Modelling crop yield response to precipitation redistribution on slopes

In undulating or sloping land, water distribution in soil has a major influence on crop yield through stresses on vegetation. It is difficult to predict the impacts, however, so a crop model is required to simulate topography-related horizontal redistribution of summer precipitation and its effect on yield. This study uses a potato model (POMOD), operating with the concept of meteorologically possible yield (MPY). It was supplemented to assess precipitation redistribution by runoff on a sloping surface. Slope incline, soil moisture and rainfall intensity were environmental parameters, with rainfall intensities replaced empirically with more convenient daily rainfall sums. Differences in the water balance, as compared to a non-sloping level surface, were computed for three different parts of a notional slope 3°. Modelled differences from long-term meteorological data allowed computation of comparative long-term series of MPY in two climatologically different localities in Estonia. These were the generally moister Tallinn and the frequently dry Kuressaare regions. The locations responded differently, but there was a significant influence in both of slope on potato yield. In the frequently dry Kuressaare, yield was limited by water deficiency, as was characterized by the change in MPY through slope. However, the moister Tallinn had the worst growing conditions at the foothill due to excess water. Tallinn had the greatest topography-related differences, leading to the conclusion that excess water causes more loss in potato yield than drought in Estonia. Events of extreme rainfall drive these losses.     

气候变化背景下中国南方地区季节性干旱特征与适应Ⅵ.防旱避灾种植模式优化布局

南方地区是我国重要的农业种植区,季节性干旱严重影响该地区的农业生产.本文基于南方地区不同干旱分区中选取的13个典型地区1981-2007年气象资料和作物生育期、产量等资料,依据各地逐年降水量将其分为干旱年、正常年和丰水年3种不同降水年型,利用作物水分临界期需水量与降水量的耦合度、气象产量、单位面积产值以及全生育期的水分利用效率和降水量5个指标,对典型地区种植模式的综合效益进行评价,得到南方不同区域不同降水年型下的优化种植模式.结果表明: 半干旱区在干旱年型下,宜采取2种抗旱种植模式：马铃-玉米-甘薯和冬小麦-中稻-甘薯.半湿润区在干旱年型下,种植模式以冬小麦-中稻-甘薯最优,油菜-中稻-甘薯次之.在温润区(即典型的季节性干旱区),江南地区在3种年型下均以马铃薯-双季稻最优;西南地区宜搭配抗旱作物进行三熟制种植,如冬小麦-中稻-甘薯、冬小麦-玉米-甘薯、马铃薯-双季稻等.从最大程度利用水热资源角度考虑,三熟种植模式最优,以水旱轮作为主,丰水年型宜搭配水稻.     

A deep learning approach to conflating heterogeneous geospatial data for corn yield estimation: A case study of the US Corn Belt at the county level

Understanding large‐scale crop growth and its responses to climate change are critical for yield estimation and prediction, especially under the increased frequency of extreme climate and weather events. County‐level corn phenology varies spatially and interannually across the Corn Belt in the United States, where precipitation and heat stress presents a temporal pattern among growth phases (GPs) and vary interannually. In this study, we developed a long short‐term memory (LSTM) model that integrates heterogeneous crop phenology, meteorology, and remote sensing data to estimate county‐level corn yields. By conflating heterogeneous phenology‐based remote sensing and meteorological indices, the LSTM model accounted for 76% of yield variations across the Corn Belt, improved from 39% of yield variations explained by phenology‐based meteorological indices alone. The LSTM model outperformed least absolute shrinkage and selection operator (LASSO) regression and random forest (RF) approaches for end‐of‐the‐season yield estimation, as a result of its recurrent neural network structure that can incorporate cumulative and nonlinear relationships between corn yield and environmental factors. The results showed that the period from silking to dough was most critical for crop yield estimation. The LSTM model presented a robust yield estimation under extreme weather events in 2012, which reduced the root‐mean‐square error to 1.47 Mg/ha from 1.93 Mg/ha for LASSO and 2.43 Mg/ha for RF. The LSTM model has the capability to learn general patterns from high‐dimensional (spectral, spatial, and temporal) input features to achieve a robust county‐level crop yield estimation. This deep learning approach holds great promise for better understanding the global condition of crop growth based on publicly available remote sensing and meteorological data.     

