• Authors:
    • Harapiak, J.
    • Lafond, G.
    • Johnston, A.
    • Head, W.
  • Source: Journal of Production Agriculture
  • Volume: 10
  • Issue: 3
  • Year: 1997
  • Summary: A research study was conducted in Saskatchewan and Alberta to determine the potential for precision side band application of partially liquified anhydrous ammonia (AA) at sowing. While AA reduced plant stand over that observed with urea for both wheat and canola [rape], no effect on grain yields of wheat were observed from seven field trials. The use of AA did not adversely affect the rate of wheat establishment as measured by main stem Haun stage or plant development as measured by number of root axes and frequency of tillers produced. With canola, a reduction in seed yield was observed at only one of the five trial sites. The lower canola yield reflects the N loss when AA is applied on clay soils. Loss of AA on clay and silty clay soils, which were wet at application, resulted in reduced crop N uptake and lowered N use efficiency relative to urea at one wheat and two of the canola trial locations. It is suggested that given adequate seed-fertilizer separation, partially liquified AA can be safely applied at sowing in a precision side band application. Soil conditions that are known to cause N loss on application of AA, in particular wet clay and silty clay soils, may benefit more from an alternative N source such as granular urea or solution N.
  • Authors:
    • Franzluebbers, A. J.
    • Arshad, M. A.
  • Source: Soil Science Society of America Journal
  • Volume: 60
  • Issue: 5
  • Year: 1996
  • Summary: Changes in soil organic matter (SOM) pools during adoption of reduced (RT) or zero tillage (ZT) can influence soil physical properties, nutrient cycling, and CO2 flux between soil and atmosphere. We determined soil organic C (SOC), soil microbial biomass C (SMBC), basal soil respiration (BSR), and mineralizable N to a depth of 200 mm at the end of 3, 5, and 6 yr after implementation of tillage management on a Falher clay (fine, montmorillonitic, frigid Typic Natriboralf) near Rycroft, Alberta, in a canola (Brassica campestris L.)-wheat (Triticum Aestivum L.)-barley (Hordeum vulgare L.)-fallow cropping system. At the end of 6 yr, SOC was not different among tillage regimes and averaged 8.6 kg m−2. At the end of 3 and 5 yr, SMBC was not significantly different among tillage regimes, but at the end of 6 yr SMBC was 7% greater in RT and 9% greater in ZT than in conventional tillage (CT). Basal soil respiration and mineralizable N at the end of 6 yr were not different among tillage regimes following barley and averaged 2.7 g CO2-C m−2 d−1 and 5.0 g inorganic N m−2 24 d−1, respectively. However, BSR following fallow was 2.2, 2.5, and 2.6 g CO2-C m−2 d−1 in CT, RT, and ZT, respectively. Mineralizable N following fallow was 5.8 g inorganic N m−2 (24 d)−1 in RT and ZT and 7.3 g inorganic N m−2 (24 d)−1 in CT. At 0 to 50 mm, there was no significant increase in SOC at the end of 6 yr, a 17 to 36% increase in SMBC, and a 12 to 69% increase in BSR with ZT compared with CT, depending on rotation phase. Relatively small changes in SOM pools with adoption of conservation tillage may be attributable to the large amount of SOM initially present and the cold, semiarid climate that limits SOM turnover.
  • Authors:
    • Porter, P.
  • Source: Journal of Production Agriculture
  • Volume: 8
  • Issue: 2
  • Year: 1995
  • Summary: A study was conducted on an Orangeburg loamy sand (fine-loamy, siliceous, thermic Typic Paleudults) near Blackville, South Carolina in 1990-92 to determine the effect of deep tillage on both canola [rape] and wheat, the subsequent response of doublecropped soyabeans, and response of wheat grown following the soyabean crop when controlled traffic and minimum tillage practices were used. Canola yields averaged 37.8 bu/acre in 1991 and 43.2 bu/acre in 1992, whereas wheat yields were 58.0 and 72.5 bu/acre, respectively. In both years, deep tillage (chiselling to 11 in) had no effect on wheat yields when compared with discing. Deep tillage increased canola yields by 12.5% in the drier of the two growing seasons. Soyabean yields were not significantly affected by the tillage used for the previous crops. Subsoiled soyabeans yielded 33.7 vs. 31.9 bu/acre for no-till soyabeans in 1991, and 22.6 vs. 19.4 bu/acre in 1992. In 1992, soyabean tillage following wheat did not affect soyabean yield but following canola, in-row subsoiling resulted in greater soyabean yields than no-till. Wheat following soyabeans was not affected by the tillage practice used for the previous winter crops, and the 1992 wheat yields were unaffected by previous winter crop or soyabean tillage. In 1993, soyabean tillage did not affect subsequent wheat yield but following canola, in-row subsoiling resulted in greater wheat yields than no-till. It is suggested that canola has no adverse effect on either soyabeans or wheat when grown in sequence on a Coastal Plain soil.
  • Authors:
    • Miller, M.
    • O'Halloran, I.
    • Arnold, G.
  • Source: Canadian Journal of Soil Science
  • Volume: 66
  • Issue: 2
  • Year: 1986
  • Summary: In 1981, phosphorus absorption by young corn plants was greater from no-till than from plowed plots with similar NaHCO 3-extractable P (Ext P) concentrations. A series of growth room studies was conducted to explain this difference. Corn plants grown on cores from the no-till plots had a higher P concentration than plants grown on soil from the plowed plots, in spite of a lower root growth and a lower Ext P content. Disturbance of the no-till soil eliminated the effect. A parameter, accessible P (Acc-P), was calculated from root length and Ext P assuming P was absorbed from a cylinder of soil around each root. Shoot P content at a given Acc-P content was always higher with the undisturbed no-till soil than with either the disturbed no-till or the plowed soil. Irradiation (gamma-ray) of the no-till soil reduced P absorption by a similar degree to disturbance, indicating that a biological factor was involved. Disturbance of soil had no influence on P content of canola ( Brassica napus L.), a nonmycorrhizal crop. Soil disturbance reduced the intensity of mycorrhizal infection in corn roots. It is hypothesized that disturbance of the no-till soil reduced P absorption by reducing the effectiveness of the mycorrhizal symbiosis.