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Understanding the components of water consumption plays a critical role in agricultural management in arid regions. This study aimed to analyze the characteristics of the components of the water consumption of winter wheat on the Loess Plateau in China to investigate their effects on yield and water use efficiency (WUE). Winter wheat observation data were collected from 1981 to 2020 at the Xifeng Agrometeorological Station on the Loess Plateau. The results show that over the past 40 years, the average water consumption of the winter wheat fields was 315 mm, but there were large differences between years. The soil water was first converted from precipitation (P) during the growing season, accounting for 69.4%, and then consumed via soil water storage (ΔW) in the fallow period, accounting for 30.6%. The yield of winter wheat varied from 1057 to 6914 kg·ha−1. The correlation between winter wheat yield and P during the growth period was stronger than the correlation between winter wheat yield and ΔW. The average WUE was 11.0 kg·ha−1·mm−1 from 1981 to 2020, with the highest value of 13.7 kg·ha−1·mm−1 occurring in the 2010s and the lowest value of 9.6 kg·ha−1·mm−1 occurring in the 2000s. The WUE was positively correlated with P (p < 0.01) during the growth period and negatively correlated with ΔW (p < 0.05). Therefore, P can increase yield and WUE more effectively than ΔW. These findings provide a theoretical basis for the efficient utilization of water resources on the Loess Plateau and the sustainable development of dry farming.

Southern China is the nation’s major grain-producing areas. In recent years, under the background of global climate change, regional drought disasters have been increased, and caused serious agricultural drought loss and obvious anomaly characteristics. However, the variation characteristics of agricultural drought loss and drought hazard mechanism are still unclear in south China, which seriously affects the in-depth understanding of southern agriculture drought and its assessments. Therefore, based on agricultural drought disaster conditions, crop acreage, meteorological drought monitoring index and conventional meteorological factors and other related data, systematical and comprehensive agricultural drought loss rate variation and its relationship with climate-formative factors have been analyzed in recent 50 years. Agricultural drought comprehensive loss rate is used as an agricultural drought disaster or risk characteristics loss severity index. Agricultural drought comprehensive loss rate is an integrated index that can reflect severity of loss caused by agricultural drought disaster and established by drought-affected crop planting area at different levels and planting area. The results showed that comprehensive agricultural drought loss rate increased obviously and with a rate of about 2.5%, the relative increased rate reached to as high as 80%. Agricultural drought disasters loss has been increased seriously and doughty disasters risk also has been increased more higher than before, southwest is more apparently than south and southeast. With respect to spatial distribution, probability of climate tendency rate for comprehensive loss rate in south China ranges from 0.1%/10 a to 1.8%/ 10 a. In addition, increase in climate tendency rate in the southwest is more obvious than that in the south and southeast. And, as a result of crop growth stages on the climate elements in dependence on different season and climate factors of non-uniform distribution characteristics, agricultural drought loss rate is mainly affected by key period meteorological drought and the effects of climate change, mainly precipitation and temperature. As for precipitation, 6 months including April, May, June, July, August and October serve as key impacting periods. As for temperature, 5 months including January, June, July, August and October serve as key impacting periods. As for MCI, only two months including July and August serve as key impacting periods. But other climatic factors change is not obvious influence on agricultural drought loss rate. In south China, key impacting periods of MCI coincide with key growth phases of most crops; common key impacting periods of temperature and precipitation coincide with major growth phases of most crops in south China; key impacting periods of precipitation coincide with major or key growth phases of some crops; while key impacting periods of temperature coincide with key periods for overwintering of winter wheat. As a result, the fitting relationship between the south agricultural drought loss rate and the critical period climate factor is much better than its relationship with throughout annual climate, and more key climate factors has more obvious advantages in fitting relationship compared with single factor. Such multi-factor relationship can not only describe the disaster-causing effect of meteorological drought, but also reflect the roles played by severe evapotranspiration and soaking rain processes on drought disaster-causing process. Meanwhile, the agricultural drought loss assessment model with multiple factor relationship had been done for cross validation method, correlation, error level and reliability are the relevance of the ideal, which indicated that the model is an optional reliable and objective model for evaluating the impact of drought disasters on agricultural yield in south China or estimation on risks of agricultural drought disasters in future climate scenarios. The study results have important scientific reference significance for the development of south China agriculture dry drought damage assessment method.

Agro-drought risk analysis is helpful for improving the ability of regional disaster management and reducing potential drought risk under climate change. In this paper, we use daily meteorological observations from 60 stations and maize yield data in Southwest China during the period from 1961 to 2012. Based on natural disaster risk theory, maize drought risk assessment model is established from four factors: hazard, exposure, vulnerability, drought prevention and mitigation, and maize drought risk is zoned and analyzed in Southwest China under climate change. The results show that under climate warming, the high and sub high risk zones are decreased in Yunnan Province and emerged in central and northwest Sichuan Province, the low and sub low risk zones are largely reduced in Sichuan Province, Guizhou Province and Chongqing City, and the other increasing zones are mainly moderate risk zones. In summary, maize drought risk mainly depends on the maize drought hazard; the maize drought risk increases in the north and decreases in most of south under climate warming in Southwest China. Enhancing maize drought risk management helps to reduce the potential risk to agricultural production in southwest China under climate change.

Drought is a serious ecological problem around the world, and its impact on crops and water availability for humans can jeopardize human life. Although drought has always been common, the drought risk has become increasingly prominent because of the climatic warming that has occurred during the past century. However, it still does not comprehensively understand the mechanisms that determine the occurrence of the drought risk it poses to humans, particularly in the context of global climate change. In this paper, we summarize the progress of research on drought and the associated risk, introduce the principle of a drought “transition” from one stage to another, synthesize the characteristics of key factors and their interactions, discuss the potential effect of climatic warming on drought risk, and use this discussion to define the basic requirements for a drought risk management system. We also discuss the main measures that can be used to prevent or mitigate droughts in the context of a risk management strategy.

Drought is a serious problem in southwestern China, where drought risk exceeds the national average. Climate change is likely to exacerbate the problem, thereby endangering China’s food security. In this paper, we used the analytic hierarchy process and meteorological, geographic, soil, and remote-sensing data to develop a drought risk assessment model based on the drought hazard, environmental vulnerability, sensitivity and exposure of the values at risk, and capacity to prevent or mitigate the problem. Using the model, we assessed the drought risk (defined using a comprehensive drought risk index, R) and its spatial distribution in southwestern China and revealed complex zonality. The eastern part of the study area had an extremely high risk, and risk was generally greater in the north than in the south, and increased from southwest to northeast. The comprehensive risk (R) was lowest in Yunnan province. It was highest in Sichuan Province and Chongqing Municipality. The contribution of the risk factors to R was highest for the capacity for prevention and mitigation, followed by the drought hazard, sensitivity and exposure, and environmental vulnerability.