TY  - JA
AU  - Mtambanengwe,F.
AU  - Mapfumo,P.
TI  - Smallholder farmer management impacts on particulate and labile carbon fractions of granitic sandy soils in Zimbabwe
SN  - 1385-1314
PY  - 2008///
CY  - Dordrecht (Netherlands)
PB  - Springer
KW  - Maize
KW  - AGROVOC
KW  - Crop yield
KW  - Organic matter
KW  - Smallholders
N1  - Peer review; Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=1385-1314
N2  - Crop production in maize-based smallholder farming systems of Southern Africa is hampered by lack of options for efficiently managing limited and different quality organic nutrient resources. This study examined impacts of farmers’ short- and long-term organic resource allocation patterns on sizes and quality of soil organic matter (SOM) fractions. Farmers’ most- (rich) and least- (poor) productive fields were studied for two seasons under low (450–650 mm yr-1) to high (>750 mm yr-1) rainfall areas in Zimbabwe, on Lixisols with -6% clay and 88% sand. Rich fields received 0.5–14 Mg C ha-1 compared with <4 Mg C ha-1 for poor fields, and the differences were reflected in soil particulate organic matter (POM) fractions. Organic inputs were consistent with resource endowments, with well-endowed farmers applying at least five times the amounts used by resource-constrained farmers. Rich fields had 100% more macro-POM (250–2,000 lm diameter) and three times more meso-POM (53–250 um) than poor fields. Application of high quality (>25 mg N kg-1) materials increased labile C (KMnO4 oxidizable) in top 60 cm of soil profile, with 1.6 Mg C ha-1 of Crotalaria juncea yielding labile C amounts similar to 6 Mg C ha-1 of manure. Labile C was significantly related to mineralizable N in POM fractions, and apparently to maize yields (P<0.01). Farmers’ preferential allocation of nutrient resources to already productive fields helps to maintain critical levels of labile SOM necessary to sustain high maize yields
UR  - https://hdl.handle.net/20.500.12665/81
T2  - Nutrient Cycling in Agroecosystems
DO  - https://doi.org/10.1007/s10705-007-9136-0
ER  -