• Authors:
    • Stenberg, B.
    • Stenberg, M.
    • Rydberg, T.
  • Source: Applied Soil Ecology
  • Volume: 14
  • Issue: 2
  • Year: 2000
  • Summary: The effects of reduced tillage and lime on crop yield and soil physical and microbial properties were studied in a weakly-structured silty clay loam soil at a site in Sweden. Two autumn primary tillage practices were compared, mouldboard ploughing to 20-25 cm and cultivation to 12 cm. Seedbed preparation was carried out by several harrowing operations in the mouldboard ploughed treatment, and with a harrow in the same operation as sowing in the shallow cultivation treatment. The tillage treatments were applied alone or were combined with liming aimed at soil structural improvement. Lime was added as 6.5 t CaO ha -1 before the start of the experiment and mixed into the top 12 cm of soil with a disc cultivator. A 4-year crop rotation was used: spring barley, spring oilseed rape, spring/winter wheat and oats, and all crops were compared each year. Crop residues were retained in the experiment and incorporated at cultivation. Aggregate stability was improved by the shallower tillage depth, probably as an effect of an increase in soil organic matter and a more active microbial biomass. Liming had little effect on soil structure variables but increased microbial activity to some extent. This was reflected in higher crop yields, especially when the shallow tillage depth was combined with liming. Penetration resistance in the seedbed subsoil was highest when mouldboard ploughing was carried out in plots without liming. Data were examined with principal component analyses, and the structures in the data were presented as scores and loading plots, which showed groupings between samples and relationships between variables, respectively.
  • Authors:
    • Clark, K.
  • Source: Regional on-farm experiments 1999: Deniliquin, Finley, Hillston, Leeton & Beckom agronomy districts
  • Year: 2000
  • Summary: Tabulated yield data are presented from variety trials conducted throughout New South Wales, Australia, for barley, rape, lentils, lupins, oats, peas, wheat and narbon ( Vicia narbonensis).
  • Authors:
    • Gurin, A. G.
  • Source: Sadovodstvo i Vinogradarstvo
  • Issue: 1
  • Year: 2000
  • Summary: In Russia, strips of shelter plants are sometimes grown between the rows of strawberries, so that at the end of the growing season the first frosts will kill off the tops of these plants which then fall and cover the strawberry plants like a mulch, and help to retain a protective snow cover through the winter. An account is given of the performance of oats, barley, rape, and mustard sown as shelter plants between the rows of Redgauntlet strawberries, with details of the snow accumulation and of the strawberry yields. The shelter plants did depress the growth of the strawberry plants somewhat, but had little or no effect on fruit yields, and also significantly reduced weed growth.
  • Authors:
    • Knezevic, S. Z.
    • Leeson, J. Y.
    • Thomas, A. G.
    • Acker, R. C. van
    • Frick, B. L.
  • Source: Canadian Journal of Plant Science
  • Volume: 80
  • Issue: 4
  • Year: 2000
  • Summary: In 1997, a weed survey was conducted during July and August in fields of wheat, barley, oat, canola [rape] and flax in Manitoba, Canada. Field selection was based on a stratified-random sampling methodology using ecodistricts as strata. Species in the Poaceae family were most commonly observed in the survey, followed by species in the Polygonaceae, Asteraceae and Brassicaceae families. The six most abundant weed species were green foxtail ( Setaria viridis), wild oats ( Avena fatua), wild buckwheat ( Polygonum convolvulus) [ Fallopia convolvulus], Canada thistle ( Cirsium arvense), red-root pigweed ( Amaranthus retroflexus) and wild mustard ( Sinapis arvensis). The survey highlighted significant differences between ecoregions and between crops in residual weed infestations. The weed community in the Boreal Transition ecoregion was dominated by seven species, whereas fields in the Aspen Parkland and Lake Manitoba Plain ecoregions were dominated by two species and the Interlake Plain ecoregion was dominated by only one species. Although significant differences were found between the weed communities in crops, they were not as great as differences between ecoregions. The Manitoba residual weed community in 1997 was very similar to that reported for 1978-81 and 1986, suggesting that the same species should remain a focus for weed management.
  • Authors:
    • Bertholdsson, N. O.
  • Source: Sveriges Utsädesförenings Tidskrift
  • Volume: 110
  • Issue: 4
  • Year: 2000
  • Summary: The use of hydroponic techniques to measure the response to stress by cereals is discussed with reference to studies on drought, low N inputs and crop weed competition with barley, wheat, oats, triticale and rape.
  • Authors:
    • Tanni, R.
    • Pietola, L.
