Long-term straw return is a key measure for enhancing soil organic carbon (SOC). However, the mechanisms by which prolonged straw return influences SOC accumulation through soil microbial community regulation according to maize growth stage remain unclear. This study was based on a long-term field plot experiment in which soil biochemical properties were measured at three critical maize growth stages—jointing (V12), tasseling and silking (R1), and milk (R3)—under straw return practices of 5, 7, and 9 years, as well as under a no-straw-return control. Effects on SOC content, microbial communities, and their functional attributes were investigated. Long-term straw return generally increased the contents of SOC, microbial biomass carbon (MBC), total nitrogen (TN), available phosphorus, and total phosphorus; however, the response varied according to duration of straw return. Straw return duration and maize growth stage jointly shaped microbial community structure; fungal diversity showed greater sensitivity to growth stage variation. During growth progression, the relative abundance of Actinobacteria increased, enhancing soil capacity for straw decomposition. Predictive functional profiling suggested that long-term straw return can enhance bacterial chemoautotrophic pathway activity and aerobic nutrient-related processes, while promoting straw assimilation and utilization. Fungal communities, primarily characterized by saprotrophic nutrition, were predicted to play major roles in the potential decomposition of cellulose, hemicellulose, and lignin, thus regulating soil carbon cycling. Structural equation modeling revealed that a 7-year straw return strategy achieves optimal SOC sequestration by positively regulating fungal communities; MBC and TN served as key mediating factors in SOC enhancement. This study establishes an optimized field management strategy for straw return in black soil regions and provides theoretical support for advancing sustainable agriculture through coordination of the straw–microorganism–SOC interaction. However, considering soil type specificity and environmental variability, further research across diverse agroecosystems is required to verify the broader applicability of these mechanisms.

Soil salinization in farmland is a critical factor limiting global soil health, food security, and ecosystem productivity. Biochar has recently shown great application potential in agricultural fields in many domains, such as soil structure improvement, carbon sequestration, and reductions in greenhouse gas emissions. Here, a meta-analysis of 113 published papers was carried out to quantify the effects of biochar on the remediation of saline-alkali soil and crop yield in terms of climatic conditions and agricultural management, with the aim of determining the optimal agricultural management strategy for biochar application to saline-alkali soils. The results show that adding biochar to saline-alkali farmland increases the TOC in soil (44.0%) and water utilization efficiency (8.7%), and decreases soil salinity (−9.6%), certain salt ion contents in particular (Na+, 12.5%; Cl−, 23.4%; HCO3−, −17.7%), along with soil pH (−2.2%), resulting in a 20.8% higher crop yield. Applying shell biochar at a rate of 10–20 t·ha−1 for monoculture is the most promising way to bolster the yield in severely saline-alkali irrigated farmland. However, adding biochar raises CO2 and CH4 emissions by 9.8% and 31.6%, respectively, but lowers the emission of N2O by 29.4%. These findings provide scientific recommendations for the sustainable application of biochar in saline-alkali farmland areas worldwide.

Drip irrigation (DI) could effectively reduce greenhouse gas (GHG) emissions from dryland agriculture, helping mitigate global warming. Here, we performed a meta-analysis to quantify the effects of dryland DI on GHG emissions under different climatic conditions, soil conditions, and agricultural management practices. The results showed that DI can reduce GHG emissions by decreasing the soil moisture content (i.e., water-filled pore space). The N2O and CO2 emissions decreased by 29.2% and 6.1%, respectively, and global warming potential decreased by 18.7%, but CH4 emissions increased by 9.7%-14.0%. When the irrigation scheduling was higher than 70% and the nitrogen application was 180-300 kg ha-1, shallow buried DI with water flow controlled below 2 L hr-1 was the best strategy for emission reduction. In addition, compared with traditional irrigation methods, DI demonstrates greater long-term effectiveness in reducing N2O and CO2 emissions. We also found that greenhouse vegetable production combined with DI has great potential for reducing GHG emissions. This study provides evidence for the application of DI technology to reduce global dryland GHG emissions.

