Partial root-zone irrigation (PRI), as a water-saving technology, offers advantages for enhancing crop salt resistance in saline land. A key challenge in saline farmland is balancing the dual objectives of reducing salt stress by leaching salts and increasing water use efficiency (WUE). A two-year field experiment was conducted employing a split-plot design in saline land in North China Plain. The main-plot treatment is irrigation patterns, including conventional irrigation (CI), fixed root-zone irrigation (FRI) and alternate root-zone irrigation (ARI), while the subplot treatment is irrigation rate such as 80 mm (W1) and 160 mm (W2). The study aimed to assess the effects of PRI and irrigation rate on maize salt resistance and WUE. Increasing irrigation input reduced stress and increased transpiration rate (Tr), yield, and profit. Compared to CI, FRI and ARI decreased Tr and malondialdehyde (MDA) content, while increased root indices, proline content, K+/Na+ ratio, photosynthetic rate (Pn), yield, profit, and WUE. With FRI, irrigated roots enhanced yield by reducing soil salt content and promoting root growth, whereas non-irrigated roots improved yield by enhancing crop Na+ /K+ ratio. Compared with FRI, ARI promoted balanced root development in both root zones, and increased Pn, yield and WUE. Compared to the CI with 160 mm irrigation water, the ARI with 80 mm increased proline content and K+/Na+ ratio, decreased evapotranspiration (ET) by 15%, maintained yield and profit (p > 0.05), and improved WUE by 19%. In conclusion, ARI achieves a trade-off between improved stress resistance and water saving, providing a viable strategy to address limited freshwater resource in saline land.

The physico-chemical mechanisms underlying the effect of tillage on soil organic carbon (SOC) sequestration are not fully understood, especially those involving soil macropores and iron-aluminum (Fe-Al) oxides. A long-term field experimental setup from 2002 was carried out to investigate the effects of two tillage practices (subsoiling, SS, and rotary tillage, RT) on macropore system, Fe-Al oxides distribution, aggregate stability and SOC sequestration. Soil macropores were evaluated by X-ray computed tomography. Results showed that SS increased 10-40 cm soil profile total macroporosity, especially > 2000 & micro;m macroporosity (33.9-191.3 %), surface area (67.8-100.9 %), volume (51.6-127.6 %), and fractal dimension (3.3-6.4 %), as compared with RT. SS also improved pore throat parameters (coordination number, length, radius, and volume) in 20-40 cm soil depth. Consequently, the proportion of 20-40 mean weight diameter (MWD) of SS increased by 12.4 % as compared with RT. Compared to RT, SS also increased the free Fe-oxides, free Al-oxides, complex Fe-oxides, and complex Al-oxides by 8.3-10.7 %, 14.0-24.3 %, 8.8-13.8 %, and 7.8-11.0 %, respectively, which play a crucial role in stabilizing SOC. Mantel analysis showed macropore parameters (>2000 & micro;m macropore, surface area and volume), pore throat parameters (length, volume) and Fe-Al oxides exhibited strong correlations with SOC (p < 0.01). Consequently, SS increased 20-40 cm SOC content by 24.4 % and 0-40 cm soil profile SOC stocks by 18.7 %. Our study demonstrates that SS concurrently optimizes soil physical architecture and enriches reactive mineral phases. These findings provide a basis for understanding the coupled biogeochemical and biophysical processes driving SOC persistence, offering empirical support for SS as a climate-smart agricultural practice.