  • Source: Agricultural and Food Science in Finland
  • Volume: 8
  • Issue: 4/5
  • Year: 1999
  • Summary: The role of plant growth regulators (PGR) in nitrogen (N) fertilization of spring wheat and oats (CCC [chlormequat]), fodder barley (etephon/mepiquat) an oilseed rape (etephone) in crop rotation was studied in 1993-96 on loamy clay soil. Carry over effect of the N fertilization rates (0-180 kg/ha) was evaluated in 1997. N fertilization rate for the best grain/seed yield (120-150 kg/ha) was not affected by PGRs. The seed and N yields of oilseed rape were improved frequently by the recommended use of PGR. The yield of oats increased in 1995-96. Even though PGR effectively shortened the plant height of spring wheat, the grain yield increased only in 1995. N yield of wheat grains was not increased. Response of fodder barley to PGR was insignificant or even negative in 1995. The data suggest that PGRs may decrease some N leaching at high N rates by improving N uptake by grain/seeds, if the yield is improved. The carryover study showed that in soils with no N fertilization, as well as in soils of high N rates, N uptake was higher than in soils with moderate N fertilization (60-90 kg/ha), independent of PGRs. According to soil mineral N contents, N leaching risk was significant (15-35 kg/ha) only after dry and warm late seasons. After a favourable season of high yields, the N rates did not significantly affect soil mineral N contents.
  • Authors:
    • Izaurralde, R.
    • Gill, K.
    • Arshad, M.
  • Source: Journal of Sustainable Agriculture
  • Volume: 12
  • Issue: 2/3
  • Year: 1998
  • Summary: Properties of a silt loam (Dark Gray Luvisol), weed population and wheat production ( Triticum aestivum) in canola ( Brassica campestris)-wheat-wheat (C), fallow-wheat-wheat (F), field pea ( Pisum sativum)-wheat-wheat (P) and continuous wheat (W) cropping systems were compared under conventional tillage (CT) and no-till (NT) in field trials near Beaverlodge, Alberta, Canada. Percentage of water stable aggregates (WSA) was reduced after a fallow season. Soil NO 3-N was similar among cropped plots which was significantly lower than fallow plots in two of the three years. Ammonium-N, extractable P and penetration resistance (PR) of soil were not affected by crop rotation. The W plots tended to have more weeds than both the first (W1) and second (W2) year wheat plots in rotations. Wheat appeared to suppress weeds better than canola, field pea or fallow. Average annual production of 3.95 t/ha as grain and 10.7 t/ha as above-ground dry matter (AGDM) by W1 were significantly greater than the corresponding production by W2 and W. Wheat grain and AGDM production in the two years of C, F, P and W systems were not significantly different in most cases. However, cumulative yields by C, P and W systems for three years of rotation were greater than the corresponding grain and AGDM yields from F rotation by 1.10-4.19 and 4.3-8.7 t/ha, respectively. Tillage did not affect NO 3-N, NH 4-N, P and WSA in soil but reduced its PR. The NT system provided better control of annual broadleaf weeds whereas perennial weeds were better controlled by CT. The CT system produced more grains (average of 0.42 t/ha per year) than NT system. Crop rotation by tillage interaction effects on soil properties, weed populations and crop yields were not significant which indicated that the crop rotations were equally effective under both the tillage systems. Benefits of crop rotation over monoculture in this study were of similar nature as in earlier studies conducted on fields already under annual cropping systems. Canola and field pea were more beneficial than wheat as previous-crop for wheat production. Replacing fallow with a crop resulted in increased crop production and straw returned to soil, reduced potential for leaching of NO 3-N, and improved water stable aggregation of soil.
  • Authors:
    • Myers, R.
    • Pullins, E.
  • Source: American Journal of Alternative Agriculture
  • Volume: 13
  • Issue: 3
  • Year: 1998
  • Summary: The agronomic and economic performance of five alternative crops was assessed in comparison to the no-till wheat-soyabean double-cropping system prevalent in the southern Corn Belt of the USA. A field site was established in 1992 at the University of Missouri-Columbia and two further sites in Missouri were added in 1993. Amaranth, buckwheat, sunflower, and pearl millet were planted after the harvest of canola [rape] or wheat, or after fallow. Alternative double-crop grain yield, production costs, and net returns were compared with those of double-crop soyabean. Wheat yielded more than canola. Sunflower grain yields did not differ significantly after winter-crop treatments at any site. Yields of amaranth, buckwheat, soyabean, and pearl millet differed after winter crops at some sites. At three study yield levels, net returns were positive and greatest for double-crop wheat-amaranth, canola-amaranth, wheat-sunflower, and canola-sunflower systems. All double-crop systems except canola-pearl millet had positive net returns at median study yield levels. Low or negative net returns resulted from the combination of low yield and low price for some double crops. Canola was shown to be an economically feasible alternative to wheat in a double-cropping system for central and southern Missouri. Buckwheat and sunflower were shown to be agronomically and economically competitive alternatives to soyabean following either canola or winter wheat, with buckwheat most valuable in late-season planting conditions.
