• Authors:
    • Pimentel, I.
    • Gabardo, J.
    • Brondani, G.
    • Dionisio, J.
    • Motta, A.
    • Roveda, L.
    • Cuquel, F.
  • Source: Revista Brasileira de Agrociencia
  • Volume: 17
  • Issue: 3
  • Year: 2011
  • Summary: The reuse of industrial waste with low potential contaminant in agriculture is an important option for final disposal. To evaluate the agronomic potential of waste liquid from the production of enzymes (WLPE), set up an experiment in a Cambissoil cultivated under no tillage. There were two treatments (with and without the addition of 50 m 3 of WLPE). It was evaluated in soil pH CaCl 2, (H+Al), P, K, Ca, Mg and V% in 4 depths and in three samples of soil. The effects of three successive crops on the yield and nutrient content in the tissue: black bean ( Phaseolus vulgaris), a consortium of oat ( Avena strigosa)+forage turnip ( Raphanus sativus) and maize ( Zea mays L.). Increases in soil available P were observed, there were no changes in pH, (H+Al), K, Ca, Mg and V% using RLPE, and this provided no change in productivity in beans and corn, but a large increase in productivity and cycling of nutrients in plant cover (oat+turnip forage) were observed. There was no change in the concentration of nutrients in plant tissue of beans and oats+turnip indicating changes in nutritional status. The RLPE presented as an alternative for the supply of P, growth and cycling of nutrients in oats+turnip.
  • Authors:
    • Carneiro, L.
    • Furtini Neto, A.
    • Silva, T.
    • Paludo, V.
  • Source: SEMINA-CIENCIAS AGRARIAS
  • Volume: 32
  • Issue: 4
  • Year: 2011
  • Summary: This work aimed to evaluate biomass production and phosphorus uptake by cover crops growing in two different soil types fertilized with two different sources of phosphorus. The experiment was carried out under greenhouse condition, at the Department of Soil Science, Federal University of Lavras. The experimental set up was a completely randomized design, in a 5*2*2 factorial scheme, testing five cover crops ( Brachiaria decumbens, Brachiaria brizantha cv. Marandu, Panicum maximum cv. Tanzania, Avena strigosa - oat cv. Common and Lupinus albus L. - lupine cv. Common), two P fertilizers (triple superphosphate - ST and rock phosphate araxa - FA), and two soil types (Oxisol - LVdf and Entisol - RQo), with four replications. Doses of phosphate used were 90 and 50 mg.dm -3 of P, based on the total P 2O 5 in LVdf and RQo, respectively. Plants were harvested 70 days after seedling emergence. In both soils, shoot and root biomass was higher in the ST treatment than in FNA treatment. This was probably due to the higher P accumulation in the plants. Satisfactory vegetative cover was observed when oat was cultivated using ST as a P source. For lupine, best results were obtained using FA as a P source.
  • Authors:
    • Weeks, A.
    • Hoffmann, A.
    • Tsitsilas, A.
    • Umina, P.
  • Source: Australian Journal of Entomology
  • Volume: 50
  • Issue: 1
  • Year: 2011
  • Summary: Non-crop vegetation adjacent to broad-acre pastures and crops can influence the abundance of invertebrate pests by promoting populations of beneficial natural enemies. However, characteristics of adjoining vegetation that consistently promote natural enemies are often unknown. Here we manipulate the height of grasses and herbaceous plants within windbreaks at five geographically separated sites in south-eastern Australia to examine the effects of on-ground vegetation structure on the abundance of pest mites and natural enemy complexes. Reducing the height and cover of vegetation across 2 years led to decreased numbers of predatory mites, predatory beetles and spiders within windbreaks and at sites 5 m from the windbreak edge within adjacent pastures. There was also an associated increase in numbers of pest earth mites, the redlegged earth mite ( Halotydeus destructor) and blue oat mites ( Penthaleus spp.). Similar findings were found in manipulative experiments under semifield conditions using microcosms. These results suggest that an increase in height and perhaps complexity of groundcover act to promote populations of beneficial natural enemies with potential suppression of pest mite species. These findings point to a simple way for increasing populations of beneficial invertebrate species at the farm scale that could contribute to integrated pest management programs.
  • Authors:
    • Muys, B.
    • Hermy, M.
    • Govers, G.
    • Pina, A.
    • Valckx, J.
