases of 20.9% and 15.0% for the years 2021 and 2022, indicating substantial differences. At the maturity stage, the DOC content trends in both the 0–20 cm and 20–40 cm soil layers were congruent with those observed at the jointing stage, indicating that the NTFS treatment had a significant advantage over CT. Minor increases were also noted for NTHS and NT, albeit without significant distinction. Nevertheless, the DOC content during the maturity stage was found to be marginally lower than that during the jointing stage in both soil layers, a difference that did not reach statistical significance.

3.4. Soil Wind Erosion

3.4.1. Soil Sediment Transport Capacity

The sediment transport data, presented in

Table 5. Sediment transport at different heights. Different letters represent significant differences at 5% probability level.

Year	Treatment	30–40 cm	40–50 cm	50–60 cm	60–70 cm	70–80 cm
2021	NTFS	24.5 ± 1.1 c	20.5 ± 2.2 a	19.6 ± 3.3 a	15.9 ± 2.2 a	13.8 ± 1.1 a
	NTHS	25.2 ± 0.7 bc	19.1 ± 0.6 a	16.2 ± 0.4 a	14.7 ± 1.0 a	13.7 ± 1.0 a
	NT	30.2 ± 3.3 ab	22.3 ± 4.2 a	19.2 ± 4.4 a	16.8 ± 4.0 a	14.9 ± 3.4 a
	CT	34.5 ± 3.2 a	23.6 ± 5.2 a	20.9 ± 3.5 a	17.4 ± 2.5 a	16.1 ± 2.2 a
2022	NTFS	25.0 ± 2.6 b	19.9 ± 1.7 a	17.0 ± 0.8 a	13.7 ± 1.2 a	13.1 ± 0.4 a
	NTHS	25.8 ± 4.3 b	20.9 ± 2.9 a	16.6 ± 1.5 a	14.7 ± 1.2 a	13.7 ± 1.2 a
	NT	29.0 ± 1.9 ab	22.5 ± 3.8 a	19.2 ± 3.8 a	16.5 ± 2.9 a	15.2 ± 3.2 a
	CT	33.0 ± 5.1 a	22.8 ± 3.3 a	18.9 ± 2.4 a	16.7 ± 1.4 a	15.9 ± 1.3 a

, revealed a trend of decreasing sediment transport with increasing height above the ground. Notably, the highest sediment transport rates were observed at the 30 cm height mark. By analyzing the impact of different treatments, it was found that, at the 30–40 cm height range, the conventional tillage (CT) treatment resulted in the greatest sediment transport in both 2021 and 2022. This was significantly higher than all the straw mulching treatments. Between the heights of 40 and 80 cm from the surface, while the sediment transport under the no-tillage with full straw mulching (NTFS), no-tillage with half straw mulching (NTHS), and NT treatments showed a decline, the variations were not statistically significant when compared with the CT treatment. Based on this, the focus of the sediment sampler’s observation height was 30 cm and above. This soil stratum exhibits heightened susceptibility to wind erosion, particularly in response to the treatment measures implemented in this investigation.

3.4.2. Soil Wind Erosion

Figure 5 displays the soil wind erosion data for each treatment. The data demonstrate that, during the two-year period, conventional tillage (CT) exhibited the highest levels of soil wind erosion, indicating that this conventional practice may not be effective in mitigating wind erosion. In contrast, the various conservation tillage practices demonstrated varying levels of efficacy in reducing soil wind erosion, with the following order of effectiveness: no-tillage with full straw mulching (NTFS), no-tillage with half straw mulching (NTHS), no-tillage (NT), and CT. Notably, both the NTFS and NTHS treatments showed significantly lower soil wind erosion than NT and CT. However, the differences in erosion levels between NTFS and NTHS were not statistically significant.

3.5. Crop Photosynthesis

Figure 6 illustrates the net photosynthetic rates of functional maize leaves under diverse treatment conditions. The figure clearly demonstrates the varying impacts of these treatments on the net photosynthetic rate at different stages of maize development. A consistent pattern of an initial increase followed by a subsequent decline was observed as the plant progressed through its growth stages. Specifically, during the jointing stage, leaves subjected to conservation tillage treatments exhibited significantly higher net photosynthetic rates compared to those under conventional tillage (CT). Notably, the no-tillage with full straw mulching (NTFS) treatment outperformed the no-tillage (NT) treatment, showing a significant difference in net photosynthetic rates, while no significant discrepancy was evident between NTFS and no-tillage with half straw mulching (NTHS). Similarly, at the silking and filling stages of maize, both NTFS and NTHS treatments displayed notably elevated net photosynthetic rates in contrast to the CT treatment, with no significant distinctions between the two conservation tillage methods.

