• Authors:
    • Lafond, G.
    • Gan, Y.
    • Brandt, S.
    • McConkey, B.
    • Cutforth, H.
    • Angadi, S.
    • Judiesch, D.
  • Source: Canadian Journal of Plant Science
  • Volume: 89
  • Issue: 3
  • Year: 2009
  • Summary: Canola is a viable crop when grown under fallow in the semiarid prairie, but is also grown in longer rotations, most often no-till seeded into standing stubble. Selecting the proper N fertilizer rate is a very challenging production decision, but most of the available nitrogen response for canola has been derived for the more subhumid parts of the Canadian prairies. We developed simple quadratic equations to describe the yield relationship for stubble-seeded open-pollinated and hybrid canola in the semiarid Canadian prairie. These relationships indicate that hybrid canola produced higher grain yields at all fertilizer rates and had optimum N fertilizer rates about 50% higher than those for open-pollinated canola.
  • Authors:
    • Wang, H.
    • Schoenau, J. J.
    • Brandt, S.
    • Lafond, G.
    • Malhi, S. S.
    • Mooleki, S. P.
    • Lemke, R. L.
    • Thavarajah, D.
    • Hultgreen, G.
    • May, W. E.
  • Source: Canadian Journal of Plant Science
  • Volume: 89
  • Issue: 1
  • Year: 2009
  • Summary: No-till (NT) requires all fertilizer nutrients to be applied during planting, but high rates of fertilizer nitrogen (N) in close proximity to the seed can negatively affect seedling development; therefore, different placement technologies have been developed to place seed and N in a single operation while maintaining an adequate separation between them. We conducted a 3-yr field study (2000 to 2002) at four sites in Saskatchewan. The objective was to determine the effects of N fertilizer form [urea (U) and anhydrous ammonia (AA)], placement [broadcast, side-band (SB) and mid-row band (MRB)], timing (fall vs. spring), rate (0 to 90 or 120 kg N ha -1), and P fertilizer placement on yield, seed protein content and N uptake in canola. The N fertilizer managements had no significant effect on crop emergence. Yield, seed protein concentration and N uptake increased with increasing N fertilizer rate. Seed protein was significantly higher on SB compared with MRB and on U compared with AA. Seed yield and seed and straw N uptake were higher when U was SB compared with broadcast. Plant density was higher when P was placed in SB rather than with the seed, but the reverse was true for seed yield and seed N uptake.
  • Authors:
    • Ruiz, J. C.
    • Vanderlinden, K.
    • Melero, S.
    • Madejon, E.
  • Source: The Journal of Agricultural Science
  • Volume: 147
  • Issue: 1
  • Year: 2009
  • Summary: Soil enzyme activities are widely utilized as rapid and sensitive indicators in discriminating among soil management effects. The objective of the present study was to compare the influence of conservation tillage, i.e. direct drilling (DD) (residue cover is left on the soil surface) v. conventional tillage (CT), on soil chemical and biochemical properties in a crop rotation (cereals-sunflower-legumes) under dryland production in a semi-arid Mediterranean Vertisol after 23 years. A randomized experimental design was established. Soil biological status was evaluated by measuring of enzymatic activities (dehydrogenase, beta-glucosidase, alkaline phosphatase and protease). Total organic carbon (TOC) contents were greater in soils managed by DD than those found by CT. Except for protease activity, enzymatic activity values were approximately 2-fold higher in soils under DD than in soils under CT. The beta-glucosidase, alkaline phosphatase and dehydrogenase values showed a high correlation (from r=0.481 to r=0.886, P≤0.01) with TOC contents and they were correlated with each other (from r=0.664 to r=0.923, P≤0.01). The coefficient of variation of biochemical properties was higher than those of chemical properties in both treatments. Principal component analysis (PCA) showed that two principal components explained 58% and 20% of the total variability. The first principal component was influenced mostly by beta-glucosidase, dehydrogenase and TOC, whereas the second was influenced by pH. The first component effectively differentiated managed soil under both agriculture practices. In general, long-term soil conservation management by DD in a dryland farming system improved the quality of this Vertisol by enhancing its organic matter content and biochemical activity.
  • Authors:
    • Wu, J. Q.
    • Singh, P.
    • Flury, M.
    • Schillinger, W. F.
    • Huggins, D. R.
    • Stoeckle, C. O.
    • Al-Mulla, Y. A.
