Effects of Vacant Hills on Growth and Yields of Rice (Oryza sativa L.) under Different Cultural Conditions

Abstract

Field trials were conducted to evaluate the effects of vacant hills on growth and yield characteristics of rice (Oryza sativa L.) under several cultural conditions. In side dressing of readily available fertilizer with conventional tillage, the number of stems and grain yield seemed to decrease with increasing number of vacant hills. In contrast, the panicle number and number of grains per head seemed to increase with increasing the number of vacant hills in the same cultivation. The compensatory effects of plants adjacent to vacant hills were particularly obvious in plants located in the same row, as compared with those in adjacent rows. However, the magnitude of the compensatory effects varied with the method of fertilizer application, plant type, plant density, and the presence or absence of tillage ; the effects of vacant hills on the performance of the rice plant was smaller in CAF(controlled availability fertilizer) and sparse planting plots, and this was not the case in any plots of many-tillering type cultivar and no-tillage cultivation with CAF.