基于WOFOST模型的辽宁省春玉米干旱灾损风险评估

利用锦州农业气象试验站的作物生长发育和土壤实测数据对WOFOST模型水分胁迫模块进行了调参，适用性验证表明，WOFOST模型适用于辽宁省春玉米生长发育和产量的模拟，辽宁省春玉米受干旱的影响可以利用WOFOST模型较敏感地反映出来。利用调参后的WOFOST模型模拟了全生育期及出苗~拔节、拔节~抽雄、抽雄~乳熟和乳熟~成熟各阶段发生轻、中、重旱情景对辽宁省春玉米产量的影响，并根据模拟结果确定了不同干旱风险等级下辽宁省东、中、西部玉米生产的灾损范围。结果表明：不同生育期发生干旱对产量的影响不同，总体上，抽雄~乳熟期发生干旱的影响最大，其次是拔节~抽雄期，而出苗~拔节期和乳熟~成熟期发生干旱对产量的影响较小，全省春玉米在抽雄~乳熟期发生重旱的减产风险达30%~70%；在相同干旱水平下，不同区域受影响程度也不同，在全生育期及各生育阶段发生轻、中、重旱情景下，干旱导致的减产率总体上表现为由东部向西部地区逐渐加重的趋势，在全生育期重旱情景下，辽宁省东部的春玉米减产率为40%~75%，中部为60%~90%，西部达65%~95%。     

烯效唑浸种对干旱胁迫下工业大麻幼苗形态、渗透调节物质及内源激素的影响

选用0.4 mg·L~(-1)的烯效唑(S_(3307))浸种工业大麻"火麻一号"种子,采用盆栽试验方法,于大麻三叶期设置清水浸种后正常供水(CK)、清水浸种后干旱胁迫(D)和烯效唑浸种后干旱胁迫(D+S)3个处理,探讨烯效唑浸种对干旱胁迫下工业大麻幼苗形态、渗透调节物质及内源激素的影响。结果表明:与D处理的植株相比,D+S处理显著提高了根系干、鲜重,分别提高46.67%～61.54%和16.46%～25.53%;恢复了胁迫后期的地上部干、鲜重,复水4 d后地上部干、鲜重较D处理分别提高了4.38%和2.23%;促进了根系生长的能力,干旱胁迫8 d后,D+S处理较D处理根长、根表面积、根体积、根总投影面积、分枝数、交叉数和根尖数分别增加了34.48%、34.77%、69.10%、70.00%、29.62%、54.28%和33.07%;提高了幼苗叶片SPAD值,降低了细胞膜透性,增加了可溶性糖和可溶性蛋白含量,干旱胁迫8 d后D+S处理较D处理SPAD值增加了28.30%,细胞膜透性减少了17.22%,可溶性糖和可溶性蛋白含量分别增加了17.32%～36.78%和5.07%～7.94%。干旱胁迫8 d后,D+S处理使工业大麻叶片中脱落酸(ABA)含量增加了1.02倍,水杨酸(SA)和茉莉酸(JA)含量分别降低了17.79%和14.40%。可见,烯效唑浸种能通过调控工业大麻幼苗生长及生理指标来增强其抗旱能力,缓解干旱胁迫对幼苗造成的伤害。     

Modelling Wheat Stomatal Resistance in Hourly Time Steps from Micrometeorological Variables and Soil Water Status

An accurate estimation of stomatal resistance (r_S) also under drought stress conditions is of pivotal importance for any process‐based prediction of transpiration and the energy budget of real crop canopies and quantification of drought stress. A new model for r_S was developed and parameterized for winter wheat using data from field experiments accounting for the influences of net radiation (R_Net), air temperature (T_Air) and vapour pressure deficit of the atmosphere (VPD) interacting with an average water potential in the rooted soil (ψ_RootedSoil). r_S is simulated with a limiting factor approach as maximum of the metabolic (related to photosynthesis) and hydraulic (related to drought stress) acting influences assuming that, if drought stress occurs, it will dominate stomatal control: r_S = max(r_S(T_Air), r_S(R_Net), r_S(VPD, ψ_RootedSoil)). This transitional approach is suited to reproduce measured daily time courses of r_S with a varying accuracy for the single measurement dates but performed satisfactorily for the whole data set (r² = 0.63, RMSE = 59 s m^?1, EF = 0.60). This new semi‐empiric approach calculates r_S directly from external environmental conditions. Therefore, it can be easily implemented in existing model frameworks as link between operational crop growth models that use the concept of radiation use efficiency instead of mechanistic photosynthesis modelling and soil–vegetation–atmosphere transport models.     

