Population occurrence of the fall armyworm,Spodoptera frugiperda(Lepidoptera: Noctuidae), in the winter season of China

Fall armyworm(FAW), Spodoptera frugiperda(J.E. Smith), has become an important pest in Chinese agricultural systems since its invasion on 11 December 2018. After its establishment, FAW months in the year-round breeding region have become the main source population migrating to other areas in China. Field investigations were conducted in tropical and subtropical regions to improve understanding of its year-round breeding area in China. The results showed that FAW larval density was significantly correlated with the seasonal temperature of the location surveyed. The FAW larvae maintained a high density in the tropical area and were frequently found in sites of the south subtropical region, but were absent from the north subtropical region and the northern part of the central subtropical region. These results indicated that FAW can reproduce annually in the tropical and south subtropical regions of China, including Hainan, Taiwan and the southern area of Fujian, Guangdong, Guangxi, Guizhou, and Yunnan. Hence, great effort should be made to monitor and control FAW in the year-round breeding region to suppress the population density of this area and to reduce migration of moths into northern parts of China. This study clarifies the occurrence area of the pest in winter in China and provides much valuable information for its population forecasting and management.     

Influence of surface ozone on crop yield of maize in China

This study investigated the adverse effect of surface ozone on the maize yield using a unique panel from 880 counties in China. To identify the impact of elevated surface ozone concentrations, we constructed an econometric model by controlling the impact of climate variables and related economic variables. This study also considered the potential spatial correlation in the measurement of the impact of surface ozone on maize yield. Results confirmed that the increase of ozone concentration decreased the maize yield. Moreover, maize was found to be the most sensitive to ozone at the end of the second month of the growing season. The average annual loss of maize caused by ozone pollution is about 4.234 million tons in 2013–2015, accounting for 1.9% of the average output.     

Estimation of irrigation requirements for drip-irrigated maize in a sub-humid climate

Drip-irrigation is increasingly applied in maize (Zea mays L.) production in sub-humid region. It is critical to quantify irrigation requirements during different growth stages under diverse climatic conditions. In this study, the Hybrid-Maize model was calibrated and applied in a sub-humid Heilongjiang Province in Northeast China to estimate irrigation requirements for drip-irrigated maize during different crop physiological development stages and under diverse agro-climatic conditions. Using dimensionless scales, the whole growing season of maize was divided into diverse development stages from planting to maturity. Drip-irrigation dates and irrigation amounts in each irrigation event were simulated and summarized in 30-year simulation from 1981 to 2010. The maize harvest area of Heilongjiang Province was divided into 10 agro-climatic zones based on growing degree days, arid index, and temperature seasonality. The simulated results indicated that seasonal irrigation requirements and water stress during different growth stages were highly related to initial soil water content and distribution of seasonal precipitation. In the experimental site, the average irrigation amounts and times ranged from 48 to 150 mm with initial soil water content decreasing from 100 to 20% of the maximum soil available water. Additionally, the earliest drip-irrigation event might occur during 3- to 8-leaf stage. The water stress could occur at any growth stages of maize, even in wet years with abundant total seasonal rainfall but poor distribution. And over 50% of grain yield loss could be caused by extended water stress during the kernel setting window and grain filling period. It is estimated that more than 94% of the maize harvested area in Heilongjiang Province needs to be irrigated although the yield increase varied (0 to 109%) in diverse agro-climatic zones. Consequently, at least 14% of more maize production could be achieved through drip-irrigation systems in Heilongjiang Province compared to rainfed conditions.     

