ABSTRACT

Conservation tillage for sustainable wheat intensification: the example of South Asia Vijesh Krishna, Georg-August University of Göttingen, Germany; Alwin Keil, International Maize and Wheat Improvement Center (CIMMYT), India; Sreejith Aravindakshan, Wageningen University, The Netherlands; and Mukesh Meena, Indian Institute of Soil and Water Conservation, India

1 Introduction

2 Factors affecting the diffusion of CT wheat in South Asia

3 Recent evidence of the agronomic and economic impacts of CT wheat in South Asia

4 Constraints to the diffusion of CT practices in wheat in South Asia

5 Recent developments in CT wheat

6 Concluding remarks

7 Where to look for further information

8 Acknowledgements

9 References

The wheat production sector of South Asia has registered only a sluggish productivity growth in the last two decades (FAOSTAT, 2015). The rate of growth, which is lower than the wheat yield growth realized in the rest of the world (Shiferaw et al., 2013), is inadequate to keep pace with the population expansion in the region. Along with a rapidly changing climate, degradation of the natural resource base as a result of intensive farming and inappropriate use of inputs is often cited as one of the root causes of the problem (Chauhan et al., 2012; Erenstein and Laxmi, 2008; Sekar and Pal, 2012). To achieve a sustainable yield growth rate in wheat, there has been an increased scientific interest in developing environmentally sustainable agronomic practices that are resource conserving, while ensuring financial benefit to farmers. This paradigm shift is closely associated with an increased awareness in the public policy arena towards the negative environmental externalities associated with the traditional farming practices. Most prominent among such resource-conserving technologies in the cereal systems of South Asia is conservation tillage (CT) in wheat (Derpsch et al., 2010), which is identified also as one of the key

agricultural practices that can enhance the adaptive capacity of farming communities and the potential of farming practices to mitigate the challenges of climate change in the tropics (Harvey et al., 2014; Sapkota et al., 2015). In this chapter, we examine the recently emerged evidence on the on-farm impacts of the ensemble of CT technologies in wheat production and the possible constraints hindering its widespread diffusion in the IndoGangetic Plains (IGP) of South Asia. We use the umbrella term ‘CT wheat’ to represent zero-tillage (ZT), reduced-tillage and ridge-tillage practices in wheat production.