[Effect of minimum tillage and associated agronomic practices on the physical properties of the soil in the plains of Monagas]
1995
Rivas G, E.J.
In the corn fields of the west of the Monagas state, physical degradation problems have been detected such as "harrow-foot" formation due to tillage in excess at 20 and 30 cm depth. This physical problem, along with the low precipitation (900 mm) and the low capacity of the soil moisture retention, brought as consequences the use of new technological alternatives which tend to minimize the state problem. Following this order of ideas, during 1993 six tillage systems were evaluated: minimum tillage with dead bean residues (MTBR), minimum tillage with dead natural fallow residues (MTNFR), conventional tillage and subsoiling using bean green manure (CTSMG), conventional tillage and subsoiling with incorporated natural fallow (CTSNF), conventional with green manure (CTMG) and conventonal tillage with natural fallow incorporated (CTNF). It is important to note, that the results reported are considered like tendencies because they only represent one year of experimentation. With relation to the bulk density, at planting and 10 cm depth, the minimum tillage had higher values than the conventional; while at 72 days after planting there was not a clear tendency between these systems. The same situation was observed in relation to penetration resistance. Also, the values of bulk density and penetration resistance, at planting at 10 and 20 cm depth, were lower than those obtained at 72 days after planting. In relation to the moisture by weight, the minimum tillage system showed less fluctuation in moisture content at 10, 20 and 40 cm depth, than the conventional systems, at 40 days planting. There were not found any significant differences for corn yield among the systems; however, the highest yields were obtained when the bean was used as cover and green manure.
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