A New Economic Assessment Index for the Impact of Climate Change on Grain Yield

The impact of climate change on agriculture has received wide attention by the scientific community. This paper studies how to assess the grain yield impact of climate change, according to the climate change over a long time period in the future as predicted by a climate system model. The application of the concept of a traditional ＂yield impact of meteorological factor （YIMF）＂ or ＂yield impact of weather factor＂ to the grain yield assessment of a decadal or even a longer timescale would be suffocated at the outset because the YIMF is for studying the phenomenon on an interannual timescale, and it is difficult to distinguish between the trend caused by climate change and the one resulting from changes in non-climatic factors. Therefore, the concept of the yield impact of climatic change （YICC）, which is defined as the difference in the per unit area yields （PUAY） of a grain crop under a changing and an envisaged invariant climate conditions, is presented in this paper to assess the impact of global climate change on grain yields. The climatic factor has been introduced into the renowned economic Cobb-Douglas model, yielding a quantitative assessment method of YICC using real data. The method has been tested using the historical data of Northeast China, and the results show that it has an encouraging application outlook.

Impacts of precipitation variation and soil and water conservation measures on runoff and sediment yield in the Loess Plateau Gully Region, China

The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.

Impacts of Climate Change on Rice Yield in China From 1961 to 2010 Based on Provincial Data

The impacts of climate change on rice yield in China from 1961 to 2010 were studied in this paper, based on the provincial data, in order to develop scientiifc countermeasures. The results indicated that increase of average temperature improved single cropping rice production on national level by up to 11%relative to the average over the study period, however, it resulted in an overall loss of double cropping rice by up to 1.9%. The decrease of diurnal temperature range （DTR） in the major producing regions caused the decrease by up to 3.0%for single cropping rice production and 2.0%for double cropping rice production. Moreover, the contribution of precipitation change reached about 6.2%for single cropping rice production, but no signiifcant effect for double cropping rice production in recent 50 years.

Impact of <i>Cowpea mottle virus</i>on the Growth and Yield of Bambara Groundnut (<i>Vigna subterranean</i>(L.) Verdc.)

Bambara groundnut [Vigna subterranean (L.) Verdc] is a food legume with high potential for food security in Sub-Saharan Africa. However, in addition to being a neglected crop, its production is limited by several constraints among which viral diseases are most cited. In order to contribute to the improvement of Bambara groundnut in Burkina Faso, local accessions of the crop were screened for resistance to Cowpea mottle virus (CPMoV), one of the most damaging viruses in grain legumes. Seven local accessions (C1 to C7) from two agro-ecological zones were evaluated by mechanical inoculation in field conditions in 2016 and 2017. The infected plants exhibited various symptoms of chlorosis, leaf deformation, growth retardation and plant stunting. CPMoV caused a significant reduction in the number of flowers and pods. As a result, grain yield was reduced by 49.5% to 83.9% depending on the accessions. The impact of the virus in yield loss was lowest in accessions C6 and C7 which indicated their possible used in the management of Cowpea mottle virus disease in bambara groundnut.

Spatial Pattern of Cotton Yield Variability and Its Response to Climate Change in Cotton Belt of Pakistan

Cotton is a revenue source for cotton-producing countries;as the second-largest crop in Pakistan,it significantly contributes to its economy.Over the past few decades,cotton productivity has become unstable in Pakistan,and climate change is one of the main factors that impact cotton yield.Due to climate change,it becomes very important to understand the change trend and its impact on cotton yield at the regional level.Here,we investigate the relationship of standardized cotton yield variability with the variability of climate factors using a 15-yr moving window.The piecewise regression was fitted to obtain the trend-shifting point of climate factors.The results show that precipitation has experienced an overall decreasing trend of–0.64 mm/yr during the study period,with opposing trends of–1.39 mm/yr and 1.52 mm/yr before and after the trend-shifting point,respectively.We found that cotton yield variability increased at a rate of 0.17%/yr,and this trend was highly correlated with the variability of climate factors.The multiple regression analysis explains that climate variability is a dominant factor and controlled 81%of the cotton production in the study area from 1990 to 2019,while it controlled 73%of the production from 1990 to 2002 and 84%from 2002 to 2019.These findings reveal that climate factors affact the distinct spatial pattern of changes in cotton yield variability at the tehsil level.

