Agronomy

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4 pages, 169 KiB

Open AccessEditorial

Land and Water Resources for Food and Agriculture

by Fan Zhang and Mo Li

Agronomy 2024, 14(5), 880; https://doi.org/10.3390/agronomy14050880 - 23 Apr 2024

Viewed by 999

Abstract

As the population continues to increase, the demand for food has never been greater, placing immense pressure on the sustainable management of land and water resources [...] Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

Research

Jump to: Editorial

17 pages, 10585 KiB

Open AccessArticle

Multifunctional Evaluation and Analysis of Synergistic Relationships: A Cognitive Framework for the Sustainable Use of Cropland in China

by Runyan Zou, Yuanyuan Peng, Hao Yang, Yueming Hu, Luo Liu and Xiaoyun Mao

Agronomy 2024, 14(2), 284; https://doi.org/10.3390/agronomy14020284 - 27 Jan 2024

Cited by 2 | Viewed by 1122

Abstract

Cropland is a comprehensive system influenced by the natural environment and human activities. This article collects the data of cropland use, soil, and other geographic, social and economic factors in the study area and then uses the methods of system analysis, induction and [...] Read more.

Cropland is a comprehensive system influenced by the natural environment and human activities. This article collects the data of cropland use, soil, and other geographic, social and economic factors in the study area and then uses the methods of system analysis, induction and deduction to propose a new research perspective for establishing a cognitive framework and analyzing cropland resources and their functions. The framework is used to assess the rapidly urbanizing region of Guangzhou and investigate the production, ecological, and living functions provided by cropland resources. Synergistic relationships between functions are analyzed using the hot and cold spot methods. The results indicate that the production function of cropland resources in Guangzhou is good, the ecological function is favorable, and the living function is relatively low. A synergistic relationship between the three functions is observed in 91% of areas of Guangzhou, whereas a balanced relationship occurs in some areas of the southern part of Zengcheng, the northwestern and northeastern parts of Conghua, and the western part of Nansha. This research provides guidance for managing cropland resources and ensuring their sustainable utilization. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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18 pages, 7259 KiB

Open AccessEditor’s ChoiceArticle

Cloud-Based Framework for Precision Agriculture: Optimizing Scarce Water Resources in Arid Environments amid Uncertainties

by Fan Zhang, Peixi Tang, Tingting Zhou, Jiakai Liu, Feilong Li and Baoying Shan

Agronomy 2024, 14(1), 45; https://doi.org/10.3390/agronomy14010045 - 22 Dec 2023

Cited by 2 | Viewed by 1479

Abstract

In arid agriculture, the effective allocation of scarce water resources and the assessment of irrigation shortage risks are critical water management practices. However, these practices are faced with inherent and unignorable uncertainties affecting multiple variables. This study aims to model the typical uncertainties [...] Read more.

In arid agriculture, the effective allocation of scarce water resources and the assessment of irrigation shortage risks are critical water management practices. However, these practices are faced with inherent and unignorable uncertainties affecting multiple variables. This study aims to model the typical uncertainties in these practices and understand how they impact the allocation of scarce water resources. We advocate for a nuanced consideration of variable characteristics and data availability, variation, and distribution when choosing uncertainty representation methods. We proposed a comprehensive framework that integrates the cloud model to delineate scenarios marked by subjective vagueness, such as “high” or “low” prices. Simultaneously, the stochastic method was used for modeling meteorological and hydrological variables, notably precipitation and crop evapotranspiration. Additionally, to navigate subjectivity and imprecise judgment in standards classification, this framework contains a cloud-model-based assessment method tailored for evaluating irrigation shortage risks. The proposed framework was applied to a real-world agricultural water management problem in Liangzhou County, northwest China. The results underscored the efficacy of the cloud model in representing subjective vagueness, both in the optimization process and the subsequent assessment. Notably, our findings revealed that price predominantly influences net benefits, and that precipitation and crop evapotranspiration emerge as decisive factors in determining optimal irrigation schemes. Moreover, the identification of high water storage risks for maize in the Yongchang and Jinyang districts serves as a reminder for local water managers of the need to prioritize these areas. By adeptly modeling multiple uncertainties, our framework equips water managers with tools to discern sensitive variables. We suggest that enhanced precipitation and evapotranspiration forecasts could be a promising way to narrow the uncertainties. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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28 pages, 23646 KiB

