American Journal of Agriculture and Forestry
Volume 4, Issue 3, May 2016, Pages: 56-63
Received: May 30, 2016;
Accepted: Jun. 13, 2016;
Published: Jun. 23, 2016
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Mzwandile P. Mabuza, Crop Production Department, University of Swaziland, Luyengo, Swaziland
Oghenetsavbuko T. Edje, Crop Production Department, University of Swaziland, Luyengo, Swaziland
Gideon N. Shongwe, Crop Production Department, University of Swaziland, Luyengo, Swaziland
Maize is the staple food in Swaziland but there have been shortfalls in production mainly due to the high cost of commercial fertilisers. One possible means of addressing the problem is the use of sunnhemp (Crotalaria juncea L.), a green manuring legume, which is cheap and easy to produce. A field experiment was conducted at the Malkerns Research Station during the 2014/2015 cropping season. The main objective of the study was to evaluate whether sunnhemp can be used as a substitute for inorganic fertilisers. The treatments were (1) maize with 40 kg/ha sunnhemp used as mulch, (2) maize with 80 kg/ha sunnhemp used as mulch, (3) maize with 120 kg/ha sunnhemp used as mulch, (4) maize with 40 kg/ha sunnhemp soil incorporated, (5) maize with 80 kg/ha sunnhemp soil incorporated, (6) maize with 120 kg/ha sunnhemp soil incorporated (7) maize with no fertilisers (8) maize with half rates of inorganic fertilisers and (9) Maize with recommended rates of inorganic fertilisers. The design of the experiment was a randomized complete block design and each treatment was replicated four times. Maize variety SC 403 was used. Data were collected on sunnhemp biomass, cost of placement and rate of mineralisation. Maize data were on growth, yield and yield components. The results on labour cost of placement show that soil incorporation was significantly (P < 0.01) higher than mulching with sunnhemp being 29.8 man-days/ha while it was 18.6 man-days/ha for mulching. The amount of mineralised sunnhemp was significantly (P < 0.05) higher in incorporated sunnhemp than from sunnhemp used as mulch. Maize grown with 120 kg/ha of sunnhemp yielded 7662.7 kg/ha while maize with 40 kg/ha of sunnhemp was lowest with 7251.1 kg/ha, a yield difference of 5.4%. Maize from soil incorporated sunnhemp yielded 7519.3 kg/ha while maize grown with sunnhemp used as mulch was lower with 7325.0 kg/ha, a yield difference of 2.6%. Maize grown with the recommended rates of fertilisers yielded higher than the rest of the treatments, it yielded 8405.7 kg/ha while maize grown with 80 kg/ha of sunnhemp later used as mulch was lowest with 6945.7 kg/ha. It is concluded that labour cost of sunnhemp placement was significantly (P < 0.01) higher for soil incorporation than mulching. Nitrogen mineralisation was significantly (P < 0.05) higher when sunnhemp was incorporated than when used as mulch. It is recommended that farmers grow their maize with 80 kg/ha of sunnhemp and use it as mulch seven weeks after planting.
Mzwandile P. Mabuza,
Oghenetsavbuko T. Edje,
Gideon N. Shongwe,
Effects of Inorganic Fertilisers and Sunnhemp (Crotalaria juncea [L.]) as a Green Manure Crop on Maize (Zea mays [l.]) Growth, Seed Yield and Labour Cost, American Journal of Agriculture and Forestry.
Vol. 4, No. 3,
2016, pp. 56-63.
Ambrosano, E. J., Trivelin, P. C., Cantarella, H., Ambrosano, G. M. and Muraoka, T. (2003). Nitrogen mineralization in soils amended with sunnhemp, velvet bean and common bean residues. Scientia Agricola. 60.1.133-137.
Amin, M. E. (2011). Effect of different nitrogen sources on growth, yield and quality of fodder maize (Zea mays L.). Journal of the Saudi Society of Agricultural Sciences. 10. 17-23.