  • Source: Pedobiologia
  • Volume: 54
  • Issue: Supplement 1
  • Year: 2011
  • Summary: Some of the widely used cover crops in temperate agroecosystems (including species of the Brassicaceae and Poaceae) have been shown to exhibit allelopathic effects. In particular, various Brassicaceae have been reported to act as biofumigants against a variety of soil-borne pests through the release of i.a. isothiocyanates (ITC) from glucosinolate precursors. Although these allelochemicals may potentially reduce the need for application of synthetic pesticides, their effects on beneficial soil ecosystem engineers such as earthworms (Lumbricidae) have not been assessed yet. Food choice chambers were used to assess short-term food preferences of Lumbricus terrestris L. for lacy phacelia ( Phacelia tanacetifolia BENTH.), the Poaceae Italian ryegrass ( Lolium multiflorum LAM.) and oats ( Avena sativa L.), and the Brassicaceae yellow mustard ( Sinapis alba L.) and rapeseed ( Brassica napus L.) while litter bags were used to study long-term litter preference under field conditions. Habitat preference of L. terrestris was determined through simple habitat preference units. Ryegrass residues were a preferred food resource, both in fresh and partly decomposed state, over mustard, phacelia or rapeseed residues, and these were in turn more fed on than oats. Litter disappeared at a fast and variable rate from litter bags under field conditions. No clear relationships with residue C:N ratio were observed. Habitats in which living oat plants were present were avoided in comparison to habitats with bare soil or yellow mustard plants. In conclusion, brassicaceous cover crops are not preferred nor avoided by L. terrestris compared to the other cover crops in this study. Decreased ITC release and earthworm exposure under field conditions may further lower the risk of harmful effects, but further research on the long-term impact is needed.
  • Authors:
    • Topp, C.
    • Walker, R.
    • Rees, R.
    • Edwards, A.
    • Baddeley, J.
    • Watson, C.
  • Source: Organic Agriculture
  • Volume: 1
  • Issue: 3
  • Year: 2011
  • Summary: The ability to maintain crop yield and quality in systems based on nitrogen (N) fixed by legumes rather than from synthetic N fertilisers is fundamental to the long-term viability of organic farming. This paper reports crop yield and nitrogen uptake parameters for the first spring oat crop after grass/clover ley in organically managed ley/arable rotations to indicate the amount of fertility built-up during the ley period. The trial site, at Tulloch in North East Scotland, underwent two complete cycles of 6-year ley/arable rotations with different lengths of grazed ley (3 or 4 years). Trials were sufficiently replicated so that each course of the rotation was present in every year. The rotation containing 3 years of ley was also compared with a similar rotation at a nearby site (Woodside) with lower rainfall and soil fertility over one and a half rotational cycles. Grain yields were consistently higher at Tulloch (5.1 tha -1 compared with 4.5 tha -1 at Woodside) and were unaffected by the length of ley. However, grain N percentage was higher following the 4-year ley (1.38% compared with 1.30% following the 3-year ley). While yields were maintained between the first and second cycles of all the rotations, grain N percentage declined. Annual grain yields of the organically grown oats at Tulloch were not significantly different from National List/Recommended List yields in NE Scotland for oats receiving 100 kg N ha -1. Results suggest that these particular rotation designs were suitable for maintaining acceptable grain yields under organic management conditions.
  • Authors:
    • Jansirani, R.
  • Source: Journal of Cotton Research and Development
  • Volume: 25
  • Issue: 2
  • Year: 2011
  • Summary: The study was conducted at Kovilpatti block of Tuticorin district of Tamil Nadu with the specific objective of studying extent of adoption of production technologies in Bt cotton by the growers. The area was selected based on the major cultivation of Bt areas and production of Bt cotton under irrigated condition. The selected respondents for this study were 90, who have adopted Bt cotton and non Bt cotton i.e 45 growers in each category by using simple random sampling method. The collected data were analyzed using percentage analysis. All the growers adopted Bt varieties and 95.55 per cent of the growers adopted appropriate time of planting. About 80.00 per cent of the growers adopted spacing. Three fourths (77.77%) of the growers adopted regular plucking intervals during harvest and 75.55 per cent of the growers adopted proper irrigation management followed by pest and diseases management (73.33%). More than fifty (66.66%) of the growers adopted preparation of fields to required tilth and formation of trenches followed by manures and fertilizers (62.22%) and number of split doses (57.77%). Out of ten technologies nine technologies were adopted more than fifty per cent by the growers due to the reasons that private firms have agreed to buy the produce from the farmers offering a minimum support prices. State Department of Agriculture has also introduced contract farming to assure remunerative prices to farmers.