Drought Tolerance and Water Use of Cereal Crops: A Focus on Sorghum as a Food Security Crop in Sub‐Saharan Africa

Sub‐Saharan Africa (SSA) faces twin challenges of water stress and food insecurity – challenges that are already pressing and are projected to grow. Sub‐Saharan Africa comprises 43 % arid and semi‐arid area, which is projected to increase due to climate change. Small‐scale, rainfed agriculture is the main livelihood source in arid and semi‐arid areas of SSA. Because rainfed agriculture constitutes more than 95 % of agricultural land use, water scarcity is a major limitation to production. Crop production, specifically staple cereal crop production, will have to adapt to water scarcity and improved water productivity (output per water input) to meet food requirements. We propose inclusion and promotion of drought‐tolerant cereal crops in arid and semi‐arid agro‐ecological zones of SSA where water scarcity is a major limitation to cereal production. Sorghum uniquely fits production in such regions, due to high and stable water‐use efficiency, drought and heat tolerance, high germplasm variability, comparative nutritional value and existing food value chain in SSA. However, sorghum is socio‐economically and geographically underutilized in parts of SSA. Sorghum inclusion and/or promotion in arid and semi‐arid areas of SSA, especially among subsistence farmers, will improve water productivity and food security.     

Improved Cold and Drought Tolerance of Doubled Haploid Maize Plants Selected for Resistance to Prooxidant tert‐Butyl Hydroperoxide

To improve the abiotic stress tolerance of maize (Zea mays L.), doubled haploid (DH) plants were produced by in vitro selection of microspores exposed to tert‐butyl hydroperoxide (t‐BuOOH) as a powerful prooxidant This study investigated the tolerance of the progenies of t‐BuOOH‐selected DH lines to oxidative stress, cold and drought in controlled environment pot experiments by analyses of photosynthetic electron transport and CO₂ assimilation processes, chlorophyll bleaching and lipid peroxidation of leaves. Our results demonstrated that the t‐BuOOH‐selected DH plants exhibited enhanced tolerance not only to oxidative stress‐induced by t‐BuOOH but also to cold and drought stresses. In addition, they showed elevated activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase and glutathione S‐transferase when compared with the DH lines derived from microspores that were not exposed to t‐BuOOH and to the original hybrid plants. The results suggest that the simultaneous up‐regulation of several antioxidant enzymes may contribute to the oxidative and cold stress tolerance of the t‐BuOOH‐selected DH lines, and that the in vitro microspore selection represents a potential way to improve abiotic stress tolerance in maize.     

菠萝灌溉施肥技术研究进展

季节性干旱是限制菠萝增产提质增效的重要原因,发展“以水促肥,以肥促产,水肥高效耦合”的现代灌溉施肥技术,是应对季节性干旱,促进菠萝增产提质增效的重要途径。本文从华南地区季节性干旱时空分布特征、干旱胁迫对菠萝生长发育的影响、我国菠萝水肥管理现状、灌溉施肥技术对菠萝生长发育的影响等4个方面简要阐述了我国菠萝灌溉施肥技术发展的必要性,重点从现代灌溉施肥方式、耗水规律和养分吸收规律等3方面总结了菠萝灌溉施肥技术研究进展,并结合研究进展提出我国菠萝灌溉施肥技术目前存在的问题,探讨未来可能的研究重点和发展方向,为菠萝灌溉施肥技术的研究与应用提供参考。     

芝麻不同生育阶段需水特性与干旱灌溉应用研究

探讨芝麻不同生育阶段需水特性与干旱灌溉水分生产效率,为芝麻高产栽培的合理灌溉和水分管理提供科学依据,2013-2018年在安徽、新疆等不同地域,选用6个芝麻主栽品种,开展芝麻不同生育阶段需水特性和灌溉水利用研究。结果表明：盆栽芝麻的全生育期蒸腾需水量平均为283.59mm,品种间差异大,形成100kg芝麻籽粒蒸腾需水量为263.56mm(175.7t/666.7m²),苗期、蕾期、初花期、盛花期、终花期、成熟期的蒸腾需水量分别为18.76mm、21.91mm、21.03mm、149.28mm、71.21mm和34.79mm,蒸腾模系数为5.89%、7.21%、6.85%、47.07%、23.93%和9.05%；盛花期最大,出苗期最小。池栽芝麻全生育期需水量531.36mm,其中株间蒸发量、蒸腾量分别占全生育期需水量的46.1%和53.9%；株间蒸发量最大的时期为苗期；蒸腾量最大的时期为花期。芝麻苗期、花期和成熟期需水模系数平均为18.65%、66.79%和14.56%。合肥基地出苗期、临泉基地花期遇旱喷灌,水分生产效率高达0.61kg/m³和0.65kg/m³；新疆精河基地按需滴灌处理比传统滴灌方式的水分生产效率提高43.28%,节水19.61%,这对水资源匮乏的新疆干旱区来说意义重大。芝麻需水量与栽培条件、品种、气温(r＝0.99)等密切相关。在芝麻不同生育阶段遇旱灌溉是提高水分生产效率和产量的关键措施之一。     

