Irrigation efficiency in coconut gardens-A comparative analysis of different systems of irrigation

摘要

Coconut farmers praetiee different irrigation methods to overcome the water stress during the non-rainy season. A study has been undertaken to evaluate the field performance of prevailing irrigation systems, drip, sprinkler and basin irrigations, installed in farmers' field. It is evident from the study that substantial increase in yield is possible by providing irrigation to coconut. Majority of the farmers provide sufficient or more water to coconut and hence availability of water was not a limiting factor in the productivity of the palm under irrigated condition. Loss of irrigation water due to deep percolation occurred in most of the cases. Average distribution uniformity obtained by drip and sprinkler irrigations in the study is only 46%. Clogging of emitters and undulating topography are the main reasons for the poor distribution uniformity in drip irrigated plots. Clogging due to physical impurities and obstruction to the water jet due to intercrops and other vegetation are the main reasonsfor the poor distribution uniformity in sprinkler irrigation. In basin irrigated gardens all the farmers were doi:ng irrigation manually and they took adequate care to distribute the applied water fairly uniformly in the whole basin. This is the reason for obtaining high distribution uniformity (90.33%) in basin irrigation. Irrigation application efficiency was less than 50% except in basin irrigation showing the improper utilization of irrigation water. In terms of volume of water, sprinkler irrigationconsumed five times more water than that of drip irrigation and two times more water than that of basin irrigation in fanners' field.