It is also presented in Figure 6 that the stomatal conductance of the maize leaves under the different treatments. It is evident in Figure 6 that the treatments exerted varying degrees of influence on leaf stomatal conductance at the different maize growth stages, with an overall trend of increasing first and then decreasing as the growth stage progressed. At the jointing and filling stages, NTFS exhibited significantly higher stomatal conductance than the CT and NT treatments. Both NTFS and NTHS showed significantly higher stomatal conductance than CT, although there was no significant difference between them.

3.6. Crop Yield and Water Use Efficiency

3.6.1. Yield

Table 6. Yield and water use efficiency of the different treatments. Different letters represent significant differences at 5% probability level.

Year	Treatment	Yield	WUE
		(kg·hm−2)	(kg·hm−2·mm−1)
2021	NTFS	12,578.0 ± 237.2 c	23.40 ± 0.35 b
	NTHS	12,857.5 ± 239.6 c	24.77 ± 1.02 b
	NT	11,744.5 ± 110.9 b	22.09 ± 0.09 b
	CT	10,791.8 ± 158.3 a	19.22 ± 0.32 a
2022	NTFS	12,263.5 ± 156.1 b	20.01 ± 0.49 b
	NTHS	12,465.5 ± 52.5 b	20.47 ± 0.08 b
	NT	11,121.5 ± 229.8 ab	17.07 ± 0.49 a
	CT	10,888.8 ± 274.2 a	17.31 ± 0.32 a

illustrates the impact of the various treatments on maize yield. According to the data presented, the no-tillage with full straw mulching (NTFS) and no-tillage with half straw mulching (NTHS) treatments resulted in significantly higher yields than the conventional tillage (CT) treatment in both 2021 and 2022. Although NTHS outperformed NTFS in terms of yield, the difference between these two was not statistically significant. In 2021, the no-tillage (NT) treatment yielded a significantly greater output than CT. In 2022, while the NT treatment still showed a higher yield than CT, the difference did not reach statistical significance. Notably, NTHS yielded the highest output in both years, with an increase of 16.6% in 2021 and 14.5% in 2022 relative to the CT treatment.

3.6.2. WUE

Table 6 also delineates the influence of the various treatment strategies on the water use efficiency (WUE) of maize. The data in Table 6 compellingly demonstrate that, with the exception of the no-tillage (NT) treatment in 2022, the WUE of the conservation tillage treatments significantly surpassed that of the conventional tillage (CT) treatment. In 2021, the order of WUE among the treatments was NT with half straw mulching (NTHS) > no-tillage with full straw mulching (NTFS) > NT > CT, with no significant differences among the conservation tillage methods. For 2022, the order of WUE was NTHS > NTFS > CT > NT. NTHS consistently displayed superior water use efficiency, achieving a notable enhancement of 21.7% in 2021 and 18.3% in 2022 when compared with the CT treatment.

3.7. Multi-Objective Decision Making and Evaluation Based on TOPSIS

Soil moisture, available nutrients, wind erosion, maize photosynthesis, yield, and water use efficiency served as the pivotal criteria for evaluation, with the TOPSIS method being used to conduct an exhaustive assessment of the outcomes of the four treatments (

Table 7. Evaluation of soil moisture, available nutrients, wind erosion, photosynthesis, yield, and water use efficiency based on TOPSIS.

Year	Treatment	D+	D-	SI	Ranking
2021	NTFS	0.0848	0.0320	0.2741	2
	NTHS	0.0177	0.0853	0.8282	1
	NT	0.0851	0.0237	0.2173	3
	CT	0.0841	0.0231	0.2158	4
2022	NTFS	0.3119	0.0282	0.0829	2
	NTHS	0.3240	0.0570	0.1498	1
	NT	0.3359	0.0244	0.0678	3
	CT	0.8119	0.0251	0.0300	4

). Within this evaluative framework, soil moisture, available nutrients, maize photosynthesis, yield, and water use efficiency were accorded the highest priority, whereas soil wind erosion was designated the least favorable factor. Opting for a positive evaluative direction, the soil wind erosion data underwent an assimilation process prior to the comprehensive evaluation. A higher comprehensive evaluation value, denoted as SI, corresponds to a more effective treatment strategy. For the years 2021 and 2022, the treatments were ranked from the most to least effective as follows: NTHS, NTFS, NT, and CT. NTHS exhibited the best SI value, underscoring its status as the optimal agricultural practice.

