• Authors:
    • Necula, D.
    • Necula, R.
  • Source: Lucrări Ştiinţifice
  • Volume: 14
  • Issue: 1
  • Year: 2012
  • Summary: Bucharest Ilfov Region Agriculture still occupies an important place, having large reserves of development, determined by soil quality, climate factors, technical equipment and materials and labor (or work within major research institutes in the field). However, productivity is lower productivity sector registered in EU countries due to insufficient technical equipment, small scale agricultural enterprises, which represent obstacles to effective development. Also, irrigation systems are underdeveloped.
  • Authors:
    • Gibson,Lance R.
    • Singer,Jeremy W.
    • Blaser,Brock C.
  • Source: Crop Science
  • Volume: 52
  • Issue: 1
  • Year: 2012
  • Summary: Frost-seeding red clover (Trifolium pratense L.) into winter cereals is an efficient establishment method, although performance under contrasting soil management practices remains unclear. Wheat and intercropped red clover productivity were evaluated in intensive tillage (IT), moderate tillage (MT), and no tillage (NT) with and without compost amendment in a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.]-winter wheat (Triticum aestivum L.) and red clover rotation between 2005 and 2010. Wheat yields were not affected by tillage system and averaged 3.80 Mg ha(-1) but were 10% higher in compost amended soil compared to no compost. Red clover plant density and dry matter (DM) at cereal grain harvest averaged 127 plants m(-2) and 32 g m(-2) and were not affected by tillage or amendment treatments. Maximum wheat canopy light interception was attained in late May to early June and ranged from 84 to 91% and typically exceeded 77% light interception for at least 22 d. Red clover root DM increased on average 378% between wheat harvest and 40 d after harvest compared with a 64% average increase in red clover root length. Red clover shoot: root averaged 8.5 at wheat harvest compared with 11.2 40 d after wheat harvest. Producers using this wheat and red clover intercrop should expect no difference in wheat yield or red clover productivity when using IT, MT, or NT.
  • Authors:
    • Carr, P. M.
    • Anderson, R. L.
    • Lawley, Y. E.
    • Miller, P. R.
    • Zwinger, S. F.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 27
  • Issue: Special Issue 01
  • Year: 2012
  • Summary: The use of killed cover crop mulch for weed suppression, soil erosion prevention and many other soil and crop benefits has been demonstrated in organic no-till or zero-till farming systems in eastern US regions and in Canada. Implements have been developed to make this system possible by terminating cover crops mechanically with little, if any, soil disturbance. Ongoing research in the US northern Great Plains is being conducted to identify cover crop species and termination methods for use in organic zero-till (OZ) systems that are adapted to the crop rotations and climate of this semi-arid region. Current termination strategies must be improved so that cover crop species are killed consistently and early enough in the growing season so that subsequent cash crops can be grown and harvested successfully. Delaying termination until advanced growth stages improves killing efficacy of cover crops and may provide weed-suppressive mulch for the remainder of the growing season, allowing no-till spring seeding of cash crops during the next growing season. Excessive water use by cover crops, inability of legume cover crops to supply adequate amounts of N for subsequent cash crops and failure of cover crops to suppress perennial weeds are additional obstacles that must be overcome before the use of killed cover crop mulch can be promoted as a weed control alternative to tillage in the US northern Great Plains. Use of vegetative mulch produced by killed cover crops will not be a panacea for the weed control challenges faced by organic growers, but rather one tool along with crop rotation, novel grazing strategies, the judicious use of high-residue cultivation equipment, such as the blade plow, and the use of approved herbicides with systemic activity in some instances, to provide organic farmers with new opportunities to incorporate OZ practices into their cropping systems. Emerging crop rotation designs for organic no-till systems may provide for more efficient use of nutrient and water resources, opportunities for livestock grazing before, during or after cash crop phases and improved integrated weed management strategies on organic farms.
  • Authors:
    • Fowler, D. B.
  • Source: Crop Science
  • Volume: 52
  • Issue: 1
  • Year: 2012
  • Summary: The traditional winter wheat ( Triticum aestivum L.) production area on the North American Great Plains extended as far north as southern Alberta, Canada. This paper reviews a research and development program initiated with the objective of expanding production north and east into higher winter stress areas of the Canadian prairies. Winter survival was considered the main limitation to production in this region. However, the widespread adoption of no-till seeding into standing stubble for snow trapping has proven to be a successful method of overwintering wheat if cold hardy cultivars are grown using recommended management practices. Plant breeding improvements have increased production potential and winter wheat has become western Canada's third largest wheat class. Average commercial yields of 149, 125, and 118% of spring wheat in Manitoba, Saskatchewan, and Alberta, respectively, have demonstrated the high yield potential that can be realized while employing environmentally sustainable crop management practices. In light of current environmental concerns, changing weather patterns, diminishing world wheat reserves, and an ever increasing global population to feed, one would assume that winter wheat production in western Canada would be widely embraced. However, marketing obstacles and difficulties inserting winter wheat into rotations, both of which have a direct influence on farmers' net returns, remain to be overcome for this potential to be fully realized.
