Winter Wheat Maize Research Articles

Annual emissions of N2O, NO, HONO, and NH3 from maize-wheat fields in the North China Plain

Fertilized agricultural soil is a significant source of gaseous nitrogen compounds (GNCs), including N2O, NO, HONO, and NH3. The North China Plain (NCP) is the “hot region” for the release of these GNCs due to intensive fertilization practices. However, existing research has primarily focused on N2O emissions from fertilized farmland in the NCP, lacking comprehensive observational studies on other GNCs. Therefore, a continuous cumulative sampling technique (open-top dynamic chamber system) was utilized in this study to simultaneously measure the exchange fluxes of N2O, NO, HONO, and NH3 over summer maize-winter wheat rotation fields in the NCP. Results showed that GNC emissions from the soil displayed distinct diurnal variations, with higher emissions during the day attributed to elevated soil temperature. However, N2O emissions remained consistent between day and night, potentially influenced not only by soil temperature but also by soil humidity. Annual cumulative emissions and emission factors (EFs) for four GNCs were determined, indicating that N2O, NO, and NH3 emissions during the maize season were 1.38–2.37 times higher than those during the wheat season, with 98 % of HONO emissions occurring in the maize season. Additionally, the study first presented the annual HONO EFs of 0.36 ± 0.03 % in fertilized farmland. Furthermore, a comparison revealed that the fluxes of N2O, NO, NH3, and HONO using the conventional single-point sampling method were 26.4 %, 13.9 %, and 8.10 % lower, and 7.86 % higher compared to the continuous cumulative sampling method recommended in this study. In general, this study provided precise measurements of GNC emissions from farmland, offering essential foundational data for modeling parameters and contributing to the formulation of regional air pollution prevention and control policies.

Enhanced nitrogen fertilizer combined with straw incorporation can reduce global warming potential with higher carbon sequestration in a summer maize-winter wheat rotation system

The combined effects of nitrogen (N) fertilizers and straw incorporation (SI) on GHG emissions, crop yields, and net ecosystem carbon budget (NECB) in summer maize-winter wheat rotation systems are still uncertain. We conducted a two-year field experiment to evaluate the effects of SI combined with different N fertilization practices on soil N2O emissions, ecosystem respiration (Re), NECB, grain yields, net global warming potential (NGWP), and greenhouse gas intensity (GHGI). In total, five treatments were considered, namely conventional urea-N application (FP), optimal urea-N fertilizer (OPT) with and without SI (S+OPT and OPT), and enhanced-efficiency N fertilizers (equivalent to OPT) with and without SI (S+EENF and EENF). The results showed significantly decreased average annual N2O emissions under the OPT and EENF treatments by 22.70 and 51.35% (P < 0.05), respectively, compared with that under the FP treatment. However, no significant differences in the annual Re emissions, NECB values, and crop yields were observed between the N fertilizer treatments (P > 0.05). The SI significantly increased the average annual N2O emissions, annual Re emissions, and annual grain yields by 36.01, 27.94, and 11.54% (P < 0.05), respectively, compared to no-straw treatments. The annual NECB values under the SI and no-straw treatments ranged from 1.19 to 1.94 t C ha−1 yr−1 and −1.89 to −1.19 t C ha−1 yr−1, respectively. The lower NGWP and GHGI values were observed in the S+EENF plots. The results suggest that the practice of enhanced-efficiency N fertilizers coupled with SI could improve crop yields and reduce NGWP and GHGI values in summer maize-winter wheat rotation systems.

Evaluating optimized irrigation strategies on crop productivity and field water utilization under micro sprinkling irrigation in typical cropping systems of the Huang-Huai-Hai Plain

