• Authors:
    • Buatowicz, A.
    • Ozowicka, B.
  • Source: Progress in Plant Protection
  • Volume: 49
  • Issue: 3
  • Year: 2009
  • Summary: The analysis of data obtained following sample collection within the framework of agricultural product official inspection and the results of laboratory tests revealed that cereals and oilseed rape originated from north-eastern Poland fulfilled the requirements concerning pesticide residue content (i.e. without consumer health threat). Improper plant protection treatments inconsistent with the recommendations might lead to various ecotoxicological problems. Therefore, there is a need for continuous monitoring of pesticide residues in agricultural products and pesticide contamination of the natural environment to minimize consumer health risks.
  • Authors:
    • Murari, S.
    • Masri, S.
    • Ryan, J.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 40
  • Issue: 1/6
  • Year: 2009
  • Summary: Recent concerns about the role of carbon (C) in climate change and the implications about soil organic matter (SOM) for sustainable use of soils have underlined the need to examine the role of SOM in cropping systems, particularly in fragile ecosystems. Accordingly, we examined the changes that occur in total SOM and in its more reactive fractions, labile and biomass C, within a long-term, cereal-based crop rotation trial. The rotations were wheat ( Triticum turgidum var durum) grown after vetch ( Vicia sativa), medic ( Medicago sativa), chickpea ( Cicer arietinum), lentil ( Lens culinaris), fallow, a summer crop, melon ( Citrullus vulgaris), and after wheat (i.e., continuous wheat). Secondary treatments involved nitrogen (N) fertilizer application and variable grazing intensity. Uncropped microplots were established in the main rotation plots, and in the fallow and medic ones with variable grazing. Total SOM and labile and microbial biomass C were periodically measured in the rotations throughout the cropping season. Medic and vetch were highest in the three C forms, with fallow always lowest. All forms changed with sampling time throughout the season. Organic matter decreased from 1.48% in February to 1.15% in August after cropping. Although labile C followed a similar pattern, with a large falloff between the May and August sampling, biomass C increased initially, remained stable for a few months, and decreased at the last two samplings. Although all three C forms were highest in the zero-grazing in the fallow and medic rotations, the effect of grazing was not significant. Thus, although organic C can be built up in the soil to varying extents depending on the crop rotation, it is a dynamic entity, especially the labile and biomass fractions, having implications for crop growth and soil quality.
  • Authors:
    • Murari, S.
    • Pala, M.
    • Masri, S.
    • Ryan, J.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 40
  • Issue: 1/6
  • Year: 2009
  • Summary: Mediterranean agriculture is mainly rainfed, with drought being the main crop production constraint, and is based on cereals, wheat ( Triticum spp), and barley ( Hordeum vulgare). Fallow was a traditional practice to conserve soil moisture, but because of land-use pressure it is giving way to cereal monoculture, which is unsustainable. The substudy reported here was part of a long-term rotation trial that sought to examine alternative crop rotation options, that is, durum wheat ( T. durum var durum) in rotation with fallow, summercrop (melon, Citrullus vulgaris), wheat (continuous cropping), chickpea ( Cicer arietinum), lentil ( Lens culinaris), vetch ( Vicia sativa), and medic ( Medicago spp). Ancillary treatments involved nitrogen (N) applied to the cereal phase and variable stubble grazing intensity (stubble retention, medium grazing, and heavy grazing or complete stubble removal). This substudy, conducted in the final 3 years of the 14-year trial, involved sampling soil and plants within the cropped rotation plots and sampling soil within bare microplots in selected larger rotation plots. We measured N forms in soil samples at different depths and throughout the seasons. Despite variation within and between seasons, the rotation effect of enhanced N was significant and consistent, being highest for vetch and medic, intermediate for chickpea and lentil, and least for continuous cereal, summer crop, and fallow. Therefore, legume-based cereal rotations can enhance soil N and thus save on N fertilizer. In bare microplots, total N decreased, labile N was inconsistent, mineral N increased, and biomass N increased and remained stable during the cropping season and then sharply declined. The nutrient dynamic data complemented the crop yield, water-use efficiency, and soil aggregation data from the trial to support the argument for using legumes in cereal rotations in place of fallow and continuous cereal cropping.