  • Authors:
    • Turkington, T.
    • Gill, K.
    • Arshad, M.
    • Woods, D.
  • Source: Agronomy Journal
  • Volume: 89
  • Issue: 1
  • Year: 1997
  • Summary: In a field trial near Beaverlodge, Alberta, a Hythe clay loam (fine, montmorillonitic, frigid Mollic Cryoboralf) with initial pH in CaCl 2 ~5 was limed (7.5 t ha -1) in May 1991. Liming increased soil pH to 6.6 in the autumn of 1991. During 1993 to 1995, the pH of limed soil at the 0- to 10-cm depth ranged from 6.2 to 6.3 when conventionally tilled and from 5.6 to 6.2 under no-till. A slight increase at the 10- to 20-cm depth and no change below 20 cm occurred in soil pH due to liming. Liming increased NO 3-N in the 0- to 20-cm depth significantly, but no change was detected in exchangeable Al, NH 4-N and extractable P. Weed populations were not affected by liming in 1993 and 1994, but were suppressed markedly in 1995. Liming reduced brown girdling root rot (BGRR) (caused by Rhizoctonia solani) and increased seed yield of canola [rape]. Three-year mean BGRR ratings (a scale of 0 to 5 scale, from disease-free to disease-impaired) under no lime and lime, respectively, were 2.96 and 2.59 in tilled and 2.76 and 2.63 in no-till soil. The increase in canola seed yield by liming was 0.39 (37%) t ha -1 year -1 in tilled and 0.22 (17%) t ha -1 year -1 in no-till soil. Liming increased dry matter by 1.77 t ha -1 year -1 (31%). No-till plots had higher soil water and canola yields but slightly lower soil pH (0- to 20-cm depth), and lesser BGRR, compared with the tilled system. Increased soil NO 3-N and pH, fewer weeds, and reduced BGRR-all responded to liming and contributed to increased canola yields under both tilled and no-till systems.
  • Authors:
    • Voroney, R.
    • Vyn, T.
    • Janovicek, K.
  • Source: Agronomy Journal
  • Volume: 89
  • Issue: 4
  • Year: 1997
  • Summary: Research in Ontario, Canada in 1989, 1990, and 1995 evaluated no-till maize yield response to various preceding crops and examined whether in-row residue removal affected no-till maize response to rotation crops. The soil was an imperfectly drained loam (medium, mixed, weakly to moderately calcareous Typic Hapludalf). The preceding crops were: maize harvested for grain or whole-plant silage; hard red spring wheat; barley; red clover ( Trifolium pratense) cover crops, following barley, that were killed by spraying either 3 weeks (early-kill) or 1 day (late-kill) prior to sowing maize; canola [rape]; and soyabeans. In-row residue was either retained while sowing or cleared using planter-mounted, notched-disc row cleaners. Clearing in-row cover crop residue increased early-season maize growth and was associated with yield increases of 0.61 t ha -1 (8%) following early-killed red clover and 0.43 t ha -1 (6%) ( P = 0.10) following late-killed red clover. In 2 of 3 years, maize yields following early-killed red clover were similar to following soyabeans and greater than following grain maize, provided that in-row residue was cleared. Following the other crops, grain yield response to clearing in-row residue was smaller and less consistent over years. Preceding cropping affected early-season maize growth, with the largest plants at 5 weeks after sowing following either soyabeans or silage maize and the smallest following either red clover or grain maize. In 2 of 3 years, when preceding crop effects on grain yield were statistically significant, yields following either soyabeans or spring wheat were more than 1.05 t ha -1 (16%) higher than after grain maize. That yield increase occurred regardless of in-row residue placement. Removing maize stover by harvesting as silage increased maize yield by 0.86 t ha -1 (12%) over yield following grain maize. During 1995, maize yield following silage maize was less than after soyabeans, canola, barley, or wheat; thus, no-till maize yield response to rotation is not exclusively due to the presence of surface-placed stover. In-row residue placement and preceding cropping practices affected in-row soil temperature, but this could not totally account for the treatment effects on early-season maize growth and yields.