Inefficient traditional irrigation methods have negative consequences for agricultural production and the depletion of groundwater resources. This two-year field experiment aimed to evaluate optimized irrigation practices for irrigation efficiency (IE) and water utilization in winter wheat-maize (W-M) and winter wheat-soybean (W-S) annual rotation systems. Four micro-sprinkler-based irrigation strategies were implemented during the winter wheat season, specifically when the soil water content (SWC) of the 40 cm soil layer reached 40% of the field capacity (FC) after sowing. Including W4 (irrigated to SWC at 40 cm reached 60% FC), W6 (irrigated to SWC at 60 cm reached 80% FC), FI (farmer's practice, with irrigation amount of 150 mm per irrigation, the same timing as W6), and a rain-fed (RF) as a control. Summer seasons had no irrigation except for emergence. The WHCNS model simulated water consumption. The results indicated that IE decreased with increasing irrigation volumes, and the W-S system demonstrated higher IE than W-M. Both W4 and W6 achieved the desired wetting zones, while FI resulted in water leakage. Surface runoff was not affected by irrigation. Compared to the FI treatment under both cropping systems, W4 significantly reduced field water losses, particularly deep percolation, by 18.3–39.4%. W6 and FI led to elevated winter wheat transpiration rates, impacting crop yield. W4 had comparable yields to W6 and FI, but higher crop water productivity with average increases of 17.9% and 21.3% in W-M, and 24.6% and 31.4% in W-S, respectively. W4 also showed higher harvest indexes in both systems. The W-S system had more stable interannual yields, higher water-holding capacity, and water use efficiency than W-M. Although RF had great water-saving potential, its yield losses were enormous. These optimized precision irrigation strategies significantly reduce water consumption while achieving substantial yield increases, thereby providing vital support for sustainable agricultural development.

Productivity and water use efficiency of summer soybean-winter wheat rotation system under limited water supply in the North China Plain

Development of novel crop rotations with superior water- and N-use efficiency will be fundamental in the quest for securing sustainable food supplies under environments that are increasingly resource limited. Here, our aim was to examine how replacing maize with soybean as part of winter wheat rotations impacted the nutrient-equivalent yield (EY), evapotranspiration (ET) and water-use efficiency (WUE) of rotation systems. We contrasted summer soybean-winter wheat (SW) and summer maize-winter wheat (MW) cropping systems under three nitrogen (N) fertilization regimes: no, medium, and high nitrogen application rates (0 N, MN, and HN, respectively). Results showed that SW not only resulted in lower annual yields, but also caused more variable inter-annual wheat productivity compared with MW. SW had similar annual productivities to MW in wet (2019–2020) and dry (2020–2021) years, but lower productivity than MW in an average precipitation year (45% reduction, 2018–2019). As well, SW had higher average annual ETs (633–854 mm) than MW, mainly was attributed to higher ETs (268–440 mm) in summer. SW reduced WUEs by 17% and 28% in average (2018–2019) and dry (2020–2021) years, respectively. Regardless of cropping system, N fertilization increased annual EYs and ETs by 10–18% and 5–18% compared with no fertilization, respectively. Together these comparable increments in EY and ET, we found that N fertilization had rare effects on annual WUE of both systems. Overall, our study demonstrated that replacing maize with soybean in winter wheat rotations increased annual ET and neither maintained productivity nor improved water productivity. Thus, we suggest that practitioners explore other drought tolerant grain legumes to generate more reliable yields and less water consumption under legume-based crop rotations.

Effects of reduced tillage with stubble remaining and nitrogen application on soil aggregation, soil organic carbon and grain yield in maize-wheat rotation system

Global climate change has threatened stable food production and soil carbon storage. Whether reduced tillage with stubble remaining (RTS) and nitrogen (N) application improve soil carbon storage and grain yield simultaneously and its impact on soil aggregation and soil organic carbon (SOC) fractions are still controversial. A 4-year experiment, including four treatments (CT, rotary tillage with stubble removing; RTS; CT+N; RTS+N), was conducted to explore the effects of RTS and N application on soil aggregates and soil organic carbon fractions, and answer whether the combination of RTS and N application can simultaneously improve soil carbon storage, crop yield and water productivity in summer maize-winter wheat rotation (MWR) system. The results showed that soil aggregates stability and SOC content of RTS+N increased by 34.9% and 9.2% due to increased proportion of large macroaggregate (LM, increased by 6.6%) and small macroaggregate (SM, increased by 6.9%), respectively, compared to CT+N at the end of the 4-year experiment. RTS significantly increased particular organic carbon (POC) content, and N application significantly increased the mineral-associated organic carbon (MAOC) content. Compared with CT, the POC, MAOC and POC/MAOC increased by 42.7%, 18.7% and 20.4% in bulk soil, increased by 19.6%, 8.5% and 10.5% in LM, increased by 33.2%, 14.2% and 17.1% in SM, increased by 25.9%, 16.8% and 8.3% in microaggregate, respectively, under RTS+N. Meanwhile, the mean grain yield, yield stability and water productivity of RTS+N increased by 33.7%, 206.4% and 43.4% for summer maize, and increased by 7.0%, 29.3% and 3.0% for winter wheat compared with CT+N. Therefore, reduced tillage with stubble remaining combined with nitrogen application in semi humid and drought-prone areas can simultaneously increase soil carbon storage, grain yield and water productivity in the MWR system.