A simulation of winter wheat crop responses to irrigation management using CERES-Wheat model in the North China Plain

To improve efficiency in the use of water resources in water-limited environments such as the North China Plain(NCP), where winter wheat is a major and groundwater-consuming crop, the application of water-saving irrigation strategies must be considered as a method for the sustainable development of water resources. The initial objective of this study was to evaluate and validate the ability of the CERES-Wheat model simulation to predict the winter wheat grain yield, biomass yield and water use efficiency(WUE) responses to different irrigation management methods in the NCP. The results from evaluation and validation analyses were compared to observed data from 8 field experiments, and the results indicated that the model can accurately predict these parameters. The modified CERES-Wheat model was then used to simulate the development and growth of winter wheat under different irrigation treatments ranging from rainfed to four irrigation applications(full irrigation) using historical weather data from crop seasons over 33 years(1981–2014). The data were classified into three types according to seasonal precipitation: 100 mm, 100–140 mm, and 140 mm. Our results showed that the grain and biomass yield, harvest index(HI) and WUE responses to irrigation management were influenced by precipitation among years, whereby yield increased with higher precipitation. Scenario simulation analysis also showed that two irrigation applications of 75 mm each at the jointing stage and anthesis stage(T3) resulted in the highest grain yield and WUE among the irrigation treatments. Meanwhile, productivity in this treatment remained stable through different precipitation levels among years. One irrigation at the jointing stage(T1) improved grain yield compared to the rainfed treatment and resulted in yield values near those of T3, especially when precipitation was higher. These results indicate that T3 is the most suitable irrigation strategy under variable precipitation regimes for stable yield of winter wheat with maximum water savings in the NCP. The application of one irrigation at the jointing stage may also serve as an alternative irrigation strategy for further reducing irrigation for sustainable water resources management in this area.     

定州市土壤肥力演变规律与玉米推荐施肥量研究

本研究根据1986—1994年和2007—2010年河北省定州市土壤肥力监测数据,明确了该市土壤肥力演变规律;并通过"3414"田间试验,研究了不同肥力水平下土壤基础地力贡献率和养分贡献率,以及氮磷钾肥用量与玉米产量间的关系。结果表明:1986—1994年土壤有机质、碱解氮和速效磷呈上升趋势,速效钾呈下降趋势,而2007—2010年四种肥力指标均呈上升趋势;随时间延长,土壤基础地力和养分贡献率均下降;回归分析表明,不同土壤肥力水平下玉米产量与氮磷钾肥施用量间均呈显著的三元二次和一元二次曲线相关,结合这两种模型的拟合结果,提出了本市玉米最高产量施肥量和经济最佳产量施肥量推荐范围。     

基于SSR标记构建西南玉米地方品种核心种质的方法

结合地方品种的地理起源和种质特性,以17%的抽样率选取玉米核心品种,用SSR分子标记技术对54个玉米地方品种进行遗传聚类,研究中国西南地区玉米地方品种核心种质的构建方法.结果表明,由9个核心品种构成的核心种质较好地保持了原玉米地方品种群体的遗传变异,42对SSR引物在原玉米地方品种群体和核心种质中分别检测到268、256个等位基因,平均多态信息量分别为0.76和0.73,其评价参数平均数百分率、方差百分率和变异系数可变率分别为10%、10%、83.5%,表明构建的核心种质能较好地代表原种质资源群体.     

Quantitative analysis of yield and soil water balance for summer maize on the piedmont of the North China Plain using AquaCrop

The North China Plain (NCP) is a major grain production area in China, but the current winter wheat-summer maize system has resulted in a large water deficit. This water-shortage necessitates the improvement of crop water productivity in the NCP. A crop water model, AquaCrop, was adopted to investigate yield and water productivity (WP) for rain-fed summer maize on the piedmont of the NCP. The data sets to calibrate and validate the model were obtained from a 3-year (2011–2013) field experiment conducted on the Yanshan piedmont of the NCP. The range of root mean square error (RMSE) between the simulated and measured biomass was 0.67–1.25 t·hm⁻², and that of relative error (RE) was 9.4%–15.4%, the coefficient of determination (R²) ranged from 0.992 to 0.994. The RMSE between the simulated and measured soil water storage at depth of 0–100 cm ranged from 4.09 to 4.39 mm; and RE and R² in the range of 1.07%–1.20% and 0.880–0.997, respectively. The WP as measured by crop yield per unit evapotranspiration was 2.50–2.66 kg·m⁻³. The simulated impact of long-term climate (i.e., 1980–2010) and groundwater depth on crop yield and WP revealed that the higher yield and WP could be obtained in dry years in areas with capillary recharge from groundwater, and much lower values elsewhere. The simulation also suggested that supplementary irrigation in areas without capillary groundwater would not result in groundwater over-tapping since the precipitation can meet the water required by both maize and ecosystem, thus a beneficial outcome for both food and ecosystem security can be assured.     

