Microbial biomass carbon and enzyme activities as influenced by tillage, crop rotation and residue management in a sweet sorghum cropping system in marginal soils of South Africa

Mashapa E Malobane; Adornis D Nciizah; Patrick Nyambo; Fhatuwani N Mudau; Isaiah I C Wakindiki

doi:10.1016/j.heliyon.2020.e05513

Microbial biomass carbon and enzyme activities as influenced by tillage, crop rotation and residue management in a sweet sorghum cropping system in marginal soils of South Africa

Heliyon. 2020 Nov 18;6(11):e05513. doi: 10.1016/j.heliyon.2020.e05513. eCollection 2020 Nov.

Authors

Mashapa E Malobane^{1

2}, Adornis D Nciizah^{1

2}, Patrick Nyambo³, Fhatuwani N Mudau^{2

4}, Isaiah I C Wakindiki²

Affiliations

¹ Agricultural Research Council - Institute for Soil, Climate and Water, P. Bag X79, Pretoria, South Africa.
² University of South Africa, Department of Agriculture and Animal Health, Private Bag X6, Florida, 1710, South Africa.
³ Department of Agronomy, University of Fort Hare, Private Bag X1314, Alice, 5700, South Africa.
⁴ School of Agricultural, Earth and Environmental Sciences, University of Kwazulu Natal, P. Bag X01, Scottsville, 3209, Pietermaritzburg, South Africa.

Abstract

Questions on sustainable and appropriate cropping systems for bioenergy sweet sorghum in the smallholder farming sector still exist. Therefore, a short-term experiment was carried out to study the influence of management on microbial biomass carbon (MBC), β-glucosidase, acid phosphatase, and urease activities in a sweet sorghum cropping system in South Africa. Tillage [no-till (NT) and conventional tillage (CT)], rotation [sorghum-vetch-sorghum (S-V-S) and sorghum-fallow-sorghum (S-F-S)] and residue retention [0%, 15% and 30%] were evaluated. Tillage× rotation× residue management interaction influenced (P < 0.05) MBC whilst crop rotation residue influenced (P < 0.05) β-glucosidase. Tillage affected β-glucosidase (P < 0.05), acid phosphatase (P < 0.001), and urease enzyme (P < 0.01) while crop rotation only influenced acid phosphatase (P < 0.01). Residue retention affected acid phosphatase (P < 0.001) and urease enzyme (P < 0.001). NT + S-V-S+30% interaction resulted in the highest MBC content compared to CT + S-F-S+0%. NT+30% enhanced β-glucosidase activity, S-V-S enhanced acid phosphatase compared to S-F-S. MBC and enzyme activities were positively correlated with each other. Tillage and residue management were the main factors influencing soil biological indicators under bioenergy sweet sorghum in South African marginal soils in the short-term. Soil biological indicators were higher under NT and 30% residue retention respectively. NT + S-V-S+30% was a better treatment combination to enhance soil quality under bioenergy sweet sorghum in South African marginal soils.

Keywords: Agricultural policy; Agricultural soil science; Agronomy; Conservation agriculture; Fossil fuel; Organic farming; Phosphatase; Soil biological activity; Soil quality; Urease; β-Glucosidase.