Performance Evaluation of Sweet Corn Cultivated in Greenhouse in Northern Ghana

Abstract

The study assessed the effect of conventional deficit irrigation (CDI), alternate partial rootzone drying (APRD), and fixed partial rootzone drying (FPRD) at two water regimes (80 and 60% of crop water requirement), compared to full irrigation (FI), and in conjunction with two nitrogen fertilizer rates (3.2 and 5.5 g N plant-1), on water productivity (WP), nitrogen (N) uptake, and use efficiency (NUE) in maize (Zea mays L. var saccharate). The plants were grown in the greenhouse conditions, in split-root grow bags and exposed to FI, CDI, APRD and FPRD treatments from four weeks after planting (4 WAP) to harvest. Analysis across the N-fertilization treatments showed that CDI, APRD, and FPRD significantly decreased plant height, shoot and root dry mass, shoot and root N uptake compared with the FI control.  Specifically, plant height and Leaf Area Index (LAI) were at their lowest with FPRD60 and APRD60, respectively, throughout the measured weeks. Additionally, shoot and root dry mass were notably reduced by 65.1% and 64.5% for FPRD60 and FPRD80, respectively, in comparison to FI. Water productivity remained consistent across all treatments. However, the CDI80 treatment exhibited a water-saving of 21.6% compared to FI and increased WP by 5.4%. Nitrogen use efficiency (NUE) significantly increased with increasing water deficit levels with FPRD60 increasing NUE by 52.5% compared to FI. Overall, CDI and APRD at mild stress had similar effect on plant growth, biomass and N uptake, with F-PRD demonstrating the lowest impact. The study revealed that water saved with deficit strategies across N fertilizer treatment did not significantly maintain or increase the water productivity (WP), but improved NUE.