甘蔗作为生物能源作物的潜力分析

基于目前世界性的石油危机现状,分析了甘蔗在中国作为可再生生物质能源作物的必要性及可能性。甘蔗是C4作物,其光能转换效率、光合速率、单位面积生物产量显著高于其它作物,具有高净能比,适应性广、耐旱、产量潜力大。用甘蔗加工生产酒精,成本低。巴西利用甘蔗大规模生产能源酒精取代汽油已相当成功,因此认为甘蔗是中国最有潜力的生物能源作物,但是中国需要重视能源甘蔗品种的选育,加强甘蔗能源酒精生产工艺的研究与开发,开展相适应的酒精汽油燃料动力机械的研制。可以展望,利用甘蔗发展能源酒精生产具有广阔的前景。     

Impacts of Fertilization Alternatives and Crop Straw Incorporation on N2O Emissions from a Spring Maize Field in Northeastern China

Spring maize is one of the most popular crops planted in northeastem China. The cropping systems involving spring maize have been maintaining high production through intensive management practices. However, the high rates of nitrogen （N） fertilizers application could have introduced a great amount of nitrous oxide （N2O） into the atmosphere. It is crucial for sustaining the maize production systems to reduce N2O emissions meanwhile maintaining the optimum yields by adopting alternative farming management practices. The goal of this study was to evaluate effects of alternative fertilization and crop residue management practices on N2O emission as well as crop yield for a typical maize field in northeastern China. Field experiments were conducted during the 2010-2011 maize growing seasons （from early May to late September） in Liaoning Province, northeastern China. N2O fluxes were measured at the field plots with six different treatments including no N fertilizer use （CK）, farmers＇ conventional N fertilizer application rate （FP）, reduced N fertilizer rate （OPT）, reduced N fertilizer rate combined with crop straw amendment （OPTS）, slow-release N fertilizer （CRF）, and reduced N fertilizer rate combined with nitrification inhibitor （OPT＋DCD）. The static chamber method combined with gas chromatography technique was employed to conduct the measurements of N2O fluxes. The field data showed that N2O emissions varied across the treatments. During the maize growing season in 2010, the total N2O emissions under the treatments of CK, FP, OPT, OPTS, and CRF were 0.63, 1.11, 1.03, 1.26, and 0.98 kg N ha-1, respectively. The seasonal cumulative N2O emissions were 0.54, 1.07, 0.96, 1.12, and 0.84 kg N ha1, respectively, under CK, FP, OPT, OPTS, and OPT＋DCD in 2011. In comparison with FP, CRF or OPT＋DCD reduced the N2O emissions by 12 or 21%, respectively, while the crop yields remained unchanged. The results indicate that the reduction of N-fertilizer application rate in combination with the slow-release fertilizer type or nitrification inhibitor could effectively mitigate N2O emissions from the tested field. The incorporation of crop residue didn＇t show positive effect on mitigating N2O emissions from the tested cropping system. The field study can provide useful information for the on-going debate on alternative N fertilization strategies and crop straw management in China. However, further studies would be needed to explore the long-term impacts of the alternative management practices on a wide range of environmental services.     