4. Discussion

4.1. Effects of Different Treatments on Water Utilization and Nutrient Absorption

The paucity of water resources stands as a formidable impediment to the sustainable progression of agriculture within semi-arid regions. Empirical evidence suggests that a substantial 70% of rainfall is lost to evaporation from the soil surface and transformed into runoff, leaving a mere 25–30% for absorption by crops [35]. It has been established through scholarly work that the implementation of straw mulching serves to curtail runoff, augment infiltration, curtail evaporation, and ultimately ameliorate soil moisture levels along with the soil’s capacity for water retention [36]. The strategic deployment of straw mulching produces an additional physical barrier between the soil surface and the atmospheric elements, effectively mitigating the evaporation of soil moisture. A previous study has demonstrated that adopting such an approach can increase soil water storage by up to 30.1 mm [37] and elevate soil water content by 18.8% compared with traditional tillage methods [38]. Further investigation has revealed that no-tillage and low-tillage techniques enhance soil moisture retention by reducing soil disturbance, leading to the formation of a cohesive surface layer that acts as a barrier against soil water evaporation [39]. These results highlight the effectiveness of combining straw mulching with no-tillage practices to improve soil moisture content during the critical stages of crop development. This integrated strategy not only boosts soil water storage during planting seasons but also protects crop emergence and growth, even in years with minimal variations in precipitation. It is noteworthy that, under the regimen of no-tillage complemented by straw mulching, the soil water content within the 0–20 cm and 20–40 cm strata surpassed that achieved using the traditional tillage methods. The reduced soil water content associated with conventional tillage practices can be attributed to the heightened soil porosity and exacerbated soil disturbance that occur in the absence of surface mulching, which, in turn, precipitate augmented losses of soil water through evaporation [40]. This study also showed that the soil water storage capacity of NTFS was better than that of NTFS, and the soil moisture content was higher than that of NTFS. Analyzing the reasons, compared with NTFS treatment, the appropriate straw cover in NTHS treatment covered the soil surface more evenly, and the physical barrier formed was more effective in reducing soil water evaporation. This leads to better water retention in the soil profile, which is crucial for crop growth, especially in semi-arid areas with water scarcity [18,20,21,22]. On the other hand, NTHS treatment has greater straw coverage and can maintain more favorable soil moisture conditions throughout the entire soil layer (0–20 cm and 20–40 cm). This consistent water level is beneficial for crop root development and nutrient absorption [25,27,28,29].

Beyond the issue of water scarcity, the challenge of low soil fertility significantly impedes crop productivity in arid regions susceptible to sandstorms. Soil ammonium nitrogen (${\mathrm{N}\mathrm{H}}_4^{+}-\mathrm{N}$) and nitrate nitrogen (${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$) are integral components of the soil’s inorganic nitrogen, and they are readily absorbed by crops and are sensitive to various factors such as soil moisture, oxygen levels, and organic matter content. Several studies have indicated that straw mulching can lead to a substantial increase in the levels of ${\mathrm{N}\mathrm{H}}_4^{+}-\mathrm{N}$ and ${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$ in the soil compared with non-mulched conditions. This is attributed to the large exposed area of non-mulched soil, which is more susceptible to direct precipitation wash-off and the subsequent leaching of these nitrogen forms [41]. Conversely, some studies posit that straw mulching may reduce soil levels of ${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$ by enhancing its uptake by crops [42]. When compared with traditional tillage practices, no-tillage alone did not significantly alter the levels of soil nitrate and ammonium nitrogen in the 0–20 cm soil layer. However, the integration of no-tillage with straw mulching has been shown to increase the content of these nitrogen species at the same depth [43]. In the context of this study, the amalgamation of straw mulching with no-tillage notably increased nitrate nitrogen levels during the crop’s jointing stage while concurrently leading to a marked reduction in nitrate nitrogen levels at the maturity stage. This dynamic could be attributed to the robust growth phase of maize during jointing, where no-tillage coupled with straw mulching boosts plant development and the transformation of ${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$ [24]. Conversely, during the maturation stage, the slower growth rate of maize corresponds to a decreased ${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$ content due to the substantial absorption and utilization of soil nitrogen in the earlier growth phases [44]. The examination of ammonium nitrogen revealed that no-tillage straw mulching predominantly influenced its concentration at the jointing stage, with a declining trend as the plant progressed through its growth stages. This observation aligns with the findings reported by Fiorini et al. (2020) [45]. In sum, the practice of no-tillage straw mulching exerts a notable influence on the nitrate nitrogen content in the 0–40 cm soil layer and the ammonium nitrogen content in the 0–20 cm layer, thereby facilitating enhanced absorption and utilization by crops.

