Weed population in citrus based cropping system as affected by crops association

Abstract

Intercropping studies were conducted with Sweet Orange (Citrus sinensis L. Osbeck Cv. Agege 1) between 1996 and 1999 at the National Horticultural Research Institute, Ibadan Nigeria. The objective was to investigate the effect of different intercropping system on weed dynamics in citrus (ct) based cropping system. The intercrops were maize (m) (Zea mays L.) in the early planting season, followed by cowpea (cp) Vigna unguiculata L (Walp) in sequence during the late planting season of each year (m/cp), cassava (ca) (Manihot esculenta Crantz) and pineapple (p) (Ananas comosus (L.) merr.). Sole plots of Sweet orange (sct), maize (sm), cowpea (scp), cassava (sca) and pineapple (sp) were planted as control. Weed control efficiency of the intercrops was evaluated by 1m x 1m permanent quadrat technique. Sole citrus recorded a significantly higher (P<0.05) weed biomass in the three years of cropping than other treatments. This implies that weed management in sct orchard will require higher weeding frequency than any other cropping systems. The weed spectrum in ct + p and ct + ca intercropped plots changed from predominantly monocotyledonous to dicotyledonous weed species as the cropping cycle increased. Growth of citrus was impaired by cassava intercrop, while citrus intercropped with the maize/cowpea, pineapple and sole citrus stands (sct) improved citrus growth. Forty-two months after transplanting citrus, sct, ct + m/cp and ct+ ca had 1.63, 1.45 and 0.05 citrus fruit t/ha, respectively. Citrus plants intercropped with pineapple did not produce fruit. Intercropping in citrus alley reduced frequency of weeding and stimulates orchard management interest in citrus.

Keywords: Weed Population; Citrus; Intercropping systems

Moor Journal of Agricultural Research Vol. 6 (1&2) 2005 pp. 7-15