• Authors:
    • Carbonell, R.
    • Rodriguez-Lizana, A.
    • Gonzalez, P.
    • Ordonez, R.
  • Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
  • Volume: 87
  • Issue: 2
  • Year: 2010
  • Summary: A common agricultural policy rule has banned the burning of wheat stubble. It might gradually increase the surface under no-till in Europe. The release dynamics of nutrients from the crop residues left on the soil surface has rarely been studied under Mediterranean climate conditions. As part of a long-term experiment started in 1982, a field study was carried out during the agricultural seasons 2001/2, 2002/3 and 2003/4, to determine the decomposition and nutrient release of above-ground residues deposited on a clayey soil in the south of Spain, in which a legume-cereal-sunflower rotation was followed. At the end of its decomposition cycle, the pea residue ( Pisum sativum L. cv. Ideal) had lost 60% of its initial mass, durum wheat ( Triticum durum L. cv. Amilcar) 35%, and sunflower ( Helianthus annus L. cv. Sanbro) 39%. The N release by the pea residue, wheat and sunflower was of 13.5, 6.7 and 8.5 kg ha -1, respectively. The P release was of 2.9 kg ha -1 (pea) and of 0.7 kg ha -1 (sunflower), and the highest content of released K was noted in the sunflower residue, 78 kg ha -1, compared to 22.5 kg ha -1 in wheat and 2.4 kg ha -1 in pea. In pea and sunflower, residue loss and N and P release in most cases followed simple linear and exponential functions, from which the specific decay rates were calculated. The decomposition rates of the different nutrients were higher than those of the residue in pea and sunflower, and the residue semi-decomposition periods, of 138 d in sunflower, and 191 d in pea, indicated a great persistence of the remains. The soil protection was acceptable in the case of wheat and sunflower, but not in pea. The application of the Douglas-Rickman model and the knowledge of the variation in the concentration of the nutrient in the crop remains permitted the estimation of the amount of N and P remaining in them over the intercropping period. In any case, in our climate and with soils rich in K, the release of nutrients from the residue, mainly N, is fairly scant and, in principle, does not seem to be of any interest in the fertilization programmes followed by the farmers in the area.
  • Authors:
    • Kadziuliene, Z.
    • Deveikyte, I.
    • Sarunaite, L.
  • Source: ZEMDIRBYSTE-AGRICULTURE
  • Volume: 97
  • Issue: 3
  • Year: 2010
  • Summary: The aim of the three-year study was to determine the impact of intercropping spring wheat with grain legumes on yield performance and stability, nitrogen use, weed control and grain quality. The experiment was carried out during 2007-2009 on a loamy Endocalcari-Epihypogleyic Cambisol ( CMg-p-w-can) in Dotnuva (55degrees24′N). Grain legumes: field pea ( Pisum sativum L.), lupin ( Lupinus angustifolius L.), bean ( Vicia faba L.), vetch ( Vicia sativa L.) and spring wheat ( Triticum aestivum L.) were sown as intercrops and sole crops and were grown organically for grain. The productivity of spring wheat sole crop or intercrops depended on the species of grain legume, however, the results varied over the experimental years. In 2007, the vetch and wheat intercrop produced a significantly higher grain yield than wheat in sole crop or in the other intercrops. In 2008, no advantages of legume and wheat intercrops were revealed. In 2009, the yield of sole legume crops was lower compared with the total wheat and legume intercrops. The concentration of crude protein was higher in grain yield, when spring wheat had been grown in intercrops. Vetch exhibited the best suppressing ability on weeds compared to all other grain legumes investigated. The total weed mass in spring wheat intercrops with grain legume was lower compared to that in the sole crops.
  • Authors:
    • Guiducci, M.
    • Tosti, G.
