Tuesday, November 14, 2006 - 1:30 PM

Responses of Cash Cropping Based System to Tillage, N and S.

Valtcho D. Zheljazkov, Mississippi State, North Mississippi Research and Extension Center, 5421 S Hwy 145, Verona, MS 38879, Claude D. Caldwell, Nova Scotia Agricultural College, Dept of Plant and Animal Science, 50 Pictou Rd, Truro, NS B2N 5E3, Canada, and John A. MacLeod, Agriculture and AgriFood Canada, Crops and Livestock Research Center, AAFC, 440 University Ave, Charlottetown, PE C1A 4N6, Canada.

Recent reduction in atmospheric SO2 emissions and the use of high purity fertilizers, have reduced the available S to crop plants in Atlantic Canada. A field experiment was conducted over three years to determine the effect of tillage practices (conventional and no-till), N and S applications on productivity of corn, canola, and spring wheat, on the availability of nutrients in soil and on mycorrhizae.  Overall, yields in the no-till plots were equal to or lower than yields in the conventional tillage plots.  Protein content of wheat and corn were not affected by tillage, but protein content in canola was higher under no-till.  We found that crops altered availability of most macro and micronutrients in soil. Generally, wheat promoted nutrient availability compared to canola.  Overall, highest rate of gypsum application reduced availability of P and Zn in soil. No-till increased availability of P and Pb in soil.  No-till promoted higher concentration of phytoavailable K, Mg, S, Na, and Zn in corn but decreased the amount of S in canola.  In 2002, the mycorrhizae colonization of wheat roots was greater in the no-till system.  However, in 2003 the mycorrhizae colonization of wheat and corn roots under the two tillage systems was not different.