Study of Runoff Farming System to Improve Dryland Cropping Index in Indonesia

A barrier to productivity on dryland is limited availability of water during dry season. Heavy rainfall at most in the dryland farming in Indonesia causes high runoff that occurred during precipitations. The huge potential of runoff can certainly be utilized as alternative water sources in the dry season to improve cropping index. The research purposes were to assess the potential of runoff farming system in improving the cropping index on dryland with wet climate. The study was conducted through observation field conditions, rainfall analysis, potential runoff analysis, crop water requirements analysis and water balance analysis in the dryland area. The result of the study indicated that peak of rainfall-runoff started in last decade of December until March. However, entering the second growing season, rainfall occurs until April only. It's implied that during the second growing season has led to a lack of water supply in the peak phase of crop water needs. Rainfall-runoff analysis indicates that surface runoff potential as an alternative source of irrigation in the dryland farming if managed well, one of which uses runoff farming system. With harvest runoff and store it for irrigation in dry season could increase the cropping index. The significant finding of this research was base on supply and demand water analysis shows that to increase cropping index of food crop in dryland with wet climate needed of catchment and cultivation area ratio (CCA ratio) equal to 6.2, to the form of catchment area was arable land with multi-cropping pattern and varies slope