Application of vetiver grass Vetiveria zizanioides: Poaceae (L.) as a trap plant for rice stem borer Chilo suppressalis: Crambidae (Walker) in the paddy fields

Rice is an important staple food in China and it is at risk of attack by rice striped stem borer Chilo suppressalis, which occurs in most rice growing areas. In recent years, severe C. suppressalis outbreaks have been observed in China mainly due to changes in the rice cultivation systems, wide adoption of hybrid varieties and resistance to the dominant insecticides. Management relies primarily on chemical insecticides and resistance is an important contributing factor in these outbreaks. As a result, food safety of agricultural produce is reduced and the ecological and environmental integrities are threatened as well. Recently, environmentally friendly pest management measures, such as trap plants have been introduced for C. suppressalis management and this method can greatly reduce insecticide use. Our previous results indicated that the vetiver grass (Vetiveria zizanioides) is a dead-end trap plant that can effectively attract the adult females of C. suppressalis to lay eggs on it but where larvae are unable to complete their life cycle. This paper further explored the application of vetiver grass as a trap plant to manage C. suppressalis in the paddy fields. This environment-friendly tool can not only reduce C. suppressalis populations, it can also increase the diversity and abundance of natural enemies that can provide better environmental conditions for rice production.     

基于AMMI模型和GGE双标图的西北春玉米品种区域试验综合评价

为筛选出西北地区高产稳产的品种和理想的测试点,利用AMMI模型和GGE双标图对2022年西北春玉米品种区域试验中的12个品种在19个试点的丰产性、稳产性和适应性进行分析,评价试点的区分力和代表性。结果表明,产量变异主要包括基因型、环境以及基因型与环境互作,分别占产量变异总平方和的4.39%、74.50%和10.08%。AMMI模型解释了82.76%的品种与试点互作效应。GGE双标图将19个试点分成3个生态区域;其中,甘肃省平凉市、天水市、内蒙古自治区巴彦淖尔、宁夏回族自治区平罗县、陕西省延安市、新疆维吾尔自治区昌吉州和可克达拉市7个试点的区分力和代表性较强。通过AMMI模型和GGE双标图,鉴定出适合西北地区高产稳产的品种为‘DK 2207’和‘玺旺188’。AMMI模型能够充分分解互作效应,并着重评价品种的稳定性,而GGE双标图则在评价试点的区分力和代表性方面有优势。综上,AMMI模型和GGE双标图的综合应用有助于提高西北春玉米品种和测试点评价的可靠性。     

不同施肥措施对华北潮土区玉米田土壤微生物碳源代谢多样性的影响

探讨长期不同施肥措施下华北潮土区玉米田土壤微生物碳源代谢多样性特征,为华北地区可持续性施肥管理提供理论依据和数据支持。以农业农村部环境保护科研监测所建立的武清长期定位试验站为平台,采用Biolog生态板技术,研究6种不同施肥处理[不施肥对照（A0）、单施有机肥（A1）、氮肥减量配施有机肥（A2）、常量化肥配施有机肥（A3）、氮肥增量配施有机肥（A4）和单施化肥（A5）]对华北潮土区土壤微生物碳源代谢多样性的影响。结果表明,与不施肥对照相比,A1、A2、A3、A4和A5处理显著提高了土壤全氮和硝态氮含量,显著降低了土壤碳氮比和pH;施用有机肥处理（A1、A2、A3和A4）显著增加了有机碳和微生物量氮含量。培养96 h时,反映土壤微生物活性的平均颜色变化率（AWCD）变化顺序为： A2 > A3 > A4 > A5 >A1 > A0。A2的土壤微生物Shannon指数H显著高于其他施肥处理。主成分分析表明,不同施肥处理显著影响土壤微生物的碳源利用特征,A2和A3集中在第1主成分正方向,得分系数在1.125~1.473,土壤微生物碳源利用特征相似;A0、A1、A4和A5位于第1主成分负方向,得分系数在-1.157~-0.167。土壤微生物利用的碳源主要为碳水类、羧酸类、氨基酸和聚合物类。相关分析表明,土壤碳氮比、铵态氮、硝态氮、pH和微生物量氮是影响土壤微生物碳源代谢多样性的主要因素。氮肥减量配施有机肥有利于提高土壤微生物代谢活性和碳源代谢多样性。     

