Suspended solids and nutrient loss in soil preparation for irrigated rice

Soil preparation for pre-germinated rice cultivation (1) involves a large movement of machinery (tractor, plow, harrow, rotary tiller and others) for plowing, harrowing and mud formation, eliminating weeds, incorporating residues from the previous crop and forming a suitable layer to receive the rice seeds (leveling and smoothing). In order to evaluate the levels of suspended solids and nutrients lost
in drainage waters during soil preparation for irrigated rice cultivation, water samples were collected at intervals of 0, 12, 24, 48, 72 and 96 hours after the end of preparation, from 10/21 to 11/16/94, in Gley Poor Humic and Cambisol soils, in municipalities in the south of the state. These results highlight ecological problems (Resolution No. 20 - Introduction) and the considerable losses of Suspended Solids and Nutrients.