Continuous monocropping, intercropping, and crop rotation are common planting patterns in the black soil region of Northeast China, but it remains unclear which pattern is more advantageous for simultaneously improving rhizosphere soil biological properties and enhancing crop yield. Therefore, we established a field experiment with three maize cropping systems (continuous maize cropping, maize-soybean rotation, and continuous maize-soybean intercropping) and investigated soil biological properties and yields over five consecutive years. The maize yield (per planted hectare) under the rotation treatment was 12.37 % and 8.38 % higher than that under intercropping and continuous cropping, respectively. The rotation treatment also effectively stabilized the soil pH and enhanced soil nutrient contents, particularly the total nitrogen (TN) content, which accumulated by 39.88 % over five years under the rotation treatment. Additionally, crop rotation improved rhizosphere soil catalase, urease, and acid phosphatase activities by 2.83 %-12.88 %, and boosted rhizosphere soil bacterial community richness and diversity by 12.79 %-16.93 %. Bradyrhizobium exhibited the highest relative abundance under crop rotation, and the enrichment of this genus significantly elevated bulk soil nitrogen content and maize yield. In contrast, the enrichment of Nocardioides and Pseudarthrobacter reduced maize yield. Our findings offer a theoretical basis for the optimal management and sustainable development of intensive crop cultivation in the black soil region of Northeast China.

AimsSoil nitrogen is recognized as a vital nutrient influencing soybean growth and yield. Hence, a comprehensive understanding of the intricate connections between shifts in nitrogen patterns and the behaviors of soil microbial communities and crucial enzymes in the nitrogen cycle is highly desirable.MethodsThis study involved a rotation positioning experiment spanning 11 years (2012-2022). Measurement of soil microenvironment changes during the mature period for three consecutive years (2020-2022). Based on these groups, the study delved into the alterations in nitrogen patterns within the soybean rotation, examining both soil enzyme activity and microbial community dynamics.ResultsLong-term crop rotation and nitrogen application led to an increase ranging from 2.16% to 108.34% in the nine components of soil nitrogen. Gemmatimonas, Rhodanobacter and Mrakia could effectively increase soil nitrogen content and had a reciprocal promotion with soil urease and protease activities, whereas Blastococcus and Fusarium increased soil nitrogen loss. Changes in inorganic nitrogen and total organic nitrogen resulting from crop rotation enhanced the abundance of soil microbial communities, reducing their diversity.ConclusionsOverall, findings demonstrate that long-term crop rotation and nitrogen management significantly influence soil nitrogen dynamics, microbial community structure, and enzyme activities. Thus, enhancing the functional capacities of soil microbial communities to support sustainable soybean production.

The impact of excessive rainfall or waterlogging on maize growth and yield have been widely studied, but the effects of planting density and N management under waterlogging remain unknown. We observed the changes in maize yield caused by excessive rainfall via a short-term experiment (2017 to present) in Changchun (125 degrees 14.231 '-125 degrees 14.914 ' E, 43 degrees 56.603 '-43 degrees 57.274 ' N), China. The experiment was conducted at four planting densities (45,000, 60,000, 75,000 and 90,000 plants/ha) and three nitrogen (N) rates (120, 180, and 240 kg/ha). The objective was to explore the effect of excessive precipitation on maize yield through changes in maize growing conditions, and the uptake, allocation, and utilization of N under different planting densities and N rates from 2019 to 2022. The precipitation during the whole growth period of maize in 2019 (542.9 mm) and 2020 (560.0 mm) was normal, while it was excessive in 2021 (829.10 mm) and 2022 (953.56 mm), especially during the vegetative stage from V12 to VT (355.60-482.10 mm). Excessive rainfall negatively affected the growth, photosynthetic characteristics (Pn: -20.00 %, SPAD: -50.50 %), absorption (-56.86 %), distribution (-15.83 %), N utilization efficiency (NUE: -29.69 %), and grain yield (-44.67 %) of maize. Our results indicate that yield loss was minimized (-22.88 %) when the planting density was appropriately reduced (from 75,000 to 60,000 plants/ha) and the N rate was increased from 180 to 240 kg/ha. The effect of different waterlogging durations on yield exhibited a significantly negative linear relation (R-2 > 0.80). This study revealed the physiological mechanism of the sustained effects of excessive rainfall on maize growth and yield. Waterlogging significantly affected the SPAD of maize (p < 0.01, R2 = 0.04), resulting in insufficient kernel N content (p < 0.001, R2 = 0.16) and decreased NUE (p < 0.001, R2 = 0.48). These factors significantly affected yield and exerted a significant negative correlation with planting density (p < 0.05). Our findings improved understanding of planting density and N management for growth and yield of maize under excessive rainfall conditions in midhigh latitude agriculture areas of the world.