Within the agricultural ecosystem, the adoption of various farming practices and the incorporation of straw back into the fields are recognized as the primary catalysts for the renewal and turnover of soil organic carbon. Dissolved organic carbon (DOC), being the most dynamic component of the soil organic carbon reservoir, is profoundly influenced by such agricultural practices and the return of straw to the fields [46]. Empirical studies have consistently indicated that the return of straw to agricultural lands can lead to a notable increase in the soil’s DOC levels, with a concurrent decrease in content as soil depth increases [47]. The implementation of short-term no-tillage has been found to markedly enhance the soluble organic carbon content, particularly during the critical booting stage of rice cultivation [48]. The findings of this study corroborate these effects, revealing that an increase in straw mulch application corresponds to a higher soil DOC content. The application of no-tillage with full straw mulching notably surpassed that of conventional tillage (CT) in terms of DOC enrichment. While the half mulching and no-tillage straw treatments also demonstrated an increase compared to CT, the difference did not reach statistical significance. On the one hand, the reintroduction of straw mulch to the field alters the soil’s carbon and nitrogen nutrient input [49]. On the other hand, straw mulching creates a favorable water and temperature microenvironment for soil microorganisms, thereby enhancing their activity and facilitating the gradual decomposition of carbon and nitrogen. This process, in turn, leads to an increased production of soluble organic carbon [50].

This study also showed that compared to NTFS, NTHS significantly affected the levels of nitrate nitrogen, soluble organic carbon, and ammonium nitrogen at the top 0–20 cm of the soil, creating optimal conditions for the availability of essential nutrients for maize cultivation. Analyzing the reasons, compared to NTFS processing, NTHS processing involves more uniform straw-covering applications. This suitable covering provides a larger surface area for nutrient retention, including nitrogen forms such as ${\mathrm{N}\mathrm{H}}_4^{+}-\mathrm{N}$ and ${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$. Under NTHS, the enhancement of soil nutrient retention capacity can lead to a significant increase in the levels of these inorganic nitrogen components, which is crucial for crop growth [20,28,30,36]. On the other hand, in the NTHS treatment, more uniform straw input contributes to the formation and transformation of soil organic matter, which not only provides a source of nutrients but also enhances the soil’s nutrient retention capacity, promoting better nutrient absorption by crops [43,46,47].

4.2. Effects of Different Treatments on Soil Wind Erosion

In arid and semi-arid regions, wind erosion is identified as a grave environmental threat. The soil loss from agricultural lands due to wind erosion not only leads to the depletion of soil nutrients but also results in a coarse soil texture. These factors culminate in land degradation and a concomitant decline in agricultural productivity. Ensuring vegetation cover has emerged as one of the most effective strategies for mitigating soil erosion [51]. Zhang et al. (2015) demonstrated that soil sediment transport under straw mulching could be dramatically reduced by 90.4% compared with bare soil conditions. Moreover, in no-tillage systems, soil sediment transport under wind erosion was significantly lowered, with reductions ranging from 66.0% to 94.1% compared with in-ridge tillage areas [52]. Sediment transport decreases precipitously with increasing height above the ground, particularly in the 0–100 cm zone. Li et al. (2019) revealed that sediment transport at heights between 0 and 30 cm can be a sensitive indicator, accurately reflecting the variance in sediment transport among diverse tillage practices [53]. When contrasted with conventional tillage, the sediment transport at this height was found to be reduced by 17.4–46.7% with no-tillage and by 21.7–45.2% with no-tillage combined with straw mulching. It was observed that, as the altitude increased from 30 to 80 cm above the ground, sediment transport correspondingly decreased. Notably, no-tillage straw mulching had a pronounced effect on sediment transport in the 30–40 cm soil layer, which was markedly lower than that with traditional tillage, with the reductions observed to be between 26.9% and 28.9% and between 21.8% and 24.2% for the years 2021 and 2022, respectively. This underscores the substantial impact of no-tillage straw mulching on curtailing sediment transport in the 30–40 cm soil layer, especially in semi-arid regions characterized by wind-blown sand.