To make agricultural systems sustainable in terms of their greenness and efficiency, it is essential to optimize the tillage and fertilization practices. To assess the effect of tilling and fertilization practices in the wheat-maize cropping systems, we carried out a three-year field experiment designed to quantify the carbon footprint (CF), and energy efficiency of the cropping systems in the North China Plain. As the study parameters, we used four tillage practices (no tillage (NT), conventional tillage (CT), rotary tillage (RT) and subsoiling rotary tillage (SRT)), and two fertilizer regimes (inorganic fertilizer (IF), and hybrid fertilizer with organic and inorganic components (HF)). Our results indicated that the most prominent energy inputs and greenhouse gas (GHG) emissions could be ascribed to the use of fertilizers and fuel consumption. Assuming the same fertilization regime, ranking the tillage patterns with respect to the value of the crop yield, the profit, the CF, the energy use efficiency (EUE) or the energy productivity (EP) for either wheat or maize always gave the following result: SRT>RT>CT>NT. For the same tillage, the energy consumption associated with HF was higher than IF, but its GHG emissions and CF were lower while the yield and profit were better. In terms of the overall performance, tilling is more beneficial than NT, and reduced tillage (RT and SRT) are more beneficial than CT. The fertilization regime with the best overall performance was HF. Combining SRT with HF has significant potential for reducing CF and increasing EUE, improving the sustainability. Adopting measures promoting these optimizations can help overcome the challenges posed by lack of food security, energy crises and ecological stress.

Ridge and furrow (RF) crop cultivation systems with crops planted in furrows or on ridges, modifies soil properties by altering field topography and optimizing water and N fluxes as well as temperature regime. The RF cultivation can be used to mitigate environmental stresses that restrict crop production, such as drought, low temperatures, high soil bulk density, and even flooding. There is broad diversity of RF systems, each of which is tailored to specific objectives under local climatic and soil conditions. Despite the worldwide spread and importance of these cultivation systems, there is no clear systematization of RF fields or evaluation of changes in water and N fluxes compared with flat cultivation. Here, we performed a meta-analysis and literature review to provide a comprehensive characterization of RF cultivation on the basis of the main aims, and management of water and nutrients. The most important difference between RF and flat cultivation practices is the complete change in water infiltration and fluxes in soils as well as associated nutrient losses, especially nitrogen (N). Furrow planting involves the collection of rainwater in the rooted zone, providing an advantage under droughts. Increasing the N content in rooted soil is the main advantage of ridge planting, but the low soil moisture in ridges may limit N availability. Covering ridges with mulch optimizes water redistribution and reduces N leaching, NH3 volatilization and N2O emissions, which in turn increases the benefits of RF cultivation. With a broad range of crops, RF cultivation raises yield and N uptake, and generally increase N use efficiency (NUE; yield / N uptake) and water use efficiency (WUE; yield/evapotranspiration (ET)), and reduce ET, compared with flat planting. RF cultivation has good adaptability to climate change, effectively addressing various environmental stresses. Moderate temperatures maximize the rate of yield increase under RF cultivation. Furrow planting can more effectively increases yields in dry climates than in wet climates. Under humid conditions, ridge planting retains moisture in the ridges, thereby increasing WUE, NUE and yield, while reducing waterlogging. Factors such as microtopography, mulch coverage, stemflow, irrigation, climate, and plant uptake influence water and N redistribution, vertical and lateral infiltration. Lateral infiltration is critical in regulating soil moisture and water storage in the root zone, thereby reducing water loss and raising water uptake by roots. Preventing fertilizer N loss through water infiltration and maintaining N availability increase NUE and WUE, while reducing N losses. Modelling and upscaling of water and N fluxes in RF systems are highly challenging. Future research should focus on the redistribution of factors limiting crop growth via RF topography and mulching as well as to consider the specifics of soil surface modification.

Fusarium head blight (FHB), caused by Fusarium graminearum, is a predominant disease of wheat. Due to the lack of disease-resistant germplasm, chemical control is an important means to control wheat scab. Volatile substances produced in near-isogenic wheat lines were detected after inoculation with F. graminearum, and 4-propylphenol, which appears in FHB-resistant lines, was identified. In vitro and in vivo antifungal activity tests demonstrate that 4-propylphenol effectively inhibits the mycelial growth of F. graminearum. Metabolomics analysis showed changes in glutathione metabolism, indicating that 4-propylphenol triggered reactive oxygen species (ROS) stress. This was consistent with the increasing ROS levels in Fusarium cells treated with 4-propylphenol. Further results demonstrated that excessive accumulation of ROS induced DNA and cell membrane damage in the mycelium. Moreover, 4-propylphenol showed different degrees of inhibition against other soil-borne pathogens (fungi and oomycetes). These findings illustrated that 4-propylphenol has broad spectrum and high antifungal activity and should be considered for use as an ecological fungicide.