The meteorological sensitivity of ischaemic heart disease mortality events in Birmingham, UK

Winter ischaemic heart disease (IHD) mortality events (ME) were identified in order to establish their degree of meteorological sensitivity. Sensitivity was evaluated using regression of surface meteorological and large-scale atmospheric circulation variables on daily mortality for each mortality event. Critical meteorological variables affecting IHD mortality appear to be local surface dry-bulb and dew-point temperature and large-scale southerly and westerly wind components, atmospheric pressure and vorticity. The rate of change and departure from normal conditions of these variables appear to be especially important for engendering IHD mortality events. Associated with IHD mortality are two broad types of weather conditions: (1) blustery westerly flows and rapidly changing weather from the west and (2) climatologically strong northeasterly to southeasterly flows of cold air, which bring rapidly changing and anomalous thermal conditions to the study area. The general atmospheric circulation patterns that produce these conditions are identified and the implications of results for weather and health studies are discussed. Received: 24 October 2000 / Revised: 16 April 2001 / Accepted: 18 April 2001     

基于干热风危害指数的黄淮海地区冬小麦干热风灾损评估

全球气候变化背景下,农业气象灾害呈上升态势。干热风灾害发生区域、次数和强度都发生了明显的变化。研究干热风灾害对农作物的影响对于我国农业可持续发展、保障粮食安全等均具有重要的现实意义。利用黄淮海地区68个气象台站1961—2010年的逐日气象资料,和54个农业气象试验站1981—2006年小麦的发育期、产量、干热风灾害等数据,采用公认的中国气象局2007年发布的气象行业标准《小麦干热风灾害等级》中冬小麦干热风灾害指标,计算干热风危害指数,进一步细化发育期,确定冬小麦抽穗前气象条件对气象产量影响的关键气象因子,分离干热风年冬小麦气象产量,构建重度干热风影响下干热风危害指数与冬小麦抽穗—成熟阶段气象条件对气象产量影响的统计模型,进行1981—2006年黄淮海地区冬小麦干热风灾损的评估。结果表明:(1)重度干热风危害下,1981—2006年期间黄淮海各地区冬小麦不同发育时段的干热风危害指数平均在抽穗—开花时段最大,乳熟—成熟时段居中,开花—乳熟时段最小,分别为0.17、0.15和0.14,平均0.15;(2)冬小麦抽穗前气象条件对气象产量影响的关键气象因子为:播种—出苗期间的最低气温、拔节—孕穗期间的平均气温和孕穗—抽穗期间的平均气温,各个单因子相关系数分别为0.64、0.86和0.99,均达到极显著水平。其中播种—出苗的最低气温可决定小麦出苗的迟早和苗情;拔节—孕穗期间,在小花原基形成期—四分体形成期气温偏低可延长小穗、小花分化时间,防止退化,提高结实率;孕穗—抽穗的平均气温偏高有利于提早抽穗,延长后期灌浆时间,且晴天有利于开花授粉;(3)分离干热风年冬小麦气象产量后,构建了重度干热风影响下干热风危害指数与冬小麦抽穗—成熟3个阶段气象条件对气象产量影响的统计模型,验证结果表明该模型客观上能够综合地反映干热风在不同发育阶段对小麦产量的影响。进一步灾损评估表明:重度干热风危害下,黄淮海地区冬小麦减产率在21.52%—39.80%之间,平均为27.83%。     