The potential for soil C sequestration and N fixation under different planting patterns depends on the carbon and nitrogen content and stability of soil aggregates

The winter wheat-summer maize rotation system is common in the Huang-Huai-Hai Plain due to its consistent yield, however, it may cause soil quality degradation and increased risk of greenhouse gas emissions. To evaluate the effects of different planting patterns on soil organic carbon (SOC) and total nitrogen (TN) sequestration, as well as aggregate and C-N distribution, a three-year field experiment that included three annual double-cropping rotation patterns: winter wheat-maize (W-M), winter wheat-soybean (W-S), and winter wheat-sweet potato (W-SP) was conducted from 2020 to 2022, with W-M as the control. Our research revealed significant differences in soil carbon sequestration rates among the various planting systems. Specifically, the SOC stock in the W-S system was 12.21 % to 24.51 % higher than that of the W-M system and 10.28 % to 35.73 % higher than that of the W-SP system. While TN stock demonstrated an increase of 9.85 % to 37.39 % compared to the W-M system and 8.14 % to 67.43 % compared to the W-SP system. Moreover, SOC and TN sequestration were largely related to soil aggregates, with macroaggregates being the primary component in both W-S and W-M planting patterns, while microaggregates were more common in W-SP patterns. The accumulation of SOC and TN occurred mainly in macroaggregates, leading to a significant increase in C and N content in soil macroaggregates under the W-S planting pattern. The structural equation model suggested that the TN stock had both direct and indirect effects on SOC sequestration, with a total impact coefficient of 0.872. Our three-year field results indicate that the W-S model is advantageous in enhancing soil C and N sequestration capacity and had great potential in reducing greenhouse gas emissions in farmland.

Biochar application significantly increases soil organic carbon under conservation tillage: an 11-year field experiment

Biochar application and conservation tillage are significant for long-term organic carbon (OC) sequestration in soil and enhancing crop yields, however, their effects on native soil organic carbon (native SOC) without biochar carbon sequestration in situ remain largely unknown. Here, an 11-year field experiment was carried out to examine different biochar application rates (0, 30, 60, and 90 Mg ha−1) on native SOC pools (native labile SOC pool I and II, and native recalcitrant SOC) and microbial activities in calcareous soil across an entire winter wheat–maize rotation. The proportions of C3 and C4-derived native SOC mineralization were quantified using soil basal respiration (SBR) combined with 13C natural isotope abundance measurements. The results showed that 39–51% of the biochar remained in the top 30 cm after 11 years. Biochar application rates significantly increased native SOC and native recalcitrant SOC contents but decreased the proportion of native labile SOC [native labile SOC pool I and II, dissolved organic carbon (DOC), and microbial biomass carbon (MBC)]. Biochar application tended to increase the indicators of microbial activities associated with SOC degradation, such as SBR, fluorescein diacetate hydrolysis activity, and metabolic quotient (qCO2). Meanwhile, higher biochar application rates (B60 and B90) significantly increased the C4-derived CO2 proportion of the SBR and enhanced C4-derived native SOC mineralization. The effect of the biochar application rate on the content and proportion of native SOC fractions occurred in the 0–15 cm layer, however, there were no significant differences at 15–30 cm. Soil depth also significantly increased native labile SOC pool I and II contents and decreased qCO2. In conclusion, the biochar application rate significantly increased native SOC accumulation in calcareous soil by enhancing the proportion of native recalcitrant SOC, and biochar application and soil depth collectively influenced the seasonal turnover of native SOC fractions, which has important implications for long-term agricultural soil organic carbon sequestration.Graphical

Effects of combined application of biochar and nitrogen fertilizer on soil quality of summer maize-winter wheat system

