• Authors:
    • Risede, J.-M.
    • Foster, J.
    • Rhodes, R.
    • Berry, S. D.
    • van Antwerpen, R.
  • Source: International Journal of Pest Management
  • Volume: 57
  • Issue: 4
  • Year: 2011
  • Summary: Plant-parasitic nematodes cause significant yield losses to sugarcane crops in South Africa. The currently available chemicals for nematode control are both expensive and potentially detrimental to the environment. Various alternative crops have been reported to reduce the numbers of plant-parasitic nematodes. Mindful of this, we evaluated 27 cover crops in pot trials to assess their host status to important plant-parasitic nematodes of sugarcane. All of the crops tested in pots hosted significantly lower numbers of Pratylenchus than did sugarcane. Crops such as cowpeas, tomato and grazing vetch were good hosts for Meloidogyne and would not be good choices as part of a sugarcane rotation system in heavily-infested soils. Conversely, crops such as oats, wheat, forage peanuts and marigolds reduced numbers of Meloidogyne. Velvet beans increased the abundance of Helicotylenchus, a beneficial nematode genus. A field trial was also conducted to study the effect of different cover cropping sequences. Our results show that changes in nematode communities occurred within three months of growing these crops and often remained low for the duration (the remaining 15 months) of the crops' growth. Nematodes such as Pratylenchus and Tylenchorhynchus were significantly lowered and remained so for the duration of the trial.
  • Authors:
    • Maul, J. E.
    • Buyer, J. S.
    • Austin, E. E.
    • Treonis, A. M.
    • Spicer, L.
    • Zasada, I. A.
  • Source: Applied Soil Ecology
  • Volume: 46
  • Issue: 1
  • Year: 2010
  • Summary: Soil microorganisms (bacteria, fungi) and microfauna (nematodes, protozoa) have been shown to be sensitive to organic amendments, but few experiments have investigated the responses of all these organisms simultaneously and across the soil profile. We investigated the impact of organic amendment and tillage on the soil food web at two depths in a field experiment. Over three growing seasons, field plots received seasonal organic amendment that was either incorporated into the soil (tilled) or not (no-till) as part of a tomato/soybean/corn cropping system. Un-amended, control plots that were either tilled or no-till were also included. We hypothesized that the addition of amendments would have a bottom-up effect on the soil food web, positively influencing the abundance of microorganisms, protozoa, and nematodes, primarily in the surface layers of the soil, but that this effect could be extended into deeper layers via tillage. Organic amendment had positive effects on most measured variables, including organic matter, respiration, protozoan and nematode density, and the abundance of PLFA biomarkers for bacteria and fungi. These effects were more pronounced in the 0-5 cm depth, but most variables increased with amendment in the deeper layer as well, especially with tillage. Denaturing Gradient Gel Electrophoresis (DGGE) of bacterial rDNA fragments indicated that distinct bacterial communities were selected for among tillage and amendment treatments and depths. Nematode faunal indices were not influenced by amendment, however. Increased nematode density in amended soils encompassed all trophic groups of free-living nematodes, with the greatest response among fungal-feeders, particularly with tillage. Increased biomass of microorganisms and decomposer microfauna in amended, tilled soils (0-5 cm depth) corresponded with a decline in the abundance of plant-parasitic nematodes. In control soils (0-5 cm depth), tillage reduced the relative abundance of fungal-feeding nematodes and increased the density of bacterial-feeding nematodes, in particular nematode species contributing to the Enrichment Index. When combined with organic amendment however, tillage was associated with increases in fungal-feeding nematodes and fungal biomarker PLFA. The results of this study suggest that when combined with amendment, tillage enhances the soil food web beyond the effect of amendment alone and is associated with declines in plant-parasitic nematodes.
  • Authors:
    • Radicetti, E.
    • Mancinelli, R.
    • Campiglia, E.
    • Caporali, F.