Open AccessArticle

A Stochastic Bayesian Artificial Intelligence Framework to Assess Climatological Water Balance under Missing Variables for Evapotranspiration Estimates

by Vitor P. Ribeiro, Luiz Desuó Neto, Patricia A. A. Marques, Jorge A. Achcar, Adriano M. Junqueira, Adilson W. Chinatto, Jr., Cynthia C. M. Junqueira, Carlos D. Maciel and José Antônio P. Balestieri

Agronomy 2023, 13(12), 2970; https://doi.org/10.3390/agronomy13122970 - 30 Nov 2023

Cited by 2 | Viewed by 1752

Abstract

The sustainable use of water resources is of utmost importance given climatological changes and water scarcity, alongside the many socioeconomic factors that rely on clean water availability, such as food security. In this context, developing tools to minimize water waste in irrigation is [...] Read more.

The sustainable use of water resources is of utmost importance given climatological changes and water scarcity, alongside the many socioeconomic factors that rely on clean water availability, such as food security. In this context, developing tools to minimize water waste in irrigation is paramount for sustainable food production. The evapotranspiration estimate is a tool to evaluate the water volume required to achieve optimal crop yield with the least amount of water waste. The Penman-Monteith equation is the gold standard for this task, despite it becoming inapplicable if any of its required climatological variables are missing. In this paper, we present a stochastic Bayesian framework to model the non-linear and non-stationary time series for the evapotranspiration estimate via Bayesian regression. We also leverage Bayesian networks and Bayesian inference to provide estimates for missing climatological data. Our obtained Bayesian regression equation achieves 0.087 mm · day

^{- 1}

for the RMSE metric, compared to the expected time series, with wind speed and net incident solar radiation as the main components. Lastly, we show that the evapotranspiration time series, with missing climatological data inferred by the Bayesian network, achieves an RMSE metric ranging from

0.074

to 0.286 mm · day

^{- 1}

. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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25 pages, 7965 KiB

Open AccessArticle

Cultivated Land Sustainable Use Evaluation from the Perspective of the Water–Land–Energy–Food Nexus: A Case Study of the Major Grain-Producing Regions in Quzhou, China

by Aiqi Chen, Zhen Hao, Rong Wang, Hongli Zhao, Jinmin Hao, Ran Xu and Hao Duan

Agronomy 2023, 13(9), 2362; https://doi.org/10.3390/agronomy13092362 - 11 Sep 2023

Cited by 6 | Viewed by 2241

Abstract

Cultivated land is the basis of food security and an important component of the construction of ecological civilization. The sustainable use of cultivated land is an important issue in land resource management, and it is also an inevitable factor when addressing the contradiction [...] Read more.

Cultivated land is the basis of food security and an important component of the construction of ecological civilization. The sustainable use of cultivated land is an important issue in land resource management, and it is also an inevitable factor when addressing the contradiction between food demands and resource and environmental constraints. Cultivated land use is both a food production process and a water- and energy-intensive process. Therefore, sustainable use of cultivated land is important not only for cultivated land itself but also for the associated social, economic, and ecological impacts of water and energy input. Therefore, based on the water–land–energy–food nexus, this paper carries out a theoretical analysis of cultivated land use following the element–structure–function framework and builds an evaluation framework of the sustainable use of cultivated land. Finally, this paper selects appropriate evaluation indicators to evaluate the changes in element coordination and function trade-offs of cultivated land use in Quzhou County from 2000 to 2020; analyzes the key influencing factors in detail; and proposes future development directions. The results reflect the fact that the element coordination degree showed obvious continuous decline three times in a row, then a brief rise, and it finally stabilized at a high level, whereas the synergies between the functions decreased and then increased. This means that the sustainable use level of cultivated land in Quzhou County basically presents a good trend. At present, the obstacle that is restricting the efficient use of cultivated land and sustainable development is water, which should be improved by some measures in the future. The results of this evaluation have important theoretical and practical significance for identifying the characteristics of changes in cultivated land use and for guiding future sustainable use in Quzhou County and other regions. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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16 pages, 4648 KiB

