Sistematização com declividade variada como ferramenta para diversificação de sistemas produtivos em terras baixas

Abstract

In an experimental area belonging to the National Institute of Agricultural Research (INIA-Uruguay), rice and soybean crops were implanted in an area with and without land leveling with varying slopes for irrigation (LFI). To measure the effect of DVI on rice yield, a comparative study of the 2018-2019 and 2019-2020 two-year rice crops was carried out in a semi-commercial field (12 ha) in Uruguay. This was the first time that LFI was implemented in this country. To achieve the LFI alternative, a soil movement of 104 m3 ha-1 was determined. The cutting depth averaged 0.03 meters, with a maximum cut of 0.16 meters. The total length and number of rice levees were reduced by 14% and 28%, respectively, compared to the adjacent Control field in which the LFI was not performed. In this same area, the effect of LFI on some physical and chemical properties of the soil was evaluated. The results showed that the mean values of clay, Corg, PH, Ca, Mg and P increased and silt, sand, K, Na decreased after DVI. The main soil property affected by cutting and filling was organic matter. Productivity showed a significant reduction in cut zones, but with an increase in fill zones. In general, the LFI system did not show major changes in soil properties. To measure the effect of LFI on soybean yield, soybean yields were compared between a field accurately classified LFI and that of a traditional field (control). For this, a comparative study of the 2018-2019 and 2019-2020 soybean crops was carried out in a semi-commercial field (10 ha) in Uruguay. To achieve the LFI alternative with ridge irrigation, a soil movement of 108 m3 ha-1 was determined. The cutting depth averaged 0.02 meters, with a maximum cut of 0.08 meters. The productivity variability was verified from the apparent electrical conductivity of the soil at 0.30 m (ECa30), this is because the Eca30 had a very strong positive correlation with the soil sodium content (Na), which is an element that reduces the productivity of culture. For both years of the study, there were differences (P<0.05) in mean field grain yields between the DVI and Control treatments, although yield increases and yield decreases were often associated with zones of high ECa30. The LFI System in a zone with low Na concentration showed up to 35% more than the Control treatment.