Carbon Input and Maize Productivity as Influenced by Tillage, Crop Rotation, Residue Management and Biochar in a Semiarid Region in South Africa

Abstract

Conservation agriculture (CA) as a system is still evolving on many of the smallholder farms in sub-Saharan Africa (SSA) and questions on the impact of individual components and pathways toward adoption still require answers. A short-term study was conducted to investigate the effect of tillage, crop rotation, and crop residue management, including maize residue biochar on above ground biomass, cumulative carbon (C) input, soil organic carbon (SOC), and maize grain yield. A split–split plot design was used to evaluate two tillage operations (conventional tillage (CT) and no-till (NT)), three crop rotations (maize–fallow–maize (MFM), maize–oat–maize (MOM), and maize–vetch–maize (MVM)), and three-crop residue management (retention (R+), removal (R−), and biochar (B)). The cumulative above ground biomass produced in the MOM rotation was significantly higher by 78.9% and 88.7% relative to MVM and MFM rotations, respectively. The cumulative C input under residue management treatments ranged from 10.65 to 12.16 Mg ha−1. The highest SOC was observed under R+ (1.10%) followed by B (1.0%) and the lowest was in R− (0.96%). Crop residue management significantly affected grain yields in 2015/2016 (p < 0.05) and 2016/2017 (p < 0.01) summer seasons. Biochar did not result in an obvious improvement in both C input and crop yield. Smallholder farmers can potentially switch from CT to NT without any significant yield penalty, as well as adopt MOM and R+ practices for increased biomass and C input.

A Two-Year Study on Yield and Yield Components of Maize-White Bean Intercropping Systems under Different Sowing Techniques

“…Our study contradicted these findings in the literature, with a maximum grain yield in sole sowing. Other studies support our findings and report that the grain yield of maize was maximized in sole sowing compared with intercropping [37,[48][49][50]. Rao reported that, in intercropping, the yield might be lower compared with sole sowing due to an increase in inter-species competition in the root zone, which is caused by the proximity of the root zone of plants [51].…”

Long‐term soybean–maize rotation experiments in cereal‐based farming systems at Bako, Western Ethiopia

“…The increase in yield of maize rotated with soybean may be attributed to soybean residue containing organic N and other nutrients that are released by soil microbes after breakdown for succeeding maize. This is constant with the prior study, which shows that a soybean–maize rotation improves yield (Boomsma et al, 2010; Franke et al, 2018; Lauer et al, 1997; Nyambo et al, 2020; Uzoh et al, 2019). When compared to cereals grown continuously, soybean–maize rotations boost SSA cereal yields by 0.49 tons ha −1 or more in fields planted following a legume (Acevedo‐Siaca & Goldsmith, 2020).…”

Innovative agroecological practices can restore degraded farmlands and revive crop yields

“…Pyame et al (2016) reported the high soil moisture and organic matter content in a similar agroecological package in DR Congo to boost plant growth. Soleymani et al (2016) and Nyambo et al (2020) reported crop residue retention and the establishment of cover crops to contribute to the improvement of various soil properties and crop yields.…”

“…The T3 package improved soil moisture content, soil porosity, and earthworm population, collectively creating suitable conditions for the growth of crops. Agroecological practices such as minimum tillage, fallowing and ensuring a permanent ground cover have been reported to improve physical, chemical, and biological soil conditions for improved crop growth (Pyame et al, 2016;Das et al, 2019;Nyambo et al, 2020). According to Page et al (2019) and Xiao et al (2019) minimum tillage as practiced in T3, most often leads to higher yields compared to conventional tillage-based agriculture.…”