  • Source: Crop Protection
  • Volume: 29
  • Issue: 4
  • Year: 2010
  • Summary: Cover crops and mulches are a suitable choice for sustainable agriculture because they improve weed control and crop performance. The aim of this research was to investigate weed control and nitrogen supply by using different winter cover crop species which were converted into mulches in spring. We carried out a 2-year field experiment where a tomato crop was transplanted into four different types of mulches coming from winter cover crops [(hairy vetch ( Vicia villosa Roth.), subclover ( Trifolium subterraneum L.), oat ( Avena sativa L.), and a mixture of hairy vetch/oat)] and in conventional treatment (tilled soil without mulch). The mixture of hairy vetch/oat cover crop produced the highest aboveground biomass (7.9 t ha -1 of DM), while the hairy vetch accumulated the highest N in the aboveground biomass (258 kg N ha -1). The oat cover crop was the most effective cover crop for suppressing weeds (on average -93% of weed aboveground biomass compared to other cover crops). After mowing the cover crop aboveground biomass was placed in strips as dead mulch into which the tomato was transplanted in paired rows. Weed density and total weed aboveground biomass were assessed at 15 and 30 days after tomato transplanting to evaluate the effect of mulches on weed control. All mulches suppressed weeds in density and aboveground biomass compared to the conventional system (on average -80% and -35%, respectively). The oat was the best mulch for weed control but also had a negative effect on the marketable tomato yield (-15% compared to the conventional treatment). Amaranthus retroflexus L. and Chenopodium album L. were typical weeds associated with the conventional treatment while a more heterogeneous weed composition was found in mulched tomato. Legume mulches, in particular hairy vetch, gave the best marketable tomato yield 28% higher than the conventional system both with and without nitrogen fertilization. This research shows that winter cover crops converted into dead mulch in spring could be used successfully in integrated weed management programs to reduce weed infestation in tomato crops.
  • Authors:
    • Crozat, Y.
    • Pineau, S.
    • Corre-Hellou, G.
    • Naudin, C.
    • Jeuffroy, M. H.
  • Source: Field Crops Research
  • Volume: 119
  • Issue: 1
  • Year: 2010
  • Summary: Cereal-legume intercrops are a promising way to combine high productivity and several ecological benefits in temperate agro-ecosystems. However, the proportion of each species in the mixture at harvest is highly variable. The aim of this study was to test whether the timing of small application of N fertilizer is an effective way of influencing the dynamic interactions between species during crop growth and affecting the percentage of each species in the biomass of the mixture without greatly disturbing N 2 fixation. The influence of timing of nitrogen fertilization in pea-wheat intercrops was studied as regards (i) the dynamics of crop growth, (ii) nitrogen acquisition of each species, (iii) the inhibition and recovery of symbiotic N 2 fixation (SNF) after N application and (iv) final performance (yield, % of wheat, grain protein content). This was assessed in winter pea-wheat ( Pisum sativum L.- Triticum aestivum L.) intercrops in 2007 and 2008 at two locations in France. Whatever the stage of application, N fertilizer tended to increase wheat growth and to decrease pea growth. N fertilization (applied once at different dates from tillering to the end of stem elongation) delayed the decrease in the contribution of wheat to total biomass and maintained the competitive ability of wheat over pea for longer than in unfertilized intercrops. N acquisition dynamics and N sharing between the two species were modified by N fertilization and its timing. Crop conditions at the time of N application (growth and phenology of each species, and their proportions in the intercrop biomass) greatly influenced intercrop response to N fertilization. Partitioning between species of soil and fertilizer N was correlated with the proportion of wheat in the total intercrop biomass observed at the date of N application. Short-term inhibition of nitrates on SNF was shown during the few days after N application, whatever its date. SNF recovery after N applications was observed only until pea flowering, but was prematurely stopped by N fertilization after this stage. The effect of N fertilization on the amount of fixed N 2 at harvest was correlated with pea biomass. N fertilization affects N 2 fixation mainly by affecting crop growth rather than %Ndfa in pea-wheat intercrops. In conclusion, N fertilization could be used as a tool to enhance the contribution of wheat in the intercrop biomass but may reduce the amount of fixed N 2 in the intercrop by decreasing pea biomass.
  • Authors:
    • Sakai, R. H.
