Assessing the effect of deficit drip irrigation regimes on crop performance of eggplant

Abstract

Irrigation of eggplants tremendously increases their yields amidst climate change. However, little is known about the deficit irrigation level for optimum growth of eggplant crops. This study investigated the effect of deficit drip irrigation on performance of eggplants to guide improvement in irrigation water use efficiency (IWUE). The study was conducted on sandy clay loam soil for two growing seasons using a randomized complete block design (RCBD) field experimental set up. The considered treatments were: percentages of Field Capacity (FC) as T1: 25 % FC; T2: 50 % FC; T3: 75 % FC; T4: 100 % FC; with a control being no irrigation (T0: 0 % FC), and all were performed in triplicates. Irrigation scheduling was based on the readings of the ML3 Thetaprobe sensor from which the soil moisture deficit was calculated and adjusted to percentages corresponding to the different treatments, under supplementary irrigation. All Treatments were subjected to the same agronomic treatments. Plant growth parameters, yield, IWUE, and fruit quality parameters were determined. Analysis of Variance was performed with R Studio software at 5 % significance level, and Tukey multiple comparison test was used for separating the means. Results showed that plant growth, yield, IWUE, and crop quality parameters significantly differed (p < 0.05) across the deficit levels. The highest mean yield, and IWUE of 39.1 ton/ha and 18.1 kg/m3 respectively were obtained in T3. The lowest mean yield was 13.5 ton/ha in T0, while the lowest mean IWUE was 6.2 kg/m3 in T1. The results imply that T3 is a limit of crop water application beyond which yield and IWUE of eggplants cease to increase and thus, start reducing. This study therefore, concludes that irrigating eggplants at 75 % FC maximizes yield and water saving in sandy clay loam soil.