• Authors:
    • McSorley, R.
  • Source: Nematropica
  • Volume: 41
  • Issue: 2
  • Year: 2011
  • Summary: Studies that utilized rotation crops for management of root-knot nematodes in the southeastern United States were examined to evaluate the overall performance of rotation crops. In general, nematode-susceptible crops that followed effective rotation crops produced yields and supported nematode numbers similar to those obtained on crops treated with most standard nematicides. Fumigation with methyl bromide was an exception, and resulted in low nematode numbers up to the end of the susceptible target crop, whereas nematode numbers recovered following rotation crops. Performance of rotation crops was similar to clean fallow in most studies, and there was little evidence that rotation crops could suppress nematode numbers below levels obtained after clean fallow. Large reductions in nematode numbers often were achieved following rotation crops. In sites with relatively low initial population levels before rotation crops were used, effective rotation crops sometimes maintained relatively low nematode numbers through the following susceptible target crop, and nematode recovery was not observed until the second year of the rotation sequences. Where practical, very long rotations such as bahiagrass pastures were often effective in preventing increase in nematode numbers on subsequent susceptible crops. Rehabilitation of heavily infested sites is difficult, could require several years of rotation crops, and the benefit gained may last only through one susceptible crop.
  • Authors:
    • Nelson, S. O.
    • Trabelsi, S.
  • Source: Transactions of the American Society of Agricultural and Biological Engineers
  • Volume: 54
  • Issue: 2
  • Year: 2011
  • Summary: Based on microwave dielectric properties of wheat, corn, barley, oats, grain sorghum, soybeans, canola, shelled peanuts and pod peanuts measured over ranges of frequency and moisture content, models for predicting the dielectric constant and loss factor of these commodities are described. Nearly linear relationships between dielectric properties and log of frequency or frequency and moisture content permitted multiple linear regression models to be developed for predicting dielectric constants and loss factors for each type of grain and seed at 23degreesC. Models predicted dielectric constants with s.e. of 1 to 2% with some up to approx. 4% for grain and seed at frequencies in the range 5 to 15 GHz over given moisture ranges. Loss factors are predicted with s.e. of a few percent, but much larger errors can naturally result when loss factors are very small.
  • Authors:
    • Jauhiainen, L.
    • Peltonen-Sainio, P.
    • Hakala, K.
  • Source: The Journal of Agricultural Science
  • Volume: 149
  • Year: 2011
  • Summary: Global warming has accelerated in recent decades and the years 1995-2006 were the warmest ever recorded. Also, in Finland, the last decade has been exceptionally warm. Hence, this study examines how current field crop cultivars, adapted to northern long-day conditions and short growing seasons, have responded to the elevated temperatures, especially with regard to determination of yield potential and quality. These comparisons were carried out with spring and winter wheat (Triticum aestivum L.), oats (Avena sativa L.), barley (Hordeum vulgare L.), winter rye (Secale cereale L.), pea (Pisum sativum L.) and rapeseed (turnip rape, Brassica rapa L. and oilseed rape, B. napus L.). Long-term data sets of MTT Official Variety Trials and the Finnish Meteorological Institute were used to study crop responses to precipitation and elevated temperatures at different growth phases. The MTT data sets were also grouped into experiments that could be considered typical of the temperature conditions in the period 1971-2000 seasons (termed '1985' conditions) or typical of the period 2010-39 (termed '2025'). At elevated temperatures, yields generally declined in these relatively cool growing conditions of northern Europe, except for pea. Elevated temperatures tended to have negative effects both in the pre- and post-anthesis phases, but the response depended on species. The response was probably associated with reduced water availability, which limited yield determination, especially in early growth phases. For example, in spring cereals a decrease in early summer precipitation by 10 mm decreased yields by 45-75 kg/ha. As warmer conditions also typically hastened development and growth in such generally cool growing conditions of Finland, it is essential that breeding programmes produce cultivars that are less sensitive to elevated temperatures, which are likely to become more frequent in future.
  • Authors:
    • Jauhiainen, L.
    • Peltonen-Sainio, P.
    • Sadras, V. O.