Crop rotation increases crop yield, improves soil health, and reduces plant disease. However, few studies were conducted on the use of intensive cropping patterns to improve the microenvironment of saline soils. The present study thoroughly evaluated the impact of a three-year maize-peanut-millet crop rotation pattern on the crop yield. The rhizosphere soil of the crop was collected at maturity to assess the effects of crop rotation on the composition and function of microbial communities in different tillage layers (0-20 cm and 20-40 cm) of sandy saline-alkaline soils. After three years of crop rotation, the maize yield and economic benefits rose by an average of 32.07% and 22.25%, respectively, while output/input grew by 10.26%. The pH of the 0-40 cm tillage layer of saline-alkaline soils decreased by 2.36%, organic matter rose by 13.44%-15.84%, and soil-available nutrients of the 0-20 cm tillage layer increased by 11.94%-69.14%. As compared to continuous cropping, crop rotation boosted soil nitrogen and phosphorus metabolism capacity by 8.61%-88.65%. Enrichment of Actinobacteria and Basidiomycota increased crop yield. Crop rotation increases microbial community richness while decreasing diversity. The increase in abundance can diminish competitive relationships between species, boost synergistic capabilities, alter bacterial and fungal community structure, and enhance microbial community function, all of which elevate crop yields. The obtained insights can contribute to achieving optimal management of intensive cultivation patterns and green sustainable development.

Currently, China’s soybean self-sufficiency rate is only 15%, highlighting the soybean crisis and the supply chain risks that pose a major threat to China’s food security. Thus, it has become imperative to step up efforts to boost soybean production capacity while promoting the green and sustainable development of regional farmland ecosystems. In this context, the present study comprehensively investigated the effects of intercropping and nitrogen application rate on soybean yield, as well as the changes in gradients generated by different levels of nitrogen application. Based on six consecutive years of maize–soybean intercropping planting patterns, the inter-root soils of soybeans were collected at the flowering stage and evaluated for soil nitrogen content, nitrogen-assimilating enzyme activities, and microbial community composition of soybean, which were correlated with yield, to clarify the main pathways and modes of intercropping effects. The N2 level (80 kg·ha−1) was favourable for higher yield. In comparison to monocropping, the intercropping reduced yield by 9.65–13.01%, photosynthetic characteristics by 1.33–7.31%, and plant nitrogen-assimilating enzyme activities by 8.08–32.01% at the same level of N application. Likewise, soil urease and catalase activities were reduced by 9.22 and 1.80%, while soil nitrogen content declined by an average of 6.38%. Gemmatimonas and Bradyrhizobium enrichment significantly increased soil nitrogen content, photosynthetic characteristics, and soybean yield, while it was reduced by Candidatus_Udaeobacter and Candidatus_Solibacte enrichment. The results of this study provide a theoretical basis for further optimising maize–soybean intercropping, which is crucial for enhancing the agricultural production structure and improving the overall soybean production capacity.

