YIELD AND FORAGE QUALITY OF SALTBUSH IRRIGATED WITH REJECT BRINE FROM DESALINATION PLANT BY REVERSE OSMOSIS

Rural communities located in the Brazilian Northeast, especially in the semiarid zone, live with water shortages resulting from erratic rainfall. This work proposes the cultivation of saltbush ( Atriplex nummularia ) in the Rural Settlement Project of Boa Fé, Mossoró/RN as alternative to the disposal of reject brine from desalination plant on yield of forage. The statistical design was a split - plot design, being four treatments at the plots, related to irrigation with reject brine water, at different levels of soil moisture by moisture from Field Capacity (FC) (100, 85, 70 and 50% of FC) and in subplots and two levels of organic manure (without fertilized and fertilized) with four replications. The variables of yield and forage quality of saltbush were analyzed. It was observed that saltbush has a great production capacity in terms of fresh matter and drought for saltbush under a level of 85% soil moisture in relation to the field capacity of soil, presenting minimal loss of yield; however, this proved to be productive even with the dry soil. The total yield was satisfactory, showing its viability for forage production

Resposta de cultivares de alface à salinidade da solução nutritiva com rejeito salino em hidroponia Response of lettuce cultivars to nutrient solution salinity with saline rejects in hydropony

No processo de dessalinização se gera, além da água potável, um rejeito altamente salino e de poder poluente elevado, o qual pode ser utilizado na produção agrícola rentável dependendo da adoção de práticas culturais adequadas e da tolerância das plantas às condições salinas. Nos últimos anos a tendência tem sido a substituição da agricultura convencional por sistemas hidropônicos de cultivos, considerados um dos mais eficientes no uso de água. O objetivo desta pesquisa foi analisar a resposta de duas cultivares de alface sob sistema hidropônico de cultivo (Lactuca sativa L., cvs. Verônica e Babá de verão) em diferentes níveis de salinidade da solução nutritiva preparadas com água de abastecimento, água de rejeito coletada no dessalinizador e da sua diluição com água de abastecimento a 75, 50 e 25%, resultando em condutividades elétricas da solução nutritiva (CEs) de 1,1; 2,4; 3,6; 4,7 e 5,7 dS m-1 após as diluições e adição de fertilizantes. Ocorreu variação genotípica sob as variáveis de crescimento e produção da alface, exceto para o número de folhas, sendo a cultivar Babá de verão a que produziu maior rendimento, independentemente do nível de salinidade e, portanto, a cultivar mais tolerante à salinidade da água com rejeito salino.<br>In desalination process, besides the potable water, highly salty and polluted water (brine) is generated, which can be used for producing profitable crops depending on the adequate cultural practices as well as on the plant ability of reacting to saline conditions. The trend in recent years has been towards conversion of conventional agriculture to soilless agriculture which is considered to be a more efficient use of water system. The aim of this research was to examine the response of two lettuce cultivars (Lactuca sativa L. cvs. Veronica, Babá de verão) under hydroponic system to different levels of salinity of the nutrient solutions prepared with tap water, reject from desalination plant, and its dilution with tap water at 75, 50 and 25%, giving a range of electrical conductivities of the nutrient solution (ECs) of 1.1, 2.4, 3.6, 4.7 and 5.7 dS m-1 after the dilutions and fertilizer addition. Genotypic variation for all analysed variables except number of leaves was observed, and the cultivar Babá de verão produced higher yield regardless of salinity level, therefore more tolerant to water salinity with saline rejects