Response of Jute Mallow (Corchorus olitorius L.) to organic manure and inorganic fertilizer on a ferruginous soil in North-eastern Benin

Objective: The study aimed to evaluate the effects of three types of fertilizers (Municipal solids waste compost, cow dung and chemical fertilizer) on growth characters and leaf yield of Corchorus olitorius under irrigated conditionsMethodology and results: A field experiment was conducted in Parakou in the dry season using a randomized complete block design with three factors and twelve treatments: 1) Municipal solids waste Compost (MSWC) at 0, 10, 20 and 30 t.ha-1; 2) Cow dung at 0, 10, 20 and 30 t.ha-1; Urea fertilizer (46% N) at 0, 50, 100 and 200 kg.ha-1. The plant height and stem diameter were significantly higher with Compost (20 t/ha) and lowest was recorded in control at all growth stages. The application of compost, cow dung and chemical fertilizer significantly increased the total number of branches at all growth stages. The highest number was recorded in MSWC 20 t.ha-1 as compared to the other treatments. The highest marketable leaves yield was obtained with MSWC at 20 t.ha-1 (8.1 t.ha-1) followed by MSWC at 30 t.ha-1 (6.6 t.ha-1), cow dung at 30 t.ha-1 (5.4 t.ha-1) and urea at 100 kg.ha-1 (5.4 t.ha-1), while control recorded lower values. A significant quadratic response on fresh leaf yield was observed with MSWC leading to a maximum of yield of 8.15 t.ha-1 at 23.03 t.ha-1.Conclusion and application of results: The results indicated that the MSWC performs better when used at the optimal rate (23.03 t.ha-1), and can be used as a promising fertilizer source in Corchorus olitorius production in Benin.Key words: Leaf yield, waste compost, cow dung, Corchorus olitorius, Beni

Reuse of domestic wastewater treated in macrophyte ponds to irrigate tomato and eggplant in semi-arid West-Africa: benefits and risks

The scarcity of freshwater resources is a critical problem in semi-arid zones and marginal quality water is increasingly being used in agriculture. This paper aimed at evaluating the physico-chemical and biological risks on irrigated soils and fruits of macrophyte treated wastewater (TWW), the nutrients supply, and the effect on tomato and eggplant production in semi-arid Burkina Faso. During three years of experiments, treated wastewater was used, with fresh water as control, in combination with or without mineral fertilizer application at recommended rate (140 kg N/ha + 180 kg P2O5/ha + 180 kg K2O/ha). The study revealed that the treated wastewater provided variable nutrients supply depending on year and element. The treated wastewater without mineral fertilizer improved eggplant yield (40% in average) compared to the freshwater. Both crops responded better to mineral fertilizer (52% for tomato and 82% for eggplant) and the effects of the treated wastewater and fertilizer were additive. As the N supply of TWW was very unsteady (8-227% of crop need), and P2O5 supply did not satisfy in whole crop need (3-58%) during any of the three years of experiment, we recommended that moderate N and P2O5 fertilizers be applied when irrigating with TWW in semi-arid West-Africa. On the contrary, the K2O supply was more steady and close to crop requirement (78-126%) over the three years of experiment and no addition of K fertilizer may be needed when irrigated with TWW. Faecal coliforms and helminth eggs were observed in treated wastewater and irrigated soils at rate over the FAO and WHO recommended limits for vegetable to be eaten uncooked. Tomato fruits were observed to be faecal coliform contaminated with the direct on-foliage irrigation with treated wastewater. Our results indicate that treated wastewater can effectively be used as both nutrients source and crop water supply in market gardening in the semi-arid Sub-Saharan West Africa (SSWA) where freshwater and farm income are limiting. Yet consumers should properly cook or disinfect treated-wastewater irrigated vegetables before eating, and market gardeners should also be careful manipulating treated wastewater to avoid direct health contamination in this environment. (c) 2010 Elsevier B.V. All rights reserved

Decision support tools for site-specific fertilizer recommendations and agricultural planning in selected countries in sub-Sahara Africa

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