Background and aims The practice of returning corn stalks back to fields is widely implemented in maize cropping systems, but its impacts on maize yield is inconsistent due to different methods employed. We hypothesized soybean-maize rotation system with returning crop stalks to enhance soil health and maize yield. Methods A field trial was carried out from 2013 to 2018, comparing a soybean-maize rotation system with sole maize cultivation. Soil physicochemical properties, agronomic traits of maize and soil microbial community were determined. Results Maize yield and ear diameter were significantly higher in the rotational cropping system in 2018, compared to monocropping. Over the years, organic matter contents remained stable in the soil under rotational cropping but decreased in the monocropping soil. Different cropping systems also led to shifts in soil microbial communities: rotational cropping augmented fungal diversity, though the overall compositions of bacterial and fungal communities did not significantly differ between the two cropping systems. The proliferation and beneficial impact of functional microorganisms involved in crop residue decomposition, biological control of soil-borne disease, nutrient metabolism, and nutrient uptake were closely related to the improvement of maize yield and soil nutrition within the rotational cropping system. Conclusions Maize-soybean rotation and plant residue return sustained increased maize yield and organic matter contents of soil. The overall effect of the soil microbiome exhibited a positive association with both soil health and maize yield. This study highlights the potential of combining crop residue returns with crop rotation in bolstering soil health and fostering increased maize yield.

Soil erosion is amplified by the increased precipitation and rainfall erosivity caused by the changing climate, particularly for global mid-high latitude areas. Yet soil erosion processes and proper tillage practices are not well understood at the crop seedling stage, when the annual precipitation is usually concentrated in these regions. Simulated rainfall experiments were conducted at the rainfall intensities of 50- and 100-mm h- 1 to investigate the differences in soil erosion of a 5 degrees hillslope during the maize seedling stage between conservation and conventional tillage measures, including cornstalk mulching (Cm), horizontal ridging (Hr), horizontal ridging + mulching (Hr+Cm), vertical ridging + mulching (Vr+Cm), vertical ridging (Vr) and flat-tillage (CK). The results demonstrated that crops, at the seedling stage, can reduce soil erosion by altering the distribution of raindrops and reduce its kinetic energy. Conservation tillage measures significantly reduced total runoff (11.7 %-100 %) and sediment yield (71.1 %-100 %), delayed runoff-yield start time (85 s-26.1 min), decreased runoff velocity (71.5 %-96.7 %), and reduced runoff and soil loss rates, compared to conventional tillage measures. Mulching showed better performance than Hr. It reduced sediment concentration (similar to 70.6 %-100 %) by reducing runoff velocity and soil particle filtration. The contour ridge ruptured earlier at 100 mm h- 1 than at 50 mm h(- 1) and changed the characteristics of the soil erosion by providing a larger source of sediment for surface runoff. Runoff rate, rather than soil erodibility, was the key factor affecting soil erosion. Decreasing runoff velocity was more important than controlling the amount of runoff. The Hr + Cm treatment exhibited the lowest soil erosion and is recommended for adoption at the maize seedling stage in sloping farmland. Our findings provide an optimized tillage method to mitigate soil erosion in spring in Northeast China.

Abstract Aims Soil nitrogen is recognized as a vital nutrient influencing soybean growth and yield. Hence, a comprehensive understanding of the intricate connections between shifts in nitrogen patterns and the behaviors of soil microbial communities and crucial enzymes in the nitrogen cycle is highly desirable. Methods This study involved a rotation positioning experiment spanning 9 to 11 years. Measurement of soil microenvironment changes during the mature period for three consecutive years, focusing on the corn-soybean rotation with varying fertilizer application rates. Six distinct treatment groups were established for investigation. Based on these groups, the study delved into the alterations in nitrogen patterns within the soybean rotation, examining both soil enzyme activity and microbial community dynamics. Results Long-term crop rotation and nitrogen application led to an increase ranging from 2.16% to 108.34% in the nine components of soil nitrogen. The variations in total nitrogen, heavy fraction organic nitrogen, and light fraction organic nitrogen were primarily influenced by the enrichment of the Actinobacteriota phylum. The environmental factors affecting the changes in inorganic nitrogen, alkaline hydrolyzable nitrogen, exchangeable ammonium and acid hydrolyzable nitrogen were linked to the Ascomycota phylum. The Proteobacteria phylum and urease were key factors in the variations of organic nitrogen and nitrate-nitrogencomponents, respectively. Conclusions Changes in inorganic nitrogen and total organic nitrogen resulting from crop rotation enhanced the richness of soil microbial communities, reducing their diversity. This alteration influenced the bacterial and fungal communities composition, ultimately augmenting their functional capacities.

