Phosphorus availability to rice from phosphate rock and Sesbania rostrata and Vicia faba green manure

A greenhouse study was conducted to determine Sesbania rostrata and Vicia faba green manure production and phosphorus (P) uptake from a reactive North Carolina phosphate rock (NC PR) and a low reactivity Tahoua phosphate rock (TA PR), applied in 1.250 kg pots at 0, 500, and 1000 mg P kg;Dry matter production increased 2 fold for V. faba and 1.6 fold for S. rostrata while P uptake increased 3 fold for V. faba and 3.3 fold for S. rostrata in Crowley soil treated with 1000 mg P kg;Vicia faba green manure applied at 10.6 g pot;Vicia faba green manure applied at 10.6 g pot;Sesbania rostrata green manure at 8.5 g pot;Results from this greenhouse and laboratory research suggest that the use of PR in combination with S. rostrata or V. faba green manure can be utilized on low P, acid soils to supply adequate P and create sustainable rice production systems provided the difficulties inherent to PR and green manure use in ricelands are resolved.