Changes in soil organic matter indices following 32 years of different wheat production management practices in semi-arid South Africa

Loke, P. F. and Kotze, E. and Du Preez, C. C. (2012) Changes in soil organic matter indices following 32 years of different wheat production management practices in semi-arid South Africa. Nutrient Cycling in Agroecosystems. pp. 1-13.

[img] PDF (Online First) - Published Version
Restricted to ICRISAT researchers only


Soil organic matter (SOM) degradation is common in semi-arid regions due to frequent and intensive cultivation, removal of crop residues after harvesting and warmer environmental conditions. Therefore, we evaluated the effects of long-term wheat production management practices on organic matter content of a Plinthosol in semi-arid South Africa. The treatments included two methods of straw management (unburned and burned), three methods of tillage (no-tillage, stubble mulch and ploughing) and two methods of weeding (chemical and mechanical). Soil samples were collected in 2010 at various depths and analysed for soil organic carbon (SOC), soil total nitrogen (STN) and soil total sulfur (STS) as organic matter indices. Treatments where straw was not burned had greater STN and STS, but lower SOC levels than those where straw was burned. No-tillage had higher SOC levels than the stubble mulch and ploughing treatments only in the 0–50 mm soil layer. Below 100 mm soil depth, higher SOC levels were recorded in the ploughed plots. No-tillage and stubble mulch enhanced STN throughout the soil profile compared to ploughing. Ploughing and stubble mulch treatments had greater STS levels than no-tillage treatments in the upper 250 mm soil layer, and STS in the 0–450 mm soil layer was higher in mechanically weeded plots than in chemically weeded plots. Treatment combinations also showed some signifi- cant interactions on these indices, but lack of consistency made it difficult to single out the combination that was superior to others. However, to maintain or improve SOM of this Plinthosol priority should be given to no-tillage and stubble mulch management practices. Wheat grain yields over the 32 years trial period were significantly influenced by straw management and tillage methods, but not by weeding methods.

Item Type: Article
Uncontrolled Keywords: Conservation tillage, Conventional tillage, Soil organic carbon, Soil total nitrogen, Soil total sulfur
Author Affiliation: Department of Soil, Crop and Climate Sciences, University of the Free State, Bloemfontein 9300, South Africa
Subjects: Soil Science and Microbiology > Soil Sciences
Divisions: Other Crops
Depositing User: Mr Siva Shankar
Date Deposited: 11 Sep 2012 03:43
Last Modified: 11 Sep 2012 03:43
Official URL:

Actions (login required)

View Item View Item