Search Results (21)

Nitrogen (N) and water are key resources for crop production and improving the efficiency with which they are used remains a major global challenge in intensive cropping systems. Here, we report how crop yield, N and water use efficiency, N surplus, and economic benefits can be improved from optimized management and crop rotations. A conventional winter wheat–summer maize double cropping (CN/WM) rotation in a three-year field experiment in the North China Plain is compared with alternative optimized rotations. The first three optimized treatments were wheat–summer maize rotation with optimized N and irrigation rates, tillage and straw management (ON/WM), and partial manure substitution (ONM/WM) or biochar addition (ONB/WM); the fourth optimized treatment was winter wheat–summer maize–spring maize producing three harvests in two years (ON/WMM); and the last was spring maize incorporating green manure during the fallow season for one harvest per year (ON/GM). The results showed that the ON/WM, ONM/WM, and ONB/WM had comparable yields to CN/WM, but significantly increased N use efficiency by 19–41% and water use efficiency by 13–20% and reduced N surplus to 353–531 kg N ha⁻¹ 2yr⁻¹. From these three optimized treatments, the ONM/WM performed better, with a comprehensive evaluation index of 0.66 and the highest economic benefits. The ON/WMM and ON/GM treatments also significantly increased N and water use efficiency but resulted in relatively low crop yields and profits; nevertheless, they significantly reduced water use and are suitable for water saving cropping systems. We concluded that optimized management-combined manure with synthetic N fertilization in wheat–summer maize rotations can achieve high crop productivity, environmental, and economic benefits, which contribute to a more sustainable crop production. Full article

Soil available nitrogen (AN) is a critical nutrient for plant absorption and utilization. Accurately mapping its spatial distribution is essential for improving crop yields and advancing precision agriculture. In this study, 188 AN soil samples (0–20 cm) were collected at Heshan Farm, Nenjiang County, Heihe City, Heilongjiang Province, in 2023. The soil available nitrogen content ranged from 65.81 to 387.10 mg kg⁻¹, with a mean value of 213.85 ± 61.16 mg kg⁻¹. Sentinel-2 images and normalized vegetation index (NDVI) and enhanced vegetation index (EVI) time series data were acquired on the Google Earth Engine (GEE) platform in the study area during the bare soil period (April, May, and October) and the growth period (June–September). These remote sensing variables were combined with soil sample data, crop type information, and crop growth period data as predictive factors and input into a Random Forest (RF) model optimized using the Optuna hyperparameter tuning algorithm. The accuracy of different strategies was evaluated using 5-fold cross-validation. The research results indicate that (1) the introduction of growth information at different growth periods of soybean and maize has different effects on the accuracy of soil AN mapping. In soybean plantations, the introduction of EVI data during the pod setting period increased the mapping accuracy R² by 0.024–0.088 compared to other growth periods. In maize plantations, the introduction of EVI data during the grouting period increased R² by 0.004–0.033 compared to other growth periods, which is closely related to the nitrogen absorption intensity and spectral response characteristics during the reproductive growth period of crops. (2) Combining the crop types and their optimal period growth information could improve the mapping accuracy, compared with only using the bare soil period image (R² = 0.597)—the R² increased by 0.035, the root mean square error (RMSE) decreased by 0.504%, and the mapping accuracy of R² could be up to 0.632. (3) The mapping accuracy of the bare soil period image differed significantly among different months, with a higher mapping accuracy for the spring data than the fall, the R² value improved by 0.106 and 0.100 compared with that of the fall, and the month of April was the optimal window period of the bare soil period in the present study area. The study shows that when mapping the soil AN content in arable land, different crop types, data collection time, and crop growth differences should be considered comprehensively, and the combination of specific crop types and their optimal period growth information has a greater potential to improve the accuracy of mapping soil AN content. This method not only opens up a new technological path to improve the accuracy of remote sensing mapping of soil attributes but also lays a solid foundation for the research and development of precision agriculture and sustainability. Full article