西北温凉半湿润区气候变化对马铃薯生长发育的影响——以甘肃岷县为例

利用西北温凉半湿润区马铃薯生长发育定位观测资料、加密观测和对应平行气象观测资料,分析气候变化对马铃薯生长发育的影响,以及马铃薯块茎生长与气象条件的关系。结果表明,研究区域降水量年际变化呈下降趋势,降水量变化曲线线性拟合倾向率为-8.329 mm/10 a。降水量存在3 a的年际周期变化。气温年际变化呈上升趋势,气温变化曲线线性拟合倾向率为0.144℃/10 a。作物生长季干燥指数呈显著上升趋势,干燥指数变化曲线线性拟合倾向率为0.042/10 a,20世纪90年代初至2007年明显趋于干旱化。马铃薯播种到采收约需150-168d,需≥0℃积温2000-2300℃,降水量400-500mm,日照时数900-1100h。马铃薯在播种后105d开始,块茎由缓慢生长转为迅速生长阶段;在播种后127d,块茎生长速度最大;播种后149d开始,块茎生长从迅速生长又转为缓慢生长。对马铃薯生长发育全生育期而言,受气候变暖的影响,马铃薯花序形成期每10 a提前8-9d,开花期每10 a提前4-5d。气温对马铃薯产量形成除采收期外,其余为负效应,块茎膨大期对气温变化十分敏感;而降水量的影响函数同热量的影响函数呈反相位分布,除出苗期和采收期降水量为负效应外,其余时段降水量对马铃薯产量形成均为正效应,马铃薯分枝期到开花期对降水量变化十分敏感。     

Modelling the predicted geographic and economic response of UK cropping systems to climate change scenarios: the case of potatoes

Geographical changes in suitability in England and Wales for the cultivation of potatoes under a climate change scenario were predicted for the years 2023 and 2065 by integrating a climate database (1951-80) with climate-driven crop growth models. Initially, model outputs were produced as point values (meteorological site locations) of predicted potential yields for current crop production. The model outputs were validated statistically using actual crop yield figures collated from bibliographic analysis. The most suitable model was run again incorporating projected temperature and precipitation changes for 2023 and 2065. These outputs were then used to predict possible economic changes to farm profitability and general market trends. Results indicated that, although yields may rise, gross margins for maincrop and especially early potatoes may also rise due to shifts in production, to a fall in overall potato output and to price increases.     

基于降水利用比较分析的四川省种植制度优化

比较分析四川8个农业生态区典型站点及其主要种植模式的降水盈亏产量降低率、产量降低率风险指数、降水利用效率和降水经济效率。结果表明:(1)四川省不同区域、不同种植模式、不同作物及其不同生育阶段基于降水盈亏的产量降低率多年均值差异较大。区域分布上,雅安最低,仅23％,攀西最高,达50％以上,其余地区30％-40％;种植制度上,麦-玉-苕等旱三熟低于麦-稻等水旱轮作两熟制;作物种类上,冬小麦、冬油菜、秋播马铃薯等作物普遍高于水稻、玉米、棉花、红薯和大豆作物;生育阶段上,冬小麦、冬油菜、秋播马铃薯作物开花前后普遍较高,各种作物生育末期较低。(2)基于自然降水,攀西地区遭遇旱灾的风险极大,麦-玉-苕等旱三熟的产量降低率风险指数相对较小;雅安等盆地内部多数区域由于阶段性降水过多引起湿害偏重,导致麦-稻等水旱轮作两熟制略优于旱三熟。基于降水利用效率和降水经济效率,各地比较一致,较优的种植制度首先是麦(油、薯)-稻两熟制,其次才是麦(油)-玉-苕(豆)旱三熟。(3)综合旱涝灾害风险、降水利用效率和降水经济效率,以及复杂地形等因素,有较好灌溉条件的农田应以麦(油、薯)-稻水旱轮作两熟制为主,而无水源保障的旱地则以麦(油)-玉-苕(豆)旱三熟为主。     

气候变化对中国农作物病害发生的影响

基于全国农区527个气象站点1961—2010年逐日气象资料、逐年农作物病害发生面积以及产量资料,从气温、降水、日照等角度,采用相关分析方法,研究了气候变化背景下各气象要素变化对中国农作物病害发生的影响。结果表明:近50年来,气候变化导致的各气象因子变化总体有利于病害发生,年平均温度以0.27℃·10a-1的速率升高,其每升高1℃,可导致病害发生面积增加6094.4万hm2次;年平均降雨强度以0.24mm·d-1·10a-1的速度增加,其每增加1mm·d-1,可导致病害发生面积增加6540.4万hm2次;年平均日照时数以47.4h·10a-1的速率减少,其每减少100h,可导致病害发生面积增加3418.8万hm2次;在气候变化导致的光、温、水变化中,温度增加对病害发生面积增加的影响最为显著,其次为日照时数减少、第三为平均降雨强度增大,其标准化回归系数依次为0.508、-0.374、0.112。     