从作物轮作角度评价华南典型赤红壤农区耕地质量空间差异

为从作物轮作角度分析华南典型赤红壤农区耕地质量空间差异,针对华南典型赤红壤农区构建作物轮作系统遥感分类体系,基于空间分析、文献支持、野外实地调查、农户访谈与专家知识,建立不同作物轮作系统与耕地质量等级之间的关联关系;基于Sentinel-1与Sentinel-2时间序列遥感数据、利用决策树制图方法,开展作物轮作系统遥感制图,并在不同空间尺度分析耕地质量空间差异与规律。结果表明,作物轮作系统与耕地质量之间存在关联关系,总体而言,水田轮作系统由于化肥投入较低、对土壤干扰较小、长时间被水面覆盖,不易引起土壤酸化等耕地质量问题,耕地质量等级较高;蔬菜、果园系统由于化肥投入较高,耕地质量一般较低,具体表现为土壤酸化、土壤重金属污染等问题。研究区蔬菜轮作系统比例最高,其次为果园系统。研究区耕地质量总体一般,主要为三等地,呈现出明显的空间分异。本研究初步探明作物轮作与耕地质量的关联关系,并将作物轮作遥感制图结果应用于耕地质量空间差异研究,由于耕地质量特征较难直接通过遥感反演获取,通过监测地表作物种植情况进而反演耕地质量具有理论可行性,未来有必要深入解析作物轮作、地形地貌、气象水文等要素与耕地质量的关联关系,构建大数据驱动的耕地质量时空差异评估技术体系,支撑跨尺度耕地质量监测与评价研究。     

Integrated application of February Orchid(Orychophragmus violaceus) as green manure with chemical fertilizer for improving grain yield and reducing nitrogen losses in spring maize system in northern China

The development of more efficient management systems is crucial to achieving high grain yields with high nitrogen use efficiency(NUE). February Orchid-spring maize rotation system is a newly established planting system with the benefits of ground cover and potential wind erosion in northern China. A field experiment was conducted to evaluate the effects of integrated application of February Orchid as green manure with reduction of chemical fertilizers(INTEGRATED) on spring maize yield, N uptake, ammonium volatilization, and soil residual mineral N in northern China. Compared to farmers' traditional fertilization(CON), integrated application of February Orchid as green manure with 30% reduction of nitrogen fertilizers(INTEGRATED) increased maize grain yield and biomass by 9.9 and 10.2%, respectively. The 0–100 cm soil residual Nmin at harvest was decreased by 58.5% and thus nitrogen use efficiency was increased significantly by 26.7%. The nitrogen balance calculation further demonstrated that the INTEGRATED approach performed better than CON with lower apparent nitrogen loss(decreased by 48.9%) which evidenced by the ammonium volatilization of top-dressing fertilizer was decreased by 31.1%, the N_(min) movement to the deeper soil layers was reduced, and the apparent nitrogen leaching loss nearly equal to 0 under the INTEGRATED treatment. Therefore, in northern China, integrated application of green manure and chemical fertilizers is an efficient management approach for improving maize yields and NUE simultaneously.     

基于CiteSpace的华北冬小麦-夏玉米周年优化灌溉制度的节水潜力分析

为探究华北地区冬小麦-夏玉米一年两熟制周年优化灌溉制度的节水潜力,基于文献计量学方法,系统梳理了1995—2020年有关华北地区冬小麦-夏玉米一年两熟制周年优化灌溉制度的文献发文量、被引量、高影响力期刊、作者、研究单位、高频词、试验站点,以分析其研究态势,并利用CiteSpace进行了可视化与关联分析。在此基础上,进一步整理了该模式中高灌溉需水量作物冬小麦的关键节水技术,包括了工程节水技术(喷灌、滴灌、微喷灌)、生物节水技术(品种选育)与典型农艺节水技术(优化灌溉制度)等,系统分析了各节水技术对冬小麦产量、耗水量、水分利用效率的影响。结果表明:1)华北地区冬小麦-夏玉米一年两熟制周年优化灌溉制度研究的相关发文量在近年来呈明显增加趋势,发展态势良好,但同时缺乏高被引论文。中国农业大学、中国科学院遗传与发育生物学研究所农业资源研究中心、河南农业大学发文数量排在前三位,分别占总发文数的27%、10%和10%,在该领域具有较高的活跃度;2)从高频词来看,该领域主要聚焦于水分利用效率、产量、光合特性、生长特性、模型模拟等。但相关领域也存在问题,如主要作者、一些研究机构间合作不够密切,田间实验站点分布不均匀且缺少长期稳定的定位观测试验等;3)对于高灌溉需水量作物冬小麦的文献计量研究表明,喷灌、滴灌、微喷灌、选用抗旱节水品种等技术,可降低田间耗水量7%~13%、产量不同程度增加2%~10%,水分利用效率提高约5%~28%。优化灌溉制度,减少灌溉次数,且根据不同降水年型保证冬小麦关键生育期的需水,可降低田间耗水9%~25%,产量降低2%~18%,水分利用效率提高约6%~9%。综上,为进一步保证粮食生产与水资源安全,应将冬小麦-夏玉米一年两茬作为一个整体来充分考虑周年的水分利用,合理优化周年的灌溉制度,构建整合配套的农艺节水技术体系和灌溉设备与技术。     