Open AccessArticle

Evolution of Hydrological Conditions and Driving Factors Analysis of the Yongding River in a Changing Environment: A Case Study of the Xiangshuipu Section

by Yiyang Yang, Siyu Cai, Hao Wang, Ping Wang and Wei Li

Agronomy 2023, 13(9), 2289; https://doi.org/10.3390/agronomy13092289 - 30 Aug 2023

Cited by 2 | Viewed by 2125

Abstract

Hydrological conditions are key factors in the evaluation of water resources and ecosystems. The Yongding River Basin has many irrigated areas, and excessive agricultural water consumption has led to serious water shortages and ecosystem damage. To investigate the evolution of ecohydrological conditions and [...] Read more.

Hydrological conditions are key factors in the evaluation of water resources and ecosystems. The Yongding River Basin has many irrigated areas, and excessive agricultural water consumption has led to serious water shortages and ecosystem damage. To investigate the evolution of ecohydrological conditions and their driving factors in the Yongding River basin in a changing environment, this study combines indicators of hydrologic alteration with the range of variability approach (IHA-RVA) to identify the most ecologically relevant hydrological indicators (ERHIs) and to determine the periods of hydrological variability in the basin, using the Xiangshuipu section on the Yang River as the study area. By calculating the degree of hydrological alteration, the evolutionary pattern of ecohydrological conditions in the basin was analyzed, and the WetSpa model was used to quantitatively identify the contributions of climate change, reservoir storage, and irrigation water withdrawal to the alteration of hydrological conditions. The results showed that the rise and fall rate; maximum and minimum 1 day flows; dates of maximum flow; and July flows were the most ecologically relevant hydrological indicators for the Xiangshuipu section. Variability of this section occurred between 1982 and 1988; except for the annual maximum 1 day flows and fall rate, which underwent moderate changes; all other indicators exhibited small changes and the overall hydrological alteration of the Xiangshuipu section was low. The most influential change in the hydrological conditions was irrigation water withdrawal (from specific irrigation); followed by climate change and reservoir storage. The results of this study provide an important basis for water resources utilization and ecological management in the Yongding River basin. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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23 pages, 2961 KiB

Open AccessArticle

An Optimisation–Evaluation Framework for the Sustainable Management of the Water–Energy–Food Nexus for an Irrigation District under Uncertainty

by Yan Zhou, Xinrui Zhang, Yingshan Chen and Heng Li

Agronomy 2023, 13(7), 1714; https://doi.org/10.3390/agronomy13071714 - 26 Jun 2023

Cited by 7 | Viewed by 1879

Abstract

The synergistic regulation of the water–energy–food nexus in irrigation districts is important for promoting the sustainable management of agricultural resources in irrigation districts. In this paper, a new integrated optimization–evaluation modelling framework for the water–energy–food nexus in agricultural irrigation areas is developed. It [...] Read more.

The synergistic regulation of the water–energy–food nexus in irrigation districts is important for promoting the sustainable management of agricultural resources in irrigation districts. In this paper, a new integrated optimization–evaluation modelling framework for the water–energy–food nexus in agricultural irrigation areas is developed. It can measure the synergistic effects of economic, social and environmental multidimensional objectives on the sustainable management of agricultural resources in irrigation areas. The model couples an optimisation module and an evaluation module, combines a multiobjective nonlinear planning model with an opportunity-constrained planning model and uses an entropy-weighted TOPSIS assessment approach to sustainably assess the multidimensional indicators of the water–energy–food nexus in irrigation districts, with full consideration given to the effects of uncertainty in agricultural water and soil resources and social systems. The feasibility of the constructed model is verified through a study of the Jinxi irrigation district. The results show that compared to the actual area, the optimised surface water and groundwater availability increased by 23.5% and 22.7%; the optimised total area increased by 4%, whereas corn decreased by 40%, rice increased by 34.6% and soybean decreased by 33.8%; the energy consumption decreased by 17.6% and the total recycled resources amounted to 8.97 × 10⁹ kg, with a combined net economic benefit of CNY 1.25 × 10⁹ more than the actual current amount. The synergistic development of the water–energy–food nexus (WEFN) in the district is relatively harmonious, suggesting that the district should focus on developing agricultural mechanisation and balancing economic benefits with environmental and ecological protection; furthermore, the model constructed should provide decision-making support for the efficient use of agricultural resources in the irrigation district. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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16 pages, 3582 KiB