Irrigation patterns and K fertilization are the key measures used to improve the salt tolerance of crops in saline land. A pot experiment was carried out to assess the effects of partial root-zone irrigation and K fertilization on maize in saline land. For the study parameters, we used a split plot design with three irrigation treatments (conventional irrigation (CI), fixed root-zone irrigation (FRI) and alternate root-zone irrigation (ARI)) and two K application rates (0 (K0) and 120 (K1) kg K2O ha(-1)). Compared with the CI treatment, the FRI and ARI treatments reduced the transpiration rate (Tr) and MDA content but increased the root length density (RLD), root surface density (RSD), root volume density (RVD), root dry weight density (RDWD), proline content, plant K/Na ratio, photosynthetic rate (Pn), yield, water use efficiency (WUE) and K use efficiency (KUE). Compared with the FRI treatment, the ARI treatment increased RLD, RSD, RVD, RDWD, the Tr, the proline content, the plant K/Na ratio and the Pn but decreased the MDA content; these factors increased yield, WUE and KUE. K application decreased the MDA content; improved root growth; and increased the stomatal conductance, Tr, proline content, Pn, yield and WUE. Of all the treatments, the ARI-K1 treatment maximized RLD, RSD, RVD, RDWD, the Pn and yield while minimizing the MDA content. Therefore, ARI combined with K application can maximize resistance to salt stress and osmotic stress, delay senescence, and improve photosynthesis, yield and WUE.

In the North China Plain (NCP), the deployment of sub-optimal crop management methods has resulted in low maize grain yields and significant environmental costs arising from a low N partial factor productivity (NPFP) and a rampant greenhouse gas emission intensity (GHGi). We hypothesize that in-situ analysis of the grain yield, NPFP and GHGi at local farms might contribute to improving the crop yield, as well as the environmental sus-tainability of maize production systems. In this study, we investigated the maize production systems deployed at 1574 local farms in the NCP, and quantified the total yield gap (defined as the difference between the yield potential as simulated by the DSSAT-CERES-Maize model and the actual yield achieved by farmers) and the exploitable yield gap (defined as the difference between the attainable yield as calculated by using the Boundary Line Function (BLF) analysis and the average actual yield achieved by farmers). By combining the results from crop modelling, farmer survey data, and on-farm trials, we were able to identify the dominant factors driving the variability in summer maize yield, NPFP, and GHGi. The results revealed that the average grain yield for summer maize in the NCP was 8.3 t ha-1, and that the total and exploitable yield gaps were 4.9 t ha-1 and 3.0 t ha-1, respectively. The average NPFP was 41 kg kg-1, which amounts to 54% of the attainable NPFP. The average GHGi was 463 kg CO2 eq t-1 grain, which constitutes an increase of 119% over the attainable GHGi. The main factors driving yield include the harvest date and the planting density, and the main factors driving NPFP and GHGi include the N, P and K fertilization rate, where it should be noted that these factors exhibit regional dif-ferences. After testing our optimized integrated agronomic management measures in the field experiments, we could confirm that it is possible to narrow the yield gap by 2.7 t ha-1, increase NPFP by 38%, and reduce GHGi by 28%. Obviously, optimizing integrated agronomic management has a great potential for narrowing the yield gap and improving the sustainability of agricultural production.

Subsoiling can affect the stability of soil aggregates and soil organic carbon (SOC) sequestration. However, the effects of subsoiling depth on soil aggregation and SOC storage in different aggregates remain largely unknown. In this study, we evaluated the impact of subsoiling in the North China Plains (NCP) on soil aggregate stability and aggregate-associated SOC. Tillage practices included conventional tillage to a depth of 25 cm (CT25) and subsoiling with three depths of 30 cm (SS30), 35 cm (SS35), and 40 cm (SS40). SS35 and SS40 had significantly higher proportions of macro-aggregates in the 0–20-cm soil than CT25 (p < 0.05). Mean weight diameter of wet aggregates in the 0–20 cm is significantly higher (p < 0.05) under SS30, SS35, and SS40 by 39.5