  • Source: Applied Engineering in Agriculture
  • Volume: 25
  • Issue: 1
  • Year: 2009
  • Summary: Establishing winter wheat in the dryland Pacific Northwest requires soil water at depths that the seeds are planted in the early fall. Usually, a soil mulch is created and maintained to conserve seed-zone water and to promote the early establishment of winter wheat. Unfortunately, the tillage used to create the soil mulch often results in unacceptable levels of wind erosion. Chemical (no-till) fallow (CF) and reduced-tillage fallow (RT) are two alternatives for reducing wind erosion, but their effectiveness in maintaining sufficient seed-zone water is unknown. Our objectives were to: (i) assess the effects of CF and RT on seed- and root-zone temperature and water; and (ii) test a model (Simultaneous Heat and Water, SHAW) for simulating management effects on soil temperature and water. Weather data, soil temperature, and water content were monitored in CF and RT treatments. The RT treatment was observed to retain more seed-zone water over summer compared to CF. During the wet winter, CF gained more water than RT. Observed soil temperatures were higher in the CF than in RT. SHAW-simulated water contents followed the trend of the field data, though it slightly under-predicted soil water content for CF and over-predicted for RT. We concluded that RT would provide more seed-zone water for winter wheat establishment than CF. In addition, the SHAW model proved adequate in simulating soil water and temperature, and therefore may serve as a useful modeling tool for evaluating tillage and residue management alternatives.
  • Authors:
    • Lal, R.
  • Source: Journal of Sustainable Agriculture
  • Volume: 33
  • Issue: 1
  • Year: 2009
  • Authors:
    • Davis, R. A.
    • Huggins, D. R.
    • Cook, R. J.
    • Paulitz, T. C.
  • Source: Canadian Journal of Plant Pathology
  • Volume: 31
  • Issue: 4
  • Year: 2009
  • Summary: Fusarium crown rot of wheat (Triticum aestivum), caused by Fusarium pseudograminearum and Fusarium culmorum, is a yield-limiting disease in the dryland wheat-production area of the intermountain Pacific Northwest and is exacerbated in water-stressed plants induced by overfertilizing with nitrogen (N). Plants with excess N deplete water from the soil profile more rapidly and become drought stressed prematurely. Traditionally a problem on winter wheat in summer fallow, this disease has become more important for spring wheat in continuous cropping areas managed for high grain protein levels. During 3 years with direct seeding (no till) near Pullman, Washington, we investigated whether a split application of N, with some applied the previous fall and some with planting, could limit the disease compared with all N applied in the spring and with no N as the check. We also investigated the influence of the previous (rotation) crop (winter and spring canola, Brassica rapa; barley, Hordeum vulgare; or peas, Pisum sativum) on disease, grain yield, grain protein concentration, and populations of Fusarium in the soil. Overall, the DNA concentration of F. culmorum was significantly greater than F. pseudograminearum, and F. culmorum was highest following spring barley. Disease severity and yield were consistently lower in the no-N treatments compared with the other N treatments. The split application reduced disease in only 1 of 3 years. The all-spring application resulted in higher grain protein in 2 of 3 years compared with the split application, but yield was not affected. The previous crop had small but significant effects on disease, but they were not consistent from year to year and often interacted with the N treatment. Grain protein was higher in wheat after pea in 2 of 3 years. In conclusion, splitting of N had little effect on fusarium crown rot, probably because the N level in both treatments was conducive for disease development. Even if not a host species, the previous crop had little effect on subsequent disease, probably because Fusarium persists for more than one season as chlamydospores and in crop residue in this dry summer climate.
  • Authors:
    • Lal,R.
    • Dubey,A.
  • Source: Journal of Crop Improvement
  • Volume: 23
  • Issue: 4
  • Year: 2009
  • Summary: Sustainability of agricultural systems depends on their carbon (C) footprint, and the C output:C input ratio. Thus, this study was conducted with the objectives to: (i) assess the agricultural C emissions in relation to predominant farming systems in Punjab, India, and Ohio, USA; (ii) evaluate C-use efficiency of production systems; and (iii) determine the relative sustainability of agronomic production systems as determined by their C footprints. The data collated on C-based input into the soil for predominant crops for both regions included the amounts of fertilizers (N, P, K), herbicides and pesticides used for each crop annually, tillage methods, cropland area, total production of each crop, area under different farming systems, water-management practices (e.g., tubewell irrigation), and total number of livestock. These data were used to compute C equivalent (CE) per hectare of input and output, and the relative sustainability indices as a measure of the C-production efficiency. There existed a linear relationship observed between C input and C output for Punjab, indicating that an increase of 1 Tg/yr (1 Tg=teragram=10 12 g=million ton) of C input resulted in the corresponding C output of ~12 Tg/yr. A similar linear relationship between input and net C output between the 1930s and 1980s was observed for Ohio, and the ratio reached a plateau during 1990s. The average C-sustainability index (increase in C output as % of C-based input) value for Ohio from 1990 to 2005 was 35-43, almost 2.5 times that of Punjab. Since 1989, there has been a major shift in Ohio from conventional tillage to reduced and conservation tillage along with a decline in fertilizer use. No-till farming is practiced on about 35% of the cultivated area, which involves elimination of plowing, retention of crop residue mulch, and judicious use of chemicals. In Punjab, crop residues are removed, resulting in loss of C from the soil organic carbon pool. Hence, the C-based sustainability index is much higher in Ohio than in Punjab. C-efficient systems are more sustainable than inefficient farming systems, and residue removal reduces agricultural sustainability by depleting the soil C pool.