The effects of nitrogen fertilizer and biochar on topsoil quality in the drylands of northwest China were studied in field trials for two years. A split plot design with two factors was adopted, with five nitrogen rates (0, 75, 150, 225 and 300 kg N·hm-2) as main plots, and two rates of biochar (0 and 7.5 t·hm-2) as submain plots. We collected soil samples at 0-15 cm depth after two years of winter wheat-summer maize rotation and measured physical, chemical, and biological properties. The minimum data set (MDS) was established by using principal component analysis and correlation analysis to analyze the responses of soil quality to nitrogen fertilizer and biochar addition. The results showed that the combined application of nitrogen fertilizer and biochar could improve soil physical properties, increase macroaggregate content, reduce soil bulk density, and increase soil porosity. Both fertilizer application and biochar application had a significant effect on soil microbial biomass carbon and nitrogen. The application of biochar could improve soil urease activity and the contents of soil nutrients and organic carbon. Six out of 16 indicators (urease, microbial biomass carbon, total phosphorous, total nitrogen, pH, and available potassium) relating to soil quality were used to construct MDS, and soil quality index (SQI) was calculated. The variation range of SQI was 0.14-0.87, with that of 225 and 300 kg N·hm-2 nitrogen application combined with biochar application being significantly higher than other treatments. Soil quality could be significantly improved by application of nitrogen fertilizer and biochar. Interactive effect was observed, which was particularly stronger under high nitrogen application rate.

Nitric Oxide Emissions from Chinese Upland Cropping Systems and Mitigation Strategies: A Meta-analysis

Agroecosystems are a significant source of nitric oxide (NO), a potent atmospheric pollutant. It has been well documented that the NO emissions from upland cropping systems and their emission factors are large relative to those from paddy fields. However, a clear understanding of their uncertainty and regulating factors is still lacking. To date, various field experiments have been conducted to investigate NO emissions and mitigation, providing an opportunity for a Meta-analysis. The aims of this study were to 1 investigate the uncertainty and regulating factors of NO emissions and emission factors from maize-winter wheat rotations, non-waterlogging period in rice-winter wheat rotations, vegetable fields, tea plantations, and fruit orchards across China by extracting data from peer-reviewed publications, and 2 quantify the mitigation potential of management practices, such as reducing nitrogen fertilizer input, organic substitution with chemical fertilizers, and application of enhanced-efficiency nitrogen fertilizers or biochar by performing a pairwise Meta-analysis. A total of 49 references (published from 2006 to 2021) were collected. The results showed that annual NO emissions from the maize-winter wheat rotations, tea plantations, and fruit orchards averaged 1.44, 7.45, and 0.92 kg·hm-2, respectively, with significant differences among the three cropping systems (P<0.05). The seasonal NO emissions from the non-waterlogging period in rice-winter wheat rotations and vegetable fields within a single growth period averaged 2.13 kg·hm-2 and 2.09 kg·hm-2, respectively. The NO emissions positively related to nitrogen inputs in the maize-winter wheat rotations, non-waterlogging period in rice-winter wheat rotations, and tea plantations (P<0.01) but not in the vegetable fields and fruit orchards. The emission factors averaged 0.31%, 0.71%, 0.96%, 1.74%, and 0.13% in the maize-winter wheat rotations, non-waterlogging period in rice-winter wheat rotations, vegetable fields, tea plantations, and fruit orchards, respectively, with significant differences among the cropping systems (P<0.01), except between the maize-winter wheat rotations and non-waterlogging period in rice-winter wheat rotations or vegetable fields (P>0.05). Considering the substantial differences in emission factors among the cropping systems, a specific emission factor for each system should be applied when estimating an agricultural NO budget at a regional or national scale. Reducing nitrogen input only mitigated NO emissions (by 36%) at a reducing nitrogen ratio above 25% but did not impact emission factors. An optimal reducing nitrogen ratio has to be further evaluated without crop productivity penalties. Organic substitution in soils with organic carbon content<15 g·kg-1 or pH<7 and application of enhanced-efficiency fertilizers in the maize-winter wheat rotation simultaneously mitigated NO emissions (by -46%- -38%) and emission factors (by -62%- -45%). By contrast, biochar amendment had no significant effects on either NO emissions or emission factors. These findings highlight a possibility of choosing an effective NO mitigation strategy under specific field conditions.

Long-term integrated soil-crop management improves soil microbial community structure to reduce GHG emission and increase yield.