  • Source: European Journal of Agronomy
  • Volume: 33
  • Issue: 3
  • Year: 2010
  • Summary: Intercropping cereals and grain legumes is a common practice because of the advantages in N use, in pest and volunteer plant smothering, but when the grains need to be separated, there are several technical difficulties. These problems may be overcome by adopting a particular form of intercropping (termed "temporary intercropping") where the coexistence of the crops is limited to a portion of their life cycles. In a cereal-legume temporary row-intercropping, the legume component is ploughed into the soil before cereal shooting; thus the legume is used with a mere fertility purpose in order to improve N availability for the cereal component. The presence of such a positive effect, already confirmed in permanent intercropping, needs to be verified in temporary intercropping systems. In an organic farming system, a field experiment was carried out in two consecutive years (2005 and 2006) to evaluate the technical feasibility of a temporary intercropping between three varieties of durum wheat ( Triticum durum Desf.) and faba bean ( Vicia faba L. var. minor Beck.) and to test the effects on interspecific competition for light, N availability, cereal grain yield and quality. The species were temporarily intercropped following an additive design, and there was no fertilisation or crop protection. The N incorporated into the soil by the faba bean biomass was rather stable across years. The competitive effect of the legume reduced the biomass accumulation of the intercropped wheat, but the cereal N status was considerably improved. After the faba bean incorporation into the soil, the marked asymmetry of the temporary intercropped wheat (i.e. large inter-row space coupled with high plant density in the row) affected the radiation balance, nevertheless the yield was positively affected and the wheat grain protein content was increased to an excellent (from 12.0 to 13.9% in 2005) or a good (from 10.2 to 11.5% in 2006) level. Temporary intercropping was shown to be excellent method to improve the quality of organic durum wheat in the Mediterranean environmental conditions.
  • 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:
    • Bryan, B. A.
    • King, D.
    • Wang, E.
  • Source: Global Change Biology Bioenergy
  • Volume: 2
  • Issue: 6
  • Year: 2010
  • Summary: First-generation biofuels are an existing, scalable form of renewable energy of the type urgently required to mitigate climate change. In this study, we assessed the potential benefits, costs, and trade-offs associated with biofuels agriculture to inform bioenergy policy. We assessed different climate change and carbon subsidy scenarios in an 11.9 million ha (5.48 million ha arable) region in southern Australia. We modeled the spatial distribution of agricultural production, full life-cycle net greenhouse gas (GHG) emissions and net energy, and economic profitability for both food agriculture (wheat, legumes, sheep rotation) and biofuels agriculture (wheat, canola rotation for ethanol/biodiesel production). The costs, benefits, and trade-offs associated with biofuels agriculture varied geographically, with climate change, and with the level of carbon subsidy. Below we describe the results in general and provide (in parentheses) illustrative results under historical mean climate and a carbon subsidy of A$20 t−1 CO2−e. Biofuels agriculture was more profitable over an extensive area (2.85 million ha) of the most productive arable land and produced large quantities of biofuels (1.7 GL yr−1). Biofuels agriculture substantially increased economic profit (145.8 million $A yr−1 or 30%), but had only a modest net GHG abatement (−2.57 million t CO2−e yr−1), and a negligible effect on net energy production (−0.11 PJ yr−1). However, food production was considerably reduced in terms of grain (−3.04 million t yr−1) and sheep meat (−1.89 million head yr−1). Wool fiber production was also substantially reduced (−23.19 kt yr−1). While biofuels agriculture can produce short-term benefits, it also has costs, and the vulnerability of biofuels to climatic warming and drying renders it a myopic strategy. Nonetheless, in some areas the profitability of biofuels agriculture is robust to variation in climate and level of carbon subsidy and these areas may form part of a long-term diversified mix of land-use solutions to climate change if trade-offs can be managed.
  • Authors:
    • Radford, B. J.
    • Thornton, C. M.
    • Huth, N. I.
    • Thorburn, P. J.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 136
  • Issue: 3-4
  • Year: 2010
  • Authors:
    • Caesar-TonThat, T.
    • Wright, S. F.
    • Sainju, U. M.
    • Kolberg, R.
    • West, M.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a Changing World, Brisbane, Australia, 1-6 August 2010. Congress Symposium 2: Soil ecosystem services
  • Year: 2010
  • Summary: Lentil ( Lens culinaris Medikus CV. Indianhead) used to replace fallow in spring-wheat ( Triticum aestivum) rotation in the semi-arid Eastern Montana USA, may improve soil quality. We evaluate the 14 years influence of continuous wheat under no-tillage (WNT), fallow-wheat under conventional tillage (FCT) and no-tillage (FNT), lentil-wheat under tillage (LCT) and no-tillage (LNT) on soil formation and stability, and on the amount of immunoreactive easily-extractable glomalin (IREEG) and soil aggregating basidiomycete fungi in the 4.75-2.00, 2.00-1.00, 1.00-0.50, 0.50-0.25, and 0.25-0.00 mm aggregate-size classes, at 0-5 cm soil depth. The 4.75-2.00 mm aggregate proportion was higher in LNT than FNT and higher in LT than FT treatments and mean weight diameter (MWD) was higher when lentil was used to replace fallow under NT. No-till systems had higher glomalin and basidiomycete amount than CT in all aggregate-size classes and glomalin was higher in LNT than FNT in aggregate-size classes less than 0.50 mm. We conclude that residue input in NT systems triggers fungal populations which are involved in soil binding in aggregates, and that replacing fallow by lentil in spring wheat rotation in dryland seems to favor aggregate formation/stability under NT probably by increasing N fertility during the course of 14 years.
