Toposequencial terraces environment and use of fertilizer influenced grain yield of rainfed lowland rice in the mid-hills of Nepal

Cultivation of rainfed lowland rice in manmade terraces of different toposequencial environment is common farming practices of the farmers in the mid-hills of Nepal. Therefore, surveys and experiments were conducted to study the influences of four different toposequencial terraces environment and four different fertilizer doses on the grain yield of rainfed lowland rice for two years with farmer’s participation in the mid-hills of Nepal using questionnaire and split-plot design. Survey results of two years showed that farmers of four villages in mid-hills produced significantly highest mean grain yield of 3.28 t ha^-1 at the terraces near to house while the least mean grain yield of 2.46 t ha^-1 was produced at upper terraces environment. Experiments in the farmers’ field showed that among the toposequencial terraces environment, terraces near to house produced significantly highest mean grain yield of 4.38 t ha^-1 while upper terraces produced the least mean grain yield of 2.46 t ha^-1. Similarly, among the four fertilizer doses, use of 60;30;20 kg NPK ha^-1 produced significantly highest mean grain yield of 4.11 t ha^-1 while control or zero fertilizer produced the least mean grain yield of 3.12 t ha^-1. Higher mean grain yield production at terraces near to house and use of nutrients at 60;30;20 kg NPK ha^-1 were attributed by the higher yield attributing characters such as numbers of grains per panicle, number of tillers per square meter and panicle length per plants. Similarly, fertility status of the soil at toposequencial terraces environment near to house was comparatively highest soil nutrient content of the other toposequencial terraces environment. Therefore, based on these studies, it is concluded that manmade toposequencial terraces environment near to house and the use of nutrients at 60:30:20 kg NPK ha^-1 can produce the highest grain yield of rainfed lowland rice and thereby the net income in the mid-hills of Nepal.

Keywords: Manmade toposequencial terrace environment; farmer’s participation; rainfed lowland rice; fertilizers; grain yield