Open AccessArticle

Strategy for Deriving Sacramento Model Parameters Using Soil Properties to Improve Its Runoff Simulation Performances

by Bin Wang, Hao Sun, Shuaishuai Guo, Jinbai Huang, Zhongbo Wang, Xuefeng Bai, Xinglong Gong and Xiaoli Jin

Agronomy 2023, 13(6), 1473; https://doi.org/10.3390/agronomy13061473 - 26 May 2023

Cited by 2 | Viewed by 2106

Abstract

Physically-based parameter estimations are essential to improve the simulation performance of a hydrologic model and to produce physically reasonable parameters with spatial consistency. This study proposed a parameter derivation strategy to improve the Sacramento Soil Moisture Accounting (SAC-SMA) model simulation performance based on [...] Read more.

Physically-based parameter estimations are essential to improve the simulation performance of a hydrologic model and to produce physically reasonable parameters with spatial consistency. This study proposed a parameter derivation strategy to improve the Sacramento Soil Moisture Accounting (SAC-SMA) model simulation performance based on the publicly accessible Harmonized World Soil Database (HWSD). The HWSD soil properties were used to estimate the soil moisture characteristics, and the HWSD soil texture classifications and International Geosphere-Biosphere Programme (IGBP) land cover types were used to identify the Soil Conservation Service (SCS) runoff curve number (CN). After the soil moisture characteristics and CNs were identified, the major parameters of the SAC-SMA model were derived. The simulation results were evaluated using the Nash efficiency coefficient (NSEC), and Free Search (FS) algorithm was used to further adjust and calibrate the parameters. Compared with the simulation accuracy (NSEC = 0.66~0.88) and parameter transferability (NSEC = 0.22~0.83) obtained for the SAC-SMA model using directly calibrated parameters, the HWSD data-derived parameters allowed the SAC-SMA model to achieve a similar simulation accuracy (NSEC = 0.65~0.86) and a better transferability (NSEC = 0.61~0.85). Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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13 pages, 2176 KiB

Open AccessArticle

Factors Influencing Farm-Land Value in the Czech Republic

by Petr Prochazka, Mansoor Maitah, Kevin J. Mullen, Vladimir Honig, Jana Soukupova, Martina Zamkova, Stanislav Rojik, Lubos Smutka, Inna Cabelkova, Jana Hinke, Marek Dvorak and Petra Sanova

Agronomy 2023, 13(3), 892; https://doi.org/10.3390/agronomy13030892 - 17 Mar 2023

Cited by 3 | Viewed by 3049

Abstract

Czech farm-land had enjoyed considerable growth in value from 2008 to 2019. This paper identifies the main determinants of agricultural land prices variations and how these variations are influenced by urbanization, lease payments, and subsidies. These three factors were thoroughly examined for the [...] Read more.

