16 research outputs found
Rice yields enhanced through integrated management of cover crops and phosphate rock in phosphorus-deficient ultisols in West Africa
The relatively low solubility and availability of phosphorus (P) from indigenous phosphate rock could be enhanced by legumes in the acid soils of humid forest agroecosystems. Crotalaria micans L. was grown in a screenhouse without P or with P from triple superphosphate (TSP) and Malian Tilemsi Rock P. The P response of 20 cover crops was field-evaluated using TSP and Rock P. In both experiments, the fertilized cover crops were followed by upland rice without mineral N or P application. Mean rice grain yield and agronomic residual P-use efficiency were similar for both P sources. In the field, 1-year fallow treatment of Canavalia ensiformis (velvet bean) supplied with Mali Rock P gave the highest rice grain yield of 3.1 Mg ha-1, more than 180% that of 2-year continuous unfertilized rice (cv. 'WAB 56-50'). Among continuous rice plots, 'NERICA 2' (interspecific rice) supplied with Rock P produced the highest yield (2.0 Mg ha-1), suggesting that 'NERICA 2' might have greater potential to solubilize rock P. Results indicate that when combined with an appropriate legume, indigenous rock-P can release sufficient P to meet the P requirement of the legume and a following upland rice crop in rotation
Response of interspecific and sativa upland rices to Mali phosphate rock and soluble phosphate fertilizer
In West Africa, two-thirds of upland rice is grown on acidic phosphorus (P)-
deficient soils. Phosphorus is one of the most limiting-nutrients affecting crop
productivity. A three-year field experiment was conducted on a Ferralsol in CoË te
dâIvoire to study the response of four interspecific rice cultivars and a sativa
(control cultivar) to Tilemsi phosphate rock (PR) and soluble triple superphosphate
(TSP) fertilizer. PR was applied at 0, 150, 300, and 450 kg ha71 P once in
the first year and residual effects were measured in the following years. TSP (0, 50,
100 and 150 kg ha71 P) was applied yearly. More significant yield increasing
(38%) was observed in the second year. Annual application of 50 kg P ha71 as
TSP or a one-time application of 150 kg P ha71 as PR was the optimum rate for
the production of all cultivars. Higher rates of P from TSP (100 and 150 kg P
ha71) gave 2â3 times greater residual P in soil than the optimum rate, inducing no
further response of rice. Two interspecific cultivars were identified as the most
acid- and low P-tolerant cultivars for improving rice production in West Africa
humid forest zone
Why NERICA is a successful innovation for African farmers
This paper responds to âFunding international agricultural research and the need to be noticed: a case study of NERICA riceâ by Stuart Orr, James Sumberg, Olaf Erenstein and Andreas Oswald, published in this issue of Outlook on Agriculture.
In summary, the article by Orr et al, based on an internal WARDA document written in November 2003 and augmented with results from Internet searches, is outdated and does not seem to be fair, objective or useful. We invite the authors to visit WARDA or any of its partners in Sub-Saharan Africa for evidence of the impact of NERICA varieties or the other improved varieties and technologies that have been developed and disseminated by WARDA in recent years