Influência da adubação verde intercalar e do manejo da palhada sobre as perdas por erosão na cultura do milho

Resumo

The following treatments involving com culture were compared on experimental plots having runoff catching tanks: (a) stock burning; (b) interplanted green manure, jack bean (Canavalia ensiformis) seeded 100 days after the corn and later turned under with the corn stocks; (c) stocks turned under; (d) stocks piled on contour, one meter apart. Five plots having 16,57 slope and seven plots having 217 slope were used. The corn was planted on the contour and was fertilized annually, with exception of the last year, with 15 t/ha of manure and 25 kg,of N, 60 kg of P05, and 60 kg of K20 per hectare. The study was conducted over a period of six years, from 1966/ 67 to 1971/72.

The treatments (a), (b), and (c) gave similar results, The average annual soil loss reached 20,6, 33.0, and 27.0 t/ha, respectively. The average annual water loss were 18.4, 20.9, and 18.1% of the rainfall, respectively,

In treatment (d) the erosion was relatively well controlled. The average soil and water losses were 1.6 t/ha and 9.2%, respectively.

The erosion did not affect the corn yield, possibly due to the manure and chemical fertilizer applications.