A SOIL SURFACE TRAFFIC - CORN YIELD MODEL FOR A CERRADO SOIL IN BRAZIL WITH LESS THAN 10 YEARS OF CULTIVATION (COMPACTION, TRAFFIC)
Abstract
Due to the rapid expansion of the brazilian agriculture frontier and adoption of mechanization technology, the "Cerrados" area has begun to show some signs of mismanagement. One area of mismanagement is the mechanization process especially how it affects soil compaction. This study was conducted at the National Research Center for Corn and Sorghum GMBRAPA, Sete Lagoas, Minas Gerais, Brazil, 1983, with the objective to quantify the effect of surface traffic on corn yield in soil with less than 10 years of cultivation and also to model the effect of traffic on Dark Red Latosol soil. Five compaction levels (0, 1, 5, 10, 10 + subsoiler) and two irrigation levels in a split plot design were tested. The soil's critical moisture content range was 32-35% and was obtained by the Standard and 15-Blow Proctor. A Ford-6000 tractor carrying a disk harrow in an up position with 4900 Kg weight was used as static force and its front and rear contact pressure was 0.70 and 0.78 Kg/cm('2). A soil characterization of the plots was performed before and after soil compaction at 0-7.5, 7.5-15, 15-22.5, 22.5-30, 30-37.5 and 37.5-45 cm depth and the parameters studied were: bulk density, particle density, pore size distribution, particle size distribution, aggregate stability and soil strength. Also plant growth, soil moisture content, root weight, and grain yield were evaluated under the tested compaction levels. A stepwise regression program was used and the best set of independent variable was found to establish a regression model. There was no significant difference among the ten compaction treatments for its effect on corn yield.
Degree
Ph.D.
Subject Area
Agricultural engineering
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