秸秆还田配施化肥对土壤养分及青稞农艺性状、产量的影响

本研究旨在探讨西藏地区油菜秸秆还田与化肥配施对土壤养分、青稞农艺性状及其产量的影响,以期为该地区油菜秸秆资源的高效肥料化利用提供科学依据。通过田间试验,选用‘藏青3000’作为试验作物,设置4种不同的油菜秸秆还田水平(0、1500、3000、6000 kg/hm^(2))和4种施肥水平(尿素和磷酸二铵分别为0、60、120、180 kg/hm^(2)和0、75、150、225 kg/hm^(2))。研究结果显示:油菜秸秆还田量处理显著影响耕层土壤的全磷和有机质含量,而施肥处理则主要影响土壤的全氮和全磷含量,对其他土壤养分的影响不显著。在青稞的基本苗数、株高、有效穗数和产量等农艺性状方面,不同施肥量之间的差异显著;同时,基本苗数和产量在不同秸秆还田量处理间也存在显著差异。研究发现,秸秆还田配施化肥相较于单独施用化肥可以有效提高青稞的产量,尤其是当秸秆还田量达到6000 kg/hm^(2)(全量还田),配合尿素、磷酸二铵各180、225 kg/hm^(2)时,青稞的产量最高,比同等施肥水平下无秸秆还田处理的产量增加了4.03%。综上所述,在西藏地区,油菜秸秆还田配施化肥不仅可以改善土壤养分,还可以有效提升青稞的产量。

关于不同施肥模式对茶叶产量影响的研究

茶叶作为我国传统的重要农产品,随着农业生产方式的转变及环境污染问题的日益突出,如何提高茶叶的产量与品质成为该行业生产经营与科学研究的重点。综合分析了施肥对茶叶产量的影响机制,结合不同施肥模式分析了对茶叶产量造成的影响,旨在为茶树施肥管理提供科学依据,从而促进茶树产业的健康发展。

近40年气候变化对甘肃天水梨树产量形成的影响

甘肃天水因其地处陇中黄土高原腹地,光热充足,土层深厚,成为中国北方干寒梨区水果生产基地。然而,随全球性气候变暖的趋势,天水地区气象灾害的影响日益严重。特别是对于梨树这样的高大植物,其早花期和长生长周期使其在气候变化面前尤为脆弱,进而影响产量的形成。为掌握气候变化对梨树总产量的影响,本研究通过统计学方法分析了近40 a来影响天水梨树产量的主要农业气象条件。分析发现,影响梨产量的关键农业气象要素主要包括上一年秋季9月下旬的降水量、春季4月上旬的平均气温以及春末5月上中旬的日照时数。进一步研究表明,秋冬季温度的显著升高以及初春干旱气候的加剧,增加了果树营养耗损,不利花芽的正常发育,从而对果树产量构成负面影响。本研究结果为当地果树生产和管理部门在有效利用气候资源及其产业化布局方面提供了决策依据。

祁连山南麓草原干旱和牧草产量特征及影响

了解土壤湿度的时空变化特征与规律,对充分利用土壤水分资源及应对气候变化有重要意义。基于祁连山南麓高寒草原天峻生态气象观测站2004—2022年解冻期草原土壤水分监测资料,分析了高寒草原土壤相对湿度的年际、季节变化趋势,以及天然草场土壤干旱季节变化特征,并结合围栏内外牧草产量,对比分析了草原整体土壤相对湿度与牧草产量的相关性。结果表明:祁连山南麓高寒草原整体土壤相对湿度年内逐月变化和季节变化特征明显,2004—2022年,年、季节和各月整体土壤相对湿度均呈逐年上升趋势,土壤干旱化程度减轻。祁连山南麓高寒草原虽然各季节干旱出现频次和程度不尽相同,但春、夏、秋三季连旱的概率也较高。各季节各等级干旱发生频次大小均为轻旱>中旱>重旱>特旱,春季中旱和重旱的频率高达34.8%,春末夏初是一年中最为干旱的时段。2004—2022年围栏内和围栏外牧草产量均表现为显著的增加(P<0.05)趋势,围栏内牧草产量增加的变化速率是围栏外牧草产量的1.6倍。通过气象因子分别与整体土壤相对湿度和牧草产量间的相关关系分析,分别构建的整体土壤相对湿度和牧草产量模型具有较好的使用价值,可在实际业务工作中推广应用。

陇东塬区春季气候变化对冬小麦产量的影响评估

为研究世界最大黄土塬面“董志塬”腹地的陇东塬区典型代表区域——庆阳市西峰区春季气候变化对冬小麦产量形成的影响,利用1985—2020年春季平均气温、降水量、日照时数距平和冬小麦产量资料,分析了春季气候变化特征及其对冬小麦产量形成的丰歉及利弊影响。结果表明,春季平均气温距平随年代增加呈极显著上升趋势,上升速率为1.04℃/10a,增温幅度远高于全球和全国平均水平;降水量距平百分率呈波动减少趋势,减少速率为2.72 mm/10a;日照时数距平百分率呈增加趋势,增加速率为2.45 h/10a;冬小麦产量呈增加趋势,增加速率每10 a为470.14 kg/hm^(2)。用气候产量的丰歉反映冬小麦关键生育期气候资源与其产量形成的匹配程度,36年来匹配较好的丰产年占58%,歉产年占42%;气象条件有利于冬小麦产量形成的年份占53%,不利年份占47%。研究结果可以根据气候变化指导该地区作物布局及农业生产,趋利避害,对促进冬小麦提质增产具有一定的积极作用。