  • Authors:
    • DeHaan,L. R.
    • Cox,C. M.
    • Tassel,D. L. van
    • Cox,T. S.
  • Source: Crop & Pasture Science
  • Volume: 61
  • Issue: 7
  • Year: 2010
  • Summary: Annual cereal, legume and oilseed crops remain staples of the global food supply. Because most annual crops have less extensive, shorter-lived root systems than do perennial species, with a correspondingly lower capacity to manage nutrients and water, annual cropping systems tend to suffer higher levels of soil erosion and generate greater water contamination than do perennial systems. In an effort to reduce soil degradation and water contamination simultaneously - something that neither no-till nor organic cropping alone can accomplish - researchers in the United States, Australia and other countries have begun breeding perennial counterparts of annual grain and legume crops. Initial cycles of hybridization, propagation and selection in wheat, wheatgrasses, sorghum, sunflower and Illinois bundleflower have produced perennial progenies with phenotypes intermediate between wild and cultivated species, along with improved grain production. Further breeding cycles will be required to develop agronomically adapted perennial crops with high grain yields.
  • Authors:
    • Ghosh, P. K.
    • Das, A.
    • Saha, R.
    • Kharkrang, E.
    • Tripathi, A. K.
    • Munda, G. C.
    • Ngachan, S. V.
  • Source: Current Science
  • Volume: 99
  • Issue: 7
  • Year: 2010
  • Summary: Productivity of rainfed monocropping farming system in North Eastern Region of India is low and it is a high economic risk activity. Intensive natural resources mining, continuous degradation of natural resources (soil, water, vegetation) and practice of monocropping under conventional agricultural practices will not ensure farm productivity and food security in the coming years. In order to keep the production system in different land situations sustainable, conservation agriculture based on no-till system is an alternative to reconcile agriculture with its environment and overcome the imposed constraints of climate change and continuous inputs cost. Studies on conservation tillage and residue management in different land situations were conducted during 2006-2009 and they are highlighted in this article. In terrace upland, growing mustard completely on residual moisture following upland rice/maize was possible when it is practised under conservation tillage (crop residue of all crops, including weed biomass incorporated). Similarly, in valley upland, growing second crop of pea in rice fallow is possible if two-thirds or half of rice residues are retained on the soil surface under zero tillage. A long-term study (2006-2009) revealed that double no-till practice in rice-based system is cost-effective, restored soil organic carbon (70.75%), favoured biological activity (46.7%), conserved water and produced yield (49%) higher than conventional tillage. Therefore, conservation tillage practised in terrace upland, valley upland and low-land situations ensured double-cropping, improved farm income and livelihood in rainfed NE India.
  • Authors:
    • Horwath, W. R.
    • Rolston, D. E.
    • Kallenbach, C. M.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 137
  • Issue: 3
  • Year: 2010
  • Summary: Agricultural management practices such as subsurface drip irrigation (SDI) and winter legume cover cropping (WLCC) influence soil water dynamics as well as carbon and nitrogen cycling, potentially changing emission rates of soil CO2 and N2), principal greenhouse gases. A split plot tomato field trial in California's Central Valley was used to evaluate the use of SDI and WLCC on event-based CO2 and N2O emissions. SDI and WLCC were compared to the region's more conventional practices: furrow irrigation (FI) and no cover crop (NCC). Our results indicate that SDI offers the potential to manage cover crops without the significant increases in greenhouse gas production during the growing season as seen under FI cover-cropped systems. The highest N2O emissions occurred during the beginning of the rainy season in November in the FI-WLCC treatment(5 mg m-2 h-1) and the lowest in August in the SDI-NCC treatments (4.87 [micro]g m-2 h-1). CO2 emissions under WLCC were 40% and 15% greater compared to NCC under FI and SDI, respectively. The treatment with the greatest effect on CO2 and N2O emissions was WLCC, which increased average growing season N2O and CO2 emissions under FI by 60 [micro]g N2O m-2 h-1 and 425 mg CO2 m-2 h-1 compared to NCC. In SDI there was no effect of a cover crop on growing season CO2 and N2O emissions. In the rainy season, however, SDI N2O and CO2 emissions were not different from FI. In the rainy season, the cover crop increased N2O emissions in SDI only and increased CO2 emissions only under FI. Subsurface drip shows promise in reducing overall N2O emissions in crop rotations with legume cover crops.