Applying plant-derived fungicides is a safe and sustainable way to control wheat scab. In this study, volatile organic compounds (VOCs) of wheat cultivars with and without the resistance gene Fhb1 were analyzed by GC-MS, and 2-phenylethanol was screened out. The biocontrol function of 2-phenylethanol on Fusarium graminearum was evaluated in vitro and in vivo. Metabolomics analysis indicated that 2-phenylethanol altered the amino acid pathways of F. graminearum, affecting its normal life activities. Under SEM and TEM observation, the mycelial morphology changed, and the integrity of the cell membrane was destroyed. Furthermore, 2-phenylethanol could inhibit the production of mycotoxins (DON, 3-ADON, 15-ADON) by F. graminearum and reduce grain contamination. This research provides new ideas for green prevention and control of wheat FHB in the field.

Energy analysis of agricultural production is essential to promote sustainable agricultural development. However, the current research on agricultural sustainability in the North China Plain (NCP) mainly focuses on improving grain yield and nitrogen utilization efficiency (NUE), while there are few studies on their energy utilization. This study evaluated the energy utilization characteristics of different yield and NUE category farms and three integrated agronomic approaches in the NCP based on farmer surveys and farm experiments. Compared with the average level of smallholder farms, the net energy (NE) and the energy utilization efficiency (EUE) of high-yield and high-NUE group farms increased by 17% and 22%, respectively, the NE of the high-yield and low-NUE group farms increased by 9%, but the EUE decreased by 12%. The control experiment showed that the NE and EUE achieved using high-yield and high-efficiency agronomic practice (HH) increased by 34% and 18% compared with achieved using traditional farmers' practices, respectively. In conclusion, there is a great opportunity to improve the NE and EUE of the maize production in the NCP by optimizing agronomic practices. Popularizing HH technology by improving agricultural technology extension services is of great significance for improving farmers’ EUE and promoting sustainable agricultural development.

CONTEXT: The maize production sector in the North China Plain (NCP) is facing the dual pressures of having to increase its grain yield and improve its environmental sustainability. Evaluating the yield gap and ascertaining the factors that limit the grain yield might suggest new approaches to address these challenges.OBJECTIVE: The objective of this study was to estimate the yield potential and the yield gap associated with smallholdings in the NCP using a hybrid method; to determine the factors driving the grain yield and corresponding sustainability indicators; and to evaluate to what degree the introduction of scientifically developed high-yield and high-efficiency agronomic practices (HH) to smallholders might help to sustainably narrow the exploitable yield gap.METHODS: Combined with diagnostic smallholder survey and crop modeling exercise to characterize and decompose yield gaps. With survey data, we assessed the existing variation with respect to various key perfor-mance indicators and carried out a number of controlled comparative experiments at farms (HH vs traditional farming practices (FP)) in multiple locations.RESULTS AND CONCLUSIONS: Our work revealed the total and exploitable yield gap were 4.3 t ha-1 and 1.8 t ha-1 for rainfed summer maize, and 4.4 t ha-1 and 1.9 t ha-1 for irrigated summer maize across the entire NCP, indicating a large potential for yield improvements. The main factors driving the yield from the entire region were the planting density, the fertilization frequency, and the irrigation frequency. It should be noted that farmers whose yield was in the top 25% bracket of the yield distribution also achieved relatively high utilization efficiencies with respect to N, P, and K fertilizers (15%, 16%, and 16% above the average values, respectively) while their profit was 41% above average. Comparative experiments conducted over several seasons support insights from surveys by demonstrating that major gains in grain yield (+30%), the fertilizer utilization effi-ciency (+37% in N partial factor productivity, +48% in P partial factor productivity, and + 32% in K partial factor productivity) and economic profit (+62%) are achievable through the adoption of HH.SIGNIFICANCE: Through a hybrid method, our results suggest that agricultural intensification can be achieved in the NCP without having to trade off yield against environmental sustainability. Evidently, smallholders can simultaneously improve their maize grain yield, fertilizer utilization efficiency, and profit by adopting straightforward non-disruptive optimizations of their agronomic practices.

