Effect of sawdust mulch and fertilizer on weed Flora composition and growth in plantain/cocoyam intercrop in the Nigerian rainforest zone.

摘要

A field experiment was conducted at the Crop Research Farm of the University of Calabar in 2000-2002 to evaluate the effect of sawdust mulch and N P K 20:10:10 fertilizer rates on weed flora composition and growth in plantain/cocoyam intercrop. Mulch influenced high composition (81%) of broad leaves/herbaceous weeds which were more abundant in mulched plots, while the gramminaceous species (19%) were mostly found in bare plots. Weed cover score and weed dry weight significantly (P=0.05) varied between the mulched and bare plots. Weed interference was more severe in bare than in mulched plots irrespective of the fertilizer rate applied. Bare plots had high weed density with cover scores ranging from 7.5-9.2, but scores were low in sole mulch plots (4.2) and moderate in fertilized mulched plots (4.8-6.2). Weed dry weight was lowest (2.5 g/m2) in sole mulch plots and ranged from 3.3-2 g/m2 in fertilized mulched plots, while in non-mulched treatments, the dry weights were 3.8 g/m2 in the control but increased with increasing fertilizer rates and were 4.3, 6.8 and 8.2 g/m2 in plots treated with sole fertilizer at 200, 300 and 400 kg N P k 20:10:10/ha, respectively. Low weed prevalence in mulched plots indicates high weed smothering efficiency of sawdust mulch. Mulching the intercrop with 20 tonnes of sawdust/ha could be strategic in reduced weed interference with the crops, labour conservation and hence reduced cost of production and high fertilizer efficiency resulting in optimum productivity of the intercrop.