Evaluation of Long Term No-till Effects on Soil Fertility

The adoption of no-till seeding systems in western Canada has been driven by a variety of factors, moisture conservation and economic efficiency likely the major ones. This project was conducted to evaluate whether or not the conversion of fields to no-till has been shown to increase soil organic carbon, total nitrogen, as well as increasing soil water use efficiency by crops.

IPNI-2003-CAN-SK36

30 Dec 2003

2003 Annual Interpretive Summary


Evaluation of Long-Term No-Till Effects on Soil Fertility, 2003

The adoption of no-till seeding systems in western Canada has been driven by a variety of factors, with moisture conservation and economic efficiency the major ones. The conversion of fields to no-till has been shown to increase soil organic carbon (C) and nitrogen (N) as well as water use efficiency by crops. Together, these factors lead to increased productive potential of the soil. This project was initiated on two adjacent fields, one recently converted to no-till and the other with a 20-year no-till history, to determine the differences in N and phosphorus (P) nutrient supply and fertilizer response.

Drier than normal conditions were recorded in 2003, limiting yield potential at the experimental site. An N response trial with wheat and oats on the two soils indicated that the long-term no-till field reached maximum yield at about 27 lb N/A less than the short-term no-till, reflecting a higher level of N mineralization. Spring wheat and field pea were grown at various fertilizer P rates. However, no differences in yields were observed due to P addition, even though the long-term field had four times the soil test P of the short-term field [9 parts per million (ppm) vs. 2 ppm]. Finally, N timing was evaluated on the short- vs. long-term no-till fields, comparing all post-emergence at the 1-5 leaf stage, or one-third at seeding and two-thirds post-emergent at the 1-5 leaf stage. While no difference was recorded between the split and all post-emergence application timing on the long-term no-till, the split N application significantly increased yields on the short-term no-till field. Again, this reflected an increased N-mineralization capability for the long-term no-till field, supporting early season crop development. This project will be continued in 2004. SK-36F