In order to improve the grain yield of food crops, which is necessary to ensure food security, it is crucial to narrow existing yield gaps. Quantitative analyses of crop yield gaps can provide theoretical support for ascertaining the primary cause of these yield gaps, and then it can be used to increase the grain yield. We evaluated the size and characteristics of the summer maize yield gap in the North China Plain by combining crop models, farmer surveys, and farm experiments. We simulated the summer maize population of farmers’ yield level, attainable yield level and potential yield level by establishing three cultivation modes: traditional farming practices (FP), established high-yield and high-efficiency practices (HH) and super-high-yield practices (SH), and introduce the cultivation relying solely on the basic soil fertility (BSF) to reveal the impact of environmental and management factors on yield gap. We explored the driving factors causing observed variations of yield gaps through a quantitative analysis of several additional parameters that are commonly used to characterize the efficiency of the maize production process, including the contribution rates of dry matter and harvest index to grain yield, the radiation interception rate and the radiation conversion efficiency. Our results show that the total yield gap based on farmer surveys and crop models was 4.9 t ha-1, accounting for 37% of the potential yield, of which 46% was exploitable. The total yield gap based on the farm experiments was 3.9 t ha-1, accounting for 30% of the potential yield, of which 69% was exploitable. The grain yield of FP significantly positively correlated with the grain yield of BSF, HH and SH. The contribution rates of dry matter and harvest index to grain yield of FP treatment were 45.7% and 54.3%, respectively. With the increase of yield level, the contribution rate of dry matter increased and the contribution rate of harvest index decreased. In summary, we found a sizeable total yield gap in summer maize in the North China Plain, and a considerable part is exploitable. Optimizing integrated agronomic management has a great potential for closing the exploitable yield gap. Narrowing the yield gap requires a synergistic increase in the contribution rate of dry matter and harvest index to grain yield, but a substantial increase in dry matter is more important. At present, narrowing the exploitable yield gap requires synergistic improvement of radiation interception rate and radiation conversion efficiency to increase the dry matter of maize population. In the future, the regulation measures aiming at narrowing the unexploitable yield gap should further focus on improving the radiation conversion efficiency.

Aiming to optimize the nitrogen (N) application rate during maize production and to improve the production process, we carried out a 2-year field study included 5 N application rates and five recommended production patterns (maize grain (P1); maize grain and straw (P2); the whole maize plant (WMP) forage (P3); grain, straw and milk (P4); WMP forage and milk (P5)). The results showed that reducing N application rate from 400 to 300 kg N ha(-1) maintained the maize yield and the forage quality for different patterns. Compared to 400 kg N ha(-1), 300 kg N ha(-1) increased the economic profit and the economic efficiency of N fertilizer (EEN) of all patterns. Compared to the optimal N rate with the same pattern, the 75% of optimal N rate caused in a 2% decrease in economic profits, but saved N fertilizer by 25% and increased EEN by 30%; the 75% of optimal N rate saved N fertilizer by 50% and increased EEN by about 40%, but caused in a 8-9% decrease in economic profits. Therefore, the 75% of optimal N rate was optimal in improving maize production. When the economic profits from the five patterns were optimized based on regression equations, ranking the optimal N rates and economic profits in increasing order led to the following result: P1 < P2 < P3 < P4 < P5. The extending maize production chain from P1 to P5 improved economic profits, and increased the optimal N rate, improving the productivity of N fertilizer.

The N application used for the production of forage affects environment stress. The N application rate used for the production of the whole maize (Zea mays L.) plant (WMP) affects the produced feed and environment. We carried out a 2-year field experiment aiming to measure how N application rates affect WMP forage production, and estimated the impact on the environment. Five N application treatments (0, 100, 200, 300 and 400 kg N ha−1) were included in our study. The results showed that N application improved forage yield, achieving a higher economic and ecological profit. After reaching a certain optimal rate, however, increasing the N rate further no longer increased the yield and quality of WMP forage, but instead greatly increased estimated N losses, thereby reducing ecological profits. The comprehensive benefit of the optimal N rate was ordered: the optimal N rate that maximized agronomic profit > that maximized economic profit > that maximized ecological benefit. The optimal N rate maximizing ecological profit was lower by 21% and 37% than that maximizing economic profit and forage yield, respectively. N application rates with the highest ecological profit (USD 2478 ha−1 in 2017 and USD 2448 ha−1 in 2018) were 248 and 245 kg N ha−1, respectively, in 2017 and 2018. The optimized N rate that maximized ecological profit maintained the economic profit while reducing N fertilizer input and associated N losses; it also carried a lower economic and ecological cost due to estimated N losses. Ecological criteria, which combine economic profit and economic losses due to their environmental impact, are more efficient than agronomic or economic criteria when used to provide guidance for WMP forage production. Therefore, in WMP forage production, optimizing N application rate by ecological criteria could maintain a high forage yield and economic profit, but greatly reduce input costs and ecological stress, maximizing ecological profit.