  • Authors:
    • Machado, S.
    • Smiley, R.
  • Source: Plant Disease
  • Volume: 93
  • Issue: 3
  • Year: 2009
  • Summary: Wheat ( Triticum aestivum) in low-precipitation regions of eastern Oregon and Washington is grown mostly as rainfed biennial winter wheat (10-month growing season) planted into cultivated fallow (14-month crop-free period). There are increasing trends for cultivated fallow to be replaced by chemical fallow and for spring cereals to be planted annually without tillage. Most fields are infested by the root-lesion nematodes Pratylenchus neglectus or P. thornei. A replicated multiyear experiment was conducted to compare cropping systems on soil infested by P. neglectus. Populations became greater with increasing frequency of the host crops mustard, pea, and wheat. Annual winter wheat had the highest P. neglectus populations, the lowest capacity to extract soil water, and a lower grain yield compared with wheat grown biennially or rotated with other crops. Populations of P. neglectus did not differ for cultivated versus chemical fallow. Lowest populations occurred in annual spring barley. Winter wheat yield was inversely correlated with the population of P. neglectus. Measures to monitor and to reduce the population of P. neglectus in Pacific Northwest wheat fields are recommended.
  • Authors:
    • Bergtold, J. S.
    • Raper, R. L.
    • Price, A. J.
    • Kornecki, T. S.
  • Source: Applied Engineering in Agriculture
  • Volume: 25
  • Issue: 6
  • Year: 2009
  • Summary: In a weed-free field with ideal weather conditions, a cash crop can be planted 3 weeks after rolling a mature cereal rye winter cover crop without using herbicides. However, cloudy and wet weather can delay the rolling and/or desiccation of rye, thereby delaying cash crop planting which can negatively impact yield. One effective way to reduce the time between rolling and planting is to spray herbicide while rolling. However, a continuous spray may not be required if a roller/crimper is used due to the additive effect of the roller. Two different methods of applying glyphosate (Roundup (TM)) to rolled rye were compared. First, a felt strip saturated with herbicide was attached to the roller's crimping bar to provide glyphosate application with every crimp. The second method consisted of a boom (five nozzles controlled by solenoid valves) mounted on the roller applying a spray continuously, and intermittent spray every second crimp, or every fourth crimp. The average results over three growing seasons showed that 7 days after rolling, rye termination rates for all rolled/glyphosate treatments surpassed 90% (91% for glyphosate saturated felt strip and 98% for continuous spray), exceeding the termination rates for rye recommended to planting cash crops into rye residue cover. For the roller/crimper alone and the non-treated check (standing rye), termination rates were 82% and 54%, respectively. Since spraying glyphosate every fourth crimp provided a 93% termination rate one week after rolling, this method may facilitate planting the cash crop in a timely fashion while reducing input costs. Economic savings of $12.63 to $36.87 ha(1) may be attained by incorporating herbicide applications with rolling activities. One and two weeks after the rolling treatment, volumetric soil moisture content for all rolled rye/chemical treatments were significantly higher than the non-treated check.
  • Authors:
    • Jauhiainen, L.
    • Peltonen-Sainio, P.
    • Hakala, K.