信阳气候资源变化特征及对信阳毛尖茶产量的影响分析

分析了信阳气候资源变化特征,并进行了气象要素与茶叶产量的相关性分析,以揭示气候资源变化与茶叶产量的关系。利用信阳站1951—2022年信阳气温、降水、日照和土壤湿度等资料,运用趋势分析、Mann-Kendall突变检验等方法分析全年和春茶生长季(2—4月)的气候变化规律。研究发现,信阳气候变化明显,全年和2—4月10年平均气温分别升高了1.9℃和2.8℃,年降水量、降水日数、日照、土壤湿度呈减少趋势,但极端降水、暴雨日数有所增加。同时,2—4月历年日平均气温有4个相对稳定的低温周期时段,对信阳毛尖春茶影响很大。随着全球气候的变化,信阳的气候资源也发生了相应变化,对信阳毛尖茶叶产量有积极影响。通过逐步回归筛选出2—4月≥10℃活动积温、土壤湿度、降水量和日照时数等4个与茶产量相关性显著的气候因子,回归分析发现,气候资源产量与≥10℃活动积温、土壤湿度呈正相关,与降水量、日照时数呈负相关。回归结果通过了F检验(P<0.05),且其平均偏差为3.1%,最大偏差为7.4%,较好地揭示了气候资源变化与信阳毛尖茶叶产量的关系。

冻害对山东省茶叶产量的影响评估

为科学评估山东省茶树冻害影响情况,将山东省茶树冻害分为越冬期和春茶期冻害两类,分别找出影响两类冻害发生的主要气象因子,通过多元线性回归分别建立了山东省茶树越冬期和春茶期冻害减产预测模型。经验证,所得预测模型准确率较高,可以用来指导茶农科学防冻,提高茶叶产量和品质,推动山东省茶产业高质量发展。

X70管线钢生产工艺及性能研究

通过合理设计X70管线钢成分,分析研究双机架轧制工艺、控冷工艺及矫直模型,同时采取标准化参数作业指导和设备改善两方面的攻关措施,成功生产出了性能合格的X70管线钢。验证结果表明,邯钢生产出的X70管线钢以粒状贝氏体组织为主,屈服强度、抗拉强度以及冲击韧性等力学性能良好,达到了标准和用户要求,产线具备进行稳定生产的能力。

PVC-U排水管材的密度与物理力学指标关系分析

按GB/T 5636.1—2018对367批次PVC-U排水管的密度、拉伸屈服应力、断裂伸长率和落锤冲击试验指标进行了测试并统计分析。研究发现,随着密度的增加,拉伸屈服应力不合格发生在密度不合格之前,而断裂伸长率和落锤冲击试验不合格发生在密度不合格之后。从实际应用、理论与标准化的角度分析了密度指标在PVC-U排水管材中设立的原理和效果,认为在PVC-U管材产品标准中设立密度指标缺乏实用价值,建议取消。

慈林山煤业沿空掘巷让压支护技术应用

为解决小煤柱沿空掘巷煤柱支承应力较大以及采空区顶板坚硬岩层断裂产生动载破坏围岩支护的问题,对慈林山煤矿15208工作面运输顺槽沿空掘巷支护存在的问题进行分析,开展单泡让压管和双泡让压管抗压试验,同时优化锚杆、锚索的施工。结果表明让压管能够提高锚索的延伸率,在压力显现时能够吸收围岩传递的能量,保证锚杆、锚索的有效性;在此基础上对帮锚索的优化能保证支护强度的同时还能提高生产效率并降低支护成本。

基于屈服线理论的混凝土护栏和桥面板悬臂设计研究

为提高桥梁混凝土护栏和桥面板悬臂抗撞性能,文章论述了混凝土护栏的车辆横向撞击力的三要素,建议了其最小作用高度;依据屈服线理论和虚功原理推导了混凝土护栏对横向荷载的抗力标准值和屈服线发生的临界长度。结果表明:通过实例验证了混凝土护栏和《公路桥涵通用图》桥面板悬臂的抗撞性能,混凝土护栏的极限承载力满足车辆横向碰撞的要求,而空心板桥面板悬臂的抗撞性能不足,并提出了设计建议,以为桥梁设计提供借鉴和参考。

