Evaluation location: Texas, United States
Accessions from the Cowpea Core Collection were evaluated for growth response to rock phosphate (RP) application. The aspect of soil fertililty that most negatively affects crop production is phosphorus deficiency. Naturally occurring rock phosphate is an alternative that is relatively inexpensive compared to chemical fertlizers. The study was conducted in a glasshouse at the Texas AgriLife Research Station in Bushland, Texas. Soil used was a Betis sand which is similar to the seriously P deficient soils of the West African Sahel. The Betis sand had a pH of 4.7 in 1:1 water:soil mixture, and plant-available P level of 3 mg kg-1 using the Melich III method. Phosphate treatment was added as 300 mg P kg-1 soil as RP from Niger, Tahoua. After 8 weeks, plant height was measured and shoots were harvested, dried, and weighed. Total biomass (shoot dry weight + root dry weight) was calculated. Results were grouped into five categories from highly responsive to least responsive to added RP.