RESPONSE OF SLENDER LEAF SPECIES CROTALARIA BREVIDENS AND CROTALARIA OCHROLEUCA TO DIFFERENT PHOSPHORUS LEVELS

Abstract

Nearly 30% of Kenyan’s children are classified as undernourished and have micronutrient deficiencies, a problemthat can be alleviated by consumption of African indigenous vegetables such as slender leaf (Crotalaria spp).Slender leaf is rich in Vitamins A, C iron and protein. Although slender leaf has been commercially produced inKenya, only 2-4 tons per hectare have been achieved and yet it has potential of producing 10-12 tons per hectare.Declining soil fertility in the tropical soils and low phosphorus levels are among the major causes of its lowproductivity. The objective of this study was to evaluate the effects of different phosphorus application rates ongrowth and yield of Crotalaria brevidens and Crotalaria ochroleuca species grown under greenhouse conditions. Agreenhouse pot experiment was conducted between January 2013-June2013,in a complete randomized designwith sixteen treatment combinations of two factors that were eight phosphorus fertilizer rates,0,15,30,45,60,75,90and 105kgP2O5ha-1 and two slender leaf species Crotalaria brevidens and Crotalaria ochroleuca replicated fourtimes. Growth parameters observed weekly included plant height, branch number, leaf number, flower number,pod number, thousand seed weight and seed yield taken from two weeks after germination up to 15 weeks whenthe seeds were harvested. Results showed that phosphorus had significant effect (p≤0.05) on leaf number with thehighest leaf number achieved after application of 105kg P205 ha-1 for both varieties. Crotalaria brevidens achievedhighest number of leaves (100.25±10.16) and while the highest number of leaves for Crotalaria ochroleuca was(50.5 ±4.28). Effect of phosphorus on branch number was significant (p≤0.05) at application of 90kg P205 ha-1 forboth varieties. Phosphorus application significantly affected flower numbers (p≤0.05) with the highest flowersrecorded at application of 75kg P205 ha-1 for Crotalaria brevidens (96.8±10.8) and application of 105kg P205 ha-1 forCrotalaria ochroleuca (54.5±10.11). Phosphorus had a significant effect (p≤0.05) on seed weight with the highestweight per plant recorded at application of 75kg P205 ha- for both varieties. We conclude that phosphorusapplication can significantly improve yield of slender leaf species in Rhodic Ferrasols of Kenya.