Assessing the effect of deficit irrigation on maize production during the wet season.

Abstract

Maize is an important staple and cereal crop for majority of the population in Uganda and also serving other purposes like providing silage for animals. However, due to climate change that is causing erratic and unfavorable change in weather patterns, maize farmers become vulnerable to risks such as low returns and complete losses. This research was done to establish the optimal deficit irrigation treatments for maize to improve its yields. The experiment was laid out at Makerere University Agricultural Institute Kabanyolo (MUARIK) where a drip system was installed and used for irrigation during the period between January and June. The experiment consisted of four treatments; complete irrigation (100% Treatment), Medium Irrigation (50% Treatment), low irrigation (25% Treatment) and no irrigation which were replicated four times. Soil tests were carried out at the start of the project and also collection of daily readings of the soil moisture contents that were used for the irrigation scheduling part. Data on the parameters observed included that of plant heights, leaf areas, the stem diameters that was collected on a weekly basis, the above-ground biomass and grain yield at the time of harvest whose results when subjected to analysis in R-studio Software and Microsoft Excel, exhibited differences and similarities. However, the plants from the plots that were subjected to complete irrigation, medium irrigation and low irrigation exhibited growth values that were insignificant to each other, nonetheless significantly different from the values of plants from 0% irrigation plots. It was concluded that it is important to supply the deficit amount of water required by the plants for their growth in order to maximize both growth and yield production. On computing for the water productivity which is estimated as yield(kg/ha) of maize per irrigation water(mm) applied, it was shown that the water productivity of complete irrigation was 38.8%, for medium irrigation, it was 5.3%, for low irrigation, it was 9.9% while for 0% irrigation, it was 13%. Basing on the computations of water productivity, it is economically feasible not to apply water in less amounts than the required ones since it’s better to obtain maximum yields with optimal water inputs during the wet season.