  • Source: Field Crops Research
  • Volume: 124
  • Issue: 2
  • Year: 2011
  • Summary: In the northernmost European environments of Finland, large variability in the yield and quality of crops is a critical source of uncertainty for growers and end-users of grain. The aims of this study were (i) to quantify and compare the plasticity, i.e., cultivar responsiveness to environment, in yield of spring oat, spring wheat, six-row barley, two-row barley, winter rye, winter wheat, turnip rape and oilseed rape, (ii) to explore the existence of hierarchies or positive correlations in the plasticity of agronomic, yield and quality traits and (iii) to probe for trends in yield plasticity associated with different eras of breeding for yield potential and agronomic traits. Plasticities of yield, agronomic and quality traits were derived as slopes of norms of reaction using MTT Agrifood Research Finland data sets combining long-term (1970-2008 for cereals and 1976-2008 for rapeseed) results from 15 to 26 locations. Plasticity of yield ranged typically between 0.8 and 1.2, was smallest for six-row barley (0.84-1.11) and largest for winter rye (0.72-1.36). We found two types of associations between plasticity of yield and yield under stressful or favourable conditions for cereals but none for rape. In spring wheat, oat and six-row barley, high yield plasticity was associated with crop responsiveness to favourable conditions rather than yield reductions under stressful conditions. Modern spring wheat cultivars had higher maximum grain yields compared to older ones at the same level of plasticity. In winter wheat and rye, high yield plasticity resulted from the combination of high yield in favourable conditions and low yield in stressful environments. Many associations between yield plasticity and other traits were identified in cereals: e.g., high yield plasticity was often associated with higher grain weight, more grains per square meter, later maturity (contrary to turnip rape), shorter plants, less lodging and lower grain protein content and in winter cereals with higher winter damage. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Smith, J. P.
    • Smith, M. K.
    • Stirling, G. R.
  • Source: Soil & Tillage Research
  • Volume: 114
  • Issue: 2
  • Year: 2011
  • Summary: Ginger (Zingiber officinale) production is facing increasing disease and pest pressure and declining yield with continuing intensive cultivation practices. A four year experiment was established in south-eastern Queensland on a red ferrosol that had a long (>60 years) history of ginger farming. Minimal tillage and organic amendments were compared with conventional practice that involved frequent tillage and soil fumigation using 1,3-dichloropropene (Telone (R)). Ginger crops were grown in the second and fourth year of the experiment, following an annual rotation with different cover crops including oats (Avena sativa), Brassica spp., soybean (Glycine max) and forage sorghum (Sorghum bicolour X S. sudanese). A pasture ley of Pangola grass (Digitaria eriantha subsp. pentzii) provided a treatment continuum from major to minor disruption in the soil's physical fertility and biological communities, and was therefore only planted to ginger in the fourth year of the experiment. Ginger seed-pieces (sections of the rhizome used for planting) were planted into both tilled and untilled beds using a double disc opener on a specially designed ginger planter. Rhizome yield in the final year was greatest (74.2 t/ha) and losses to pathogens (Pythium myriotylum and Fusarium oxysporum f. sp. zingiberi) minimal (7.0%) in the pasture ley that had been cultivated prior to planting ginger. Furthermore, the minimum-tilled cover cropped treatment, which likewise had been cultivated prior to planting ginger, yielded well (62.0 t/ha), with few losses (5.0%) from rhizome rots. Conversely the fumigated treatment had the highest losses (35.9%) due to Pythium Soft Rot and lowest yields (20.2 t/ha). Minimum-tilled plantings of ginger, however, resulted in poor yields (30.9-43.1 t/ha) but had acceptable levels of disease. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Budzynski, W.
    • Szemplinski, W.
  • Source: ACTA Scientiarum Polonorum, Agricultura
  • Volume: 10
  • Issue: 2
  • Year: 2011
  • Summary: The paper comprises a review of the results of studies on cereal mixtures published in 2003-2007 in the Polish scientific literature. There are presented herein the most important issues concerning yield ability, weed, pest and diseases infestation. Cereal mixtures occupy the highest area among spring cereals in Poland and grain harvested from mixtures plays an important role in production of feedstock in the country. The highest concentration of mixtures is noted in the eastern region and the lowest in the south-western part of Poland. The higher yield ability of mixtures compared to pure cereal stands is connected with complementary utilization of environmental resources in different time, space (under- or aboveground) or form (water, light, nutrients) by mixtures' components as well as with competition, responsible for changes in proportion of components in the mixture yield. The better stability of yield is attributed to a better competition ability against weeds and lower susceptibility of mixtures to diseases compared to pure stands. Mixed stands show a better response to some agronomical factors, such as irrigation, mineral fertilization and chemical protection against pests, weeds and diseases. A higher proportion of naked forms of barley and oat in mixtures has been recommended recently. Therefore, the mixture yields are lower than those of mixtures with hulled forms but their feeding value is higher, because of a lower content of fibre and a higher content of protein and fat.
  • Authors:
    • Calin, L.
    • Taranu, I.
    • Tabuc, C.
