Effect of organic amendments on maize cultivation under agricultural drought conditions in Central Java, Indonesia

Abstract

This study examined the effect of three organic amendments − compost (CP), sugarcane bagasse (SB), and rice husk ash (RA) − on soil moisture and maize growth in rainfed farmland under agricultural drought conditions in Central Java, Indonesia. The wet organic amendments were applied at a rate of 20 t ha–1 and mixed into the root zone 3 days before seeding. Chemical fertilizers were not included in any treatment during the experiment. CP and RA kept the soil moisture above the soil suction of pF 1.0 between initial planting and harvesting. By contrast, SB treatment exacerbated the impact of the agricultural drought com-pared with the control (CO) or no organic material. The maize yields of CP (690 kg ha–1) and RA (538 kg ha–1) were higher than those of CO (456 kg ha–1) and SB (382 kg ha–1); all yields were lower than the regional average in Central Java (698 kg ha–1). Maize yield was correlated with the lowest soil moisture value (R2 = 0.80). Overall, CP and RA substantially reduced the damage to rain-fed farmland caused by agricultural drought. The lowest soil moisture value was a major explanatory factor with respect to the yield gap of maize under agricultural drought conditions.