Drought is a major meteorological disaster that affects the growth of spring maize in Inner Mongolia. Understanding the spatiotemporal characteristics of drought is crucial for maintaining crop production. This study categorized Inner Mongolia into five climatic regions based on geography and climate characteristics: hyper-arid, arid, semi-arid, dry and semi-humid, and moist and semi-humid, reflecting Regions I to V, respectively. Based on data collected from 107 meteorological stations, the standardized precipitation evapotranspiration index (SPEI) was used to assess the characteristics of drought occurrence in different climatic regions during the spring maize growing season over the past 60 years, as well as the impact of drought on yield. SPEI decreased across all regions during growth periods, with mid-growth stages showing the smallest decline and a slight slowdown in drought severity. Spatially, 15 stations showed reduced drought during the early growth stage, which increased to 20 stations during the mid-growth stage. The overall drought trend of intensification was obtained across various climate regions, with Region I showing the most severe drought. The drought frequency during the growth period of spring maize ranged from 20% to 42%, and the drought frequency decreased from light drought, moderate drought, and severe drought to extreme drought. The drought range in each growth stage increased, with localized and regional drought dominating the region. The drought intensity also increased. Precipitation is the main factor affecting spring maize yield, and water replenishment during the early and middle stages of growth is crucial. These findings provide a basis for efficient water resource management in the region. Full article

Drought is one of the most severe natural disasters globally, with its frequency and intensity escalating due to climate change, posing significant threats to agricultural production. This is particularly critical in major food-producing regions, where drought profoundly impacts crop yields. Such impacts can trigger food crises in affected regions and disrupt global food trade patterns, thereby posing substantial risks to global food security. Based on historical data, this study examines the yield response characteristics of key crops—maize, rice, soybean, spring wheat, and winter wheat—under drought conditions during their growth cycles, highlighting variations in drought sensitivity among major food-producing countries. The findings reveal that maize and soybean yield in China, the United States, and Brazil are among the most sensitive and severely affected by drought. Furthermore, using precipitation simulation data from CMIP6 climate models, the study evaluates drought trends and associated crop yield risks under different future emission scenarios. Results indicate that under high-emission scenarios, crops face heightened drought risks during their growth cycles, with China and the United States particularly vulnerable to yield reductions. Additionally, employing copula functions, the study analyzes the probability of simultaneous drought occurrences across multiple countries, shedding light on the evolving trends of multicountry drought events in major food-producing regions. These findings provide a scientific basis for assessing global food security risks and offer policy recommendations to address uncertainties in food supply under climate change. Full article

The Mediterranean region is highly vulnerable to climate change. Longer and more intense heatwaves and droughts are expected. The Gordes Dam in Turkey provides drinking water for Izmir city and irrigation water for a wide range of crops grown in the basin. Using the Soil and Water Assessment Tool (SWAT), this study examined the effects of projected climate change (RCP 4.5 and RCP 8.5) on the simulated streamflow, nitrogen loads, and crop yields in the basin for the period of 2031–2060. A hierarchical approach to define the hydrological response units (HRUs) of SWAT and the Fast Automatic Calibration Tool (FACT) were used to reduce computational time and improve model performance. The simulations showed that the average annual discharge into the reservoir is projected to increase by between 0.7 m³/s and 4 m³/s under RCP 4.5 and RCP 8.5 climate change scenarios. The steep slopes and changes in precipitation in the study area may lead to higher simulated streamflow. In addition, the rising temperatures predicted in the projections could lead to earlier spring snowmelt. This could also lead to increased streamflow. Projected nitrogen loads increased by between 8.8 and 25.1 t/year. The results for agricultural production were more variable. While the yields of poppy, tobacco, winter barley, and winter wheat will increase to some extent because of climate change, the yields of maize, cucumbers, and potatoes are all predicted to be negatively affected. Non-continuous and limited data on water quality and crop yields lead to uncertainties, so that the accuracy of the model is affected by these limitations and inconsistencies. However, the results of this study provide a basis for developing sustainable water and land management practices at the catchment scale in response to climate change. The changes in water quality and quantity and the ecological balance resulting from changes in land use and management patterns for economic benefit could not be fully demonstrated in this study. To explore the most appropriate management strategies for sustainable crop production, the SWAT model developed in this study should be further used in a multi-criteria land use optimization analysis that considers not only crop yields but also water quantity and quality targets. Full article