Czech farm-land had enjoyed considerable growth in value from 2008 to 2019. This paper identifies the main determinants of agricultural land prices variations and how these variations are influenced by urbanization, lease payments, and subsidies. These three factors were thoroughly examined for the existence of a unit root using the Augmented Dickey Fuller Test. The long-run relationship between farm-land value and these elements was estimated using the co-integration approach, specifically the Johansen procedure. The estimation confirms the existence of this long-run relationship. Short-run fluctuation in agricultural land prices is explained using the Error Correction Model. As the most important variable in the short-run performance of Czech agricultural land prices, the authors identified the influence of urbanization. This information could be used to help regulators avoid potential agricultural land value instabilities and volatility in the market and hence would contribute to sustainable land use. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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22 pages, 1955 KiB

Open AccessArticle

Basic Farmland Protection System in China: Changes, Conflicts and Prospects

by Nan Wang, Jinmin Hao, Lei Zhang, Wenkai Duan, Yunyang Shi, Jinyi Zhang and Paruke Wusimanjiang

Agronomy 2023, 13(3), 651; https://doi.org/10.3390/agronomy13030651 - 23 Feb 2023

Cited by 18 | Viewed by 4385

Abstract

Farmland protection is important for ensuring national food security and promoting sustainable socioeconomic development. China has a far lower amount of farmland area per capita than the global average. To improve farmland productivity, the Chinese government has implemented a basic farmland protection system [...] Read more.

Farmland protection is important for ensuring national food security and promoting sustainable socioeconomic development. China has a far lower amount of farmland area per capita than the global average. To improve farmland productivity, the Chinese government has implemented a basic farmland protection system (BFPS). A comprehensive and systematic analysis of the evolution mechanism of the BFPS, the failures of the BFPS and the key measures of the modern BFPS reform is lacking in the current literature. Based on a systematic review of the history of China’s BFPS, this study first summarizes the evolutionary mechanism of the BFPS, then analyzes the current conflicts faced by the BFPS on this basis, proposes several main breakthrough strategies for improving the BFPS and finally provides key ideas for further strengthening the development of the BFPS in the future. The results of this study show that China’s BFPS has gone through three development stages since 1963 and that there are differences in the main factors hindering the improvement in basic farmland productivity in the different stages. Correspondingly, the systems adopted to meet the demands for basic farmland protection are also different. The evolution of the BFPS is similar to a “scale” that constantly seeks balance between “system demand” and “system supply”. In the present stage, the main conflicts faced by China’s BFPS are between basic farmland quality and requirements for supplementary delimitation and production patterns; between basic farmland quantity, urban development and food security; and between basic farmland-use regulation and modern agriculture and the market economy. The Chinese government should further optimize the BFPS through improving the delimitation system, establishing a classified protection system and strengthening the basic farmland protection compensation system. To accelerate the establishment of a territorial spatial planning system in the future, the BFPS should also be fully integrated with the concept of an ecological civilization, be applied to resolve the contradiction between development and protection and be used to help improve the land-space-utilization control system, thus creating a unified development guide for national land. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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23 pages, 5282 KiB

Open AccessArticle

The Dynamic Response of Runoff to Human Activities and Climate Change Based on a Combined Hierarchical Structure Hydrological Model and Vector Autoregressive Model

by Lianpeng Zhang, Hongxue Zhang, Dengfeng Liu, Qiang Huang, Jianxia Chang and Siyuan Liu

Agronomy 2023, 13(2), 510; https://doi.org/10.3390/agronomy13020510 - 10 Feb 2023

Cited by 3 | Viewed by 1841

Abstract

Climate change refers to a statistically significant change in the average state of the climate or a climate alteration that lasts for a long period of time. Runoff (R) is as a measure of the interaction between climate change and human activities and [...] Read more.