Integrated soil-crop management (ISCM) has been shown as an effective strategy to increase efficiency and yield while its soil microbial community structure and function remain unclear. We evaluated changes in soil physicochemical factors, bacterial community structure responses, and the contributions of soil properties and bacterial communities to summer maize-winter wheat yield and GHG emissions through an ISCM experiment [T1 (local smallholder farmers practice system), T2 (improved management system), T3 (high-yield production system), and T4 (optimized management system)], which could provide scientific guidance for sustainable development of soil in summer maize-winter wheat rotation system. The results showed that the optimized ISCM could improve the soil quality, which significantly changed the soil bacterial community structure to reduce GHG emissions and increase yield. The co-occurrence network density of T3 was increased significantly. The Acidobacteria (class) and OM190 (class) were enriched in T2 and T4. The Frankiales (order) and Gaiellales (order) were enriched in T3. However, the changes in different crop growth stages were different. At the wheat jointing stage and maize mature stage, T4 could enhance carbon-related functional groups, such as aromatic hydrocarbon degradation and hydrocarbon degradation, to increase the soil organic carbon content. And at the maize tasseling stage, T4 could enhance nitrogen-related functional groups. And soil bacteria structure and function indirectly affected annual yield and GHG emission. T2 and T4 exhibited a similar soil microbial community. However, the yield and nitrogen use efficiency of T2 were reduced compared to those of T4. The yield of T3 was the highest, but the GHG emission increased and soil pH and nitrogen use efficiency decreased significantly. Therefore, T4 was a suitable management system to improve soil quality and soil bacterial community structure and function to decrease GHG emissions and increase the yield of the summer maize-winter wheat rotation system.

Daily, seasonal and inter-annual variations in CO2 fluxes and carbon budget in a winter-wheat and summer-maize rotation system in the North China Plain

Investigating CO2 fluxes and carbon budget in agro-ecosystems is essential to develop climate smart agriculture. Here, we conducted a thorough analysis on the daily, seasonal and inter-annual variations in CO2 fluxes and carbon budget in a winter-wheat and summer-maize rotation system in the North China Plain (NCP) to better understand the CO2 flux exchange and the underlying mechanisms of carbon budget dynamics. During 2003-2010, the inter-annual variability of monthly gross primary productivity was significantly correlated with leaf area index (LAI), temperature and net radiation. The inter-annual variability of monthly ecosystem respiration was significantly correlated with LAI, soil temperature and moisture. Daily and monthly variability in net ecosystem exchange (NEE) was significantly correlated with LAI. At a seasonal scale, soil moisture was one of the primary factors controlling carbon sequestration of wheat system. Nitrogen application rate and water conditions were the primary factors controlling carbon sequestration of maize system. The NEE for winter wheat system, maize system, and winter wheat-maize rotation system in the NCP ranged from -418 to -29, -448 to -119, and -857 to -274 gCm−2, respectively. The net biome productivity (NBP) for winter wheat system, maize system, and winter wheat-maize rotation system in the NCP ranged from -223 to 151, -236 to 94, and -239 to 237 gCm−2, respectively. Taking greenhouse gas (GHG) emissions from irrigation, fertilization, herbicides, fungicide, insecticide, and field operations, the associated net GHG emissions ranged from -39 to 325 gCm−2 for wheat system and -22 to 287 gCm−2 for maize system. Wheat and maize systems in the region were a medium source of GHG emissions in most of years, mainly due to the large application rates of fertilization and irrigation. Our findings gain new insights into the mechanisms underlying the inter-annual variations in CO2 fluxes and carbon budget, highlighting the optimization of genotype, environment and management interactions to realize climate smart agriculture.

How Do Long Term Crop Rotations Influence Weed Populations: Exploring the Impacts of More than 50 Years of Crop Management in Serbia

Crop rotation is known as an eco-friendlier approach, as provides diversification in crop management systems, modifies intensive pressure on the agricultural ecosystem, utilizes various soil horizons, and prevents the establishment of specific pests and weeds. We set out here a study on the farms that have been managed over 50 years of specific continuous crop management programs. The experimental treatments were in a different management system: monoculture of maize, winter wheat, and soybean, 2-year crop rotation (winter wheat–maize) with and without chemical fertilizer, and 3-year crop rotation (winter wheat–soybean–maize) with and without chemical fertilizer and manure. We took soil samples six times from 2014 to 2017 prior to sowing and after harvesting each year. Weed seeds were extracted from soils and identified and counted by species. We, upon the data of a long term experiment of crop rotation, could conclude that crop rotations with more crops in the sequence are significantly effective in maintaining weed populations, a low-input crop production could reach a constant low population below an important damaging density, and therefore will be a more sustainable crop production while chemical fertilizers would change the soil’s chemical and structure and imbalance the plant population diversity and manures with high weed seed infestations have the potential to totally eradicate crop rotation effects, Therefore, clean manures or compost are highly recommended.

