Intervalo hídrico ótimo de um solo submetido a dois preparos conservacionistas para a produção de cana-de-açúcar

Abstract

Sugarcane (Saccharum spp.) is one of the most economically important crops in the world, Brazil being the country with the largest planted area, accounting for approximately 55% of the world's sugarcane production, Due to this great importance, we have sought soil management practices that promote minimal changes in the physical attributes of the soil, and the use of intensive conventional practices adversely affects it and promote its degradation, resulting in losses of productivity and quality of the soil cultivation of sugarcane. However, there are conservationist practices of soil preparation that promote better conditions for the growth of the plants, since the preparation for the sugarcane crop must be done only once, for the whole cycle of the same, having on average one cycle of 5 years. This work consisted in evaluating the quality of the preparation of a oxisol in two soil conservation systems using the Least limiting water range (LLWR) as an indicator of its physical-water quality. For this study, volumetric moisture was determined in the field capacity and at the permanent wilting point, the minimum aeration porosity and the mechanical resistance of the soil to the penetration, obtained in areas cultivated with sugarcane with soil managed on reduced tillage and notillage. The least limiting water range has been shown to be a good indicator of the physical-water quality of soil cultivated with sugarcane under both conservationist techniques. No-tillage presented a greater amplitude of the optimum water range when compared to reduced tillage, regardless of the soil resistance value to the penetration adopted as restrictive to the development of sugarcane. The critical soil density managed by Cane Direct Plantation is between 1.48 and 1.53 Mg m-3 for penetration resistance of 2 and 4 MPa, while when run with reduced tillage it is between 1.44 and 1.51 Mg m-3.