Multiple cropping systems of the world and the potential for increasing cropping intensity

Katharina Waha,Jan Philipp Dietrich,Felix T Portmann,Stefan Siebert,Philip K Thornton,Alberte Bondeau,Mario Herrero

doi:10.1016/j.gloenvcha.2020.102131

Abstract

Multiple cropping, defined as harvesting more than once a year, is a widespread land management strategy in tropical and subtropical agriculture. It is a way of intensifying agricultural production and diversifying the crop mix for economic and environmental benefits. Here we present the first global gridded data set of multiple cropping systems and quantify the physical area of more than 200 systems, the global multiple cropping area and the potential for increasing cropping intensity. We use national and sub-national data on monthly crop-specific growing areas around the year 2000 (1998–2002) for 26 crop groups, global cropland extent and crop harvested areas to identify sequential cropping systems of two or three crops with non-overlapping growing seasons. We find multiple cropping systems on 135 million hectares (12% of global cropland) with 85 million hectares in irrigated agriculture. 34%, 13% and 10% of the rice, wheat and maize area, respectively are under multiple cropping, demonstrating the importance of such cropping systems for cereal production. Harvesting currently single cropped areas a second time could increase global harvested areas by 87–395 million hectares, which is about 45% lower than previous estimates. Some scenarios of intensification indicate that it could be enough land to avoid expanding physical cropland into other land uses but attainable intensification will depend on the local context and the crop yields attainable in the second cycle and its related environmental costs.

Highlights

Multiple cropping is common and a widespread land use manage ment strategy in low-land tropical and subtropical agriculture where rainy seasons are long enough or irrigation is viable
We develop a method for mapping multiple cropping systems globally (Fig. 1) and present the first global gridded data set of physical area and growing seasons of more than 200 different double and triple cropping systems
We estimate that 134.4 million hectares (Mha) land is under multiple cropping, 12% of global cropland (Fig. 3). 5% of global rainfed cropland and 40% of global irrigated cropland is under multiple cropping (Table 1)

Summary

Introduction

Multiple cropping is common and a widespread land use manage ment strategy in low-land tropical and subtropical agriculture where rainy seasons are long enough or irrigation is viable. Intensification occurs in systems with multiple harvests of the same crop, for example in some Asian rice-based systems, while other systems are more diverse with different types of crops grown at the same time or in a sequence and interacting with each other It is ex pected that higher diversity increases the sustainability of crop pro duction (Altieri, 1999), pest regulation (Khan et al, 1997), resistance to climate events (Isbell et al, 2015; Lin, 2011) and reduces fertilizer use in associations with legumes (Peoples et al, 2009) all of which can lead to increases in production or profitability in the short or long term (for a review see Francis, 1986; Gaba et al, 2015). On the other hand, growing a second or third crop can increase the risk of crop failure (Ojeda et al, 2018) and the environmental costs of production (Damien et al, 2017; Ladha et al, 2003; Timsina and Connor, 2001) but these problems are crop-, location- and management-specific

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