Ammonia mitigation potential in an optimized crop-layer production system

Livestock and crop production are the main sources of ammonia (NH3) emissions, which are known to degrade the air quality. Numerous studies have been conducted to explore the mitigation potential of various approaches, although few have examined the systematic NH3 emission mitigation potential when considering both crop and livestock systems based on coherent in situ measurement results. Herein, we design an optimal system wherein coupled crop and layer production systems reveal feasible approaches for significant mitigation potential at each stage of the process. Specifically, these measures involve (i) using a low crude protein (LCP) feed, (ii) composting manure with certain additives, and (iii) substituting manure with optimal fertilization in a summer maize-winter wheat cropping system. The results show that (i) LCP feed leads to a 14 % reduction in NH3 emissions at the housing stage, (ii) introducing additives during the composing stage reduces NH3 emissions by 16 %–46 %, and (iii) the NH3 reduction potential reaches 35 %–44 % at the field application stage. In the overall crop-layer system, the optimal system with the improved management strategy applied at every stage results in a 48 % and 56 % reduction in NH3 emissions for per unit eggs and grain production, respectively, relative to a traditional production system. This study confirms that NH3 emissions can be cut in half by implementing optimal crop-livestock systems with appropriate mitigation approaches. This is a feasible model that can be promoted and extended in various agricultural areas, which together with technological, policy, and economic support can enable significant mitigation potential for sustainable agriculture development.

Effects of Climate Warming on the Potential Northern Planting Boundaries of Three Main Grain Crops in China

The production of wheat, maize and rice accounts for more than 90% of the total grain production of China. Assessing the impact of climate warming on suitable planting regions, especially the potential northern planting boundaries of these crops, is therefore critical to help guide agricultural policymaking and further maintain food security. In this study, we analyzed the effect of climate warming on the potential northern planting boundaries of three specific crops (winter wheat, spring maize, double and triple rice cropping systems) during two time periods (1961–1990 and 1991–2020) using meteorological data from 2437 national weather stations. Results show that the potential planting boundaries of these crops present a northward movement and a westward expansion during the time period of 1991–2020 under the background of temperature increase compared with the time period of 1961–1990. Moreover, the boundaries of winter wheat and spring maize also show a trend of expansion to high-altitude areas (e.g., the Qinghai–Tibet Plateau). The average moving distance of these crops ranged from 20 km to 300 km. In general, the potential planting boundaries of winter wheat, spring maize, double and triple rice cropping systems changed significantly due to climate warming, and the suitable planting area was increased. Our study aims to provide a more recent and accurate result than those of previous studies, which is expected to strengthen our understanding of the effect of climate change on the potential northern planting boundaries of the three main grain crops in China.

A three-year measurement reveals that partial conversion from synthetic fertilizer to dairy manure increases cumulative nitric oxide emissions from a long-term experimental cropland

Conversion from synthetic nitrogen (N) fertilizer to organic manure has been well documented to effectively mitigate nitric oxide (NO) emissions in the current year or growing season. However, a clear understanding of NO emissions following long-term manure substitution is lacking. We hypothesize that soil conditions (particularly the accumulation of organic matter) following long-term manure substitution may stimulate NO emissions by providing more N substrates under favorable conditions. The primary aims of this study were to (1) quantify the long-term effects of manure substitution on NO emissions, and (2) identify the major regulating factors that contribute to the variations. Field measurements were conducted under summer maize-winter wheat rotations in a long-term fertilization experiment (since 1990) over three experimental years (from June 2016 to May 2019). The three treatments included an unfertilized control (CK), full synthetic urea in both crop seasons (NPK), and full synthetic urea in the maize season with 70% urea substituted by dairy manure in the winter wheat season (NPKM). Annual NO emissions varied from 0.10 to 0.22 kg N ha−1 and from 0.32 to 1.53 kg N ha−1 in CK and the fertilized treatments, respectively. We attributed the variations in annual NO emissions from the fertilized treatments to mean soil temperature by fitting a significant linear regression between the two variables (r2 = 0.681, p = 0.008). Seasonal NO emissions from NPKM treatment were lower (range, 2–66%, not always significant) and larger (range, 115–294%, not always significant) than those from NPK during the winter wheat and maize seasons, respectively. Annual NO emissions from NPKM treatment were 78% larger (range, 44–112%, not always significant) than those from NPK across the experimental years. Overall, this three-year field measurement revealed that cumulative NO emissions from NPKM treatment were significantly (p = 0.038) larger than those from NPK (2.73 versus 1.53 kg N ha−1). We concluded that long-term manure substitution for synthetic fertilizer in the winter wheat seasons did not mitigate, but rather stimulated cumulative NO emissions.

