Influência da água tratada magneticamente na produção e manejo de irrigação da alface americana

Abstract

Aiming to reduce water consumption and increase agricultural production, new irrigation management techniques are being studied. Using tensiometry and magnetic water treatment are promising alternatives. Because lettuce is a demanding crop in water and of great importance for horticulture, it is important to carry out the correct irrigation management. This study aimed to evaluate the influence of the use of water subjected to magnetic treatment with drip irrigation, under different water tensions in the soil to start irrigation, on the responses of irrigation management, on the development and production of Lucy Brown lettuce (Lactuca sativa L.) in a greenhouse. The experiment was conducted in a greenhouse, with a completely randomized design in a factorial scheme with two factors, combining two types of water (magnetically treated water - AM and water without magnetic treatment - AC) and four water tensions in the soil to start irrigation (T1 - 15 kPa, T2 - 25 kPa, T3 - 40 kPa and T4 - 70 kPa), with 3 repetitions. Soil water retention curves were performed in the field. The soil water retention curve used to perform irrigation management was obtained with field data. The evaluated parameters were: - gross irrigation depth; - number of irrigation events; - total fresh and dry mass of the aerial part; - commercial head fresh and dry mass; - fresh and dry root mass; - fresh and dry stem mass; - stem length and diameter; - percentage of leaves with tipburn; - total and commercial productivity; - total and commercial water use efficiency; - covered area; - unit mass; - dry matter content; - coefficient of evapotranspiration; - electric power consumption. In general, the treatments with magnetized water showed a lower number of irrigations, decreasing the amount of water applied and electric energy consumed in the cultivation of iceberg lettuce. Despite determining greater water use efficiency, the magnetic treatment may have made it difficult to remove water from the soil by the crop, especially with the increase in soil water tension.