Resumen Este estudio evaluó la contribución de la nutrición con potasio (K) y la aplicación de las láminas de las aguas residuales al rendimiento agronómico del algodón colorido. Los tratamientos consistieron en cinco láminas de riego (50, 75, 100, 125 y 150% de la evapotranspiración del cultivo - ETC) y cinco dosis de K (0, 50, 100, 150 y 200% de la recomendación del cultivo). Fue también utilizado un control absoluto de riego con lámina 100% de la ETC y fertilizado con una recomendación de 100% N-P-K. Así como los tratamientos el control también tuvo cuatro repeticiones. La altura de la planta, el diámetro del tallo, el área de la hoja y la acumulación de materia seca del algodón en los brotes se evaluaron a los 130 días después de la emergencia (DAE), mientras que el peso del algodón semilla, se evaluó a 135 DAE. Los resultados indican que el uso de aguas residuales domésticas tratadas para compensación del 100% de ETC promueve un mayor aumento de peso y crecimiento del algodón colorido sin la necesidad de fertilización con K, lo que evidencia el potencial de las aguas residuales para el algodón colorido para una agricultura sostenible.

Abstract This study evaluated the contribution of potassium (K) nutrition and application of wastewater depths to the agronomic performance of colored cotton. Treatments consisted of five irrigation depths (50, 75, 100, 125 and 150% of crop evapotranspiration - ETC) and five K doses (0, 50, 100, 150 and 200% of the recommendation for the crop) and an absolute control irrigated with 100% ETC water depth and fertilized with 100% N-P-K recommendation. Each treatment and the control had four replicates. Plant height, stem diameter, leaf area and shoot dry matter accumulation of cotton were evaluated at 130 days after emergence (DAE), whereas seed cotton weight was evaluated at 135 DAE. Our findings indicate that the use of treated domestic sewage for 100% ETC replacement promotes greater gains of weight and growth in colored cotton without the need for K fertilization, evidencing the potential of wastewater for colored cotton for sustainable agriculture.

O manejo inadequado da irrigação pode resultar no acúmulo de sais no solo, cuja intensidade depende da qualidade da água utilizada na irrigação, da fração de lixiviação adotada e da demanda evapotranspirativa da região. O presente trabalho teve como objetivo avaliar os atributos físicos e químicos dos solos do perímetro irrigado Califórnia, localizado no extremo noroeste do Estado de Sergipe. Para tal, foram realizadas amostragens em 42 lotes, correspondendo a 16,4% dos lotes deste perímetro. As maiores concentrações de sais e de sódio ocorreram na camada superficial (0-0,2m) do solo, o que evidenciou a falta de um manejo da irrigação adequado visando ao controle da salinidade. O aumento do pH do solo foi correlacionado significativamente com a porcentagem de sódio trocável, atingindo valores acima de 9,5. Correlações positivas significativas foram observadas entre a condutividade elétrica e os teores de Ca e Mg, indicando que sais desses íons podem estar se acumulando no solo pela ascensão do lençol freático, associado à ausência de lixiviação e drenagem.

The improper irrigation management may result in the accumulation of salts in the soil profile, which intensity depends on the irrigation water quality, the leaching fraction adopted and on the evapotranspiration demand of the region. The objective of the present study was to study the physical and chemical characteristics of the soils in the irrigated district of California, located in the northwest of the State of Sergipe. Thus, soil sampling were made in 54 lots, corresponding to 16.4% of the lots of this district. The highest salt and sodium concentrations occurred in the shallowest soil layer (0-0.2m), evidencing the lack of an appropriate irrigation management in order to control the salinity build up. The increasing of the soil pH was significantly correlated to the exchangeable sodium percentage, reaching values over 9.5. Significant positive correlations were observed between the electrical conductivity and the Ca and Mg content, indicating that salts of both ions could be accumulating in soil by the capillary rise of the water table, associated to the lack of leaching and drainage.