Carbon neutrality is an important target in China’s efforts to combat the climate crisis. The implementation of carbon neutrality requires high crop yields in farmland ecosystems of arid regions. However, the responses of farmland ecosystems to environmental changes and their effects on the conversion and intensity of carbon sources/sinks within farmlands in arid regions remain unclear, which limits carbon sequestration. In this study, we used a set of eddy covariance systems to observe carbon and water fluxes in cotton and spring maize, two typical crops in arid regions of Northern Xinjiang in China. The carbon and water exchange and water use efficiency (WUE) of cotton and spring maize were evaluated over the entire growth cycle with respect to changes in the environment. Our results show that the carbon sequestration capacity of farmland ecosystems in arid regions is undeniable and is strongly influenced by the growth and development of plants. Spring maize, as a representative of C4 plants, exhibited a 58.4% higher carbon sequestration efficiency than cotton, a C3 plant, and they both reached their carbon sequestration efficiency peak in July. Throughout the growth period, temperature, net surface radiation, and saturated vapor pressure differences (VPD) significantly affected the carbon sequestration capacity and WUE of both crops. Optimal temperatures can maximize the carbon sequestration efficiency of cotton and spring maize; for cotton, they are 20–25 °C, and for spring maize, they are 22–27 °C, respectively. In addition, it is recommended that spring maize be harvested at the end of July when it meets the harvesting standards for silage feed and achieves the maximum carbon sequestration. Afterward, winter crops should be planted to maximize the yield and improve the carbon sequestration capacity of farmlands. Full article

A method was put forward to identify the combined heat and drought (CHD) events that occurred in summer and affected spring maize in Liaoning province. The spatial and temporal characteristics of CHD and its effects on maize were evaluated based on daily meteorological data at 52 meteorological stations in Liaoning from 1961 to 2020, as well as agricultural data including details of the maize development periods. The effects of CHD on the photosynthetic capacity of maize were evaluated using SIF remote sensing data from 2001 to 2020. The differences in maize photosynthetic capacity in the summers of 2009 and 2018 were compared in detail. The results show that from 1961 to 2020, the occurrence range, frequency, and severity of summer CHD events increased in Liaoning. CHD events were more frequent in June/July, and higher-intensity CHD events were more frequent in July/August. From 1961 to 2020, CHD events occurred in 69% of the years of reduced meteorological yield, and reduced meteorological yield occurred in 41% of the years with CHD events. Maize solar-induced chlorophyll fluorescence (SIF), an index of photosynthesis, was sensitive to temperature (negatively correlated) and precipitation (positively correlated). The CHD events slowed the increasing SIF from the three-leaf stage to the jointing stage, and they stopped the increasing SIF or decreased it at the tasseling–flowering to silking stages. Therefore, maize photosynthesis may be most sensitive to CHD during the flowering to silking stages, and CHD during the silking to milk stages may have the greatest impact on maize yield. Understanding the effects of CHD on maize growth/yield provides a scientific basis for reducing its negative impacts on maize production. Full article

The State of Veracruz (Mexico) is highly vulnerable to climate change. Therefore, it is necessary to identify and analyze local climate extreme trends and explore potential relationships between climate indices and maize. The objectives of this research were (1) to describe recent trends of climate indices (1979–2018) and (2) to compare these climate indices with maize yields produced in Veracruz, Mexico, under rainfed conditions. The methodology calculated and analyzed the sector-specific climate indices (Rx5day, PRCPTOT, SPI6, R20mm, TXx, TNn, TXgt50p, and TXge35) in 18 observation sites using Climpact. Climate indices were calculated over the spring-summer agricultural cycle and correlated with rainfed maize yields. Results show increasing trends for Rx5day, TXx, TXgt50p, and TXge35 indices in 65%, 56%, 89%, and 67% of the analyzed sites, respectively, whereas decreasing trends in PRCPTOT and R20mm indices were detected in 59% and 47% of the sites. Significant correlations (p < 0.05) between climate indices and maize yield were found in eight municipalities, of which 62% were positive. In conclusion, extreme temperature and precipitation local events are increasing in frequency, duration, and intensity, and depending on the site’s local climate, these might positively or negatively impact maize yields. Full article

