• Authors:
    • Ilievski, M.
    • Spasov, D.
    • Spasova, D.
    • Atanasova, B.
  • Source: Biotechnology in Animal Husbandry
  • Volume: 27
  • Issue: 3, Book 2
  • Year: 2011
  • Summary: In the period 2005-2007 trials with five oats populations ( Krivogastani, Trebenishta, Radolishta, Bugarija, Kuceviste) and three oats varieties ( Rajac, Slavuj and Lovcen), were carried out. The trials were set up in conditions of organic and conventional production. The main objective of this investigation was to determine the differences in some morphological characteristics of the tested genotypes, which directly or indirectly affect the yield, and also, to determine the differences that came up as a result of the different systems of production (conventional and organic production). The average height of the oats plant cultivated in organic production (114,4 cm) was higher absolutely by 2,2 cm or relatively by 2.0% than the height of the oats plantcultivated in conventional production. The system of production showed no effect on the length of the panicle. The yield of oats grain by panicle in organic production (3,30 g) was higher absolutely by 0,3 g or relatively by 9.1% than the yield of oats grain by panicle in conventional production (3,0 g). The system of production did not impact significantly on the percentage of the glumes. The lowest percentage of glumes in both systems of production gave variety Rajac.
  • Authors:
    • Gawronska-Kulesza, A.
    • Suwara, I.
  • Source: Fragmenta Agronomica
  • Volume: 28
  • Issue: 2
  • Year: 2011
  • Summary: Soil structure is one of the most important factors affecting soil fertility. In the structure-forming process the main role is played by organic matter and biological processes occurring in soil. The role of plants largely depends on their influence on the content of organic matter in the soil. The favourable influence of continuous pasture and red clover on formation of the granular structure are commonly known. The aim of these studies was to determine the effect of annual plants grown in narrow (spring barley, winter rye, winter oilseed rape, white mustard) and wide row-spacing (potato, maize) on the structure of light soil. The plants were cultivated in four-year crop rotation: potatoes (or maize) - spring barley - oilseed winter rape (or white mustard) - winter rye. In a permanent fertilization experiment at yczyn near Warsaw established in 1960 soil crumb composition and water resistance were investigated in years 1994-1997. The field was situated on lessive soil, the upper layer of which constitutes light loamy sand on boulder loam. The soil for studies was taken from the arable layer of 0-20 cm. The cultivated plants significantly influenced soil structure and water resistance of soil aggregates. The soil from plots in which winter plants were grown in narrow row-spacing (winter oilseed rape, winter rye) was characterised by the best structure. The highest water resistance of aggregates was formed on these plots. Potato and maize, grown in wide row-spacing had the worst influence on the soil crumb composition and water resistance of aggregates. Their action on the soil started relatively late, what had an effect on the formation of water resistance of aggregates. Plants shading the soil well over the year favour the increase in water resistance of aggregates and those shading poorly like potatoes and maize - its decrease.
  • Authors:
    • Tendziagolska, E.
    • Wacawowicz, R.
  • Source: Progress in Plant Protection
  • Volume: 51
  • Issue: 3
  • Year: 2011
  • Summary: The objective of the studies was to assess the changes in weed seedbank over 5-year period. Two terms were considered in the experiment: (1) soil preparation for organic farming (2004-2005) and organic plant cultivation with crop rotation (2005-2008). Three variants of cereal crop sequence (A - oats - winter rye, B - oats - spring triticale, C - spring triticale - spring triticale) were included in two-year period of conversion. Over the three years of organic cultivation, a significant increase of weed species diversity in each examined layer was observed in comparison with seed species number determined after soil conversion. Strongly dominant species in both terms of the study was Chenopodium album, which has declined in its number over three years of the organic cultivation. Among the weed species, which did not appear during conversion but have appeared after organic cultivation Erigeron canadensis was noted in the highest number.
  • Authors:
    • Gradin, B.
    • Holm, F.
    • Stevenson, F.
    • Leeson, J.
    • Legere, A.
    • Thomas, A.
  • Source: Weed Research
  • Volume: 51
  • Issue: 1
  • Year: 2011
  • Summary: Contrasting approaches to integrated weed management (IWM) for prairie cropping systems were evaluated by measuring weed response to six IWM systems in a wheat-oilseed rape-barley-pea rotation at Saskatoon and Watrous, Saskatchewan, Canada. The six IWM systems (high herbicide/zero tillage; medium herbicide/zero tillage; low herbicide/zero tillage; low herbicide/low tillage; medium herbicide/medium tillage; no herbicide/high tillage) included various combinations of seeding rate and date, herbicide timing and rate, and tillage operations, in order to achieve similar weed management levels. Changes in weed communities were assessed over 4 years by monitoring species composition and abundance at various times during the growth season. Principal response curves indicated a gradual increase in Thlaspi arvense, Chenopodium album, Amaranthus retroflexus and Fallopia convolvulus in the no herbicide/high tillage system. Winter and early spring annuals and perennials increased in most systems, but particularly in the low herbicide/zero tillage and medium herbicide/zero tillage systems. Although five of the six IWM systems provided similar results, changes in weed communities would suggest that operations could be revised to improve the overall management of certain weed species and reduce seed return in the no herbicide/high tillage system and in systems with low herbicide inputs and zero tillage. This study confirms the potential of contrasting IWM systems under the challenging environmental conditions of the Canadian Prairies.
