Crescimento, estado nutricional e produção de abóbora hibrida, em função de adubação mineral e orgânica.

• Ano de defesa: 1997
• Autor(a) principal: Silva, Natan Fontoura da
• Orientador(a): Ferreira, Francisco Affonso
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Área do conhecimento CNPq: Fitotecnia
• Link de acesso: http://www.locus.ufv.br/handle/123456789/11926

Two expertiments were carried out at the Federal University of Viçosa and two were conducted on a Cambic Yellow-Red Podzol soil under field conditions in EPAMIG Experimental Farm at Ponte Nova, Minas Gerais State. In the first, models were developed to estimate squash foliar area through leaf linear measurements. In the second, under field conditions, it was tested five rates of mineral fertilizer 4-14-8 (0, 215, 430, 860, 1,720 kg/ha), with six replicates on a randomized block design. In the third, under greenhouse conditions, it was tested five rates of organic compound (0, 25, 50, 100, 150 g/dmª, expressed on dry basis) and three rates of mineral fertilizer (0, 1 and 2) arranged on a 5 x 3 factorial with four replicates on a randomized block design. In the fourth, conducted in the Ponte Nova region, under field conditions, it was studied the gradual replacement of mineral fertilizer by the organic compound through five fertilizing treatments combining mineral and organic fertilizers besides the control treatment (without fertilization), in a randomized block design with four replicates. In the first experiment, a cubic square-root-base type model (Ã = -83.63-5 1.1 12 * L +111.378JZ+ 9.8047 * *Ll-ª) based on the greater leaf width was suitable to estimate the plant leaf area under greenhouse conditions and a quadratic model (Ã = 3.85-1.272L+0.7756**L2) for plants grown on the field. In the second, the mineral fertilizer rates affected yield and mean fruit weight and N, P, K leaf concentrations. It was estimated that the 772 kg/ha of 4-14-8 provided the highest economic returns. ln the third, the organic compound rates increased the leaf area, the shoot dry weight, the leaf blade P, K and 8 concentrations; in the highest organic compound rate (150 g/dmª) was obtained the optimum dry matter yield. In the fourth, the replacement of mineral fertilizer part by the organic compound resulted greater shoot dry matter and fruit yield. Fruit yield reached the maximum value of 13,596 kg/ha with 6,402 kg/ha of the organic compound and 360 kg/ha of the 4-14-8 mineral fertilizer but the maximum economic efficiency was obtained with a 5,347 kg/ha of the organic compound and a 434 kg/ha of the 4-14-8, mineral fertilizer.