Biodegradable mulches have the same temperature- and moisture-preservation effects as ordinary plastic mulches before degradation. After degradation, rainwater enters the soil through the damaged parts, improving precipitation utilization. Under drip irrigation with mulching, this study explores precipitation utilization of biodegradable mulches under different precipitation intensities and the effects of different biodegradable mulches on the yield and water use efficiency (WUE) of spring maize in the West Liaohe Plain, China. In this paper, in situ field observation experiments were conducted for three consecutive years from 2016 to 2018. Three types of white degradable mulch films were set up, with induction periods of 60 d (WM60), 80 d (WM80), and 100 d (WM100). Three types of black degradable mulch films were also used, with induction periods of 60 d (BM60), 80 d (BM80), and 100 d (BM100). Precipitation utilization, yield, and WUE under biodegradable mulches were studied, with ordinary plastic mulches (PM) and bare land (CK) set as controls. The results showed that as precipitation increased, the effective infiltration of precipitation decreased first and then increased. When precipitation reached 89.21 mm, plastic film mulching no longer affected precipitation utilization. Under the same precipitation intensity, the precipitation effective infiltration ratio increased as the damage to the biodegradable film increased. Still, the intensity of this increase gradually decreased as the damage increased. The highest yield and WUE were observed for the degradable mulch film with an induction period of 60 days in years with normal rainfall and for the degradable mulch film with an induction period of 100 days in dry years. In the West Liaohe Plain, maize planted under film receives drip irrigation. We recommend that growers select a degradable mulch film with a degradation rate of 36.64% and an induction period of approximately 60 days in years with normal rainfall, and a degradable mulch film with an induction period of 100 days in dry years. Full article

Limited tillage provides a number of benefits, but a question remains how it affects weed community and biodiversity evolving from the weed community. Our field experiment was established in the cadastral area of Branišovice (South Moravian Region, Czech Republic). Three different tillage technologies were used in this field experiment: conventional tillage, minimum tillage, and no-tillage technology. In 2001–2004, infestation by weeds was evaluated in the stands of spring barley, winter wheat grown after a dicot pre-crop (rape, soybean), in the stands of wheat grown after wheat, and in stands of maize. The recorded weed species were divided according to the criteria of biological relevance. Based on the results of the four-year field experiment, it is possible to state that tillage technologies have only a limited influence on the intensity of weeding but substantially alter the species spectrum of weeds. Weed vegetation in the no-tillage variant exhibits higher values of biological relevance, which allows a higher occurrence of weed-dependent species of organisms. Weed vegetation in the minimum soil tillage variant has the lowest biological relevance values, which limits the occurrence of weed-dependent organisms. Alterations in weeding caused by different tillage technologies are part of the process of vegetation microevolution in the agricultural landscape. Full article

The research aimed to assess the contribution of fertilizer, density, and row spacing in integrated cultivation measures and identify their regulation mechanism on canopy architecture and factors in biomass accumulation in spring maize. Zhengdan 958 was used as the experimental material, and the optimum mode (OM) was identified based on a preliminary experiment, including the optimal fertilizer management, suitable plant density and wide-narrow row spacing, and dramatic yield performance (11,445.16 kg ha⁻¹ in 2017). Then, the effects of these practices on maize canopy structure performance were analyzed using the omission factors design experiment in optimum mode (OM). Treatments were set as follows: without fertilization (OM-F), without density (OM-D), and without wide-narrow plant spacing (OM-S). The results showed that the contribution of fertilization was maximum (23.85%), the second was intensive planting (16.05%), which promoted nitrogen accumulation and transport in leaves and stems via increased leaf area index and dry matter accumulation around the anthesis simultaneously, elevating the radiation utilization efficiency of the canopy and allowing a higher grain weight to be obtained. Wide-narrow row spacing yield contribution is minimum among the measures (8.649%), which could regulate the leaf and radiation transmittance in the middle and bottom layer of the canopy, while increasing the nitrogen accumulation of leaves and stalks in the silking stage, then significantly enhance the nitrogen transport and the matter accumulation of maize after anthesis. Our results showed that fertilizer management and density were the essential practices for integrated cultivation mode for northeast China. Moreover, wide-narrow row planting was advocated if permitted, which could elevate the utilization efficiency of radiation to 1%, and the yield of more than 11,000 kg ha⁻¹ was obtained in Northeast China. Full article

Water consumption and energy consumption are inevitable in grain production, but few studies have focused on the integrated assessment of these two indicators and their relationships. To address the research deficiency, taking the North China Plain (NCP) as a case study, this paper quantifies the changes in grain crop planting structure and the accompanying changes in irrigation water consumption (IWC) and energy consumption (EC) in the NCP. On this basis, the water-energy coupling index (CI) is constructed to analyze the water-energy coupling relationship in the context of grain crop planting structure change. The results revealed that the sown area of three of the four main grain crops in the NCP, namely winter wheat, summer maize, and rice, roughly increased in the south and decreased in the north, while the sown area of spring maize increased in most counties where it was planted in the NCP from 2000 to 2015. With the change of grain crop planting structure, IWC and EC of winter wheat in the NCP decreased by 19.87 × 10⁶ m³ and 16.78 × 10⁸ MJ, respectively, mainly distributed in the Beijing-Tianjin-Hebei region, while IWC and EC of other crops all increased. In terms of CI values, although that of spring maize increased, those of winter wheat, summer maize, and rice all decreased, and the overall CI values of grain production in the NCP decreased from 0.442 in 2000 to 0.438 in 2015, indicating that grain crop distribution has been optimized toward a less water- and energy-intensive and more sustainable layout in the NCP. This paper can add case and methodological support to the food-water-energy (FEW) nexus research and can also provide policy suggestions for regional crop optimization layout and conservation of both water and energy resources. Full article

