Effect of Moistube and subsurface drip irrigation on cowpea (Vigna unguiculata (l.) Walp) production in South Africa

Abstract

Moistube irrigation (MTI) is a new subsurface irrigation technology where the water emits from a semi-permeable membrane at a slow rate depending on applied pressure and soil water potential. There is lack of information on how various crops respond to MTI. This study determined growth, yield and water use efficiency (WUE) of cowpea (Vigna unguiculata (L.) Walp) under varying water regimes under MTI and subsurface drip irrigation (SDI), using field and glasshouse experiments in summer and winter of 2018, respectively. A split-plot design arranged in randomized complete blocks, replicated 3 times, with SDI as the control experiment was used. The main plot was irrigation type while the sub-plots were the water regimes. The water treatments consisted of full irrigation (100% of crop water requirement (ETc)), and deficit irrigation (DI) of 70% ETc and 40% ETc. Water deficit had a significant effect (p < 0.05) on time to flowering; plants under 40% ETc flowered 14 days earlier than plants at 100% ETc. There were significant (p < 0.05) differences in yield components. Grain yields were 1 280 kg∙ha-1, 2 401 kg∙ha-1 and 3 189 kg∙ha-1 for 40% ETc, 70% ETc and 100% ETc, respectively, but no significant (p > 0.05) differences were recorded between SDI and MTI. However, at 40% ETc, SDI had 15% higher yield than MTI. Biomass varied significantly (p < 0.05) with irrigation type and water treatment. Grain WUE varied significantly (p < 0.05) among the water regimes. The highest WUE was achieved under SDI at 70% ETc but was not significantly different from that under MTI at 70% ETc. In conclusion, performance of cowpea was similar under the two irrigation systems under moderate DI but was better for SDI under severe DI with respect to biomass and WUE for the summer trial. Moderate DI improved the grain WUE while all the DI conditions improved the biomass WUE.

Effect of Surface and Subsurface Drip Irrigation and Furrows Irrigation System on Water Productivity, Growth and Yield of Lettuce (Lactuca Sativa L)

“…The use of large amounts of water led to an increase in the length of the head and similarly when little water was used the lowest head length was observed. This can also be due to the adequate dissolution of nutrients at high water levels [8][9][10] mentioned the effect of irrigation treatments on the head length of lettuce at the level of irrigation of 100% ETc which gave the highest average compared to the lowest levels of irrigation.…”

Nutritional yield and nutritional water productivity of cowpea (Vigna unguiculata L. Walp) under varying irrigation water regimes

“…Cowpea was planted on 14 February 2018 and deficit irrigation treatments were introduced 21 DAP; other agronomic management practices were done accordingly based on recommended best practices (DAFF, 2014). The description of the experimental design used in this study is found in Kanda et al (2020).…”

“…The water application was applied intermittently, ranging from as low as 3 days, 5 days, and 8 days continuously per 10 days for 100% ETc, 70% ETc and 40% ETc, respectively. The description of the irrigation management is found in Kanda et al (2020).…”

“…Yao et al (2014) established that Moistube irrigated navel orange fruit had the highest photosynthetic rate, leaf respiration and yield compared to conventional irrigation and rainfed conditions. Recently, Kanda et al (2020) established that there was no difference between yield of cowpea under Moistube irrigation and subsurface drip irrigation in South Africa. The yield and water productivity under Moistube irrigation have been reported to be similar or higher than conventional irrigation in spinach, wheat and eggplant, as reviewed in Kanda et al (2019).…”

“…c , respectively. The results in Table3, including those of yield components such as pod number, seed number, seed mass and pod mass, are found inKanda et al (2020).…”