  • Source: Agricultural and Food Science
  • Volume: 18
  • Issue: 3-4
  • Year: 2009
  • Summary: As the northern hemisphere will experience the greatest increases in temperature and indications of climatic change are already visible in the north (in the 2000s average temperatures exceeded the long-term mean), we sought to establish if there are already signs of increased variability in yield and quality of the major field crops grown under the northernmost European growing conditions: spring and winter cereals (barley Hordeum vulgare L., oat Avena saliva L., wheat Triticum aestivum L., rye Secale cereale L.), spring rapeseed (turnip rape Brassica rapa L., oilseed rape B. napus L.), pea (Piston sativum L.) and potato (Solanum tuberosum L.). We used long-term yield datasets of FAO for Finland (1960s to date) and MTT Agrifood Research Finland (MTT) Official Variety Trial datasets on yield and quality of major field crops in Finland since the 1970s. Yield variability was exceptionally high in the 1980s and 1990s, but previously and subsequently national yields were clearly more stable. No progressive increase in yield variability was recorded. No marked and systematic changes in variability of quality traits were recorded, except for rapeseed, which exhibited reduced variability in seed chlorophyll content. This may at least partly attribute to the differences in intensity of input use and thereby responsiveness of the crops before and after 1980 and 1990 decades. We also noted that in the 2000s average temperatures were higher than in earlier decades and this was the case for all months of the growing season except June, which represents, however, the most critical phase for yield determination in most of the field crops in Finland. Also in the 2000s precipitation increased in the first three months of the growing season and thereafter decreased, but without signs of significantly increased numbers of heavy showers (extreme rain events). Hence, in general constant, increased average temperatures during the growing seasons of the 2000s were identified, but with reduced yield variability, which was partly attributable to the diminished use of inputs, especially fertilisers.
  • Authors:
    • Deen, W.
    • Earl, H.
    • Queen, A.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 6
  • Year: 2009
  • Summary: Red clover (Trifolium pratense L.) use as an underseeded cover crop in winter cereals has declined due to inability of growers to consistently establish uniform stands. The objective of this study was to assess the effect of light and soil moisture competition on underseeded red clover establishment and end of season dry matter production. Field trials were conducted at multiple locations in 2005 and 2006 in Ontario, Canada. Wheat (Triticum aestivum L.) N rate (67 and 135 kg N ha(-1)) and row thinning treatments (19-cm rows, every third 19-cm row removed at the 4-5 leaf stage) were used to alter light penetration and soil moisture competition. The high N rate and row thinning treatments consistently reduced light penetration, beginning as early as wheat stem elongation initiation, but had no effect on soil gravimetric moisture content. Soil moisture was primarily affected by location and year. Red clover dry weight in 2005, a relatively dry year, ranged from 688 to 1184 kg ha(-1), and in 2006, a relatively wet year, ranged from 2336 to 2805 kg ha(-1). Average final red clover stand count was 23 plants m(-2) in 2005 and 55 plants m(-2) in 2006. In 2005, plant mortality occurred before wheat anthesis. In both years, and at most locations, red clover final dry weight was positively correlated with light penetration, again beginning as early as initiation of wheat stem elongation. Final red clover dry weight in both years and red clover stand count in 2005 were correlated with soil gravimetric water content during wheat anthesis, but this was primarily due to location and year effects. Although both light penetration through the wheat canopy and soil moisture influence biomass production of underseeded red Clover, soil moisture has the greater influence and is altered very little by wheat management.
  • Authors:
    • Hou, S. Y.
    • Riley, I. T.
    • Chen, S. L.
  • Source: Cereal Cyst Nematodes: Status, Research and Outlook: Proceedings of the First Workshop of the Cereal Cyst Nematode Initiative, 21-23 October, 2009, CIMMYT, Ankara, Turkey
  • Year: 2009
  • Summary: Cereal cyst nematode (Heterodera avenae) population densities were determined in spring cereals at harvest in two high-altitude villages in Qinghai, China in order to examine the effect of crop rotations. The two rotational systems sampled were wheat with rapeseed, broad bean and/or potato, and barley with rapeseed and/or oat. The previous season's crop, including fields where two host crops had been grown in succession, did not appear to influence the final nematode density. A high degree of variation in population density appeared to be strongly influenced by the occurrence of hyperparasites, thus masking any possible crop rotation effects. Nevertheless, a third of the fields had final egg densities greater than 10 eggs/g soil, creating a risk of yield loss if an intolerant host was to be grown in the next year. From the findings, it is suggested that future research should focus on developing locally adapted resistant cultivars and examining factors that determine the efficacy of natural biocontrol.
  • Authors:
    • Sim, R.
    • Maley, S.