The cultivation of silage crops is encouraged to enhance the connection between crop and livestock production in the North China Plain (NCP). A field experiment was designed to evaluate the ammonia (NH₃), nitrous oxide (N₂O), and methane (CH₄) emissions of five silage cropping systems, including triticale-summer maize (Tr-SuM), triticale-spring maize (Tr-SpM), triticale-double forage maize (Tr-DFM), double forage maize (DFM), and winter wheat-summer maize (WW-SuM), as well as their biomass- and crude protein-scaled emission intensities, with respect to NH₃ and greenhouse gas (GHG). The annual nitrogen (N) emissions through NH₃, N₂O, and CH₄ emissions of these systems were 13.43–23.77 kg ha⁻¹ (4.2–5.6% of N fertilizer input), 3.43–4.56 kg ha⁻¹ (0.75–1.08% of N fertilizer input) and 2.10–2.85 kg ha⁻¹, respectively. The total GHG emissions of these systems was dominated by the contributions of N₂O. Ranking these systems according to their biomass and crude protein production gave Tr-DFM > DFM > WW-SuM > Tr-SuM and Tr-SpM, their partial factor productivity was in the order of Tr-DFM > WW-SuM > Tr-SuM and Tr-SpM > DFM, and the order of their emission intensity was DFM > Tr-SuM > Tr-DFM > WW-SuM > Tr-SpM. In conclusion, the Tr-DFM needs to be further investigated for its suitability in the NCP, owing to its superior productivity and moderate emission intensities. Full article

The aim of the study was to investigate specific responses of spring wheat (C₃ photosynthesis) and maize (C₄ photosynthesis) to drought and flooding stress. Analyses of water content, gas exchange intensity, photosynthetic apparatus activity, chlorophyll content, plant height and biological membrane integrity were performed on the 10th day of drought and flooding in both species at the third leaf stage. A specific response of wheat under both drought and flooding conditions involved an increase in ET_o/RC ratio, describing electron transport flux converted into a single reaction center in PSII. Correlations between electrolyte leakage and the probability of electron transport beyond the plastoquinone Q_A, and the amount of energy used for the electron transport were also found. A specific response of maize during flooding was the increase of stomatal conductance. Additionally, a significant correlation between P_N/C_i and relative water content was exhibited. Furthermore, the parameters differentiating the studied species only under stressful conditions were rendered. The application of such parameters can be widely used, e.g., for studying the reaction of a potential cultivars to drought and flooding. Providing such information to potential farmers can help better select cultivars for their environmental conditions. Full article

The cultivation of perennial wild plant mixtures (WPMs) is becoming increasingly important in Germany for providing sustainably produced bioenergy. However, perennial energy cropping systems always raise the question of how to reclaim the land for arable crops. This study examined this issue by looking at how a former WPM area was returned to arable cropping for an organic farm. From 2013 to 2018, the WPM area was harvested annually in the autumn. From 2019 to 2020, it was co-managed with the surrounding land as a semi-intensive grassland under a three-cut regime. The area was then ploughed in the spring of 2021 to grow silage maize. Weeds were controlled mechanically once. Nevertheless, the perennial wild plant species grew vigorously, with common tansy (Tanacetum vulgare L.) standing out with a total fresh matter share of 29.0%. This maize–WPM mixture achieved a dry matter yield of 15.5 ± 5.5 Mg ha⁻¹, which was notably but not significantly (p < 0.05) lower than that of silage maize growing next to the former WPM area (23.4 ± 5.5 Mg ha⁻¹). After silage maize, winter wheat was sown in the autumn of 2021 and further regrowth of common tansy was observed in the spring of 2022. Yield and quality effects must therefore be given special consideration in the first arable crop following WPM cultivation. Full article