甘肃马铃薯种植布局对区域气候变化的响应

基于甘肃省地面气象观测站1961—2008年气象观测资料和马铃薯生长条件,选择最佳小网格推算模型推算出500m×500m的高分辨率的网格序列;确立马铃薯种植适宜性气候区划指标,结合地理信息资料,运用GIS技术,开展马铃薯种植适宜性动态气候区划。结果表明:气候变化使马铃薯最适宜区和适宜区面积分别减小35%和3%,次适宜区和可种植区面积分别扩大18.5%和6.6%,不适宜区面积缩小2.0%。提出了马铃薯应对气候变化建议:各地应根据气候特点,调整作物布局;适当调整播种日期,躲避影响马铃薯产量的春霜冻、块茎形成期的高温危害及伏期干旱等;采取多种农业措施,扩大马铃薯种植面积,提高复种指数。预计随着未来气候进一步变暖,该地区的马铃薯生长发育、产量和结构布局将会继续受到影响,研究成果可为甘肃马铃薯生产以及适应气候变化提供科学参考依据。     

Influence of high temperature on carbon assimilation,enzymatic antioxidants and tuber yield of different potato cultivars

High temperature is one of the major limiting factors for cool season crops like potato in many parts of the world. This problem is more aggravated in early season planting of potato crop. This study was conducted to evaluate the performance of five potato cultivars (Solanum tuberosum L. cultivars Kufri jyoti, Kufri megha, Kufri pokraj, Rangpuria and Badami) under normal (mid October–mid January) and early season (mid August–late October) conditions during two consecutive years in terms of carbon assimilation, activities of antioxidant enzymes and tuber yield. Temperature during growth of early season crop remained 2–14°C higher than in the normal season crop, which imposed severe heat stress on early season crop. However, this heat stress in early season crop caused several folds increase in the activity of antioxidant enzymes, which had strong positive correlation with tuber yield. Although tuber yield of all tested cultivars was less in early season than in normal season; nonetheless cultivars Kufri megha and Rangpuria performed better in early season planting owing to higher net photosynthesis, carotenoid contents, membrane stability, and activities of enzymatic antioxidant enzymes. In crux, carotenoids, activities of enzymatic antioxidants, carbon assimilation and membrane stability may be used as physiological markers in future breeding programs aimed to improve the heat resistance in potato.     

基于作物需水与自然降水适配度的湖南省防旱避灾种植制度优化

季节性干旱对湖南省农业生产造成很大影响,明确防旱避灾种植制度,可为指导当地农业生产提供科学依据。基于湖南省代表站点1981-2007年的气候数据和作物生育期资料,依据干燥度和地形地势特点,划分不同类型区,并在各区域内选取代表站点和代表性种植制度,采用FAO推荐的分段单值平均作物系数法订正了作物系数。比较了主要种植制度的作物需水与自然降水适配度及作物需水与自然降水适配度保证指数,确定了湖南省基于自然降水的防旱避灾种植制度。研究结果表明:各区域基于自然降水资源的防旱避灾种植制度分别为:(1)湘中偏北湿润中低海拔地形复杂区和湘东北半湿润中低海拔山地丘陵区为麦-稻和薯-稻种植模式;(2)湘北半湿润低海拔平原区为油-棉、油-稻和豆-稻种植模式;(3)湘东偏北半干旱低海拔平原与盆地丘陵过渡区为油-苕、油-棉和油-稻种植模式;(4)湘东南较干旱中低海拔丘陵区为油-稻、麦-稻和薯-稻种植模式;(5)中南部较干旱中低海拔盆地区为油-稻和油-棉种植模式;(6)湘西北较湿润中高海拔中山低山区为薯-稻和油-苕种植模式;(7)湘西南较湿润中高海拔丘陵区为油-苕、油-稻、麦-稻和薯-稻种植模式;(8)湘西干旱高海拔山地丘陵区为油-苕和油-棉种植模式。     

Integrated Approach to the Control of the Golden Nematode, Heterodera Rostochiensis

Under high population densities of Heterodera rostochiensis, control is impossible by one method alone, whether by chemical means, crop rotation, or the use of resistant potato varieties. Integrated control using thiazone (DMTT) in autumn, resistant potato hybrid 61-8/1, or Solanum andigenum cultivars ''Antinema'' and ''Specula'', followed by cereal and clover reduced the population below the detection level in the upper 18-cm on small plots on sandy loam soil.     