山东省冬小麦-夏玉米轮作体系土壤氮素盈余指标体系的构建与评价——以德州市为例

山东省德州市是我国重要的粮食生产基地,大量施用氮肥以及氮素流失是该地氮素污染的重要原因,设定合理的氮素盈余指标体系迫在眉睫。本研究以田间试验研究和文献荟萃为基础,探究德州市冬小麦-夏玉米轮作氮素盈余情况,建立该地氮盈余指标体系,并运用欧氏距离法对德州市当前氮素管理指标进行评价。结果表明:德州市整个冬小麦-夏玉米轮作体系轮作周期氮素盈余量为196.84 kg N·hm~(-2)·a~(-1),小麦季氮素盈余量为111.07 kg N·hm~(-2),玉米季氮素盈余量为85.77 kg N·hm~(-2)。氮素盈余量在30～70 kg N·hm~(-2)·a~(-1)时为德州市整个轮作周期氮素盈余量推荐值;德州市小麦季氮素盈余量推荐值为10～50 kg N·hm~(-2);德州市玉米季氮素盈余量推荐值为20～60 kg N·hm~(-2)。在氮素的损失方面,氨挥发以及淋洗是氮素损失的主要去向。小麦季的氮素污染程度高,玉米季氮素污染程度相对较低。运用欧氏距离法计算德州市氮素管理水平(A值)为0.63,属于中级管理水平。综上,德州市冬小麦-夏玉米轮作体系农田氮素含量较高,从而导致氮素大量损失。加强氮素管理水平,提高氮素利用率是德州市氮素资源管理的长期任务。     

半干旱区旱地春小麦全膜覆土穴播对土壤水热效应及产量的影响

以春小麦"陇春27"为试材,研究半干旱区旱地全膜覆土穴播对土壤水热效应及小麦产量的影响。结果表明:与裸地平作(CK)相比,全膜覆土穴播(PM)和全沙覆盖平作(SM)增温效果呈"挂钩型",增温效果在小麦拔节期前最为明显,PM 0-25 cm土壤平均温度较CK提高1.8 ℃,全沙覆盖平作提高1.4 ℃,拔节后PM和SM的增温效果逐渐减弱直至消失,而在成熟期又呈现较弱的增温效果。PM和SM能提高小麦出苗后耗水速度并加大耗水量,其中,小麦拔节到扬花期耗水量增加最多,分别较CK平均增加54.93%和31.54%,且此阶段越是干旱,促进耗水作用越明显,PM促进作用大于SM。PM和SM能显著提高小麦阶段性水分利用效率(WUE_b),其中PM以苗期提高最多,2a平均较CK提高365.17%,SM拔节期提高最多,2年平均较CK提高119.00%。PM和SM在增温、促进耗水作用下使小麦各生育期提前并增加单株干重,产量较CK分别平均增加432.28%和375.82%, 水分利用效率(WUE)分别平均增加351.51%和338.29%,而且越干旱年份增产效应愈加明显。可见,PM和SM在越为干旱的年份促进耗水、增产和提高WUE的作用越显著,PM效果强于SM。