Aspectos agrícola e socioeconômicos do Pinhão-Manso irrigado com água salina no Seridó Paraibano.

Abstract

Jatropha (Jatropha curcas L.) is an oilseed plant, the family Euphorbiaceae, native to the Americas and is currently considered an alternative source of income for family farmers through the production of biodiesel. The objective of this research study possible effects of irrigation with saline water at different levels of evapotranspiration replacement, growth, development and oil content of jatropha seed, besides the economic and social viability of cultivation under management of agriculture family. The experiment was conducted in the field, facilities Bar Ranch in Santa Luzia - PB. The statistical design was a randomized block with seven replications and studied four levels of irrigation water - L (L1 = 0.25, L2 = 0.50, L3 = L4 = 0.75 and 1.00 evapotranspiration reference-ETo). The experimental unit consisted of ten plants grown at three plants. Irrigation was performed according to a irrigation every other day, the volume of water applied in each treatment was determined by the evapotranspiration of the class A pan, using as a base treatment L4. The irrigation with saline water has negatively affected the growth, development and productivity of plants, particularly in treatments L3 and L4. The growth variables (plant height, stem diameter, leaf number and number of flowers) were affected by the blades of evapotranspiration replacement in all periods, with greater intensity in the production variables, as greater evidence in seed production by hectare. Treatment with 0.25 and 0.50 ETo there were the highest relative growth rates of stem diameter (DC) and plant height (AP). The average yield of plants irrigated with saline water exceeded that of the control treatment. As they increased the irrigation was greater accumulation of N, P, K and Na in the leaves, directly affecting the number of floral abortion, evidenced by the low rate of production at higher irrigation. The negative effect on the production of jatropha irrigated with saline water significantly affected the economic evaluation. The oil content in seeds of the jatropha was affected as it increased the saline hydration, decreasing the percentage of oil in the dry seed, conditioning the moderate sensitivity of Jatropha curcas salinity. Improved efficiency of water use was obtained at water depth of 25% of reference evapotranspiration, winning by 4.6 g of seeds per plant each m³ of water added to soil.