淮北地区农业干旱预警模型与灌溉决策服务系统

根据2002-2005年3a的田间试验资料和1990-2005年16a的大田土壤水分观测资料,分析确定了安徽淮北地区冬小麦、夏玉米干旱等级指标和适宜土壤水分指标。基于常规气象资料建立了36个逐旬中期降水预报模型,基于温度、降水等气象要素建立了24个土壤墒情逐月回归模型,基于土壤水分平衡方程建立了农业干旱逐旬预报数学模型,对各模型进行综合集成,建立了淮北地区农业干旱综合预警模型。根据干旱预报和降水预报结果,以及作物-土壤适宜水分指标、作物需水量关键期、临界期和土壤水分临界值等,开发了淮北地区冬小麦、夏玉米的干旱预警和灌溉决策计算机服务系统,使用简便快捷,业务化程度高,在近2a的业务应用中,服务效果显著。     

宁夏南部山区农业干旱预警模型

为建立格点尺度上的农业干旱预警模型,根据自然灾害系统理论,综合干旱孕灾环境、致灾因子、承灾体的特征,选择DEM、坡度、坡向、土壤类型、历史干旱风险指数、农业投入量作为孕灾环境稳定性影响因子,选择前期干旱程度、作物水分满足率、作为致灾危险性因子,选择作物种类、作物发育期水分敏感系数、灌溉条件、作物单产水平等作为承灾体脆弱性因子,在干旱灾害系统分析的基础上,采用层次分析法（AHP）量化影响因子的影响系数,建立基于GIS和空间插值的宁南区域农业干旱预警累乘模型。检验结果表明,预警模型输出干旱等级与实测符合率达到90%以上,能准确预测未来干旱发展趋势和分布范围,比现有基于气候干旱指数的预警模型空间分辨率明显提高,模型输出结果更能反映农业干旱的发生、发展过程,模型可用于区域干旱预警和干旱趋势预测。     

甘肃省冬小麦水分盈亏指数的改进及其应用

冬小麦是甘肃省主要粮食作物,水分是限制该省旱作冬小麦生产最主要的因素,降水时空分布不均造成冬小麦干旱常年发生,因此准确监测甘肃省冬小麦干旱及定量评估灾害损失可为决策部门制定农业防灾减灾措施及保障区域粮食安全提供科学依据。利用甘肃省1981—2014年3个农业气象观测站土壤水分和冬小麦生育状况观测资料,38个冬小麦种植县气象资料、产量资料及干旱灾情资料,考虑冬小麦休闲期土壤储水及生育期水分盈亏量修订了作物水分盈亏指数,修订后作物水分盈亏指数与土壤储水、冬小麦产量要素和产量损失相关性较高,能客观、准确、定量地反映干旱对甘肃冬小麦产量的影响;利用水分盈亏指数分别建立冬小麦产量要素和产量损失评估模型。结果表明:产量要素评估模型均通过0.01水平显著性检验,产量损失评估模型大部分通过0.05水平显著性检验。产量要素评估模型回代结果与冬小麦产量要素实测值间均通过0.01水平的F检验;产量损失评估模型验证结果表明,68.4%种植县通过0.05水平F检验,基本能准确评估全省大部分地方干旱对冬小麦产量造成的损失。修订后作物水分盈亏指数能客观反映甘肃省冬小麦干旱,建立的评估模型能准确评估干旱对冬小麦造成的损失,具有一定的应用价值。     

