Aspectos produtivos da rebrota de cultivares de sorgo irrigados com água salina

Abstract

There is a growing demand for food in the world and the irrigated agriculture is an important technique to support the increase in productivity of crops. The irrigated areas in the world, around 18% of the total area under cultivation, are responsible for 44% of the total agricultural production in the world. It is estimated that the world population reaches in 2050, 9.7 billion inhabitants. So, urbanization and industrialization will increase competition for water of good quality. In this scenario increases the interest in studies of the use of alternative water sources for irrigation, for example, water with high salt levels. However, for the proper utilization of these waters must take into account the potential of culture production on these conditions. Sorghum is a rustic agricultural species, with good adaptability to environmental stresses, such as water and saline. The objective of the present work was to verify the effects of the application of saline water in relation to the accumulation of salts in the soil and productivity of different forage sorghum genotypes, and dual purpose sacarino in the second production cycle. The experiment was accomplished in the forest zone of Pernambuco, through evaluation of biomass production and agroindustrial parameters on regrowth of sorghum, the second cut. The experiment was conducted at the Experimental Station of the Instituto Agronômico de Pernambuco – IPA, in the municipality of Vitória de Santo Antão, PE. The experimental design was adopted in casualisados blocks consisting of 20 genotypes and three blocks, totaling 60 experimental units. Was assessed the production of green mass and total percentage dry thatched roofs, leaf and panicle, and water use efficiency in crop plants. The soil was collected in three different eras at the beginning of regrowth, in prefloração and in the grain paste form Milky, collection. The evaluations of the° Brix and numbers of sheets were made in two stages, prefloração and Grand Pasty, Milky Brix determined in three parts of the stem of the plant, the height was measured in prefloração. It was estimated the theoretical ethanol production. Were held five collected from water samples. With the results obtained showed that irrigation with saline water does not lead to concentration of salts in the soil solution sufficient to increase the electrical conductivity of the saturated extract about to achieve the salinity threshold for the culture of sorghum. SF-15 genotypes, T17-389-5-1x1158 and T17EPSFx2502 have excelled in the production of dry matter with 35.29; 31.38 30.49 and t ha-1 respectively. These same genotypes, in addition to the BRS 508, presented a higher water use efficiency. Sampling the° Brix should be done in two break the thatched roofs of the plants, and presents greater concentration in the grain paste form Milky. The genotypes T17-389-5-1x1158, BRS 508, SF-15 and SF-11 stood out in the production of ethanol.