Impact of a Decade of Tillage, Crop Rotation and Residue Management on Subsoil P and N Dynamics in Haplic Plinthosols Data

Conventional tillage (CT) has shaped agricultural landscapes for decades and has long-standing use in South Africa. However, recently, it has been criticised for being unsustainable, prompting a re-evaluation of CT practices in the context of South Africa’s agricultural sustainability goals. This study investigated the effect of conservation agriculture (CA) on soil profile distribution of P and N stocks in the Eastern Cape, South Africa. Conservation agriculture is the farming practice that helps protect arable land from degradation. The trial was laid out in a randomised complete block design with strip-split-split plot treatment structure. The main plots, sub plots, sub-sub plots, and sub-sub-sub plots were allocated to no-tillage (NT) and conventional tillage (CT); crop rotations maize-fallow-maize (MFM), maize-soybean-maize (MFS), maize-wheat-maize (MWM), maize-wheat-soybean (MWS), and crop residue management practices; residue retention (R+) and residue removal (R-), and soil depths 0 – 20 cm, 20 – 40 cm, and 40 – 60 cm. Analysed soil samples were collected in the 2023/24 cropping cycle. Soil pH was significantly higher (P