1. Introduction
Drought is a major global natural disaster affecting human society today [
1]. Arid regions of the world have continued to expand due to global warming. The severity and frequency of droughts have significantly increased [
2,
3], causing a marked reduction in crop production, considerable socio-economic losses in agriculture, and food security in the arid and semi-arid regions of developing countries [
4,
5,
6,
7]. Over the past 60 years, droughts have caused an annual grain output reduction of 16.159 billion kilograms and annual economic loss of
$12.8 billion in China [
8,
9]. Agriculture is the main source of livelihood in rural communities of arid and semi-arid regions of China, where drought is one of the most damaging natural hazards [
10,
11]. Thus, farmers are the most direct victims of drought, with the reduced crop yields cause huge economic losses that have catastrophic effects on the livelihood security of rural families [
8,
12,
13,
14]. It is essential to study the impact of drought on agricultural production, the livelihood of farmers, and food security in order to achieve the second Sustainable Development Goal of the United Nations in the rural areas of developing countries [
15].
Drought has a multi-dimensional impact on agricultural systems and rural families owing to its complex and uncertain characteristics with high spatial and temporal variability [
16,
17]. However, one-dimensional measurements are commonly used to analyze the impact of drought on crop yield or farmer livelihood in studies. In recent years, many studies have been conducted on crop yields, maize yields, wheat yields, and the like at different spatial scales, including global [
18,
19], national [
20,
21,
22], and regional scales [
23,
24], analyzing the relationship between crop yield and drought indices, such as the standardized precipitation index (SPI) [
15,
25]. Several regional scale studies have focused on the northeast and northwest regions of China [
26,
27,
28]. In addition, the impact of drought on the livelihood of farmers has also received considerable attention from researchers. They have investigated income loss and food security through farmer interviews and questionnaire data, respectively [
5,
12,
13,
14,
29]. Notably, rural communities are the main areas affected by drought and farmers are the main stakeholders in agricultural production. The impact of drought on the agricultural system and farmer livelihood systems is multidimensional and multi-scale. However, few studies have assessed integrated drought impact, especially in the arid and semi-arid regions of developing countries. It is difficult to systematically evaluate the integrated drought impact due to data limitations. Nevertheless, understanding the integrated impact is critical for policymakers and stakeholders to effectively mitigate and adapt to drought [
30].
Owing to geographical locations, environments, and drought mitigation measures, the temporal and spatial distribution characteristics of drought impact on crop yield are significantly different in various regions [
31]. This results in geographical variations in farmers’ vulnerability to drought; droughts with the same intensity and severity have distinct effects on farmer livelihoods in different local regions [
5]. Therefore, this study analyzed the impact of drought on crop yield and farmer livelihood in rural communities of Yuzhong County in Northwest China from an integrated perspective, using SPIs at different time scales, correlation analysis, and statistical analysis with multi-source data. The study aims to address the gap in the multi-scale impact of drought, better understand the multidimensional impact of drought, and contribute to effective drought management strategies. In particular, the objectives of this study are as follows: (1) identify drought characteristics at different time scales and temporally and spatially analyze the relationship between drought and crop yield using the standardized precipitation index (SPI); (2) compare drought disaster areas, economic loss, livelihood affordability, and food security after drought among different clusters of farmers using interviews and questionnaire data; and (3) describe the transformation of farmer livelihoods and their trajectories in regions with different crop plantings.
2. Analytical Framework to Assess the Integrated Impact of Drought
Analytical frameworks to assess the impact of drought on agricultural systems and rural families obviously differ. Numerous models and surveys have been used separately to analyze the effects of drought on crop yield and livelihood systems. Specifically, scholars have used a systemic approach to identify the impact of drought on the structure of agricultural dynamic loops with elements of drought, water resources, the growth process of crops, crop production, and the agricultural economy [
32]. They have also analyzed the impact of drought on farmer livelihood within the analytical framework of sustainable livelihood [
33]. However, this study places greater emphasis on the direct impact of drought on crop yield, farmer livelihood, and food security at the county scale and in rural communities than other studies. Hence, the analytical framework needs to integrate a wide range of drought temporal and spatial variations along with their relationship with crop yield and farmer livelihood [
34]. In this study, the analytical framework supposes that drought directly impacts crop yield, which in turn determines farmer livelihood and food security, leading to the transformation of farmer livelihoods. Whereas drought indirectly impacts farmer livelihood by affecting crop yield, farmer livelihood transformation also indirectly impacts crop yield with agricultural labor migration. On this basis, the analytical framework identifies temporal changes of drought and assesses the direct impact on crop yield, farmer livelihood, and food security using correlation analysis and statistical analysis methods, and depicts the transformation of farmer livelihoods and their trajectories with precipitation data, statistical data, and farmer surveys.