Anonymous, (2006). Soil fertility management for the maize cropping systems of small holders in Southern Africa. http://www.suelo.br/pdf/sa/v63n5/31405 pdf. 05-04-2008.
Casey, A., Wynia, R. and Row, J. (2011). Evaluation and Use of Sunn Hemp (Crotalaria juncea L.) at the Manhattan Plant Materials Center, Manhattan, Kansas. Plant Materials Center. Manhattan. Kansas. USA.
Daughtry, C. S., Walthall, C. L., Kim, M. S., Brown de Coulstoun, E. and McMurtrey, J. E. (2000). Estimating Corn Leaf Chlorophyll Concentration from Leaf and Canopy Reflectance. Remote Sensing Environment. 74: 229–239.
Dlamini, M. (2007). Evaluation of soil and water conservation techniques on performance of maize at Luyengo. Unpublished B. Sc. Final year research report. University of Swaziland, Luyengo Campus, Luyengo, Swaziland.
Food and Agricultural Organisation (2001). Soil fertility Management in support of food security in Sub-Saharan Africa. Publishing and Multimedia Service, Information Division, Food and Agriculture Organization of the United Nations, Rome. Italy.
Mabuza, M. (2009). Evaluation of sunnhemp (Crotalaria juncea L.) alone or in association with maize (Zea may L.). Unpublished B. Sc. Final year research report. University of Swaziland, Luyengo Campus, Luyengo, Swaziland.
Miracle, M. P. (2006). Maize in Tropical Africa. The University of Wisconsin Press, Madison, U.S.A.
Mthethwa, C. M. (2009). Residual effect of sunnhemp (Crotalaria juncea) as a green manure crop on a succeeding maize (Zea mays) crop. Unpublished M. Sc. Final year research report. The University of Swaziland, Luyengo campus, Luyengo, Swaziland.
Nxumalo, G., Ossom, E., Rhykerd, R. and Rhykerd, C. (2010). Alfalfa (Medicago sativa L.) Green Manuring and Ecological Properties under corn (Zea mays L.) culture in Swaziland Alfalfa (Medicago sativa L.) Green Manuring and Ecological Properties under corn (Zea mays L.) culture in Swaziland. Advances in Environmental Biology. 4 (3): 477-484.
Palm, C. A. and Sanchez, P. A. (1999). Nitrogen release levels from the leaves of some tropical legumes as affected by their lignin and polyphenolic contents. Soil Biology and Biochemistry. 22: 31-36.
Samples, D. and McCutcheon, J. (2003). Grazing Corn Residue. http://ohioline.osu.edu/anr-fact/0010.html. 29/03/2015.
Vakeesan, A., Nishanthan, T. and Mikunthan, G. (2008). Green manures: Nature’s gift to improve soil fertility. http://www.agriculturesnetwork.org/magazines/india/2-living-soils/green- manures-natures-gift-to-improve-soil/at_download/article_pdf. 25/03/2015.
Van den Berg, A. K. and Perkings, T. D. (2004). Evaluation of a portable chlorophyll meter to estimate chlorophyll and nitrogen contents in sugar maple (Acer saccharum Marsh.) leaves. Forest Ecology and Management. 200: 113–117.
Wang, K. H., McSorley, R. (2008). Management of Nematodes and Soil Fertility with Sunnhemp Cover Crop. http://edis.ifas.ufl.edu/NGO43. 12/04/2009.
Warren, J., Wilson, T. and Edwards, J, (2012). Using sunnhemp as a cover crop in Oklahoma. http://osufacts.okstate.edu. 03/03/2015.
United Nations. (2012). Swaziland Food Insecurity Intensified by Financial Crisis. http://www.futuredirections.org.au/publications/food-and-water-crises/28- global-food- and-water-crises-swa/450-swaziland-food-insecurity-intensified-by-financial-crisis.html. 02/06/2014.