Improving the productivity of vertisols in the Accra plains of Ghana using leguminous cover crops

Abstract

The productivity of the Vertisols of the Accra plains is low, in spite of its high potential fertility. This could be attributed to physical constraints and low organic matter content. A study was conducted at the Agricultural Research Centre, Kpong, to assess the suitability of Mucuna pruriens, Mimosa invisa and Stylosanthes guianensis, in short fallows, for improving the fertility, physical properties, moisture conservation and weed control in the case of these soils. Mucuna had the highest biomass of 5.3tha 21 , as opposed to 4.1tha 21 under natural fallow. The mucuna and stylosanthes biomass had comparatively higher total N values (240.75 and 203.51kgha 21 , respectively) than mimosa and natural fallow (152.46 and 162.74kgha 21 , respectively). Soil organic carbon, one year after the incorporation of cover crops, was found to be relatively higher under the cover crops (mucuna, stylosanthes and mimosa) than it was under natural fallow. Bulk densities were thus lower under the cover crops than they were under natural fallow. Also, soils under the cover crops had higher total porosity, water infiltration rates and moisture storage than they did under natural fallow. Weed cover, 115 days after planting maize, was significantly lower in plots previously under Mucuna pruriens than it was under natural fallow, Stylosanthes guianensis and Mimosa invisa. There was a negative linear correlation between cover crop biomass and weed density (R 2 ¼ 0.593-0.805). Grain and stover yields of maize were higher under Mucuna pruriens than they were under natural fallow (138 and 70 per cent higher, respectively). Burning of the natural fallow resulted in greater weed growth than when the material was worked into the soil (41 and 8 per cent, respectively). Grain yield was significantly greater under mucuna than it was under natural fallow (3.1 and 1.3tha 21 , respectively).

Evaluation of Sesbania sesban L. (Merr) and Mimosa invisa L. (Fabaceae) as sources of nitrogen in irrigated rice on the Vertisols of the Accra Plains of Ghana

“…sesban had an N content of 2.5% and total N of 239 to 259 kg N ha -1 , compared with 2.8% N and total N of 148.4 kg N ha -1 in an earlier study (Nyalemegbe et al, 2011b). On the other hand, M. invisa had N content of 2.4% and total N of 152 to 186 kg N ha -1 in the current study, compared with values of 3.2% and 152.5 kg N ha -1 , respectively in an earlier study (Nyalemegbe et al 2011a). Rinaudo et al (1983) estimated that Sesbania rostrata as green manure fixed at least 26.7 g N m -2 (that is, 267 kg N ha -1 ), and one third of the fixed N was transferred to the crop and two thirds to the soil.…”

“…Experiments were conducted on half acre plots on three farms at the Kpong Irrigation Project sites at Akuse (lat 6° 06' N and long 0° 07' E) and Asutsuare (lat 6° 04' N and long 0° 12' E), but work on two farms were successfully concluded and presented in this paper. At the beginning of the rainy season (in March), the locally growing S. sesban and M. invisa were drilled in designated basins (8 m × 6 m), with inter-row spacing of 60 cm, planting rates of 60 kg ha -1 and to a depth of 2 cm (Nyalemegbe et al, 2011a). Both S. sesban and M. invisa required upland soil condition to germinate.…”

Physical properties and organic matter content of the soils of Bade in Yobe State, Nigeria

“…The soil organic matter across the LGA was -1 low (median 1.57gkg and IQR (1.30-1.80). Generally, the soils were low in OM, this could be attributed to low vegetative cover which is a result of low rainfall that characterize such savannas (Nyalemegbe et al, 2011). Similarly the low organic matter content of the soils in all areas could be attributed to factors such as continuous Ibraheem Alhassan, Auwalu Garba Gashua, Sunday Dogo, Mahmud Sani DOI: 10.31015/jaefs.18027 cultivation, frequent burning of farm residues commonly carried out by farmers in the area which tends to destroy much of the organic materials that could have been added to the soil (Sharu et al, 2013).…”