SPI is commonly used to assess and monitor drought [
16]. In this study, SPI was computed at 6, 12, and 24 month scales to analyze drought variation. Accordingly, the correlation between drought and crop yield was determined. Next, the impact of drought on farmer livelihood and food security was analyzed by interviewing farmers, investigating the area affected, and assessing the economic losses caused by drought to the farmers and the adequacy of food for family households. Finally, farmer livelihood transformation is the outcome of the impact of drought on their livelihoods and also the response of farmers to drought (
Figure 1).
5. Conclusions, Discussion, and Policy Implications
Drought poses a significant threat of poor agricultural production and economic loss, especially to farmer incomes and food security, which are the primary sources of livelihood and food for the majority of farmers in arid and semi-arid regions. Therefore, it is critical to understand the complexity of drought impact. In this study, we proposed a drought-integrated analytical framework identifying the exposure of Yuzhong County to drought from 1960 to 2017 using SPI6, SPI12, and SPI24, and examined the impact of the spatial and temporal characteristics of drought on crop yield. Our study highlighted the impact of drought on different cluster types of farmers in terms of economic loss, livelihood, food security, and adaptation to drought through livelihood transformation. The results showed as follows:
The years with moderate and severe drought were 1981–1983, 1997, and 2011–2012. The correlation coefficients between SPI6, SPI12, SPI24, and crop yield from 2000 to 2017 were 0.563, 0.636, and 0.512, respectively, indicating that drought with SPI12 had a more severe impact on crop yield. In addition, SPI6, SPI12, and SPI24 were significantly correlated with crop yield in most towns of Yuzhong County at the spatial scale. The results indicated that slight droughts were common in Yuzhong County, but the drought events significantly impacted crop yield in Yuzhong County and most of its townships, causing sensitivity of crop yield to drought.
Five clusters of farmers in the three regions of Yuzhong County were affected by drought with a large drought disaster areas and serious economic losses, resulting in an affordability deficit and food insecurity for farmers. These effects were more severe in the southern region, with an average drought disaster area of 5.2 acres, economic loss of CNY 6878.6, affordability deficit of 33.824%, and food insecurity of 80.391% due to the large arable land area, high altitude, and poor water conservancy facilities. Thus, farmers in the southern region of Yuzhong County are more vulnerable to drought than those in other regions.
Farmer livelihoods have transformed in all three regions of Yuzhong County. The trajectories of livelihood transformations have moved toward mixed livelihoods in the northern region and part-time agricultural livelihoods in the central and southern regions. The high altitude, low vegetation cover, and poor soil quality result in low crop production in the northern region of Yuzhong County; thus, traditional agriculture is unable to increase the financial capital of farmers in this region, whereas mixed livelihoods contribute to enhanced livelihood resilience to drought. Conversely, farmers in the central and southern regions have engaged in cash crop planting, for which the income is higher than for traditional crop planting.
Due to data limitations and the absence of consistent timing of survey data, only crop yields from 2000–2017 could be used in this study to correlate with SPI. Future research can focus on studying the integrated impact of drought on agricultural systems and farmer livelihood in arid and semi-arid regions in China at a larger spatial and temporal scale. In addition, drought vulnerability and farmer livelihood vulnerability can be further assessed based on this study. The analytical framework of socio-ecological system resilience could be applied to explain rural socio-ecological system adaptations to drought in terms of drought resilience and farmer livelihood resilience.
To reduce the multi-dimensional impact and vulnerability of drought in Yuzhong County and narrow the gap between the drought impacts on the northern, central, and southern regions, it is necessary to increase the investment in water conservancy and irrigation facilities. In addition, Yuzhong County could use its location and policy advantages to promote the transformation of farmer livelihoods to non-agricultural livelihoods in the urban sub-center of Lanzhou city in Gansu Province. Meanwhile, there are national 4A scenic spots in the south of Yuzhong County, which could support the development of rural tourism. We recommend that local managers organize tourism planning to guide the participation of local farmers in tourism service activities so that they may find a new source of livelihood, thus increasing farmer livelihood resilience to cope with the negative impacts of drought.