Modeling Effects of Different Irrigation and Fertigation Strategies on Maize (Zea Mays) Response And Salinity Buildup In Root Zone Under Drip Irrigation

Abstract

Crop and water productivity can be improved by growing crops under drip irrigation coupled with balanced fertigation and adequate irrigation scheduling. This study was conducted, during spring seasons of 2015 and 2016 at experimental area of Water Management Research Centre, University of Agriculture, Faisalabad, Pakistan to investigate the maize response and root zone soil behavior under different irrigation frequencies including daily irrigation, 3rd day irrigation and 5th day irrigation. Also three rates of recommended dose of fertigation (RDF) including L1: 100% of RDF, L2: 75% of RDF and L3: 50% of RDF were investigated using imported water soluble fertilizer (IM) as well as for indigenously developed water soluble fertilizer (WN) to check their effects on maize productivity and on its economic return. Crop response was studied in terms of plant height, dry matter weight, grain yields, harvest index and water productivity. Soil behavior was investigated in terms of soil moisture behavior and soil salinity buildup. The experiment was laid under Randomized Complete Block Design (RCBD) with 54 plots for eighteen experimental treatments with three replicates and three plots for control treatment. It was observed that daily irrigation frequency produced the highest values of crop growth parameters, which decreased when irrigation frequency moved from daily to 3rd day. Regarding crop growth parameters, the 5th day irrigation frequency showed better results than that under 3rd day frequency and worse results than that under daily frequency. The results also showed that the highest plant height (192.8 cm), dry matter weight (18.17 t/ha), grain yield (9.47 t/ha), water productivity (1.80 kg/m3) and net profit (Rs. 188323/ha) were produced using WNL1 (indigenous water soluble fertilizer at 100% RDF) with daily irrigation frequency compared with other treatments. Under daily irrigation, the significantly highest ECe (2.37 ds/m) was found in the top soil layers due to lesser downward movement of salts because of limited water applications. But due to frequent water applications under daily frequency than that under 3rd day and 5th day frequencies, enough soil moisture was present in top soil layers to support better crop growth. Drip irrigation saved 48% irrigation water with cumulative irrigation depth of 556 mm in comparison to conventional ridge sowing (1063 mm). Based on results, it is recommended that maize grown under drip irrigation should be fertilized by WNL1 with daily irrigation frequency for economically better return in semi-arid area of Faisalabad, Pakistan.