基于信息抽取的食品安全事件自动问答系统方法研究

针对从海量食品安全事件新闻报道中很难抽取出所需答案的问题，以食品安全事件语料库为研究对象，提出了一种基于信息抽取技术的自动问答系统。首先，利用深度学习模型TextCNN对用户输入的问题进行分类，得到其所属类型。其次，对于输入问题，借助Lucene搜索引擎找到其最佳匹配文档。再次，根据输入问题的类型，从食品安全事件数据库（采用信息抽取技术自动提取的一个结构化数据库）中筛选出该文档所包含的答案候选句集合。最后，利用深度学习模型Bi LSTM及基于答案候选句上下文的特征提取方法构建一个答案抽取模型，该模型能从给定的答案候选句集合中提取出最终答案。为检查基于食品安全事件数据库的答案候选句筛选方式及基于答案候选句上下文的特征提取方式对整个自动问答系统性能的影响，进行了多种比较实验，结果表明含有基于食品安全事件数据库的答案候选句筛选方式和基于答案候选句上下文的特征提取方式的问答系统表现最佳，其回答准确率达到44%。这相比于传统的问答系统，具有明显的优势。     

农产品监测预警模型集群构建理论方法与应用

【目的】农产品供给与需求的准确分析测定,是农业监测预警能力提升的重要表现。构建产品多品种多环节模型集群理论方法,可高效解决单一环节或单一模型难以解决的分析技术难题。【方法】在农产品供需的重要要素即生产量、消费量、贸易量、价格等分析预测过程中,针对农产品品种间关联性强,自然、社会、经济诸多影响因素纠缠,模型多变量强耦合、非线性、参数时变的特点,提出多品种农产品“因素分类解耦、参数转用适配”方法,以构建多时空维度的监测预警模型集群。【结果】利用“因素分类解耦、参数转用适配”技术方法,研究构建了不同农产品的生产类、消费类、贸易类、价格类的模型集群。这些模型集群可用于对不同时空维度的水稻、玉米、小麦、肉类等主要农产品供需的长中短期的分析预测,支撑形成了农业展望中的主要农产品平衡表,其中主要农产品全国年度生产量6年平均预测精度高于97%。【结论】研究提出的农产品监测预警模型集群构建理论及其方法,有效提升了农产品多品种模型集群的求解效率和准确率,增强了农产品供需分析预测的系统性与智能性,为系统揭示农产品复杂的时空供需变化特征、促进农产品市场调控科学性和可预见性,提供了新技术方法。     

Root architecture of sorghum genotypes differing in root angles under different water regimes

Plant root architecture offers the potential for increasing soil water accessibility, particularly under water-limited conditions. The objectives of this study were to evaluate the root architecture in two genotypes of sorghum (Sorghum bicolor (L.) Moench) differing in root angles and to assess the influence of different deficit irrigation regimes on root architecture. The response of two sorghum genotypes, ‘Early Hegari-Sart’ (EH; steep root angle) and ‘Bk7’ (shallow root angle) to four irrigation treatments was investigated in two replicated outdoor studies using large pots. The results indicated that EH possessed steeper brace and crown root angles, fewer brace roots, greater root biomass, and root length density than Bk7 at deeper soil depths (i.e., 15–30 and 30–45 cm) compared with a shallower depth (i.e., 0–15 cm). Across the soil profile, EH had greater root length density and length of roots of small diameter (<1 mm) than Bk7. Accordingly, EH showed more rapid soil-water capture than Bk7. Different levels of irrigation input greatly affected root architecture. Severe deficit irrigation (25% of full crop transpiration throughout the season) increased the angle and number of crown roots, root biomass, and root length density compared with 75 and 100% of full crop transpiration treatments. Consequently, root system architecture can be effectively manipulated through both genotypic selection and irrigation management to ensure optimal performance under different levels of soil available water.