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In the Sudano-Sahelian zones of West Africa, cultivated land is degraded due to reduced fallow periods and Striga hermonthica (Del.) Benth. infestation, and poses a serious threat to sustainable food production. To provide options for addressing these problems, we investigated the possibility of replacing the short fallow periods with food legume cultivation. We tested this in two farming communities within the Sudan savannah zone of Ghana. In the 1997 and 1998 cropping seasons, selected farmers within each community planted soybean [Glycine max. (L.) Merr.] or bambara groundnuts [Vigna subterranea (L.) Verdc.] on continuously cropped, Striga-infested farmlands, whereas lands that were maintained under two or three years of bush fallowing were planted to millet [Pennisetum glaucum (L.) R. Br.] or sorghum [Sorghum bicolor (L.) Moench]. Analysis of soil sampled from 0-15 cm (plough layer) revealed that contents of major plant nutrients were inadequate to support long-term crop production. Within each farming community, total nitrogen content at initial sampling showed significant negative correlation with the number of Striga seeds in the plough layer. Under legume cultivation, soil organic carbon content increased and the number of Striga seeds per square metre decreased in both communities from a mean value of 28 183 seeds m À2 to 8185 seeds m À2. Under cereal cultivation Striga seed density increased from 9383 seeds m À2 to 16 696 seeds m À2. The study provides evidence that introduction of food legume cultivation on farmlands with high S. hermonthica infestation as an alternative to bush fallow system could help achieve sustainable crop production in the Sudan savannah zones of sub-Saharan Africa.

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Farmers growing desire for no shade cocoa system has reiterated the scepticism about the impact of research on farmers' adoption of cocoa Agroforestry. In this study, we assess farmers' perception about shade trees and how that influences their adoption of cocoa Agroforestry. Five cocoa growing communities in the Eastern Region of Ghana and 91 cocoa farmers were purposively sampled and interviewed. The result showed that the most desirable shade trees among the farmers were Spathodea campanulata, Terminalia superba, and Terminalia ivorensis while Alstonei boonei was the least desirable. About 87 % of farmers introduced shade trees at different stages of cocoa farm establishment while 13 % of farmers had existing trees at establishment. Farmers with less than 11 years farming experience and those with Senior High education kept the recommended number (15-18) of shade trees ha − 1 . Most farmers related the importance of shade trees to the good growth of cocoa associated crops (37 %) and as source of fodder (31 %), while higher cocoa yield and low education on the importance of shade trees were major reasons farmers removed shade trees. In conclusion, collaboration between farmers and other stakeholders in the cocoa sector is essential in reversing the growing hunger for no shaded cocoa system. This collaboration must focus on educating farmers on the importance of shade trees, and by providing money and agro-inputs support to farmers as impetus for the adoption of cocoa Agroforestry in Ghana.

A study was conducted in pots on the field to assess the effect of different quantities of poultry manure (PM), cattle manure (CM) and pig manure (PG) on the release of available phosphorus from Togo rock phosphate (RP) and lettuce growth. There were eleven (11) treatments which were: Control (soil only); 2.5g RP; 2.5g CM; 2.5gRP + 2.5g CM; 2.5gRP + 5gCM; 2.5gPM; 2.5gRP + 2.5gPM; 2.5gRP + 5gPM; 2.5gPG; 2.5gRP + 2.5gPG; 2.5gRP + 5gPG, applied per kg soil, using the Completely Randomized Design (CRD) with three replications. Available phosphorus and other parameters were assessed using standard methods. Results were statistically analyzed using the the GenStat (11 th Edition) statistical software package. The amount and type of animal manure in the amendment affected the amount of the available P released. The addition of 2.5g manure to 2.5g RP in a kg of soil significantly (P<0.05) increased available P by 4 to 7 times over the sole 2.5g RP/kg soil treatment. Doubling the amount of manure in the amendment (5g manure + 2.5g RP) almost doubled the amount of P released, with the poultry manure combinations being more significant. The amount of available P in the soil positively related to the plant height (R 2 =63), leaf area (R 2 =0.55), dry weight (R 2 =0.73) and the percentage P in the leaf (R 2 =0.88) of lettuce. The PM at 2.5gRP + 5gPM recorded the highest significant (P<0.05) values. The study has provided further basis for manure selection and quantities to be used in enhancing the release of P from rock phosphate. However, investigations need to be continued using nuclear techniques.