Climate Change Modelling and Its Roles to Chinese Crops Yield

Climate has been changing in the last fifty years in China and will continue to change regardless any efforts for mitigation. Agriculture is a climate-dependent activity and highly sensitive to climate changes and climate variability. Understanding the interactions between climate change and agricultural production is essential for society stable development of China. The first mission is to fully understand how to predict future climate and link it with agriculture production system. In this paper, recent studies both domestic and international are reviewed in order to provide an overall image of the progress in climate change researches. The methods for climate change scenarios construction are introduced. The pivotal techniques linking crop model and climate models are systematically assessed and climate change impacts on Chinese crops yield among model results are summarized. The study found that simulated productions of grain crop inherit uncertainty from using different climate models, emission scenarios and the crops simulation models. Moreover, studies have different spatial resolutions, and methods for general circulation model （GCM） downscaling which increase the uncertainty for regional impacts assessment. However, the magnitude of change in crop production due to climate change （at 700 ppm CO2 eq correct） appears within ±10% for China in these assessments. In most literatures, the three cereal crop yields showed decline under climate change scenarios and only wheat in some region showed increase. Finally, the paper points out several gaps in current researches which need more studies to shorten the distance for objective recognizing the impacts of climate change on crops. The uncertainty for crop yield projection is associated with climate change scenarios, CO2 fertilization effects and adaptation options. Therefore, more studies on the fields such as free air CO2 enrichment experiment and practical adaptations implemented need to be carried out.

Study on the Future Climate Change and Its Influence on the Growth Stage and Yield of Wheat in Weifang City

In order to study the trend of climate change in the future in Weifang,and analyze the impact of climate change on the local wheat production,the air temperature and precipitation in Weifang from 2021 to 2050 were simulated by using the regional climate model PRECIS.And then put the meteorological data into the crop model to simulate the growth of wheat under climate change conditions in the future.The results showed that there would be a trend of rising temperature and increasing precipitation in Weifang in the future.Climate warming would result in growth period of wheat to be ahead of schedule and yield reduction.If taking into account the effect of CO2,the yield of wheat would increase.

Demonstrating Effect of Rainfall Characteristics on Wheat Yield: Case of Sinana District, South Eastern Ethiopia

Demonstrating Effects of Current and Projected Rainfall Characteristics on Wheat yield has been investigated in Sinana district for the period 1995-2016. Data on rainfall and crop yield for the period 1995-2016 were obtained from National Meteorological Agency and Sinana District Agricultural Offices, respectively. Following data quality checking, rainfall data (current and future), correlation and regression studies were analyzed using Statistical software like Instat V3.36 and SPSS V20. Downscaling the output of CSIRO-Mk3.6.0 GCM model (daily rainfall data) for RCP8.5 emission scenario using a web based software tool (Marksim GCM) for the period 2020-2049 were used to determine seasonal total rainfall and ascertain its impact on yield. This study used mean, coefficient of variation, correlation and regression analysis to ascertain the relation, cause and effect relationship between rainfall characteristics and wheat yields. The results indicated that the mean onset date of the main rainy season (JJAS) for Robe and Sinana station was June 30 and July 3. Furthermore, the results of Pearson Correlation Coefficients indicated that kiremt rainfall total (JJAS) had moderate positive relationship (r = 0.499) with wheat yield in the study area. It was also observed that nearly fifty percent of total variance of crop yield is explained jointly by kiremt rainfall total and rainy day (R2 value was 47.9%). The result of projected wheat yield indicated that there will be a slight decrease in wheat yield (qt/ha) after 2030 years due to the impact of expected weakening of kiremt rainfall total. Taking in to account the above findings, it could be suggested that the farmers’ community will be encouraged encouraged to utilize timely climate information issued from National Meteorological Agency of Ethiopia (NMA) and other centers for farm level decision to enhance their crop production.

Weed Control, Environmental Impact, and Net-Profit of Two-Pass Weed Management Strategies in Dicamba-Resistant Soybean (<i>Glycine max</i>) Using Conventional Tillage

Traditional two-pass weed management strategies need to be compared with new strategies in glyphosate/dicamba-resistant soybean. Weed control, soybean yield, partial profitability and environmental impact (EI) were evaluated in glyphosate/dicamba-resistant soybean using dicamba applied alone or in a tank-mix with dimethenamid-P applied preemergence (PRE). Trials were conducted at three locations during 2014 and 2015. Several PRE herbicides provided excellent control of broadleaf and grass weeds. Dicamba provided > 91% control of broadleaf weeds, and the addition of dimethenamid-P improved grass control. All weed species at the trial locations were controlled > 94% following a postemergence (POST) application of glyphosate. Weed interference reduced soybean seed yield 33% where no herbicide was applied. A single POST application of glyphosate had the lowest EI. Several treatments improved early-season weed control and reduced early-season weed density and biomass compared to glyphosate and had similar EI values. In this study, there was no benefit to yield or partial profit by including a PRE herbicide for weed management;however, the inclusion of multiple modes-of-action in a herbicide program may reduce the selection for herbicide-resistant weeds.