Climate Change Impacts on Agriculture and Water Resource Management in the North China Plain

North China Plain (NCP) is a main agricultural production region in China, dominated by a summer maize-winter wheat double cropping system. However, the grain yield highly depends on groundwater extraction to fulfil the irrigation demand. Additionally, the warming and drying tendency under climate change will further challenge water resource availability and agricultural productivity. This study applied modelled regional precipitation and temperature within the East Asia domain from the Coordinated Regional Climate Downscaling Experiment to derive climate change indicators and quantify future water resource utilisation. Results show a 30% increase in water irrigation demand (IWD) for growing maize in Jiangsu Province and a slight decrease in central Shandong Province. While for wheat, IWD decreases by 3-24% over the NCP except for northern Hebei Province and northern Shandong Province. Therefore, we suggest reducing agricultural fields for summer maize in southern NCP and winter wheat in northern NCP, and intensifying cultivation in central Shandong Province. Mann-Kendall statistics indicate an indistinct trend for IWD but a significant increase in crop evapotranspiration (ETc) during 2021-2050, highlighting the necessity to cope with rising ETc and apply varieties with high stress-tolerance to release irrigating water intensity under future climate change.

A Novel Prediction and Planning Model for the Benefit of Irrigation Water Allocation Based on Deep Learning and Uncertain Programming

Due to population growth and human activities, water shortages have become an increasingly serious concern in the North China Plain, which has become the world’s largest underground water funnel. Because the yield per unit area, planting area of crops, and effective precipitation in the region are uncertain, it is not easy to plan the amount of irrigation water for crops. In order to improve the applicability of the uncertainty programming model, a hybrid LSTM-CPP-FPP-IPP model (long short-term memory, chance-constrained programming, fuzzy possibility programming, interval parameter programming) was developed to plan the irrigation water allocation of irrigation system under uncertainty. The LSTM (long short-term memory) model was used to predict crop yield per unit area, and CPP-FPP-IPP programming (chance-constrained programming, fuzzy possibility programming, interval parameter programming) was used to plan the crop area and the effective precipitation under uncertainty. The hybrid model was used for the crop production profit of winter wheat and summer corn in five cities in the North China Plain. The average absolute error between the model prediction value and the actual value of the yield per unit area of winter wheat and summer maize in four cities in 2020 was controlled within the range of 14.02 to 696.66 kg/hectare. It shows that the model can more accurately predict the yield per unit area of crops. The planning model for the benefit of irrigation water allocation generated three scenarios of rainfall level and four planting intentions, and compared the planned scenarios with the actual production benefits of the two crops in 2020. In a dry year, the possibility of planting areas for winter wheat and summer corn is optimized. Compared with the traditional deterministic planning method, the model takes into account the uncertain parameters, which helps decision makers seek better solutions under uncertain conditions.

