Effect of greywater irrigation on wheat and mung-bean production in clayey-loam soil

Abstract

Greywater is considered as a viable and alternative source of irrigation in many parts of the world. In Bangladesh, it is mainly the marginal farming community who use untreated urban greywater for irrigation. However, very few crop and soil specific investigations on greywater use have been carried out in Bangladesh. This study reports the results of two agronomic experiments carried out to quantify the effects of greywater irrigation on the production of two popular winter crops in Bangladesh i.e., mungbean and wheat. It also reports the status of the nutritional balance of soil due to greywater irrigation in two consecutive years i.e., 2012 and 2013. The experiment with each crop was conducted in random blocks replicating each of the six greywater treatments thrice. The results highlighted the fact that raw use of greywater was not beneficial for mungbean. On the other hand, second highest yield of wheat was obtained from the raw greywater treatment. Nonetheless, the highest crop yield was found when greywater (75%) was diluted with freshwater (25%) in a combined use. Crops irrigated with alum-treated greywater produced moderate yields. Considering the health risks associated with raw use of greywater, the alum-treatment of greywater appears to be a viable alternative to the farmers. It was found that unregulated use of greywater resource could lead to salinity problems in clayey loam soil. In particular, raw greywater irrigation was shown to be leading a buildup of P in the soil which could pose a potential environmental risk. This study recommends that crops good at up-taking phosphorus from the soil should be prioritized in greywater irrigation schemes.