Whole maize (Zea mays L.) plant (WMP) silage is an important feed for dairy cows. In northern China, yields and feed quality are adjusted by modifying the planting density. This paper is the result of a 2-yr field study aimed at determining the effects of plant density on maize silage yield and quality. Five planting densities (52,500, 60,000, 67,500, 75,000, and 82,500 plants ha(-1)) were used. The results showed that plant height and leaf area increased, while stem diameter, chlorophyll, and leaf area per plant decreased with increasing plant density. Both the biomass yield, expressed as the dry matter (DM) per ha, and the utilizable energy yield improved when the density was increased from 67,500 to 75,000 plants ha(-1), but increasing the density further reduced these values. The highest observed DM were 17,734 kg ha(-1) and 17,055 kg ha(-1), and total net energy for lactation (NEL) were 104.1 GJ ha(-1) and 97.0 GJ ha(-1) in 2017 and 2018, respectively. Feeding quality generally decreased with increasing plant density. The plant density which obtained the highest biomass yield was not the same as the plant density for optimizing feeding production. Compared with the highest predicted DM yields, the highest predicted total NEL yields increased the grading index by 4-9%, which indicated an improvement in forage quality. Total NEL yield is more efficient for the purpose of evaluating the productivity of WMP forage than biomass yield.

A 2-year field experiment was carried out to determine the combined effects of planting density and N application rate on the agronomic, economic and environmental benefits of maize production. We set three planting densities (67,500, 75,000 and 82,500 plants ha−1) and five N application rates (0, 100, 200, 300 and 400 kg N ha−1). Increasing planting density improved water use and N uptake, but reduced nitrate in soil. More N inputs over optimal rates decreased NUE and increased nitrate in soil. Compared to the modelling combination of planting density and N application rate that achieved the maximum yield and profit, the modelling combination that achieved the maximum net productive value retained yield and profit, but it used an N application rate that was 12–20% lower, and resulted in an 11–25% decrease in nitrate in soil. The optimal modelling combinations, which were a planting density of 74,387 plants ha−1 and an N application rate of 302 kg N ha−1 in 2017, and 73,528 plants ha−1 and 311 kg N ha−1 in 2018, achieved the maximum net productive values of 2620 $ ha−1 in 2017 and 2693 $ ha−1 in 2018. When the combinations maximized yield and profit, the environmental effect was more sensitive than that of the yield and profit. The optimal combination of planting density and N application rate curtailed N pollution without the great cost of yield and profit, which balanced the agronomic and environmental effect on maize production.

To meet the food demands of a growing population, the maize production systems deployed by smallholders in China have tended towards extremely intensive planting and excessive use of fertilizers, which have caused serious environmental impacts. This study investigated the balance between the maize yield and nitrogen (N) input in the North China Plain (NCP), which is one of the most important grain-producing region in China. Our study compared yield simulations generated by the DSSAT-CERES-Maize model with actual data from a number of multi-site field experiments and an extensive household surveys encompassing 1671 farmers. The smallholders' maize cultivars, plant population, and amount of N input on the crop yield and how these affects the economic benefits were analyzed. The results showed that the average traditional farming methods' yield was 72% of the attainable yield, which means that farmers have ample room to improve their yields. We also found that the maize yields varied widely between farmers, and that most of them applied excessive amounts of N but failing to achieve an optimal yield due to poor fertilization management techniques. The study found that the economic benefits achieved by the farmers were low, but after deploying high-yield (HY) methods, the yield was increased by 34.9% and the economic benefits by 14.4%. The greenhouse gas (GHG) emissions associated with the traditional farming methods were high and could potentially be reduced by 48.6%. All in all, farmers should be given guidance on how to appropriately increase the plant population, reduce the input of N fertilizer, and optimize farmland management measures, so that China can achieve intensive but sustainable agricultural production at a lower environmental cost. It was concluded that there are still numerous biological and abiotic factors that restrict production increases by smallholders. These factors vary from region to region and require further investigation.