    • Ambrosano, E. J.
    • Melo, P. C. T. de
    • Negrini, A. C. A.
    • Schammass, E. A.
    • Rossi, F.
  • Source: HORTICULTURA BRASILEIRA
  • Volume: 28
  • Issue: 1
  • Year: 2010
  • Summary: The performance of lettuce in sole and intercropped with green manures was assessed under different establishment times. The lettuce fresh and dry weight, number of leaves per plant, diameter and length of head, and fresh and dry weight of green manure were evaluated. The intercropping design was additive and both cash and cover crops were planted in rows. The experimental design was of randomized complete blocks in split plot scheme, with six replicates. The plots represented the green manure sowing days (0, 20, 40 and 60 before transplanting of lettuce), and the sub-plots were assigned by cropping systems (lettuce in sole crop and intercropped with black oat, cowpea or white lupin). Simultaneous planting in the intercropping did not affect the lettuce performance. However, when the green manures were sown before lettuce, they influenced it in a negative way. Among the green manures, cowpea increased biomass and had a higher negative effect on lettuce performance compared to white lupin, which appeared to produce less competition. The sole crop and the intercropping with simultaneous planting of the green manures resulted in a better lettuce performance.
  • Authors:
    • Ponizil, A.
    • Henriksen, B.
    • Pozdisek, J.
    • Hunady, I.
    • Loes, A. K.
  • Source: Vyzkum v Chovu Skotu
  • Volume: 52
  • Issue: 3
  • Year: 2010
  • Summary: Controlled field trials with legume-cereal mixtures and monocultures were conducted on five organic farms in CR, to determine the suitability for feeding ruminants. Mixtures of 60% peas to 40% cereals (wheat and barley) were compared with peas, wheat, and barley monocultures. The obtained results are useful to assess how mixtures may be included in animal feed rations. For feeding beef cattle, it is most beneficial to harvest green matter in the BBCH 79 growth phase (green ripeness), which is characterized by a higher protein and energy content and a lower fiber content. Advantageous crop for beef cattle appeared to be the mixture with peas and barley, because the crude protein and NEL contents come the closest to the requirements for a balanced state between breakdown and synthesis in the rumen (CP 130 g kg -1, NEL 5.9 MJ kg -1 DM). The results support that legume-cereal intercropping is a feasible technology to produce high quality feed on organic farms, which may provide animals with good health, and potential to utilize their genetic capacity for growth and production.
  • Authors:
    • Muller, C.
    • Amor, T.
  • Source: Agricultural Journal
  • Volume: 5
  • Issue: 2
  • Year: 2010
  • Summary: In this study, we estimate agricultural technology for Tunisian peasants, accounting for the crop choice of perasants and distinguishing inputs for individual crops such as: vegetable farming cereal and fruit-trees. The study employed the use of cross-section data from distinguishable irrigated crops survey conducted on a sample of 218 farmers frome 11 regions in Tunisia. The data were collected with the aid of structured questionnaire and were later analysed. The Cobb Douglass production frontier model is employed in order to analyse data collected. Among the irrigated crop farmers, the significant variables were: farmuar manuar fertiliser quantity, labor, mecanic traction and among of irrigated water applied. The estimated sigma square (sigma 2) and gamma (gamma) are widely significants for all irrigated crops and revealed that >85% of the variation in the Tunisian irrigated output among farmers in the study area are due to the differences in their efficiencies. Howerver, we find that predicted technical efficiency widely varies across farms and crops from an average of 54.7% for vegetable farming up to 80.6% for fruit-trees. The study also revealed the existing on inefficiency effects among the farmers as: education, farmer's age, irrigation techniques, lack of education, property of land.
  • Authors:
    • Pintar, M.
    • Tratnik, M.
    • Zupanc, V.
    • Cvejic, R.