An evaluation of nutritional constraints on sweet potato (Ipomoea batatas) production in the central highlands of Papua New Guinea

Sweet potato (Ipomoea batatas) is the staple food crop in the highlands of Papua New Guinea (PNG). Declining crop productivity, however, appears to be threatening the sustainability of sweet potato-based farming systems within the region, a probable cause being the exhaustion of soil nutrient reserves in continuously cultivated sweet potato gardens. To assess the extent of the problem, a survey of sweet potato gardens was conducted across four of the highlands provinces and information on soil and crop variables was obtained for old gardens (cultivated over many seasons) and new gardens (newly brought into cultivation) on soils of volcanic and non-volcanic origin. Crop leaf nutrient data collected in the survey were interpreted using the Diagnosis and Recommendation Integrated System (DRIS), to try to identify the main nutritional constraints on tuber production in different garden types on soils of volcanic or non-volcanic origin. The results suggested that K deficiency was the primary cause of poor crop production in almost a third of sweet potato gardens, but was more of a problem in old gardens than in new. Phosphorus deficiency was also a problem on volcanic soils, and S deficiency on non-volcanic soils. These latter deficiencies, however, were at least as prevalent in new gardens as in old. Important factors contributing to K and S depletion from garden systems were the removal of K and S-rich vines from cultivation areas, the shortening of fallow periods and the burning of weed and crop residues, the latter releasing S (SO₂) to the atmosphere. Correction of K and S deficiencies may require the recycling of old vines back to sweet potato cultivation areas and the adoption of a zero-burn policy for fallow management. Correction of P deficiency may necessitate the use of P-accumulating fallow species, e.g. wild Mexican sunflower (Tithonia diversifolia), to extract the P fixed by sesquioxide and allophanic minerals     

Support vector machine-based open crop model (SBOCM): Case of rice production in China

Existing crop models produce unsatisfactory simulation results and are operationally complicated. The present study, however, demonstrated the unique advantages of statistical crop models for large-scale simulation. Using rice as the research crop, a support vector machine-based open crop model (SBOCM) was developed by integrating developmental stage and yield prediction models. Basic geographical information obtained by surface weather observation stations in China and the 1:1000000 soil database published by the Chinese Academy of Sciences were used. Based on the principle of scale compatibility of modeling data, an open reading frame was designed for the dynamic daily input of meteorological data and output of rice development and yield records. This was used to generate rice developmental stage and yield prediction models, which were integrated into the SBOCM system. The parameters, methods, error resources, and other factors were analyzed. Although not a crop physiology simulation model, the proposed SBOCM can be used for perennial simulation and one-year rice predictions within certain scale ranges. It is convenient for data acquisition, regionally applicable, parametrically simple, and effective for multi-scale factor integration. It has the potential for future integration with extensive social and economic factors to improve the prediction accuracy and practicability.     

基于地理探测的黄土高原植被生长对气候的响应

为探讨黄土高原不同植被类型对气候变化的响应机制,以2002-2019年黄土高原归一化植被指数(NDVI)数据为基础,利用趋势分析、Hurst指数、地理探测器等方法分析不同植被类型NDVI变化趋势及其与气象因子的关系.结果 表明:2002-2019年,黄土高原不同植被类型NDVI以增长趋势和同向中持续性为主,仅栽培植被在...     

The variation of the water deficit during the winter wheat growing season and its impact on crop yield in the North China Plain

The North China Plain (NCP) is one of the main agricultural areas in China. However, it is also widely known for its water shortages, especially during the winter wheat growing season. Recently, climate change has significantly affected the water environment for crop growth. Analyzing the changes in the water deficit, which is only affected by climate factor, will help to improve water management in the NCP. In this study, the Decision Support System for Agrotechnology Transfer (DSSAT) was used to investigate the variations in the water deficit during the winter wheat growing season from 1961 to 2010 in 12 selected stations in the NCP. To represent the changes in the water deficit without any artificial affection, the rainfed simulation was used. Over the past 50 years, the average temperature during the winter wheat growing season increased approximately 1.42 °C. The anthesis date moved forward approximately 7–10 days and to late April, which increased the water demand in April. Precipitation in March and May showed a positive trend, but there was a negative trend in April. The water deficit in late April and early May became more serious than before, with an increasing trend of more than 0.1 mm/year. In addition, because the heading stage, which is very important to crop yield of winter wheat, moved forward, the impact of water deficit in late April was more serious to crop yield.     