The findings demonstrate that sediment transport within the 0–30 cm height range acts as a sensitive barometer, reflecting distinctions in sediment movement across various tillage methodologies. When compared with traditional tillage systems, the implementation of no-tillage and no-tillage combined with straw mulching resulted in decreases of 17.4–46.7% and 21.7–45.2% at a 0–30 cm elevation, respectively. Furthermore, an observable trend of decreasing sediment transport with increasing height between 30 and 80 cm above the soil surface was documented. Most notably, the practice of no-tillage straw mulching had a profound influence on sediment transport within the 30–40 cm soil stratum. In this layer, significant reductions of 26.9–28.9% and 21.8–24.2% were recorded for the years 2021 and 2022, respectively. These findings highlight the crucial role of no-tillage straw mulching in reducing sediment transport, especially within the 30–40 cm soil layer in semi-arid regions where wind-blown sand is a major issue. Utilizing crop residue cover alongside strategic planting methods serves as an effective approach to controlling wind erosion in agricultural environments [54]. Jia and colleagues (2019) conducted a study examining the effects of no-tillage straw mulching on wind erosion in the sandy soils of northwestern China. Their findings indicated that, at a wind velocity of 10 m·s⁻¹, the implementation of no-tillage straw mulching achieved a remarkable reduction in the wind erosion rate, reaching up to 90.2% when compared with conventional tillage methods [21]. Additional studies have highlighted that soil wind erosion is minimized when wheat straw mulch is applied at a rate of 4210 kg·hm⁻², with the potential to decrease wind erosion by an impressive 95.9% [55]. This study further discovered that the application of no-tillage with both full and half straw mulching configurations, over a span of two years, led to a significant reduction in soil wind erosion. The reductions were substantial, ranging from 31.4% to 35.8% for full mulching and from 33.7% to 37.7% for half mulching when contrasted with traditional tillage practices. Analyzing the reasons, in semi-arid areas with wind and sand, the period of high wind speed is in winter and spring, while the wind speed is relatively low in summer and autumn, which is consistent with the growth status of corn. Generally speaking, smaller crops on the soil surface in winter and smaller plant coverage in spring can lead to more severe soil erosion. However, the conservation tillage techniques we adopted, including NTFS and NTHS, increased the vegetation coverage on the soil surface, significantly reduced wind speed, improved soil erosion resistance, and thus reduced soil wind erosion [13,14,53,54]. In this study, it is observed that the mitigating effect of no-tillage with straw mulching on soil wind erosion observed in this study was relatively less pronounced than that reported by other researchers. This discrepancy may be ascribed to the constrained duration of monitoring and a potential underrepresentation of the variance in wind erosion among the different treatments [56].

4.3. Effects of Different Treatments on Maize Photosynthesis

Photosynthesis serves as the cornerstone of crop growth and biomass production, significantly influencing yield. This vital process is primarily governed by factors such as water availability, temperature, photosynthetically active radiation, and CO2 concentration. Research has highlighted that the application of mulching film and straw can markedly enhance the photosynthetic capacity of crop leaves, subsequently leading to increased yields [57]. The adoption of no-tillage planting methods has also been shown to increase leaf photosynthetic capacity. Dong et al. (2011) discovered that no-tillage, in comparison with traditional tillage, can slow the degradation of leaf chlorophyll during the middle to late stages of wheat development. This delay helps sustain a higher net photosynthetic rate, refines the photosynthetic traits of leaves, and fosters the accumulation of dry matter in crops [58,59]. In the findings of this study for the years 2021 and 2022, it was observed that, under no-tillage straw mulching conditions, the net photosynthetic rate of maize leaves experienced a significant increase when contrasted with that under conventional tillage (CT). Specifically, the no-tillage with full straw mulching (NTFS) showed an increase during the jointing stage, while both NTFS and no-tillage with half straw mulching (NTHS) demonstrated increased rates during the silking and filling stages. This enhancement may be attributed to the ability of crop roots to absorb greater quantities of soil water under these conditions, facilitating the translocation of water to the leaves and sustaining robust photosynthesis [60]. Furthermore, this study revealed that the stomatal conductance of maize leaves under no-tillage straw mulching was considerably increased compared to CT. Notably, NTFS showed significant increases during the jointing and filling stages, and both NTFS and NTHS exhibited augmented conductance during the silking stage. These outcomes suggest that no-tillage straw mulching enhances stomatal conductance in plant leaves by promoting the transfer of water from roots to leaves. This, in turn, increases the absorption and utilization of carbon dioxide, thereby boosting the net photosynthetic rate of the leaves [61].