IntroductionIntercropping practices play a crucial role in enhancing and maintaining the biodiversity and resiliency of agroecosystems, as well as promoting stable and high crop yields. Yet the relationships between soil nitrogen, microbes, and yield in maize cultivated under maize/soybean intercropping systems remain unclear.MethodsTo fill that knowledge gap, here we collected maize rhizosphere soil at the staminate stage after 6 consecutive years of maize/soybean intercropping, to investigate how intercropping and nitrogen application rates affected nitrogen utilization by crops and soil microbial community composition and function. We also examined correlations of those responses with yields, to clarify the main ways that yield is enhanced via intercropping and by nitrogenous fertilizer gradient changes generated by different nitrogen application rates.ResultsThe amount of applied fertilizer was 240 kg N ha-1 was best for obtaining a high maize yield and also led to the greatest nitrogen-use efficiency and bacterial diversity. Under the same N application rate, intercropping increased the maize yield by 31.17% and soil nitrogen (total, ammonium and nitrate nitrogen) by 14.53%, on average, in comparison to monocropping. The enrichment of Gemmatimonas and Bradyrhizobium significantly increased the soil nitrogen content, and a greater relative abundance of Sphingomonas and Gemmatimonas increased the maize yield, whereas enrichment of Candidatus_Udaeobacter and Bradyrhizobium decreased it. The benefits of intercropping mainly arise from augmenting the abundance of beneficial microorganisms and enhancing the efficiency of N use by crop plants.DiscussionThis study’s findings are of key importance to bolster the stability of agro-ecosystems, to guide the scientific rational use of nitrogen fertilizers, and to provide a sound theoretical basis for achieving the optimal management of intensive crop-planting patterns and green sustainable development.

Soil-borne diseases are exacerbated by continuous cropping and negatively impact maize health and yields. We conducted a long-term (11-year) field experiment in the black soil region of Northeast China to analyze the effects of different cropping systems on maize yield and rhizosphere soil fungal community structure and function. The experiment included three cropping systems: continuous maize cropping (CMC), maize–soybean rotation (MSR), and maize–soybean intercropping (MSI). MSI and MSR resulted in a 3.30–16.26% lower ear height coefficient and a 7.43–12.37% higher maize yield compared to CMC. The richness and diversity of rhizosphere soil fungi were 7.75–20.26% lower in MSI and MSR than in CMC. The relative abundances of Tausonia and Mortierella were associated with increased maize yield, whereas the relative abundance of Solicoccozyma was associated with decreased maize yield. MSI and MSR had higher proportions of wood saprotrophs and lower proportions of plant pathogens than CMC. Furthermore, our findings indicate that crop rotation is more effective than intercropping for enhancing maize yield and mitigating soil-borne diseases in the black soil zone of Northeast China. This study offers valuable insights for the development of sustainable agroecosystems.

Soil acidification is a global environmental problem with significant impacts on agricultural production, environmental protection, and ecosystem health. Soil acidification is widespread in China, affecting crop yields, agricultural product quality, and biodiversity. Since the 1980s, much work has been done on acidic soils in China, but it is controversial whether excessive nitrogen fertilizer application can lead to soil acidification mechanisms. To address the above issues, we conducted a meta-analysis of 115 published papers to integrate and analyze the effects of N fertilizer application on soil acidification and biological properties from 1980 to 2024. We also quantified the effect of nitrogen fertilization on soil acidification and biological changes under different climatic conditions. The results showed that under long-term application of nitrogen fertilizers in China from 1980 to 2024, soil pH decreased by an average of 15.27%, and the activities of soil urease, nitrate reductase, nitrite reductase, catalase, glutamate dehydrogenase, and glutamate synthetase decreased by an average of 9.82–22.37%. The soil microbial community richness (Chao1 index) increased by 6.53%, but the community diversity (Shannon index) decreased by 15.42%. Among the dominant soil microorganisms, the relative abundance of bacteria decreased by an average of 9.67–29.38% and the abundance of gene expression of nifH, amoA-AOA, amoA-AOB, and qnorB decreased by 9.92–19.83%. In addition, we found that the mean annual temperature and rainfall impacted soil acidification via their effect on soil microbial diversity and community composition. This study provides a scientific basis for an in-depth understanding of the spatial and temporal variation of soil acidification and biological properties in China.