  • Authors:
    • Esker, P. D.
    • Jirak-Peterson, J. C.
  • Source: Plant Disease
  • Volume: 95
  • Issue: 5
  • Year: 2011
  • Summary: Corn anthracnose (Colletotrichum graminicola) is an important disease of field coni (Zea mays). Two phases, leaf blight and stalk rot, can reduce yield through either premature leaf senescence or reduced grain harvest due to stalk lodging. Corn residue is an important source of primary inoculum and is increased through cultural practices such as no-tillage and continuous corn cropping, which are common practices in Wisconsin. Field studies conducted at the Arlington Agricultural Research Station (ARS) and the West Madison ARS showed that the incidence and severity of anthracnose leaf blight were higher in continuous-corn crop rotations than in soybean corn rotations (91% higher incidence, 24 to 78% higher severity). Anthracnose stalk rot was marginally affected by tillage in 2008 (P = 0.09), with higher incidence in chisel-plowed treatments. There was a positive association between spring residue cover and anthracnose leaf blight but no association was found between residue and stalk rot. No association was found between anthracnose leaf blight and stalk rot. There was a negative association between anthracnose leaf blight and yield but not between anthracnose stalk rot and yield. Managing residue levels through crop rotation would help to reduce anthracnose leaf blight but further work is needed to elucidate factors that lead to stalk lodging prior to harvest.
  • Authors:
    • Verma, S. B.
    • Vanegas, D. X.
    • Xiao, X. M.
    • Kalfas, J. L.
    • Suyker, A. E.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 12
  • Year: 2011
  • Summary: Information on gross primary production (GPP) of maize croplands is needed for assessing and monitoring maize crop conditions and the carbon cycle. A number of studies have used the eddy covariance technique to measure net ecosystem exchange (NEE) of CO 2 between maize cropland fields and the atmosphere and partitioned NEE data to estimate seasonal dynamics and interannual variation of GPP in maize fields having various crop rotation systems and different water management practices. How to scale up in situ observations from flux tower sites to regional and global scales is a challenging task. In this study, the Vegetation Photosynthesis Model (VPM) and satellite images from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used to estimate seasonal dynamics and interannual variation of GPP during 2001-2005 at five maize cropland sites located in Nebraska and Minnesota of the U.S.A. These sites have different crop rotation systems (continuously maize vs. maize and soybean rotated annually) and different water management practices (irrigation vs. rain-fed). The VPM is based on the concept of light absorption by chlorophyll and is driven by the Enhanced Vegetation Index (EVI) and the Land Surface Water Index (LSWI), photosynthetically active radiation (PAR), and air temperature. The seasonal dynamics of GPP predicted by the VPM agreed well with GPP estimates from eddy covariance flux tower data over the period of 2001-2005. These simulation results clearly demonstrate the potential of the VPM to scale-up GPP estimation of maize cropland, which is relevant to food, biofuel, and feedstock production, as well as food and energy security.
  • Authors:
    • Halloran, J. M.
    • Olanya, O. M.
    • Griffin, T. S.
    • Honeycutt, C. W.
    • Larkin, R. P.
    • He, Z.
  • Source: Phytopathology
  • Volume: 101
  • Issue: 1
  • Year: 2011
  • Summary: Four different potato cropping systems, designed to address specific management goals of soil conservation, soil improvement, disease suppression, and a status quo standard rotation control, were evaluated for their effects on soilborne diseases of potato and soil microbial community characteristics. The status quo system (SQ) consisted of barley under-seeded with red clover followed by potato (2-year). The soil-conserving system (SC) featured an additional year of forage grass and reduced tillage (3-year, barley/timothy-timothy-potato). The soil-improving system (SI) added yearly compost amendments to the SC rotation, and the disease-suppressive system (DS) featured diverse crops with known disease-suppressive capability (3-year, mustard/rapeseed-sudangrass/rye-potato). Each system was also compared with a continuous potato control (PP) and evaluated under both irrigated and nonirrigated conditions. Data collected over three potato seasons following full rotation cycles demonstrated that all rotations reduced stem canker (10 to 50%) relative to PP. The SQ, SC, and DS systems reduced black scurf (18 to 58%) relative to PP; ST reduced scurf under nonirri2ated but not irrigated conditions; and scurf was lower in DS than all other systems. The SQ. SC, and DS systems also reduced common scab (15 to 45%), and scab was lower in DS than all other systems. Irrigation increased black scurf and common scab but also resulted in higher yields for most rotations. SI produced the highest yields under nonirrigated conditions, and DS produced high yields and low disease under both irrigation regimes. Each cropping system resulted in distinctive changes in soil microbial community characteristics as represented by microbial populations, substrate utilization, and fatty acid methyl-ester (FAME) profiles. SI tended to increase soil moisture, microbial populations, and activity, as well result in higher proportions of monounsaturated FAMEs and the FAME biomarker for mycorrhizae (16:1 omega 6c) relative to most other rotations. DS resulted in moderate microbial populations and activity but higher substrate richness and diversity in substrate utilization profiles. DS also resulted in relatively higher proportions of FAME biomarkers for fungi (18:2 omega 6c), actinomycetes, and gram-positive bacteria than most other systems, whereas PP resulted in the lowest microbial populations and activity; substrate richness and diversity; proportions of monounsaturated and polyunsaturated FAME classes; and fungal, mycorrhizae, and actinomycete FAME biomarkers of all cropping systems. Overall, soil water, soil quality, and soilborne diseases were all important factors affecting productivity, and cropping systems addressing these constraints improved production. Cropping system approaches will need to balance these factors to achieve sustainable production and disease management.