The present study was carried out in 2016-2017 to assess the effect of subsoiling depth on the soil bulk density, stability of soil structure, soil physical properties and summer maize yield based on a field experiment started in 2015. Four tillage depths were studied: conventional tillage 25 cm (CT25); subsoiling tillage 30 cm (ST30); subsoiling tillage 35 cm (ST35) and subsoiling tillage 40 cm (ST40). The results showed that at the 20-50 cm depth ST30, ST35 and ST40 decreased the mean soil bulk by 4.59, 7.13 and 8.27%, respectively, and at the 0-40 cm depth reduced soil compactness by 17.62, 23.63 and 36.42%, respectively, as compared to CT25. ST40 reduced soil compactness in the 0-40 cm soil layer under conditions of relative drought (during the maize season growing season of 2016), ST35 and ST40 increased macroaggregates (> 0.25 mm), improved the stability of the aggregate structure (geometric mean diameter and mean weight diameter) (20-40 cm), increased soil water storage capacity at 40-60 cm and increased maize yield by 7.89% and 8.91%, respectively. Considering the improvement of soil properties and crop yield, ST35 was the optimum method to increase maize yield and modulate soil physical properties in the North China Plain.

Water resources are increasingly scarce, and droughts are frequent in the Huang-Huai-Hai Plain of China. There is an urgent need for developing water-saving technologies for winter wheat production in this region. Field experiments were carried out in silty loam soil from 2012 to 2014. Based on the same water condition in seeding period and the normal emergence of winter wheat, five supplemental irrigation (SI) regimes differing in the timing of SI were established. Crop development was categorized using the Zadoks scale. T1: no irrigation after emergence; T2: SI at jointing (4th node detectable, Z34); T3: SI at pre-wintering (average daily temperature drops to about 2 degrees and the wheat plant basically stops growing) and jointing; T4: SI at jointing and anthesis complete (Z69); T5: SI at pre-wintering, jointing and anthesis complete. The results showed that SI brought the soil water content in the 0-20 cm profile to 100% field capacity at the pre-wintering, jointing and anthesis complete stages of winter wheat, mainly improving the water supply condition in the 0-40 cm soil layer. Compared with no irrigation after emergence, SI at jointing and anthesis complete significantly increased grain yield by increasing the spike number, kernel number and grain weight. SI at the pre-wintering stage can improve grain number and yield under the condition of no SI at anthesis complete (comparing T3 with T2), but had no significant effect on grain yield when SI was supplied at jointing and anthesis complete (comparing T5 with T4), and even worse, the irrigation water use efficiency decreased. The decrease of water supply before anthesis complete significantly reduced the dry matter accumulation and photosynthetic rate at anthesis but promoted the translocation of photosynthates to the plant ear. SI at anthesis complete is advantageous for the assimilation of carbohydrates in the middle and late grain filling stage and for the distribution of those carbohydrates from vegetative organs to grain. These results indicated that SI at jointing and anthesis complete was conducive to coordinating the relationship between photosynthesis and photosynthates retranslocated after anthesis, and may improve the harvest index, grain yield and water use efficiency.

Sustainable nutrient management requires redistribution of livestock manure from nutrient‐excess areas to nutrient‐deficit areas. Field experiments were conducted to assess agronomic and environmental effects of different poultry litter application methods (surface vs. subsurface) and timings (fall vs. spring) in a potential manure‐importing region in the Chesapeake Bay Watershed in the United States. Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz at www.certifiedcropadviser.org/certifications/self‐study/798 .