基于CERES-Maize模型的玉米水分关键期干旱指数天气保险：以陕西长武为例一

水分关键期干旱是影响玉米生长和产量的主要限制因子,构建此时期玉米干旱损失模型,研究干旱指数天气保险,对于合理设计天气指数保险和解决目前传统农业保险的困境,转移农业气象灾害风险具有重要意义。针对作物特定阶段单因子气象灾害影响难以剥离的问题,本研究在西北农林科技大学旱作农业长武试验站进行了连续3a的雨养玉米观测试验,利用田间试验数据(玉米生长发育数据、气象数据、土壤数据和田间管理数据)对CERES-Maize模型进行参数校正和验证,模拟玉米水分关键期(6月21日-8月31日)干旱对生长和产量的影响,构建干旱损失模型;依据长武1990-2019年的气象数据,利用EasyFit软件筛选出玉米水分关键期干旱指数最优分布模型,模拟干旱发生概率;结合干旱损失模型,利用纯费率精算方法厘定玉米水分关键期干旱指数保险费率;采用投影寻踪的统计方法,设计干旱指数保险赔付方案。结果表明,CERES-Maize模型校正和验证的平均绝对相对误差ARE和相对均方根误差RRMSE都小于10%,符合作物模型模拟精度的要求;模拟的干旱指数(DI)与玉米减产率(y,%)间呈显著的线性函数关系,即y=-0.55DI+107.17;Log-logistic模型对干旱指数分布的拟合精度最高,Anderson-Darling(AD)检验值仅为0.20,轻旱、中旱、重旱和特旱发生的概率分别为9.75%、5.90%、3.71%和3.50%。基于Log-logistic模型厘定的玉米水分关键期干旱指数保险费率为5.6%。在玉米生长水分关键期,干旱指数保险的起赔点为DI=185,DI≤185时,进行分级赔付。     

土壤湿度驱动WOFOST模型及其适应性

WOFOST作物生长模型是以日降水量表征降水输入参数,通过推算土壤相对湿度实现作物生长模拟。由于日降水量随机性较大,很难通过控制日降水量实现不同土壤干旱等级情景设置,限制了WOFOST作物生长模型在不同水分胁迫下对作物生长的模拟,也影响了模拟试验的精度。本文提出以土壤相对湿度直接驱动WOFOST作物生长模型,并以Compaq Visual Fortran 6.5为开发平台,采用Fortran语言对WOFOST作物生长模型的源代码进行修改,将驱动模块中的日降水量文件替换为土壤相对湿度驱动文件。以2013年山东省夏津农业气象试验站玉米出苗-拔节期和抽雄-成熟期水分胁迫和整个生育期自然降水处理（对照）的试验数据为例,对修改后的WOFOST作物生长模型进行了模拟试验。结果显示,采用修订后的模型输出的实测鲜叶干重、鲜茎干重、营养器官干重、地上物质总重和叶面积指数等生物量指标均较原模型输出结果,不仅精度明显提高,而且,由于土壤湿度变化较平稳,较容易地实现了不同水分胁迫情景设置,进而实现不同土壤干旱等级条件下玉米生长的模拟,为分析不同程度干旱对玉米生长的影响及确定其生长发育指标提供了便利条件。     

采用AquaCrop作物生长模型研究中国玉米干旱脆弱性

干旱脆弱性评价作为干旱风险评估和灾损评估的重要环节,在保障国家粮食安全和农业可持续发展中具有重大意义。该文以中国5大玉米种植区为研究区域,以其中241个主要玉米种植城市为基本单元,采用扩展傅里叶幅度检验法选取出2个敏感参数(作物冠层形成后到衰老之前的作物系数和参考收获指数),并在此基础上对AquaCrop作物模型进行逐市的参数标定。利用参数标定后的模型对不同灌溉条件下玉米受到的水分胁迫及相应情景下的产量进行模拟计算,分别建立了5个玉米种植区对应的干旱脆弱性曲线。结果表明:5个区域的脆弱性曲线拟合结果均为S形曲线,当干旱强度指标达到0.2附近时,产量损失率开始迅速增加;当干旱强度指标达到0.6左右时,产量损失率接近最大值。拟合函数的决定系数R^2分别在0.47~0.98之间,曲线拟合结果较好,在中国区域性玉米干旱脆弱性研究与干旱风险评估领域具有一定的理论与应用价值。     