  • Source: Novi izzivi v poljedelstvu 2010. Zbornik simpozija
  • Year: 2010
  • Summary: Optimal use of existing irrigation systems (IS) is as important as investments in new IS. Officially there are 52 IS in Slovenia, that are actively used, however less is known about how well they are being used. The paper overviews the cultures being represented on examined IS. The research, carried out for the period 2006-2009 indicates, that the examined IS are being used below its expected potentials. On average, the groups of cultures that are normally irrigated in Slovenia (orchards, ornamental plants, vegetables) cover 27% of the surface of IS, while the cultures that are normally not irrigated (forage crops, cereals, vineyards) cover 73%. The paper identifies the possible reasons for this situation, however further field research needs to be undertaken in the future to identify the influencing factors unambiguously and find possible solutions that would result in IS being used efficiently.
  • Authors:
    • Xanthoulis, D.
    • Heens, B.
    • Fonder, N.
  • Source: Biotechnologie, Agronomie, Société et Environnement
  • Volume: 14
  • Issue: S1
  • Year: 2010
  • Summary: Experiments were performed over four years, testing five cultivations to optimise mineral nitrogen fertilisation when irrigation with wastewater occurs. The experimental site was located inside an irrigated perimeter around the agro-food industry Hesbaye Frost, producing frozen vegetables, in Belgium. Depending on the crop rotation adopted by the farmer, four vegetable cultivations (spinach, bean, carrot and broad bean) and one cereal (winter wheat) were tested. Because of the time required for implementation of the experiment and meteorological conditions, the irrigation factor was not tested for spinach (1999) and wheat (2000) cultivations. The two experimental factors were three fertilisation levels, with comparison to a reference without any mineral nitrogen supply, and irrigation with or without wastewater. These factors were assessed for their impacts on crop yields and mineral nitrogen residues in the soil after harvest. The three vegetable cultivations of bean, carrot and broad bean were irrigated and systematically presented statistically higher yields with wastewater irrigation supply than without. The fertilisation factor also significantly improved all the yields, or protein rate for cereal cultivation, except for carrot and broad bean where differences were not significant, even for the zero fertilisation rate. The nitrogen residues in the soil after harvest were acceptable and regular as long as the fertilisation advice was not exceeded; the maximum fertilisation level tested, 50% higher than the recommendation, systematically left unacceptable nitrogen residues in the soil, harmful for the environment. Mainly located on the top surface horizon layers, the nitrogen residues could be held back by a catch crop classified as a nitrogen trap, with the condition to be set on late summer, with fall being considered as too late to have any influence to avoid nitrogen leaching. For all fertilisation levels, nitrogen residues were too high for the broad beans cultivation because of the phenomenon of surface mineral nitrogen release, due to meteorological conditions and the wastewater high nitrogen load brought by irrigation. The nitrogen residues under conditions of no irrigation were higher than under irrigation. Irrigation allowed better nitrogen solubility, easier for uptake by the plants and thus left fewer residues in the soil.
  • Authors:
    • Park, S. W.
    • Lee, H. P.
    • Sung, C. H.
    • Lee, S. B.
    • Jang, T. I.
  • Source: Paddy and Water Environment
  • Volume: 8
  • Issue: 3
  • Year: 2010
  • Summary: This article describes the pilot study on the water reuse for agricultural irrigation in Korea. The project is a part of the application of wastewater reuse system for Agriculture project, a 21st Century Frontier R&D Program sponsored by the Ministry of Education, Science, and Technology and associated with the Sustainable Water Resources Research Program. The goal of the project was to develop infra-technologies necessary to reclaim wastewater for irrigation in agriculture. The project involved two phases: laboratory and field research. Reclamation techniques for irrigation and feasible reuse were developed as a first step in proposing appropriate water quality standards. Reclaimed wastewater of various qualities was used to irrigate cereal crops and vegetables, and possible adverse effects on crops, humans, and the environment were investigated. The optimal reclamation methods required to satisfy water quality standards were explored and the operational characteristics investigated. Moreover, an inventory of farmlands that could reuse reclaimed wastewater was established. Feasible delivery systems for irrigation were developed, and pilot project sites were identified. Finally, operational field data from pilot units were collected and analyzed. This research and development may help solve water shortage problems in Korea, which left unaddressed will have an adverse effect on future generations.