Climate change refers to a statistically significant change in the average state of the climate or a climate alteration that lasts for a long period of time. Runoff (R) is as a measure of the interaction between climate change and human activities and plays an important role in the hydrological cycle, as it is directly related to the development of agricultural water management. Therefore, it is a requirement to correctly simulate R and have the ability to separate the impacts due to climate change and human activities. In this paper, five single-type simulation models (Back Propagation Neural Network (BP), Non-Autoregressive (NAR), Radial Basis Function (RBF), Support Vector Machine (SVM) and TOPMODEL Hydrological Model (TOPMODEL)) were adopted to simulate the R to analyze the simulating quality by comparing the evaluation indexes like relative error (RE), relative mean squared error (RMSE) and Nash–Sutcliff Efficiency (NSE) with the combined hierarchical structure hydrological (CHSH) simulation model. In traditional studies, only the relative contribution of the impacts of human activities and climate change on R are considered; however, in this study, the relative contribution of each meteorological factor affecting R is included. To quantitatively analyze the impact of human activities and climate change on R, we used a CHSH simulation model to calculate runoff values for the Lancang River of China for a period of nine years (2005–2013). Our objective was to use this type of model to improve both the accuracy and stability of calculated values of R. For example, the RE, RMSE and NSE of simulated monthly R calculated with the CHSH model were 6.41%, 6.67 × 10⁸ m³ and 0.94, respectively. These values substantiate the improved accuracy and stability of calculated values of R obtained with single-type simulation models (the SVM model, for instance, widely used in runoff simulations, and the RE, RMSE and NSE were 14.1%, 12.19 × 10⁸ m³ and 0.87, respectively). The total contribution of human activities and climate change to R, respectively, accounted for 34% and 66% for the nine-year period based on the CHSH model. Furthermore, we adopted a vector autoregressive (VAR) model to analyze the impacts of the meteorological factors on R. The results from this analysis showed that R has a strong fluctuation response to the changes in precipitation (P) and potential water evaporation (E_p). The contribution rates of E_p, P and air temperature (T_a) to R were 15%, 14% and 2%, respectively. Based on the total climate change contribution, the corresponding contribution rates of E_p, T_a and P in the Lancang River of China were 32%, 30% and 5%, respectively. The values of R calculated with the CHSH model are more accurate and stable compared to values obtained with single-type simulation model. Further, they have the advantage of avoiding drawbacks associated when using a single-type simulation model. Moreover, moving away from the traditional method of separating the impact of meteorological factors on R, the vector autoregressive model proposed in this paper can describe the contribution of different meteorological factors on R in more detail and with precision. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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17 pages, 4902 KiB

Open AccessArticle

Zeolite as a Tool to Recycle Nitrogen and Phosphorus in Paddy Fields under Straw Returning Conditions

by Weiyu Hu, Jiang Li, Xiyun Jiao and Hongzhe Jiang

Agronomy 2023, 13(2), 327; https://doi.org/10.3390/agronomy13020327 - 21 Jan 2023

Cited by 5 | Viewed by 2365

Abstract

Excess nitrogen (N) caused by straw returning to paddy fields undergoing flooding irrigation deteriorates the water quality. The purpose of this research was to use both simulated field and pot experiments to explore a new approach using zeolite to recycle this excess N. [...] Read more.

Excess nitrogen (N) caused by straw returning to paddy fields undergoing flooding irrigation deteriorates the water quality. The purpose of this research was to use both simulated field and pot experiments to explore a new approach using zeolite to recycle this excess N. The results from simulated field experiments in stagnant water showed N adsorption with different zeolite applications (25, 50, 75, 100, 125, and 150 g L⁻¹). Pot experiments revealed how straw and reused zeolite applications affected the concentrations of ammonia N (NH₄⁺-N), nitrate N (NO₃⁻-N), total N (TN), and total phosphorus (TP) in the surface water and soil layers of the paddy field. Zeolite showed a strong ability to adsorb NH₄⁺-N in wastewater, even in a simulated drainage ditch (100 g L⁻¹ zeolite adsorbed 74% NH₄⁺-N). The zeolite recycled from the drainage ditch was still able to reduce N concentration caused by straw decomposition in the surface water. Zeolite adsorption reduced the peak values of NH₄⁺-N, TN, and TP by 30%, 19%, and 5%, respectively. Based on these findings and conventional field designs, the use of 20 t ha⁻¹ zeolite in the field is effective for recycling N and P. This research provides a sustainable development method to mitigate the water quality deterioration caused by straw returning to the field. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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17 pages, 4003 KiB

Open AccessArticle

Effects of Straw Return with Nitrogen Fertilizer Reduction on Rice (Oryza sativa L.) Morphology, Photosynthetic Capacity, Yield and Water–Nitrogen Use Efficiency Traits under Different Water Regimes

by Kaiwen Chen, Tao Ma, Jihui Ding, Shuang’en Yu, Yan Dai, Pingru He and Teng Ma

Agronomy 2023, 13(1), 133; https://doi.org/10.3390/agronomy13010133 - 30 Dec 2022

Cited by 9 | Viewed by 3218

Abstract

The sustainability of rice (Oryza sativa L.) cultivation has been threatened by water deficit and nitrogen (N)-fertilizer abuse. Straw return combined with N-fertilizer reduction could be an effective agronomic practice to improve N-use efficiency in rice production, but the interaction with water-saving [...] Read more.