基于遥感信息的区域农业干旱模拟技术研究

区域农业干旱监测预测对农业生产具有十分重大的指导意义,但受观测手段所限,目前大范围的区域农田水分信息尚无法通过常规观测直接获取。利用微波遥感(AMSR-E)获取大范围农田水分信息,继而与作物干旱模型结合对河南省冬小麦农业干旱发生发展进行了模拟研究。结果表明,加入遥感信息后,作物干旱模型对冬小麦生长发育的模拟能力有较大提高,并且区域农业干旱的模拟结果更加接近实际情况。研究表明,将遥感信息与作物干旱模型相结合,可以提高模型对农业干旱的模拟能力,这为农业旱情监测预测提供了更有力的科技支撑。     

气候变化下干旱对中国玉米产量的影响

了解干旱的时空变化特征及其对农业生产的影响对于维护农业可持续发展具有重要意义。该研究以中国五大主要玉米种植区中241个地级行政单元作为研究对象,采用AquaCrop作物模型分别对rcp2.6、rcp4.5、rcp8.5,3种代表性浓度路径情景中玉米在不同灌溉条件下的受到的水分胁迫及相应产量进行模拟,在此基础上通过建立回归模型评估干旱强度对玉米产量损失的影响。结果表明,1)未来中国的干旱强度分布及玉米产量损失在空间上均呈现由西北至东南递减的趋势;2)未来时期全国大部分地区干旱水平相比于历史时期有所上升;3)玉米干旱损失率随干旱指数的变化特征符合Logistic曲线,回归结果的R~2为0.96。4)未来北方春播玉米区和黄淮海夏播玉米区的玉米产量对干旱强度反应最敏感,应当引起格外重视。     

基于土壤-作物系统模拟模型的冬小麦田间水氮优化管理

将作物生长模型与土壤水氮管理过程模块相结合，构建了土壤-作物系统水分养分模拟模型。以灌水、施氮总量为决策变量，冬小麦生物量、水分和氮肥利用效率为优化目标，将冬小麦按生长发育时期分为6个阶段，建立了多目标的动态规划模型。在土壤-作物系统过程模型的基础上，用动态规划的方法对田间水、氮资源管理措施进行优化。通过对作物水分胁迫系数和氮肥胁迫系数的模拟计算，可获得最佳的灌水、施肥时间及用量。算例结果表明：在养分供应充足仅水分胁迫的条件下，优化方案的灌水量较对照处理平均节约了25%，水分利用效率比对照处理平均高出约1     

深度学习技术在农业干旱监测预测及风险评估中的应用

人工智能技术的发展，特别是深度学习的出现，推进了农业新发展，是农业现代化生产的新方向。深度学习具有学习能力强、覆盖范围广、适应力强、可移植性好等优点，其开发模拟数据集可以解决实际问题，在农业干旱的监测预测及风险评估中的应用越来越广泛。本文采用文献综述方法，归纳农业干旱监测预测评估技术的发展与应用，总结深度学习模型的原理、优势和不足，概述深度学习模型在农业干旱监测预测及风险评估方面的实际应用，探讨深度学习数据集要求大、数据预处理耗时长、预定义类别范围窄、遥感图像复杂的问题，并对未来研究方向进行展望。结果表明，近年来农业干旱监测预测及风险评估技术取得重要进展，然而由于农业系统的非线性及干旱灾害发生的复杂性，现有技术在适用地域、对象和精准性等方面仍难以满足新形势下实际农业生产的需求。深度学习方法为农业干旱研究提供了新手段，但深度学习模型无法准确表达作物生长具体过程与机理，可尝试探索通过深度学习模型和作物生长模型的耦合来确保深度学习模型的可解释性。对于修正预测序列中存在的误差，可建立基于深度学习模型与大气环流模式的耦合模型，进一步提升模型对中长期农业干旱的预测能力。针对灾害样本容量有限问题，加...     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.