PULSES OF GROWTH UNDER DIFFERENT LEVELS Ní ?? FERTILIZATION WITH PHOSPHATE ROCK

Abstract

With the objective of evaluating the effect of increasing doses of rock phosphate on growth and nutrient accumulation of species of legumes (Fabaceae), settled in a greenhouse, an experiment using phosphate rock from Morocco. A substrate consisting of a mixture of yellow HAPLUSTOX concretionary (0 - 20 cm) was used and washed sand and clay (B horizon) in a ratio of 2: 1: 1 (v: v: v) and sieved 2 mm mesh for plant growth and treatments. The 4 X 5 factorial design, completely randomized, with four species, five levels of phosphate and four replications, totaling 80 experimental units was adopted. The species studied were Mucuna aterrima (Piper & Tracy) Holland, Cajanus cajan (L.) Millsp., Crotalaria juncea L. and Pueraria phaseoloides (Roxb.) Benth. Phosphate levels used were 0 kg ha-1; 46 kg ha-1; 92 kg ha-1; 183 kg ha-1 and 366 kg ha-1 of P2O5. The results showed that Mucuna species aterrima produced more biomass in relation to other species. However, Pueraria phaseloides, juncea and Cajanus cajan species showed higher levels of nutrients in biomass and were more sensitive to phosphorus deficiency. They also had better responses to phosphorus fertilization, accumulating more total biomass relative to aterrima Mucuna. The species Cajanus cajan and Pueraria phaseoloides obtained the best assimilatory followed rates of Crotalaria juncea in response to fertilization with rock phosphate.