The limited available information on variations in yield gaps (differences between actual yields and the theoretically attainable yields) restricts the development of rational strategies to optimize yields and reduce environmental costs. Quantifying the yield potential and the variations in yield gaps will help identify factors that limit yields and will enable a narrowing of the current yield gap. Here, we applied an analytical framework to yield data to identify options for closing the yield gap at the county level. We used a database containing yields for 40 counties and data from 87 representative on-farm experiments in Jilin Province, China, from 2006 to 2008. The yield potential was simulated for each region-year using a Hybrid-Maize model ( http://www.hybridmaize.unl.edu/ ) and weather data. We then conducted a systematic and spatial analysis of actual yields to identify yield gaps at the county level. The simulated average potential yield at 27 representative sites was 15.2 Mg ha −1 (range 8.1–17.6 Mg ha −1 ) in Jilin Province. The on-farm experiments suggested an attainable potential yield ranging from 8.7 to 16.7 Mg ha −1 across Jilin Province. During this period, the actual maize yield varied between 4.1 and 11.9 Mg ha −1 , according to the county-level data. Farmers’ fields, therefore, achieved 52% of the model yield potential and 77% of the attainable potential yield. Widely different amounts of P fertilizer input among farmers contributed significantly to regional variations in YG E . Soil Olsen-P and rainfall were also major factors. The results indicate that there is great potential to substantially increase the maize yield in non-optimal P management regions, such as in the western Jilin Province. Hence, improvements in regional P management strategies, such as at the county level, need to be assessed separately to provide a basis for increasing the actual maize yield.

Hyperosmolality-gated calcium-permeable channels (OSCA) are characterized as an osmosensor in plants; they are able to recognize and respond to exogenous and endogenous osmotic changes, and play a vital role in plant growth and adaptability to environmental stress. To explore the potential biological functions of OSCAs in maize, we performed a bioinformatics and expression analysis of the ZmOSCA gene family. Using bioinformatics methods, we identified twelve OSCA genes from the genome database of maize. According to their sequence composition and phylogenetic relationship, the maize OSCA family was classified into four groups (Ⅰ, Ⅱ, Ⅲ, and Ⅳ). Multiple sequence alignment analysis revealed a conserved DUF221 domain in these members. We modeled the calcium binding sites of four OSCA families using the autodocking technique. The expression profiles of ZmOSCA genes were analyzed in different tissues and under diverse abiotic stresses such as drought, salt, high temperature, and chilling using quantitative real-time PCR (qRT-PCR). We found that the expression of twelve ZmOSCA genes is variant in different tissues of maize. Furthermore, abiotic stresses such as drought, salt, high temperature, and chilling differentially induced the expression of twelve ZmOSCA genes. We chose ZmOSCA2.2 and ZmOSCA2.3, which responded most strongly to temperature stress, for prediction of protein interactions. We modeled the calcium binding sites of four OSCA families using autodocking tools, obtaining a number of new results. These results are helpful in understanding the function of the plant OSCA gene family for study of the molecular mechanism of plant osmotic stress and response, as well as exploration of the interaction between osmotic stress, high-temperature stress, and low-temperature stress signal transduction mechanisms. As such, they can provide a theoretical basis for crop breeding.

Soil erosion features and ideal tillage practices are not very clear at the crop seedling stage in Chinese Mollisols. Simulated rainfall experiments were conducted at the rainfall intensities of 50 and 100 mm h-1 to investigate the differences in soil erosion of a 5° hillslope during the maize seedling stage between conservation and conventional tillage measures, including cornstalk mulching (Cm), horizontal ridging (Hr), horizontal ridging + mulching (Hr+Cm), vertical ridging + mulching (Vr+Cm), flat-tillage (CK), and vertical ridging (Vr). The results demonstrated that crops could remit soil erosion at the seedling stage by reducing the kinetic energy and changing the distribution of raindrops. The conservation tillage measures significantly alleviated total runoff (11.7%–100%) and sediment yield (71.1%–100%), postponed runoff-yielding time (85 s–26.1 min), decreased runoff velocity (71.5%–96.7%), and reduced runoff and soil loss rate, compared to the conventional tillage measures. Practices with mulching showed better performance than Hr. Mulching reduced sediment concentration by decreasing runoff velocity and soil particle filtration in a manner similar to buffer strips. The contour ridge ruptured earlier at 100 mm h-1 than at 50 mm h-1 and changed the characteristics of the soil erosion by providing a larger sediment source to the surface flow. Runoff strength, rather than soil erodibility, was the key factor affecting soil erosion. Decreasing runoff velocity was more important than controlling runoff amount. The Hr + Cm treatment exhibited the lowest soil erosion and is, thus, recommended at the corn seedling stage.