ПРОДУКТИВНІСТЬ ЯЧМЕНЮ ЯРОГО В КОРОТКОРОТАЦІЙНІЙ СІВОЗМІНІ ЛІВОБЕРЕЖНОГО ЛІСОСТЕПУ ЗАЛЕЖНО ВІД СИСТЕМИ УДОБРЕННЯ

The article analyzed the research results for 2016–2020 in a long-term stationary experiment, which was established in 2001 on typical chernozems with unstable humidity of the Left Bank Forest-Steppe of Ukraine, namely, on the Panfil research station National Science Center "Institute of Agriculture NAAS". The research results convincingly showed that 4-field crop rotations with 100 % saturation with grain crops (peas–winter wheat–maize for grain–spring barley) under different fertilization systems, such as control (without fertilizers), mineral (with the application of N60P60K60), organo-mineral (NPK + by-products of the predecessor), organic (by-products of the predecessor) fertilization systems, are most rational for highly specialized farms the in this area. The grain yield of spring barley, depending on the fertilization system, was in the range of 4.18–5.54 t/ha. Productivity of crop rotation area in a 4-field crop rotation for harvesting spring barley per 1 ha was: grain – 5.50–7.69 tons, fodder units – 7.48–10.47; digestible protein – 0.60–0.84 tons. The economic efficiency of growing spring barley in short-term crop rotation depending on the fertilization systems is: relatively net profit – 14.2–20.7 thousand UAH/ha, profitability – 122.6–197.0 %. Balanced short-term crop rotations with an optimal set and ratio of crops have been studied and introduced into production. Under market conditions, these crop rotations will ensure the production of competitive products and the preservation of soil fertility. Key words: crop rotation, rotation, fertilizers, productivity, yield, grain, fodder units, digestible protein, economic efficiency.

Phosphorus mobilization and improvement of crop agronomic performances by a new white-rot fungus Ceriporia lacerata HG2011.

Some soil microorganisms can mobilize unavailable phosphorus (P) in soils for plant use and increase P fertilizer efficiency. Thus, an abiotic P solubilization experiment and fungal incubation in solution and soil were conducted to investigate the mobilization of various P compounds by a new white-rot fungus Ceriporia lacerata HG2011. The crop agronomic performances were then evaluated in the winter barley-summer maize-winter wheat rotation field. Ceriporia lacerata HG2011 had a wide P mobilization spectrum and mobilized P by different mechanisms depending on P sources supplied in liquid culture. The chief mechanism employed by this fungus was the production of protons in mobilizing Ca3 (PO4 )2 , low-molecular-weight organic acids and other unknown substances in FePO4 and AlPO4 , phytase (an inducible enzyme in the presence of phytate) in phytate, and phosphatase in lecithin and ribonucleic acid, respectively. As a result of the large fungal biomass, P accumulated in the hypha should also be considered in the assessment of the fungal P mobilization, and not just only soluble inorganic P. As C. lacerata HG2011 colonized on and in the test soil, phosphatase and phytase activities were enhanced but pH decreased in the soil, leading to P mobilization. The application of this fungus mobilized soil P, increased crop P uptake and yields, and consecutively reduced P fertilizer use without yield sacrifices in the multiple crop rotation field. C. lacerata HG2011 showed a new use with respect to mobilizing soil P and reducing P fertilizer input in modern agriculture beyond medical purposes, environmental protection and biofuel production. © 2021 Society of Chemical Industry.

Designing productive, energy-efficient, and environmentally friendly production systems by replacing fallow period with annual forage cultivation on the Loess Plateau of China

Intensifying agriculture to meet the food requirements of the growing population could result in increased energy demands and production costs with accompanying environmental hazards such as greenhouse gas emissions. There is a need to develop environmentally friendly and economically viable cropping systems to maintain sustainable agriculture and livestock production. A 4-year field experiment (2015–2019) was conducted to investigate the energy requirements, energy efficiency, economic returns, and greenhouse gas emissions (GHGs) of six crop rotation systems. These crop rotations were established by intensifying the traditional winter wheat (Triticum aestivum L.) mono-cropping and winter wheat-maize (Zea mays L.) cropping rotation systems with forage rape (Brassica napus L.) or common vetch (Vicia sativa L.). The results showed that the average system eco-efficiency index (EEI) decreased by 63.0% and that GHGs increased by 43.3% when traditional cropping systems were intensified with forage rape. Compared to the rotations that included forage rape, the rotation with common vetch had a 67.5% higher average EEI and an 85.3% higher energy efficiency. Replacing the summer fallow period with common vetch increased the average economic return and forage yield by 22.9% and 4.41 t ha−1. The results suggested that planting common vetch during the summer fallow period may be a productive and economically sound practice that has low energy requirements. This practice could benefit agriculture by providing cleaner, more energy-efficient production under a scenario of global environmental pollution and constrained resources. Crop selection by farmers that is based on energy requirements they relate to crop market values and GHGs is crucial for the profitability and eco-efficient incorporation of forage crops into cropping systems. Further study to include other important factors such as acidification and eutrophication is recommended for a comprehensive evaluations of environmentally friendly production systems.