Seed quality and yield of selected traditional and commercial crops : vegetable water use and nutritional productivity perspectives.

Abstract

Sub-Saharan Africa (SSA) faces challenges of achieving nutrient and food security under water limitations due to climate change and variability. Under these conditions, it is important to adopt cropping systems that are likely to improve crop production. The aim of the study was to assess the feasibility of a legume - leafy vegetable intercrop system with a view to determine the yield and nutritional benefits. This was achieved through a series of studies which included conducting critical literature review, quantifying water use and nutritional water productivity efficiency of intercropping. Field trials were conducted at an Umbumbulu homestead and Fountain Hill Estate, in KwaZulu-Natal, during the 2016/2017 summer season, under rain-fed conditions. Intercrop combinations considered were sole cowpea, amaranth, garden pea and swiss chard, as well as intercrops of cowpea-amaranth, cowpea-garden pea and cowpea-swiss chard. Seed quality of selected crops were determined prior to planting to establish field planting value of seed lots. Data collection included plant growth (leaf number and plant height), and physiology (chlorophyll content index and stomatal conductance). Yield and yield components, water use (WU) and water use efficiency (WUE) were calculated at harvest. Nutritional analysis was determined after harvest. The results showed a significant (P≤0.05) difference between species with respect to seed vigour. There were significant differences (P<0.05) with respect to growth and physiological parameters among crop species. Significant differences (P<0.05) were also observed with respect to yield and yield components among crop species under cropping systems. Traditional species were significantly superior to exotic species with respect to seed germination and vigour. Field trials showed a general relationship between seed quality and crop performance. Although sole cropping showed better field crop performance than intercropping, there was evidence of significant water and nutrient productivity of the intercropping system.