Legume Cover Crops are More Beneficial than Natural Fallows in Minimally Tilled Ugandan Soils

Abstract

It is important to establish the various eff ects of legume cover crops on soil physicochemical properties because they have been considered for use as improved fallows (with shorter rest periods) to enhance development and maintenance of soil productivity. Our objectives were to assess: (i) aboveground dry matter yields of legume cover crops; and (ii) cover crop eff ects on weed infestation and soil physicochemical properties in a minimum tillage management system. Trials were conducted for 2 yr at Kawanda Agricultural Research Institute and on farmers' fi elds in Mbale and Pallisa districts, eastern Uganda. Th e experiment layout was a Randomized Complete Block Design (RCBD) in a split-plot arrangement with four replications. Natural and improved fallows were established in the second cropping season of 2004. Cover crops used in the improved fallows included mucuna [Mucuna pruriens (L.) DC.var. utiliz], Dolichos lablab (Lablab vulgaris Savi cv. Rongai), canavalia [Canavalia ensiformis (L.) DC.], and crotalaria (Crotalaria paulina Schrank). Th e fallows were reestablished in the same plots in the second cropping season of 2005 aft er maize (Zea mays L.). Canavalia yielded signifi cantly more dry matter than the other fallows regardless of year or site.With an average yield of 169 kg N ha -1 canavalia accumulated signifi cantly more N than the other fallows; all improved fallows produced signifi cantly more N than the natural fallow. Canavalia also accumulated signifi cantly more P than the other fallows; all improved fallows, with the exception of crotalaria, accumulated more P than the natural fallow. Th ere was no signifi cant change in soil physicochemical properties by the improved fallows. All eff ects considered, improved fallows were more benefi cial than natural fallow. A signifi cant improvement in soil physicochemical properties using legume cover crops might be possible, though it may require more than the two cropping cycles used in this study of degraded soils.

Influence of Integrated Weed Management and Tillage Methods on Soil Physical and Chemical Properties in Maize Production

“…However, TN in PX 1 AS 1 , AP 1 A 1 , AP 1 AS 1 , AP 1 MS 3 was significantly higher than in C 1 respectively. This is contrary to Mubiru and Coyne [51] who reported that all improved fallows produced significantly more N than the natural fallow. The order AP-CC/C 2 >PX-CC was observed.…”

Lablab purpureus—A Crop Lost for Africa?

“…Almost all of these African initiatives have included and continue to include one popular late-maturing forage cultivar, cv. Rongai (Makembe and Ndlovu 1996 ; Fischler and Wortmann 1999 ; Haque and Lupwayi 2000 ; Wortmann et al 2000 ; Shehu et al 2001 ; Mureithi et al 2003 ; Amodu et al 2004 ; Nworgu and Ajayi 2005 ; Nyambati et al 2006 ; Abeke et al 2007 ; Ojiem et al 2007 ; Abeke et al 2008 ; Mubiru and Coyne 2009 ) and, as a result, the potential role of the species as a pulse or vegetable in Africa is likely to be severely underestimated. Only recent work at ILRI in Ethiopia and CSIRO in Australia (Pengelly and Maass 2001 ) and, subsequently, in southern Africa (Whitbread and Pengelly 2004 ) explored a much larger range of accessions for feed and food and identified germplasm, which was well adapted to drier climates and crop use.…”

Addition of Cover Crops Enhances No‐Till Potential for Improving Soil Physical Properties

“…The same study showed that HV increased water infiltration in both soils. In a 2-yr study, Mubiru and Coyne (2009) This literature review indicates that the impact of CCs on soil physical properties can be variable. Cover crop impacts may depend on the type of CC, type of soil, tillage and cropping system, management history, and climate.…”

“…This increase in SOC concentration may improve soil physical properties. Some studies have indicated, however, that CCs may not always increase SOC concentration (Mendes et al, 1999;Fronninget al, 2008;Mubiru and Coyne, 2009). The influence of CCs on soil physical properties may depend on whether CCs increase the SOC concentration.…”