Effect of conserved soil moisture on the source-sink relationship in coconut (COCOS nucifera) under different agroclimatic conditions in India

Abstract

A long-term multi-location experiment was conducted during 1997-98 to 2002-2003 at different agroclimatic zones (five centers) representing the major coconut (Cocos nucifera L.) growing areas in India. Different moisture conservation practices in coconut pahn basins, viz husk burial, leaf mulching, application of farmyard manure and fanll waste, composted coir pith, application of synthetic polymer and increased potassium dose were evaluated for soil moisture conservation (SMC) at root zone during dry season. The soil moisture conservation practices resulted in the availability of soil moisture in the root zone for extended period. The 'source' parameters like net photosynthesis (Pn), water-use efficiency (WUE) and number of physiologically functional leaves in the crown increased due to irrigation and moisture conservation practices. 'Sink' parameters like, nunlber of pistillate flowers and nut retention efficiency were increased with water conservation and irrigation. The irrigated palnls produced more pistillate flowers with higher retention capacity even during summer. The results clearly denmonstrated that the prolonged soil moisture availability due to soil moisture conservation treatments helped to increase the photosynthetic source number and efficiency as also the sink capacity and efficiency.