  • Source: Archiva Zootechnica
  • Volume: 14
  • Issue: 4
  • Year: 2011
  • Summary: Fungal mycoflora and mycotoxin contamination were determined in 86 samples (21 maize, 21 wheat, 11 barley, 4 oats, 1 rye, 12 soya, 6 sunflower, 4 colza, 3 rice, 3 triticale), coming from the south-eastern part of Romania during the 2008 to 2010 period. The most frequent fungal contaminants belonged to the Aspergillus and Fusarium genera, maize was the most contaminated cereal. The main toxinogenic species identified were A. flavus, A. fumigatus, F. graminearum, F. culmorum in all cereals Aflatoxin B1 (AFB1), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEA) and fumonisins (FUMO), contents were analyzed by ELISA. More than 90% of the samples were found to be contaminated by at least one toxin. The most frequent mycotoxin was the deoxynivalenol (71.60%). Around 40% of samples were contaminated with AFB1 and FB. Ochratoxine A and zearalenone were found in 16% and 32% of samples respectively. These results demonstrated that cereals produced in Romania present a particular pattern of fungal mycoflora and mycotoxin contamination since DON, ZEA and FUMO as well as AFB1 and OTA were observed.
  • Authors:
    • LaFond, G. P.
    • May, W. E.
    • Tenuta, M.
    • Entz, M. H.
    • Turmel, M. S.
  • Source: Canadian Journal of Plant Science
  • Volume: 91
  • Issue: 6
  • Year: 2011
  • Summary: Leguminous cover crops are becoming a popular way to increase the sustainability of agricultural systems. Previously, cover crops have been found to increase colonization by arbuscular mycorrhizal fungi (AM F) and phosphorus and micronutrient uptake. Long-term field studies were conducted to test the hypothesis that self-regenerating black medic (Medicago lupulina cv. George) cover crops increase AM F colonization and early nutrient uptake in flax (Linum usitatissimum). Field experiments were established in 2000 (Manitoba) and 2002 (Saskatchewan) using a flax wheat (Triticum aestivum) oat (Avena sativa) rotation. In a second experiment, intact soil cores were harvested from the plots in spring and tested for soil disturbance and cover crop effects under controlled environment conditions (CEC). Both seedling flax crops sampled from the field in 2005 and 2006 and flax growth in CEC showed high levels of AMF root colonization, but no significant influence of the cover crop on AM F colonization by arbuscules or hyphal structures was detected. The AMF enhancing practices used in the experiments (i.e., zero-tillage and inclusion of mycorrhizal crops) may have contributed to the lack of cover crop effect on AMF colonization. The cover crop had no effect on macro- or micronutrient uptake by flax except during drought conditions (Winnipeg 2006), where flax biomass was reduced by 38% and the total uptake of N, P, Zn and Cu was decreased by 34, 30, 31 and 35%, respectively, in the medic treatment.
  • Authors:
    • Negrisoli, E.
    • Crusciol, C. A. C.
    • Castro, G. S. A.
    • Perim, L.
  • Source: Planta Daninha
  • Volume: 29
  • Year: 2011
  • Summary: Tillage and other agricultural production systems can contribute to weed suppression. Thus, the objective of this study was to evaluate weed control using different grain production systems. The treatments were: I. "Harvest-fallow" System-soybean/fallow/corn/fallow/rice/fallow/soybean; II. "Harvest-green manure" System-soybean/millet/maize/pigeon pea/rice/Crotalaria/soybean; III. "Harvest-out of season" System-soy/white oats/corn/dry bean/rice/castor oil/soybean; and IV "Harvest-fodder" System-brachiaria + soy/corn + brachiaria/brachiaria + rice/soybeans. A weed survey was carried out in November 2009, after three growing seasons. A 0.3 x 0.3 m frame was randomly launched four times within each plot. The plants were identified, and the total number of weeds, dry weight, and control percentage of the species were determined according to the production system. The phytosociological analysis of the weed community was also conducted. The systems Harvest-green manure; Harvest-out of season and Harvest-fodder presented a good weed control when compared to the Harvest-fallow system. Therefore, the presence of some type of soil cover is important to maintain favorable soil characteristics and good weed control.
  • Authors:
    • Gupta, U. S.
  • Year: 2011
  • Summary: This volume looks at the use of crops for a myriad of purposes, including the prevention and/or mitigation of various diseases, vaccine and antigen production, biofuel production, and the the suppression of weeds. It explores new emnphasis on medicinal properties of crops and examines the use of genetic engineering in crop production. The crops discussed include: rice, wheat, barley, oat, rye, maize, sorghum, potato, sweet potato, cassava, Phaseolus beans, Vigna sp., broad bean, chickpea, tomato, broccoli, cauliflower, cabbage, bitter gourd, pumpkin, spinach, onion, soyabean, groundnut, oilseed Brassica, sunflower, sugarcane, cotton, and tobacco.