4.4. Effects of Different Treatments on Maize Yield and Water Use Efficiency

Enhancing crop yield is a shared ambition for agricultural producers and researchers. There is an ongoing discourse on optimizing the use of existing resources, enhancing farmland productivity, and boosting the economic returns of crops. The technology of returning straw to the fields has demonstrated its capacity to improve soil’s water retention, curtail soil and water loss, and substantially increase crop yields [62,63]. However, it has also been noted that straw mulching may lower the temperature of the topsoil at the early stages, potentially delaying crop growth and reducing yields [64]. Cheng et al. (2023), in their study of the black soil region in Northeast China, discovered that the return of various straw mulches under no-tillage conditions positively impacted maize yield [65]. No-tillage straw mulching has been shown to increase wheat yield by enhancing physiological and ecological attributes compared with traditional tillage practices. In the context of this study, both no-tillage with full straw mulching (NTFS) and no-tillage with half straw mulching (NTHS) in 2021 and 2022 significantly outperformed conventional tillage (CT), with NTHS surpassing NTFS. NTHS achieved the highest yield in both years, with an increase of 16.6% and 14.5% over CT, respectively.

In arid and semi-arid regions, the significant disparity between water supply and demand is a key constraint on advancing WUE. While natural rainfall is the primary water source for crops in these areas, its irregular and limited distribution, coupled with seasonal drought stress, poses significant challenges to agricultural sustainability and WUE enhancement. Traditional tillage practices can damage soil structure, reduce its water retention capacity, accelerate surface soil water loss, and severely restrict WUE improvement in arid and semi-arid regions [15]. However, a multitude of studies have corroborated that straw mulching can effectively enhance soil’s moisture retention, minimize water evaporation, optimize the use of rainfall, and thus augment farmland WUE [66,67]. Notably, the water use efficiency with no-tillage straw mulching was significantly higher than with the CT treatment, with NTHS recording the highest WUE in both years, showing an increase of 21.7% and 18.3% compared to CT [68].

The TOPSIS method was employed in this study for a multi-objective comprehensive evaluation of agricultural practices in semi-arid regions, focusing on high yield, high efficiency, and environmental protection goals. The combination of straw mulching and no-tillage was compared with traditional tillage. By examining the impact of these practices on soil moisture, nutrient availability, wind erosion, maize photosynthesis, yield, and WUE, it was determined that NTHS, NTFS, and no-tillage (NT) outperformed CT in terms of supplying soil water and nutrients, protecting the soil environment, promoting crop growth, enhancing productivity, and utilizing agricultural water resources. These findings indicate that the integration of straw semi-mulching with no-tillage is well suited for agricultural production in semi-arid regions with wind-blown sand.

5. Conclusions

In this study, we examined the effectiveness of conservation tillage, especially the integration of no-tillage with straw mulching, in enhancing agricultural productivity and sustainability in Northern China’s aeolian semi-arid areas. Four tillage systems—no-till full straw mulch (NTFS), no-till half straw mulch (NTHS), no-till without straw mulch (NT), and conventional tillage (CT)—were compared in this study. The conclusions are as follows:

(1)

No-tillage combined with straw mulching, as opposed to traditional tillage, enhanced soil water content during the critical jointing and filling stages of maize growth and boosted water retention at the sowing stage. This practice significantly influenced the levels of nitrate nitrogen, soluble organic carbon, and ammonium nitrogen in the top 0–20 cm of soil, creating optimal conditions for water and nutrient availability, essential for maize cultivation.

(2)

In regions grappling with aeolian semi-arid conditions and wind-blown sand, no-tillage straw mulching proved effective in curtailing soil sediment transport and wind erosion, particularly at heights of 30–40 cm above the ground. This method aids in the management of farmland wind erosion and bolsters the protection of the ecological environment.

(3)

Both no-tillage with full straw mulching (NTFS) and no-tillage with half straw mulching (NTHS) exhibited markedly higher yields and water use efficiency (WUE) than conventional tillage (CT). Notably, NTHS outperformed the others, with its yield and WUE showing increases ranging from 14.5% to 16.6% and from 18.3% to 21.7%, respectively.

(4)

TOPSIS analysis outcomes indicate that under the NTHS treatment, there was a comprehensive improvement across various parameters—soil water, nutrient availability, wind erosion, maize photosynthesis, yield, and WUE. NTHS scored the highest in these categories, suggesting its superiority as a tillage method in semi-arid regions where wind-blown sand is a concern.