  • Authors:
    • Nzokou, P.
    • Wilson, A. R.
    • Lin, Y.
  • Source: HortScience
  • Volume: 46
  • Issue: 3
  • Year: 2011
  • Summary: High rates of inorganic fertilizers are used in conventional intensive production systems such as Abies fraseri (fraser fir) cropping systems for Christmas trees. Groundcovers can be used as green mulches, help reduce the use of farm chemicals, and provide several environmental benefits. We investigated the performance of a low-input cropping system by combining two legume cover crops [Dutch white clover (Trifolium repens) and alfalfa (Medicago sativa)] in combination with low rates of inorganic fertilizers as a step toward a more sustainable production system. The randomized block design comprised one cover crop and one of three applications of reduced rate inorganic fertilizer (75%, 50%, and 25% of the recommended rate). A conventional system using herbicides for weed control and the 100% rate of inorganic fertilizer was used as a control. Parameters measured included tree morphology, foliar nitrogen concentration, soil mineral nitrogen, and nitrate-N leaching below the root zone. A significant positive growth response (height and diameter) was obtained in all alfalfa-based cropping systems. This was accompanied by foliar nutrient concentrations similar to conventional plots and a reduction in nitrate-N leaching. However, in white clover-based cropping systems, the growth response was reduced (both height and diameter), suggesting competition for soil resources. In addition, the total nitrate-N leaching was higher in this system, suggesting an imbalance between mineral nitrogen availability and use in white clover-based cropping systems. We conclude that if the potential competition between cover crops and trees can be properly managed, legume cover crops can be effectively used to make intensive production tree-based systems more sustainable. Further studies related to mineralization and macronutrient flows are needed before any definite recommendation can be made about the use of these systems in large-scale production systems.
  • Authors:
    • Trond M. Henriksen, T. M.
    • Anne-Kristin Løes, A.-K.
    • Sjursen, H.
    • Ragnar Eltun, R.
  • Source: Acta Agriculturae Scandinavica, Section B - Soil & Plant Science
  • Volume: 61
  • Issue: 2
  • Year: 2011
  • Summary: By restricted access to manure, nitrogen (N) supply in organic agriculture relies on biological N-fixation. This study compares grain yields after one full-season green manure (FSGM) to yields with repeated use of a green-manure catch crop. At two sites in south-eastern Norway, in a simple 4-year rotation (oats/wheat/oats/wheat), the repeated use of ryegrass, clover, or a mixture of ryegrass and clover as catch crops was compared with an FSGM established as a catch crop in year 1. The FSGM treatments had no subsequent catch crops. In year 5, the final residual effects were measured in barley. The yield levels were about equal for grains with no catch crop and a ryegrass catch crop. On average, the green-manure catch crops increased subsequent cereal yields close to 30%. The FSGM increased subsequent cereal yields significantly in two years, but across the rotation the yields were comparable to those of the treatments without green-manure catch crop. To achieve acceptable yields under Norwegian conditions, more than 25% of the land should be used for full-season green manure, or this method combined with green-manure catch crops. The accumulated amount of N in aboveground biomass in late autumn did not compensate for the N removed by cereal yields. To account for the deficiency, the roots of the green-manure catch crops would have to contain about 60% of the total N (tot-N) required to balance the cereal yields. Such high average values for root N are likely not realistic to achieve. However, measurement of biomass in late autumn may not reflect all N made available to concurrent or subsequent main crops.
  • Authors:
    • Tamas, D.
    • Hoble, A.
    • Dîrja, M.
    • Luca, L. C.
  • Source: Agricultura, stiinta si practica (Agricultural Practice and Science Journal)
  • Volume: 20
  • Issue: 3/4
  • Year: 2011
  • Summary: This paper provides a comprehensive analysis of the climatic conditions during 2009, 2010 and 2011 of the agricultural area of Transylvanian Plain, in the general context of the progressive warming of the atmosphere and significantly reduced rainfall. Testing of some soyabean cultivars is initiated in 2009 in Vitisoara, Turda, under irrigated conditions and other technological factors.