Qualidade da água para irrigação no desempenho de gramíneas forrageiras no semiárido paraibano.

Abstract

The cattle production in the Brazilian semi-arid presents some limitations and research is the only way that can create alternatives to enlarge the technological knowledge in the sense of reaching satisfactory production of grassy forage. The cultivation of adapted productive varieties and the use of different water sources available in the rural properties and reuse of water in order to multiple uses, can increase food availability for the livestock in the dry period. In this way, the objective of this work was to evaluate the use of different qualities of irrigation water in the sorghum (bicolor Sorghum (L.) Moench) production, sugarcane (Saccharum officinarum, L.), millet (Pennisetum glaucum (L.) R. Brown) and grasselephant (Pennisetum purpureum Schum.). The following sources of water were used: Piancó river, well amazon and fish farming nursery cultivated with nile tilapias (Oreochromis niloticus). The study was conducted et the sit cajarana, municipality of Pombal - PB, in the period from December 06 2008 to March 16, 2009. The experiment was established in a randomized design in factorial 4x3x5, 4 grassy and 3 sources of waters with 5 replications in plots of 60 m2. To assess the yield of the grasses were studied variables, weight of green matter (PMV), plant height (AP) stem diameter (DC), besides neutral detergent fiber (FDN), acid detergent fiber (FDA), Crude Protein (PB) and hemicellulose (HC), to assess the material quality of silage. Those variables were subjected to analysis of variance and F test at 1% and 5% probability, whereas the Tukey test was applied to compare averages. The results found 100 days after planting showed that the sorghum presented higher PMV (65,56 t.ha-1) among the grasses, which did not differ from elephant grass (65,28 t.ha-1). The sugarcane with (46,57t.ha-1) differed from millet (25,84 t.ha-1) and irrigation with water of fish farming nursery provided the highest average PMV values (58,02 t.ha-1). The FDN and FDA were higher, while PB levels were below. In this case, the cut age may have contributed. From the standpoint of production of forage grasses studied, it is concluded that the reuse of effluent from fish farming nursery to irrigation in semiarid conditions represents a viable alternative farming. Key Word: fish farming effluent, silage production, production system, sorghum, millet, sugarcane, grass-elephant.