Soil Amendments for Maize Cultivation by Crop Rotations in Upland Cropping Systems of Southeast Cambodia

Abstract

A study was made of the importance of crop rotations on the growth and yield of maize in upland cropping systems of Cambodia. Maize (MZ) was grown continuously and in two-year rotations with cassava (CS), soybean (SB), mung bean (MB) and peanut (PN). Six different rotations T1, T2, T3, T4, T5 and T6 were designed and studied in the upland cropping systems in the provinces of Prey Veng and Svay Rieng in southeastern Cambodia. Mono-cropping with maize (T0) was used as the control treatment in the study. The study was undertaken in the period 2013 to 2015. The field experiments revealed an increase in crop yields in the order of T1 > T2 > T3 > T5 > T6. There was no significant difference in crop yield between T4 and the control (T0) treatment. The analysis of soils data revealed that there were no significant differences in soil nitrogen and phosphate levels pre-treatment and post–treatment in each of the rotations (paired samples t test, p > 0.05). However, post-treatment potassium levels were significantly lower than the pre-treatment levels in all cropping rotations (p < 0.05) except T0. The results of the study suggest that the maize-legume rotation is the most promising crop rotation for yield improvement in the upland cropping systems in southeast Cambodia.