In-Field Rainwater Harvesting Tillage in Semi-Arid Ecosystems: II Maize-Bean Intercrop Water and Radiation Use Efficiency

Weldemichael Tesfuhuney; Muthianzhele Ravuluma; Admire Rukudzo Dzvene; Zaid Bello; Fourie Andries; Sue Walker; Davide Cammarano

doi:10.3390/plants12162919

In-Field Rainwater Harvesting Tillage in Semi-Arid Ecosystems: II Maize-Bean Intercrop Water and Radiation Use Efficiency

Plants (Basel). 2023 Aug 11;12(16):2919. doi: 10.3390/plants12162919.

Authors

Weldemichael Tesfuhuney¹, Muthianzhele Ravuluma², Admire Rukudzo Dzvene^{1

3}, Zaid Bello⁴, Fourie Andries⁵, Sue Walker^{1

2}, Davide Cammarano⁶

Affiliations

¹ Department of Soil, Crop, and Climate Sciences, University of the Free State, Bloemfontein 9301, South Africa.
² Agricultural Research Council (ARC), Soil, Climate, Water (SWC), Pretoria 0083, South Africa.
³ Risk and Vulnerability Science Centre, Faculty of Science and Agriculture, University of Fort Hare, Alica 5700, South Africa.
⁴ Agricultural Research Council (ARC), Grains Crops, Potchefstroom 2520, South Africa.
⁵ Department of Agriculture and Rural Development (DARD), Glen, Bloemfontein 9360, South Africa.
⁶ Department of Agroecology, Aarhus University, 8000 Aarhus, Denmark.

Abstract

The purpose of this study was to evaluate alternative management practices such as in-field rainwater harvesting (IRWH) and intercropping techniques through conducting on-farm demonstrations. Seven homestead gardens in Thaba Nchu rural communities in the central part of South Africa were selected as demonstration trials. Two tillage systems, conventional (CON) and IRWH, as the main plot, and three cropping systems as sub-plot (sole maize and beans and intercropping) were used to measure water use and radiation use parameters. The water productivity (WP) of various treatments was positively related to the radiation use efficiency (RUE), and the degree of associations varied for different tillage systems. The water use in IRWH was higher by 15.1%, 8.3%, and 10.1% over the CON for sole maize and beans and intercropping, respectively. Similarly, the intercropping system showed water use advantages over the solely growing crops by 5% and 8% for maize and by 16% and 12% for beans under IRWH and CON tillage, respectively. Maximum RUE was found for sole maize and beans under IRWH, higher by 13% and 55% compared to the CON tillage, respectively. The RUE under IRWH tillage was estimated to be 0.65 and 0.39 g DM MJ^-1 in sole maize and intercropping, respectively. However, in sole and intercropped beans, the RUE showed higher values of 1.02 g DM MJ^-1 and 0.73 g DM MJ^-1, respectively. WP and RUE were associated with water deficits and proportional to lower radiation use. This relationship indicates that the intercepted radiation by plants for photosynthesis is directly related to the transpiration rate until radiation saturation occurs. Therefore, the higher water deficit and lesser efficiency in using the radiation available during the season can be improved by practicing IRWH techniques. Furthermore, in semi-arid areas, to enhance the efficiency of water and radiation usage in intercropping management, it is crucial to adjust plant population and sowing dates based on water availability and the onset of rainfall.

Keywords: evapotranspiration; radiation interception; radiation use efficiency; soil water balance; water productivity.

Grants and funding

This research was funded by the Water Research Commission, South Africa (WRC Project No. K5/2128//4 and partially supported by the National Research Foundation (NRF) of South Africa (Grant Number (NRF, No. TTK190214417227), through the University of the Free State (UFS), South Africa.