  • Authors:
    • Armengot, L.
    • Blanco-Moreno, J. M.
    • Jose-Maria, L.
    • Xavier Sans, F.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 145
  • Issue: 1
  • Year: 2011
  • Summary: Agricultural intensification, at local and landscape scales, has caused a decrease in plant diversity and changes in species composition in cereal fields. To better understand the role of landscape complexity and farming systems in shaping plant assemblages, it is of interest to focus on functional traits rather than on floristic composition, which may help to highlight trends in vegetation patterns. We analysed the relative abundance of various functional attributes (different life forms, growth forms, wind-pollinated species and wind-dispersed species) at three contrasted field positions (boundary, edge and centre) of 29 organic and 29 conventional cereal fields distributed in 15 agrarian localities of NE Spain. Agricultural intensification affected the biological attributes of the vegetation in dryland Mediterranean cereal fields; local factors (farming system and position) had a more prominent role in affecting plant functional composition than the surrounding landscape. Local factors were important for life form distribution, growth form and pollination type, whereas landscape complexity mainly affected the proportion of wind-dispersed species. Therefore, depending on the objective of the study, it is important to select functional attributes sensitive to the different scales of agricultural intensification, especially because landscape complexity and land-use intensity are commonly related.
  • Authors:
    • José-María, L.
    • Sans, F. X.
  • Source: Weed Research
  • Volume: 51
  • Issue: 6
  • Year: 2011
  • Summary: Weed seedbanks are a reserve of weed diversity and can contribute to the prediction of future weed problems in arable fields. Managing seedbanks should therefore help in optimising biodiversity and controlling weed infestations. This study assessed the effects of management system (organic vs. conventional) and landscape complexity on seedbank size and species richness at the edges and centres of Mediterranean dryland cereal fields and examines the relationship between specific management practices and seedbanks. Field edges and organic fields had more species-rich, denser seedbanks than field centres and conventional fields, and landscape complexity had a limited effect on arable seedbanks. Accordingly, the promotion of low-intensity farming practices regardless of landscape complexity, especially at field edges, would be an effective measure for conservation purposes in Mediterranean agroecosystems. Nevertheless, the high seed density of organic seedbanks reveals the need for more effective seedbank management. The analysis of the effects of specific management practices highlights the importance of cleaning crop seeds properly to reduce seedbank size and using complex rotations, especially as this tends to conserve species richness while reducing seed abundance.
  • Authors:
    • Askegaard, M.
    • Olesen, J. E.
    • Kristensen, K.
    • Rasmussen, I. A.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 142
  • Issue: 3-4
  • Year: 2011
  • Summary: Two main challenges facing organic arable farming are the supply of nitrogen (N) to the crop and the control of perennial weeds. Nitrate leaching from different organic arable crop rotations was investigated over three consecutive four-year crop rotations in a field experiment at three locations in Denmark (12 years in total). The experimental treatments were: (i) crop rotation, (ii) catch crop and (iii) animal manure. Nitrate leaching was estimated from measured soil nitrate concentration in ceramic suction cells and modelled drainage. There were significant effects on annual N leaching of location (coarse sand > loamy sand > sandy loam) and catch crops (without > with). Including a grass-clover green manure on 25% of the area did not increase N leaching compared with crop rotations without green manure. Also the application of animal manure did not influence N leaching, probably because even in the manured treatments the application rate was lower than crop demand. The results identify management of crop and soil during autumn as the main determinant of N leaching. Nitrate leaching was lowest for a catch crop soil cover during autumn and winter (avg. 20 kg N ha -1), a soil cover of weeds/volunteers had on avg. 30 kg N ha -1, and the largest N leaching losses were found after stubble cultivation (avg. 55 kg N ha -1). The N leaching losses increased with increasing number of autumn soil cultivations.
  • Authors:
    • Eckard, R. J.
    • Browne, N. A.
    • Behrendt, R.
    • Kingwell, R. S.
  • Source: Animal Feed Science and Technology
  • Volume: 166-167
  • Year: 2011