Quantitative proteomics to study the response of potato to contrasting fertilisation regimes

There is concern over the sustainability and environmental impact of mineral fertilisers and crop protection inputs used in intensive arable crop production systems. However, replacing mineral with organic fertilisers (animal and green manures) and restricting the use of chemosynthetic crop protection may significantly reduce crop yields. The effects of (a) replacing mineral with composted cattle manure fertiliser input and (b) omitting pesticide-based crop protection on potato (Solanum tuberosum) tuber yield, leaf and tuber mineral nutrient content and leaf protein profiles were investigated. Switching to organic fertiliser had a greater effect on yield and protein profiles than the omission of chemosynthetic crop protection. Leaf N and P composition were significant drivers of protein expression, particularly proteins involved in photosynthesis such as the large subunit of RuBisCO, RuBisCO activase and the photosystem I reaction centre, which were at higher abundances in potato leaves grown under mineral fertiliser regimes. Proteins known to be induced in response to stress, such as dehydroascorbate reductase and Glutathione S-transferases, were also shown to be up-regulated under mineral fertilisation, possibly associated with higher Cd composition, whereas two proteins known to be involved in biotic stress (1,3-β-d-glucan glucanohydrolase; putative Kunitz-type tuber invertase inhibitor) were more abundant under compost fertilisation. Results showed that switching from mineral to organic fertilisers led to reduced N availability, a significant change in leaf protein expression and lower tuber yield. In contrast, omission of chemosynthetic crop protection inputs had limited effects on protein expression and no significant effect on tuber yield. This study provides information on the effects of changes in nutrient supply on protein expression patterns. It is a prerequisite for the development of functional molecular markers for a directed strategy to inform breeding programmes to improve potato nutrient use efficiency.     

Analysis of a large dataset of mycorrhiza inoculation field trials on potato shows highly significant increases in yield

An increasing human population requires more food production in nutrient-efficient systems in order to simultaneously meet global food needs while reducing the environmental footprint of agriculture. Arbuscular mycorrhizal fungi (AMF) have the potential to enhance crop yield, but their efficiency has yet to be demonstrated in large-scale crop production systems. This study reports an analysis of a dataset consisting of 231 field trials in which the same AMF inoculant (Rhizophagus irregularis DAOM 197198) was applied to potato over a 4-year period in North America and Europe under authentic field conditions. The inoculation was performed using a liquid suspension of AMF spores that was sprayed onto potato seed pieces, yielding a calculated 71 spores per seed piece. Statistical analysis showed a highly significant increase in marketable potato yield (ANOVA, P?<?0.0001) for inoculated fields (42.2 tons/ha) compared with non-inoculated controls (38.3 tons/ha), irrespective of trial year. The average yield increase was 3.9 tons/ha, representing 9.5 % of total crop yield. Inoculation was profitable with a 0.67-tons/ha increase in yield, a threshold reached in almost 79 % of all trials. This finding clearly demonstrates the benefits of mycorrhizal-based inoculation on crop yield, using potato as a case study. Further improvements of these beneficial inoculants will help compensate for crop production deficits, both now and in the future.     

Climate,weather and flu diagnoses incidence in the region of Santander (Northern Spain) during the 1999–2000 epidemic diffusion period

The primary purpose of this article is to create a new branch of research to explore how climate and weather conditions affect the epidemic diffusion of the flu virus. The applied methodology is called di-break-ib. The study focused on three parameters: diversity of atmospheric circulation types, breaks occurring when circulation types changed, and the intensity of those breaks. All of these factors were found in the atmospheric circulation patterns that affected the region of Santander, Spain during the 1999–2000 flu epidemic. Results demonstrated that atmospheric circulation changes were significantly related to the weekly number of flu cases diagnosed. Meteorological variables such as temperature and air humidity can be treated as risk indicators for increases in flu cases. This information opens the possibility of using atmospheric data to create an alert system for health centres during high-risk periods.