  • Authors:
    • Hansen, N. C.
    • Allen, B. L.
    • Baumhardt, R. L.
    • Lyon, D. J.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: The Great Plains region of the United States is an area of widespread dryland crop production, with wheat being the dominant crop. Precipitation in the region ranges from 300 to 500 mm annually, with the majority of precipitation falling during hot summer months. The prevailing cropping system is a two-year rotation of wheat and summer fallow. The adoption of no-till practices has resulted in greater precipitation storage and use efficiency, which has led to greater cropping intensity, higher productivity, more diverse crop rotations, and improvements in soil properties. In Colorado, for example, a no-till rotation of winter wheat-maize-fallow increased total annualized grain yield by 75% compared to winter wheat-summer fallow. Soil erosion was reduced to just 25% of that from a conventional tillage wheat-summer fallow system. The primary challenge with reducing fallow frequency is the increase in yield variability and risk of crop failure. Improved approaches for choosing crop or fallow are being developed based on soil water content and forecasted weather. Development of alternative crops, crop rotations, and integrated livestock systems that are sustainable from both economic and ecological perspectives is an on-going effort. Other research is addressing adaptation of cropping practices to climate change and the potential for dryland biomass crop production for the developing biofuel industry.
  • Authors:
    • Harker, K. N.
    • O'Donovan, J. T.
    • Blackshaw, R. E.
    • Johnson, E. N.
    • Lafond, G. P.
    • May, W. E.
  • Source: Canadian Journal of Plant Science
  • Volume: 92
  • Issue: 4
  • Year: 2012
  • Summary: Canola seed costs are substantial, but only a relatively small proportion of planted seeds actually emerge as seedlings. Direct-seeded (no-till) experiments were conducted from 2008 to 2010 at four western Canada locations [Lacombe AB (2007-2010), Lethbridge AB, Indian Head SK, and Scott SK] to determine the influence of cultivar (hybrid vs. open-pollinated), seeding speed (6.4 vs. 11.2 k h -1), and seeding depth (1 vs. 4 cm) on the emergence, maturity, yield, and seed quality of glyphosate-resistant canola. Canola emergence density was positively associated with precipitation levels surrounding the time of seeding; other site and environmental predictors such as soil temperature, soil texture, soil organic matter, latitude and longitude did not consistently influence canola emergence density. The agronomic performance of hybrid canola, including seed yield and quality, was usually superior to open-pollinated canola, but there was no difference in emergence density between the two cultivars. However, the hybrid cultivar emerged 1 d earlier, grew faster and covered the ground more quickly than the open-pollinated cultivar; important results from a crop-weed competition standpoint. Although seeding depth did not influence average canola yield, it often had a major impact on canola emergence density. Under moist conditions, average canola emergence improved from 37 to 62% as seeding depth decreased from 4 to 1 cm, respectively. Seeding at a depth of 1 vs. 4 cm also decreased days to emergence, increased canola ground cover, decreased days to flowering and days to maturity and tended to decrease green seed levels. Relatively high canola emergence rates can reduce the need for additional herbicide applications, herbicide input costs and selection pressure for herbicide resistance. Relatively high canola stand densities can improve the ability of canola to successfully tolerate and accommodate biotic and abiotic stress.
  • Authors:
    • Vera, C. L.
    • Malhi, S. S.
    • Kutcher, H. R.
    • Willenborg, C. J.
    • Hall, L. M.
    • Dosdall, L. M.
    • Klein-Gebbinck, H.
    • Smith, E. G.
    • Lupwayi, N. Z.
    • Blackshaw, R. E.
    • O'Donovan, J. T.
    • Turkington, T. K.
    • Harker, K. N.
    • McLaren, D. L.
    • Grant, C. A.
    • May, W. E.
    • Lafond, G. P.
    • Gan, Y.
  • Source: Canadian Journal of Plant Science
  • Volume: 92
  • Issue: 2
  • Year: 2012
  • Summary: Relatively high prices and increasing demand for canola ( Brassica napus L.) have prompted growers to produce more canola on more cropland. Here we determine if canola seed yield and oil concentration can be increased over current levels with high levels of crop inputs. From 2008 to 2010, direct-seeded experiments involving two seeding rates (75 vs. 150 seeds m -2), two nitrogen rates (100 vs. 150% of soil test recommendation), and the presence or absence of polymer-coated nitrogen or fungicides, were conducted at eight western Canada locations in canola-wheat-canola or continuous canola rotations. Herbicides, insecticides and fertilizers other than nitrogen were applied as required for optimal canola production. Increasing recommended nitrogen rates by 50% increased canola yields by up to 0.25 Mg ha -1. High (150 seeds m -2) versus lower (75 seeds m -2) seeding rates increased canola yields by 0.07 to 0.16 Mg ha -1. Fungicide treatment or polymer-coated nitrogen blended with uncoated urea increased canola yields by 0.10 Mg ha -1 in 2010, but not in 2008. The highest canola input combination treatment following wheat (3.50 Mg ha -1) yielded substantially more than the same high input treatment following canola (3.22 Mg ha -1). Average site yields were influenced by site conditions such as soil organic matter, days to maturity, and temperature, but these site and environmental predictors did not alter treatment rankings. Using higher than the soil test recommended rate of nitrogen or planting 150 versus 75 seeds m -2 increased canola yields consistently across western Canada. Canola oil concentration varied among canola cultivars, but was consistently low when N rates were high (150% of recommended). Higher than normal seeding rates led to high canola seed oil concentration in some cases, but the effect was inconsistent.
