Ambiência e biofertilização no cultivo orgânico de figo, em condições semiáridas

Abstract

This study aimed to identify cultivation techniques with biofertilizer in greenhouse and open field with fig culture in Limoeiro do Norte-CE, including three production cycles, from October 2010 to December 2011. The experimental design was a randomized block with split plot with four replications. Treatments included a combination of 3 cultivation environments: greenhouse (EST), trellis (LT) and open field (CA), which constituted the plots with 4 treatments in sub plots, consisting of 4 concentrations (biofertilizer: water) in the following way : T0 (0% biofertilizer: 100% water); T1 (20% biofertilizer: 80% water), T2 (40% biofertilizer: 60% water), T3 (60% biofertilizer: 40% water), in which there were applied 3,0 L of biofertilizer per plant every 15 days. Data were submitted to analysis of variance and when significant by F test, average tests were conducted by the tukey test at 5% probability and those concerning to biofertilizer levels were submitted to regression analysis. The amount of N in the leaf dry matter increased 19%, 21% and 11%, with the growth in biofertilizer doses, for three cycles, respectively. As for P and K, increments were 25.0%, 7.0% and 13% and 12.6%, 10.5% and 29.4%, respectively, following the cycles. In the first cycle there was no significant difference between the average yield of 10.44 and 10.14 t ha-1 observed in the LT and in the EST, respectively, but they were statistically higher to that one obtained in CA with 9.62 t ha-1. In the second cycle environment did not affect significantly the variable productivity. In the third cycle the LT showed fruit yield of 6.47 t ha-1, significantly higher than those detected in EST and in CA with 4.37 and 3.81 t h-1, respectively. As for the total yield there was no significant difference between the averages 18.83 and 18.27 t ha-1, obtained in the EST and in the CA, respectively, however, they were statistically lower than that one obtained in the TL with 22.49 t ha-1. Based on the analysis of the three cycles, it can be stated as a general conclusion, that there is viability of fig organic cultivation with biofertilizer in protected low-cost type trellis, in the semiarid. And as specific conclusions, it can be stated that: the maximum temperature in the trellis environment is up to 3.1 oC lower than the one in the greenhouse, but up to 1.7 oC higher than that one observed in the open field; the relative humidity in the open atmosphere is up to 4.1% higher than the one in the greenhouse, and up to 3.7% higher than the one in the trellis. Water consumption in the trellis represented 87.3% of the registered in open field, but it was 16.4% higher of the registered in the greenhouse; plants grown in protected fields showed higher growth especially those grown in greenhouses; the biofertilizer applied to the soil increased the N, P2O5 and K2O concentration in the leaf dry matter and the 60% dose was the one that provided the best nutritional adequacy for the plant; the fruit weight, the fruit yield per plant and the fruit yield increased with the growth of biofertilizer dose applied to the soil and showed greater increases in plants grown on trellis; cultivation under greenhouse conditions allowed increased productivity and diseases more efficient control, especially rust; yields decreased in the second and third cycles due to LAI increase observed in these two cycles compared to the first one