The sustainability of rice (Oryza sativa L.) cultivation has been threatened by water deficit and nitrogen (N)-fertilizer abuse. Straw return combined with N-fertilizer reduction could be an effective agronomic practice to improve N-use efficiency in rice production, but the interaction with water-saving irrigation regimes remains largely unknown. Here, a 2-year paddy field experiment was conducted to elucidate the effects of irrigation regime (continuously flooded, CF; controlled irrigation and drainage, CID) and straw return with N reduction (conventional farmers’ fertilization practice of 300 kg N ha⁻¹ without straw return, N300; straw return with 25% N reduction, SN225; straw return with 50% N reduction, SN150) on rice growth dynamics, grain yield and water–nitrogen utilization. The results showed that CID significantly affected photosynthesis and fluorescence indicators, and increased grain yield and water productivity of rice. Straw return with N reduction reduced most rice growth traits, exhibiting lower plant height, tillers, leaf photosynthesis, chlorophyll fluorescence and dry matter accumulation, especially in vegetative growth under CF. In contrast, SN225 under CID showed compensatory effects on photosynthetic and fluorescence traits, thus improving N uptake during the reproductive growth stage. Despite a 6.6–7.1% yield reduction in SN225, 25% of N-fertilizer input was saved, with a corresponding increase in internal N-use efficiency and N-partial factor productivity. Overall, the present study indicates that straw return combined with moderate N deficiency might be a more eco-friendly and sustainable agronomic practice in water-saving irrigated rice fields. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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11 pages, 1586 KiB

Open AccessArticle

Magnetized Water Irrigation Alleviates Emitter Clogging of a Drip Fertigation System

by Kaili Shi, Jingyi Kong, Huanfang Yue, Yuan Huang, Xiaoming Wei and Lili Zhangzhong

Agronomy 2023, 13(1), 108; https://doi.org/10.3390/agronomy13010108 - 29 Dec 2022

Cited by 6 | Viewed by 2315

Abstract

Drip fertigation systems are a new technology to alleviate water shortages and improve fertilizer use efficiency. Emitter clogging is the main obstacle to their application. However, few efficient, safe, and environmentally friendly methods are available to alleviate clogging. In this study, we explored [...] Read more.

Drip fertigation systems are a new technology to alleviate water shortages and improve fertilizer use efficiency. Emitter clogging is the main obstacle to their application. However, few efficient, safe, and environmentally friendly methods are available to alleviate clogging. In this study, we explored the effects of magnetized water irrigation on emitter clogging at different fertilization levels. Field experiments were conducted to study the patterns and clogging characteristics of drip irrigation systems during two planting seasons. The results showed that with an increase in fertilizer application, clogging of the emitter was aggravated. Magnetization treatment effectively relieved emitter clogging, which increased the average discharge variation rate (Dra) by 4.1–29.0% and 2.6–64.4%, respectively, and decreased the dry weight (DW) of the clogging substance by 14.0–64.6% and 15.0–75%, respectively, in the two planting seasons, compared with that of the non-magnetization treatment. The composition of the main clogging substances was estimated using X-rays; the results showed that quartz, silicate, and carbonate were the dominant substances that induced emitter clogging. Magnetization treatment can reduce the content of clogging substances and is thus a possible mechanism to alleviate clogging. Our study demonstrated that water magnetization treatment is an effective, chemical-free treatment method with great potential for clogging control in drip fertigation systems. Full article

(This article belongs to the Special Issue Land and Water Resources for Food and Agriculture)

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