Biotech Studies 1994, Vol 3, Num, 3-4     (Pages: 033-050)

EFFECTS OF TILLAGE SYSTEMS ON NITRATE-NITROGEN ACCUMULATION AND SOIL STRUCTURE

Abdulkadir AVÇİN 1 , F.E. BOLTON 2

1 Tarla Bitkileri Merkez Araştırma Ens. ANKARA
2 Assoc. Prof. Crop Sci. Dept. Oregon State Univ. OS USA
- Effects of bare follow, stubble-mulch and no-till tillage systems on nitrate-nitrogen accumulation and soil structure were investigated. Effects of three tillage systmeson nitrate nitrogen accumulation were not significantly different. However, at the end of fallow, bare fallow, stubble-mulch and no-till accumulated 3, 3.6 and 3 kg/da nitrate, respectively. Aggregates larger than 0.84 mm were considered as a good indicator of soil resistance to wind erosion, and aggregates of 1-4.75 mm in diameter providing good soil conditions for germination and early vigor were found to be more in 0-10 cm of bare fallow plots than the others. No-till gave the lowest values. In 10-30 cm soil depth, the effect of any tillage system were not found. Water stability values of bare fallow were, superior to the other two tillage systems in the 0-10 cm layer at the end of fallow. The 10-30 cm soil layer was not affected by any tillage system, but there was significant difference between 0-10 and 10-30 cm layer in terms of agregate size distribution and agregate stability. Soil structure of the 0-10 cm layer was affected more by tillage operations than the 10-30 cm. Keywords : Fallow; tillage system; nitrate-nitrogen accumulation; aggregate