Impact of agricultural mechanization level on farmers' cropping index in Hubei Province

Increased multi-cropping index in cultivated lands is critical for food security strategies and issues concerning in agriculture, countryside and peasant communities in China. Presently, many studies exist on multiple cropping index. However, most of these studies are based on national statistics, with fewer studies on peasant household conditions. Multiple cropping of cultivated lands is the production activities of individual rural households. Therefore, the use of macro-statistical data had failed to adequately capture inherent heterogeneities in peasant conditions in different regions. Furthermore, it has limited research analysis to only the factors that affect multiple cropping index at macro scale. This has made it difficult to accurately analyze the driving factors at micro scale. Here, we used survey data from 1 682 peasant households in Hubei Province to investigate the impact of the level of agricultural mechanization on multiple cropping index at microscopic scale. To further avoid the possibility of endogeneity and sample selection bias in the model, we used IVTobit and IVProbit regression models to explore the impact of the level of agricultural mechanization on multiple-cropping index and the differences in various types of crops. The results showed that:1) ordinary least square (OLS)-estimation result without consideration for sample selection bias and endogeneity and processed result were quite different. This indicated that the original OLS regression model significantly underestimated the effect of the level of agricultural mechanization on peasant household conditions. Regression coefficients pointed out that the level of agricultural mechanization had significant positive impact on multiple cropping index. For every 1% increase in the level of agricultural mechanization, multiple cropping index increased by 1.393%. This confirmed the hypothesis that agricultural mechanization effectively reduced the time of agricultural production, ensured seasonality of multiple crops, maximized utilization of land and increased the degree of cultivation. In addition, education and age of household head, proportion of non-agricultural income, transferred land and temperature change had dramatic negative effect on multiple cropping index of cultivated lands. Family size, number of crop varieties and type of area had significant positive effect on peasant household conditions. 2) Based on the analysis of the action mechanism of multiple cropping index of cultivated lands, there was significant difference in the impact of the level of agricultural mechanization on multiple cropping index and willingness of different types of crops. The level of agricultural mechanization affected cropping index of cash crops more than grain crops. Compared with peasants who grew food crops, those who grew cash crops were more willing to plant more with increasing level of agricultural mechanization. This was mainly because economic effects of cash crops were higher and peasants were more likely to multiply cash crops them than grain crops. The latter not only had strong seasonality, but also was not plantable in off-season periods, while the former had short growth cycle with operable production process. In summary, we argued that improvement of the level of agricultural mechanization by peasants played an active role in multiple cropping index in cultivated lands, especially for increasing cropping index of cash crops. In order to further improve the degree of cultivating land and to ensure domestic food security in peasant communities, government should vigorously promote the use of agricultural mechanization, strengthen policy support for peasants who cultivate grains in plains and reform grain storage systems.