基于对吉林省长春市大田土壤温度和水分变化分析,研究不同播种日期对春玉米出苗率及产量的影响,确定最佳播种日期,为提高吉林省春玉米产量提供理论依据.以春玉米品种松玉419为试验材料,田间设置9个不同播种日期,播期间隔5～6天,监测春玉米苗期田间土壤温度和水分变化,测定春玉米产量并对产量构成因素进行分析,建立出苗率与土壤温度和水分多元线性回归数学模型.结果表明:春玉米出苗率与土壤温度和水分呈显著正相关.播种时土壤水分和土壤温度的差异显著影响成熟期籽粒产量.当土壤温度一定时,土壤体积含水率每增加1％,出苗率提高0.789％,出苗速率提高0.798％;当土壤体积含水率一定时,土壤温度每增加1℃,出苗率提高0.352％,出苗速率提高0.793％.松玉419在4月29日播种时产量最高,比正常播期(5月4日)产量提高6.66％,即每年4月底5月初,土壤平均温度在13.1～13.6,土壤体积含水率在13.1％～15.3％时播种最佳.土壤水分对春玉米出苗率影响最大,而土壤温度对春玉米出苗速率影响最大.

[目的]合理密植和施肥是提高雨养农业区作物产量和肥料利用效率的有效途径.我们研究了半湿润雨养黑土农业区玉米不同种植密度和施氮量及其互作对光能利用率和产量的影响,为进一步挖掘东北玉米产量潜力提供理论依据和数据支撑.[方法]于2017—2019年以郑单958?(ZD958)为供试品种进行了田间试验.试验采用裂区设计,种植密度为主区,分别为4.5×104株/hm2?(M4.5)、6.0?×104株/hm2?(M6.0)、7.5?×104株/hm2(M7.5)和9.0?×104株/hm2?(M9.0),施氮量为裂区,分别为N?120?kg/hm2?(N120)、180?kg/hm2?(N180)和240?kg/hm2(N240),各处理均设3次重复.分析了玉米光能利用率(LUE),玉米地上部干物质累积量、籽粒产量、净光合速率(Pn)和叶面积指数(LAI)等指标.[结果]年度间玉米产量、干物质量、LAI、净光合速率(Pn)和光能利用率(LUE)差异均达显著水平.2017、2018、2019年玉米的光能利用率(LUE)平均分别为1.58％、1.99％和2.20％.种植密度对玉米产量、干物质量、LAI、光合速率(Pn)和LUE的影响均显著(P<0.05),在密度M7.5处理下,LUE和平均产量最高(2.07％和12219?kg/hm2),在光合辐射较低年份(如2019年)可通过适当增加种植密度来提高玉米的光能利用率(LUE)和产量.施氮量对玉米干物质量和LAI有显著影响(P<0.05),LUE在N180处理下最高,平均为2.0％.密度与施氮量互作对玉米产量、干物质量、LAI、光合速率(Pn)无显著影响,但对LUE影响显著,以M7.5+N240处理LUE平均值最高(2.16％),且密度对光能利用率(LUE)的影响(9.93％)大于施氮量的影响(6.01％).[结论]在半湿润雨养黑土农业区,密度、密度与施氮量交互作用均显著影响玉米的光能利用率,密度的影响大于施氮量.适当增密(7.5×104株/hm2)和合理施氮量(N?180～240 kg/hm2)是实现玉米高产的重要措施.