Effects of cropping systems on the productivity of component crops
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Date
2003-11-28
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Abstract
A study was conducted at the Crops Research Institute, Fumesua, Kurnasi Ghana in
2002/2003 cropping season to evaluate the effects of cropping systems on the
productivity of component crops.
There were fifteen cropping systems comprising both sole and intercropped systems of cassava and maize with soybean, cowpea, and mucuna, and hush fallow.
Intercropping reduced the plant and canopy heights of cowpea. Soybean, and maize; that of cassava, however, were increased. Intercropped maize and intercropped cassava systems absorbed significantly (P<0 .05) greater Photosynthetically Active Radiation (PAR) than sole cassava and sole maize (either fertilized or unfertilized). The intensity of weed growth in sole cassava was significantly (P<0.05) higher than in all intercropped cassava, except in cassava/maize intercrop. This study has, thus proved that intercrop systems of maize and cassava are more effective in PAR utilization and weed suppression than sole crop systems of both crops.
Continuous cowpea and soybean yielded higher than the intercrops; maize relay intercropped with mucuna yielded most and was comparable to yields of maize rotated with cowpea; and tuber yields of cassava intercropped with maize was improved compared to sole crop and other intercrop systems. The grain/tuber productivity of all the intercrops was greater than 1, except maize/cowpea, which was 16% less productive compared to the sole crops. The biomass productivity of cassava/soybean, cassava/cowpea, cassava/maize intercrops, and maize/mucuna relay intercrop measured by the land equivalent ratios on the other hand, ranged between 101 and 244% while maize/soybean, maize/cowpea, and cassava/maize/soybean intercrops recorded land equivalent ratios (LERs) of less than 1. Cropping system did not significantly affect the N or crude protein content of the planting materials.
Intercropping cowpea and soybean with maize reduced the amount of biomass produced and amount of N-fixed by the legumes more than intercropping them with cassava.
African Cassava Mosaic Virus (ACMV) and Cassava Bacteria Blight (CBB) incidence declined with the onset of the dry season and increased with the rains.
Incidence of Cassava Anthracnose Disease (CAD) decreased from 230 days after planting (DAP) to 350 DAP whiles Cassava Green Mite (CGM) incidence increased from 230 DAP to 350DAP. The averaged incidences of ACMV, CAD, and CGM were higher in cassava intercropped with maize than cassava in other cropping systems but these did not affect both biomass and tuber yields. The seventies of the diseases and pest from 230DAP to 350 DAP did not, however, follow a definite pattern.
Cassava and maize should be intercropped for long-term periods on a piece of land to maximize productivity of crop land. Cassava and maize should be intercropped with each other or with legumes to ensure maximum PAR interception and weed control. Cowpea and soybean should be sole cropped in the major season. Farmers interested in the cultivation of both maize and cowpea should, however, rotate maize with cowpea in the minor season.
Description
A thesis submitted to the Department of Crop Science, College of Agriculture and Natural Resources in partial fulfilment of the requirements of Master of Science degree, 2003