An experiment was carried out using Red-yellow Podzolic soil of sandy texture, in Paraíba, (Brazil), to evaluate the yield of Dioscorea cayennensis yam, cv. Da Costa cultivated with different sources and levels of organic matter and mineral fertilization (NPK). The experimental design was of randomized blocks with split-plots in a factorial scheme of 2 x 4 + 2 and four replications. In the main plots was studied the harvest time (seven and nine months after planting date (MPD)) and, in the sub-plots four levels of cattle manure (5, 10, 15, 20 t/ha) and four levels of chicken manure (2.8; 5.6; 8.4; 11.2 t/ha), associated to 100-120-60 kg/ha of N-P2O5-K2O and two additional treatments (control and isolated mineral fertilization). Organic matter, increased in 3.8 t/ha the yield of yam harvested after nine MPD. Cattle manure surpassed significantly by 1.9 t/ha the yield obtained with the addition of chicken manure, seven MPD. Nine MPD, the addition of chicken manure resulted in a significant yield increase (2.0 t/ha) when compared to treatments with addition of cattle manure. Mineral fertilization alone resulted in significant yield increases seven (7.7 t/ha) and nine (4.4 t/ha) MPD. Cattle manure (13.3 and 12.6 t/ha) plus NPK was responsible for the maximum yam yield, (18 t/ha) when harvested at seven MPD (20 t/ha), and nine MPD, while the level of 7.0 t/ha of chicken manure resulted in maximum yam yield (15 t/ha) at seven (22 t/ha) and nine MPD. Average yield when harvesting nine MPD (18.0 t/ha) surpassed significantly, in 19.5% (3.5 t/ha) the average of 14.5 t/ha obtained at seven MPD.
Dioscorea cayennensis Lam; organic fertilization; mineral fertilization; age; yield
