Interferência das plantas daninhas e diferentes adubações na cultura da palma forrageira miúda

Abstract

Forage cactus is a crop that has multiple uses, in Brazil it is widely used in animal feed as forage, this crop is a great alternative for semi-arid regions, as it has an average of 10% dry matter and 90% water in its composition, thus increasing the water and nutritional demand of animals, especially in periods of reduced food. Several factors can influence the development and productivity of cactus pear, among them the interference exerted by weeds that emerge spontaneously and compete for water, light and nutrients, compromising the quantity and quality of harvested products and the low use of technologies that increase yields, such as fertilization management. In view of the above, two experiments were carried out in the experimental field of the Center for Engineering and Agricultural Sciences of the Federal University of Alagoas (CECA/UFAL) with the objective of evaluating the interference of weeds and different fertilizations in the culture of cactus pear (Nopalea cochenillifera). The first experiment was carried out over two production cycles (two years), and a statistical design of randomized blocks was used, with 20 treatments and four replications. The ten periods of control and coexistence between weeds and cactus remained in the plots: 0; 0-30; 0-60; 0-90; 0-120; 0-150; 0- 180; 0-240; 0-300 and 0-360 days after planting and harvesting, respectively 1st and 2nd production cycle. Before each weeding and at the time of harvest, weed species, density and dry matter were evaluated. In the palm crop, the number of cladodes per hectare, cladode area index and green mass productivity were evaluated. In the first and second production cycles, when the palm was kept free from competition with weeds, productivity was 92.9 and 95.6% higher, respectively, when compared to the treatment that was maintained throughout the cycle with the presence of weeds. The critical period for preventing interference was from 16 to 174 days after planting in the first production cycle and from 21 to 323 days after harvesting in the second production cycle. The second experiment was also conducted for two production cycles (two years), and a statistical design of randomized blocks was used in a split-plot scheme, with 12 treatments and seven replications. The four types of fertilization remained in the plots (organic plus mineral fertilization, organic, mineral and control without fertilization) and in the subplots remained the planted cladodes of 1st, 2nd and 3rd order. The interaction between types of fertilization and order of cladodes planted was not significant, a justification for this is that there was no difference in plant development regardless of the three orders of planted cladodes. Palm plants fertilized with goat manure, associated or not with chemical fertilizers, had a significant influence and promoted the best results, in the first and second production cycles, for the variables: plant height and width, number of cladodes per hectare, cladode area index, green and dry mass per hectare. When comparing the same treatments in this experiment, in the first and second cycle of cactus pear production, an increase above 230 and 340% in the variables green and dry mass per hectare, respectively, is observed. The non-fertilization of palm, despite allowing the plant to develop, causes a reduction in growth and production rates. Keywords: cactos; forage; Nopalea cochenillifera.