  • Authors:
    • Gotosa, J.
    • Gwenzi, W.
    • Chakanetsa, S.
    • Mutema, Z.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 83
  • Issue: 3
  • Year: 2009
  • Summary: In southern Africa, tillage research has focused on rainfed smallholder cropping systems, while literature on high-input irrigated cropping systems is limited. We evaluated the effects of conventional (CT), minimum (MT) and no-till (NT) tillage systems on soil organic carbon (SOC), bulk density, water-stable aggregates (WSA), mean weighted diameter (MWD) and crop yields in an irrigated wheat-cotton rotation. Soil data were monitored in the first and final year, while yields were monitored seasonally. Average bulk densities (1.5-1.7 Mg m -3) were similar among tillage systems, but often exceeded the critical limit (1.60 Mg m -3) for optimum root growth. Conversion from CT to MT and NT failed to ameliorate the high bulk densities associated with the alluvial soil. SOC (g kg -1) at 0-15 cm was higher ( P<0.05) under MT (3.9-5.8) and NT (4.2-5.6) than CT (2.9-3.3). Corresponding horizon SOC stocks (Mg C ha -1) for the tillage treatments were; 9.3-13.9 (MT), 9.3-13.5 (NT) and 7.3-7.7 (CT). In the final year, significant ( P<0.05) tillage effects on SOC stocks were also observed at 15-30 cm. Cumulative SOC stocks (Mg C ha -1) in the 0-60 cm profile were higher ( P<0.05) under MT (32.8-39.9) and NT (32.9-41.6) than CT (27.8-30.9). On average, MT and NT sequestered between 0.55 and 0.78 Mg C ha -1 year -1 at 0-30 cm depth, but a net decline (0.13 Mg C ha -1 year -1) was observed under CT. At 0-30 cm, MT and NT had higher ( P<0.05) MWD (0.19-0.23 mm) and WSA (2.3-3.5%) than CT (MWD: 0.1-0.12 mm, WSA: ~1.0%). Both MWD and WSA were significantly ( P<0.05) correlated to SOC. Seasonal yields showed significant ( P<0.05) tillage effects, but 6-year mean yields (t ha -1) were similar (CT: 4.49, MT: 4.33, NT: 4.32 for wheat; CT: 3.30, MT: 2.82, NT: 2.83 for cotton). Overall, MT and NT improved soil structural stability and carbon sequestration, while impacts on crop productivity were limited. Therefore, MT and NT are more sustainable tillage systems for the semi-arid regions than conventional tillage.
  • Authors:
    • Scialabba, N.
    • Hepperly, P.
    • Fließbach, A.
    • Niggli, U.
  • Year: 2009
  • Authors:
    • Fortin, J.
    • Tremblay, G.
    • Ziadi, N.
    • Chantigny, M. H.
    • Rochette, P.
    • Angers, D. A.
    • Poirier, V.
  • Source: Soil Science Society of America Journal
  • Volume: 73
  • Issue: 1
  • Year: 2009
  • Summary: Both tillage and fertilizer management influence soil organic C (SOC) storage, but their interactive effects remain to be determined for various soil and climatic conditions. We evaluated the long-term effects of tillage (no-till, NT, and moldboard plowing, MP), and N and P fertilization on SOC stocks and concentrations in profiles of a clay loam soil (clayey, mixed, mesic Typic Humaquept). Corn (Zea mays L.) and soybean [Glycine max (L) Merr.] were grown in a yearly rotation for 14 yr. Our results showed that NT enhanced the SOC content in the soil surface layer, but MP resulted in greater SOC content near the bottom of the plow layer. When the entire soil profile (0-60 cm) was considered, both effects compensated each other, which resulted in statistically equivalent SOC stocks for both tillage practices. Nitrogen and P fertilization with MP increased the estimated crop C inputs to the soil but did not significantly influence SOC stocks in the whole soil profile. At the 0- to 20-cm depth, however, lower C stocks were measured in the plowed soil with the highest N fertilizer level than in any other treatment, which was probably caused by a greater decomposition of crop residues and soil organic matter. Conversely, the highest SOC stocks of the 0- to 20-cm soil layer were observed in the NT treatment with the highest N rates, reflecting a greater residue accumulation at the soil Surface. When accounting for the whole soil profile, the variations in surface SOC due to tillage and fertilizer interactions were masked by tillage-induced differences in the 20- to 30-cm soil layer.