    • Fletcher, A.
    • Ruiter, J. M. de
    • George, M.
    • de Ruiter, J. M.
  • Source: Proceedings of the New Zealand Grassland Association
  • Volume: 71
  • Year: 2009
  • Summary: Dairy industry strategies have demanded feeding systems with high productivity and high quality. A 45 t DM/ha annual target for feed production was addressed. Six crop sequence treatments were established in large plots (40*12 m) at Lincoln, Canterbury, in the first year of a 2-year experiment to determine practical upper limits for yield. Summer crops included maize, kale and whole crop barley and these were followed by combinations of winter crops (oats, Italian ryegrass, forage rape, tick beans and triticale). Crops were grown with minimal transition time to reduce potential yield losses, and with optimum nitrogen and irrigation management. Highest plot yield in the first annual crop cycle was 11.9 t DM/ha short of the 45 t DM/ha target. Best productivity was with a maize - triticale+tick bean (32.5 t DM/ha) sequence followed by maize - wheat (30.0 t DM/ha), barley - oats+Italian ryegrass (28.1 t DM/ha) and kale - triticale+tick bean (26.1 t DM/ha). Fertiliser management, crop water use in high input cropping systems are discussed together with practical issues around handling crops with large accumulated biomass.
  • Authors:
    • Fonseca, A. F. da
    • Alleoni, L. R. F.
    • Caires, E. F.
    • Churka, S.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 40
  • Issue: 17/18
  • Year: 2009
  • Summary: No-till (NT) system with crop rotation is one of the most effective strategies to improve agricultural sustainability in tropical and subtropical regions. To control soil acidity in NT, lime is broadcast on the surface without incorporation. The increase in soil pH due to surface liming may decrease zinc (Zn) availability and its uptake by crops. A field experiment was performed in Paran State, Brazil, on a loamy, kaolinitic, thermic Typic Hapludox to evaluate Zn bioavailability in a NT system after surface liming and re-liming. Dolomitic lime was surface applied on the main plots in July 1993 at the rates of 0, 2, 4, and 6 Mg ha -1. In June 2000, the main plots were divided in two subplots to study of the effect of surface re-liming at the rates of 0 and 3 Mg ha -1. The cropping sequence was soybean [ Glycine max (L.) Merrill] (2001-2 and 2002-3), wheat ( Triticum aestivum L.) (2003), soybean (2003-4), corn ( Zea mays L.) (2004-5), and soybean (2005-6). Soil samples were collected at the following depths: 0-0.05, 0.05-0.10, and 0.10-0.20 m, 10 years after surface liming and 3 years after surface re-liming. Soil Zn levels were extracted by four extractants: (i) 0.005 mol L -1 diethylenetriaminepentaacetic acid (DTPA)+0.1 mol L -1 triethanolamine (TEA)+0.01 mol L -1 calcium chloride (CaCl 2) solution at pH 7.3 (DTPA-TEA), (ii) 0.1 mol L -1 hydrochloric acid (HCl) solution, (iii) Mehlich 1 solution, and (iv) Mehlich 3 solution. Zinc concentrations in leaves and grains of soybean, wheat, and corn were also determined. Soil pH (0.01 mol L -1 CaCl 2 suspension) varied from 4.4 to 6.1, at the 0- to 0.05-m depth, from 4.2 to 5.3 at the 0.05- to 0.10-m depth, and from 4.2 to 4.8 at the 0.10- to 0.20-m depth, after liming and re-liming. Zinc concentrations evaluated by DTPA-TEA, 0.1 mol L -1 HCl, Mehlich 1, and Mehlich 3 solutions were not changed as a result of lime rate application. Re-liming increased Zn concentrations extracted by 0.1 mol L -1 HCl at 0-0.05 m deep and by DTPA-TEA at 0.05-0.10 m deep. Surface-applied lime promoted a decrease in Zn concentrations of the crops, mainly in grains, because of increased soil pH at the surface layers. Regardless of the liming treatments, levels of Zn were sufficient to soybean, wheat, and corn nutrition under NT.