  • Authors:
    • Bates, R. T.
    • Gallagher, R. S.
    • Curran, W. S.
    • Harper, J. K.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 2
  • Year: 2012
  • Summary: Conservation tillage for corn (Zea mays L.) production has greatly reduced the soil erosion potential in these systems, but relies heavily on herbicides to manage weeds. Overreliance on herbicides can lead to the development of herbicide-resistant weed communities and increase the risk of ground and surface water contamination by residual herbicides. This study evaluates the integration of various mechanical soil/weed management implements and herbicide programs for surface residue cover, weed control, corn productivity, and economic net returns. A pre-plant vertical coulter/rotary harrow tended to control small annual weeds as well as a standard burn down herbicide program, but reduced surface residue cover by 15% compared to the no-till check treatments. The high residue rotary hoe had little effect on surface residue cover, but provided inconsistent early-season weed control. The high residue inter-row cultivator resulted in 23% residue cover compared to 50% in the no-till treatments, but reduced weed biomass by 53% without any supplemental residual herbicides and 88% with a banded residual herbicide compared to the weedy check treatment. Crop productivity and net return data suggest that integrating the vertical coulter/rotary harrow, high residue cultivator, and banded residual herbicide program could reduce herbicide ai rates by 70% and still achieve similar corn yields and economic returns as the herbicide intensive systems. Such integrated mechanical-chemical systems will increase the crop management complexity for farmers, which may hinder adoption. Soil erosion potential of the integrated systems requires further in-depth evaluation.
  • Authors:
    • Nicolae, I.
    • Dima, M.
    • Diaconu, A.
    • Ploae, M.
  • Source: Cercetări Agronomice în Moldova
  • Volume: 45
  • Issue: 1
  • Year: 2012
  • Summary: Less favorable conditions on sandy soils in southern Oltenia (Romania) limited number of species and varieties grown in the area. Drought and high temperatures in recent years have acted as forces dehydrated plants, disturbing their metabolism. Very high air temperature, relative humidity decreased to 25%, high surface temperature and lack of rainfall during the growing season, producing an imbalance of fluid balance in plante. Excessive foliar transpiration level can dehydrate plants, close osteoles and diminuted gas exchange in the process of photosynthesis. Irrigation plants can remove the stress factor action in the area, maintaining a positive fluid balance, that evaporated water is replaced by water traspiration administered by irrigation. On the sandy soils plant photosynthesis shows a depression at noon when the action is the maximum stress factors. Research early require selection of species with short growing season, to avoid atmospheric and soil drought in July and August. Potatoes meet these requirements, and research in the present study we aimed directing agrotechnical factors (variety, irrigation, fertilization) in order to obtain high yields and efficient, in economic terms.
  • Authors:
    • Pietrusiewicz, J.
    • Horn, R.
    • Lipiec, J.
    • Siczek, A.
  • Source: Soil & Tillage Research
  • Volume: 121
  • Year: 2012
  • Summary: Soil compaction affects pore structure and thereby plant root growth. Elongation and anatomy of seedling roots of wheat ( Triticum aestivum), barley ( Hordeum vulgare), rye ( Secale cereale), triticale ( Triticosecale Wittmack) and maize ( Zea mays) grown in uncompacted bulk field (U) and compacted headland (C) Orthic Luvisol developed from loess of the same field were compared. The seedlings were grown in a growth chamber for 7 days, in cores with undisturbed silt loam taken from 5 to 10 cm depths at compacted and uncompacted sites. Transverse root sections were taken from 25 to 30 mm behind the apex following imbedding in resin. Areas of cortex and vascular cylinder in the sections were determined using the Zeiss LSM Image Examiner. Total root length was smaller in C compared with U by, approximately, 50% for barley to 79% for triticale. Anatomical responses of the roots to soil compaction were related to the general shape of roots (circular or flattened), likely induced by the shape of pores. In the circular roots of wheat, rye and maize the primary anatomical response to soil compaction were the invaginations and associated cell deformation in the cortex. This was mostly pronounced in maize, with greater inherent root diameter. However, in the flattened roots of barley and triticale deformation of root cells was observed both in the cortex and vascular cylinder with less pronounced invaginations. Depending on plant species, the area of cortex and/or vascular cylinder decreased or increased in response to soil compaction. Total cross section area of roots increased in C compared to U among the small-grain cereals, from 9.5 in wheat to 132% in rye, while no differences could be detected in maize. The results indicate that the root elongation and anatomy exhibit considerable plasticity in response to soil compaction and strength of the local environment around the roots.