Ambientes cultivados com águas de reuso para produção de forragem no semiárido.

Abstract

The availability of water resources is of increasing concern and, above all, with its intense use in irrigation. The research was carried out at the facilities of the Center for Science and Agri-food Technology / CCTA / UFCG located in the municipality of Pombal, PB. Six Agricultural Production Environments with Surface and Subsurface Irrigation (APAIS's) were built, which consist of a soil and water containment system, from the waterproofing of 06 environments with the dimensions 2.0 x 1.0 x 1.50 m. In three environments, 100mm diameter sewage PVC pipes were placed in an upright position, approximately 30 cm above the surface, going to the sand that is the base of the system in order to make the sub-surface irrigation and then it was completed with the soil of the excavation itself. the other three environments were irrigated superficially with the aid of a watering can to compare the two irrigations. The seedlings of Campim Tifton (Cynodon dactylon) were donated by a producer in the region of the municipality of Pombal, PB. The gray water used came from a washing machine, the water supplied by the city concessionaire - CAGEPA and saline water was prepared with a saline solution with higher levels for the irrigation of this same crop with two types of irrigation. At 46 days after planting, the height of 10 plants for each treatment was measured, where plants with shorter heights were obtained when using supply and surface water (T1-S), which can be justified because of the high rate of evapotranspiration in the region, reducing the availability of water in the crop. However, when gray water is used for irrigation, the highest plant height averages (AP1) were obtained, with 52.1 cm for surface irrigation and 49.5 cm for subsurface irrigation. The treatments with application of subsurface irrigation had the highest averages when compared to the same treatment with surface irrigation, which may result from the reduction of water loss to the atmosphere, allowing greater water availability to the plant. There was a variation in plant height related to different cutting times, results similar to Taffarel et al. (2016) when evaluating the regrowth ages of tifton 85 grass in nitrogen levels. Viçosi et al. (2020) evaluating Capim Tifton with different sources of fertilizers, the highest average height obtained was about 35 cm, in the first cut. Subsurface irrigation is indicated for regions with a high rate of evapotranspiration, where gray water is an alternative type of water to be used in irrigation, either superficial or subsurface, with high levels of tifton grass production, while water with salinity of 3.3dS / m had less production, but it would be a substitution in areas that have no other type of water for irrigation, subsurface irrigation being recommended in these cases, so the installed agricultural production environments provide a way for small farmers to use to produce food bulky for the animal.