• Authors:
    • Maeder, P.
    • Niggli, U.
    • Wiemken, A.
    • Burger, D.
    • Berner, A.
    • Krauss, M.
  • Source: Soil Use and Management
  • Volume: 26
  • Issue: 1
  • Year: 2010
  • Summary: To promote conservation tillage in organic farming systems, weed control and ley removal within arable-ley rotations need to be optimized. A long-term field trial was thus established in Frick, Switzerland in 2002 on a clayey soil and with a mean precipitation of 1000 mm/year. The tillage experiment distinguished between conventional tillage with mouldboard ploughing (CT, 15 cm depth) and reduced tillage (RT), including a chisel plough (15 cm) and a stubble cleaner (5 cm). Results of a 2-year grass-clover ley (2006/2007) and silage maize (2008) are presented. Due to dry conditions, mean grass-clover yields were 25% higher in RT than in CT, indicating better water retention of RT soils. Clover cover and mineral contents of the fodder mixture were also higher in RT. The ley was successfully removed in autumn 2007 in RT plots, and a winter pea catch crop was sown before maize. In CT, ploughing took place in spring 2008. Maize yields were 34% higher in RT than in CT, despite a two- to three-fold higher but still tolerable weed infestation. Maize in RT plots benefited from an additional 61.5 kg of easily decomposable organic N/ha incorporated into the soil via the pea mulch. Measurement of arbuscular mycorrhizal colonization of maize roots indicated a similar mechanical disturbance of the topsoil through the reduced ley removal system compared with ploughing. It is suggested that RT is applicable in organic farming, even in arable-ley rotations, but long-term effects need further assessment.
  • Authors:
    • Bidders, C. L.
    • Laloy, E.
  • Source: Journal of Environmental Quality
  • Volume: 39
  • Issue: 3
  • Year: 2010
  • Summary: The management of winter cover crops is likely to influence their performance in reducing runoff and erosion during the intercropping period that precedes spring crops but also during the subsequent spring crop This study investigated the impact of two dates of destruction and burial of a rye (Secale cereale L.) and ryegrass (Lolium multifloruni Lint) cover crop on runoff and erosion, focusing on a continuous silage maize (Zea mays L) cropping system Thirty erosion plots with various intercrop management options were monitored for 3 yr at two sues. During the intercropping period. cover crops reduced runoff and erosion by more than 94% compared with muffled, post-maize harvest plots Rough tillage after maize harvest proved equally effective as a late sown cover crop There was no effect of cover crop destruction and burial dates on runoff and erosion during the intercropping period. probably because rough tillage for cover crop burial compensates for the lack of soil cover During two of the monitored maize seasons. it was observed that plots that had been covered during the previous intercropping period lost 40 to 90% less soil compared with maize plots that had been left bare during the intercropping period The burial of an aboveground cover crop biomass in excess of 1 5 t ha (1) was a necessary, yet not always sufficient. condition to induce a residual effect. Because of the possible beneficial residual effect of cover crop burial on erosion reduction, the sowing of a cover crop should be preferred over rough tillage after maize harvest
  • Authors:
    • Lehoczky, É.
    • Kismányoky, A.
  • Source: Agrokémia és Talajtan
  • Volume: 59
  • Issue: 1
  • Year: 2010
  • Summary: A long-term soil tillage experiment was conducted in 2005 to 2008 on a Ramann-type brown forest soil (Eutric Cambisol) in Keszthely, Hungary, with different cultivation methods (no-till, drill, disc tillage, conventional tillage (ploughing)) and five increasing N doses. Treatment A was the cultivation method: conventional tillage (ploughing), no-till, drill, disc tillage; and Treatment B was N fertilizer application: N 0-N 4 (0, 120, 180, 240 and 300 for maize, and 0, 120, 160, 200 and 240 kg/ha per ton for wheat, respectively). Both plots received a blanket application of 100 kg P 2O 5/ha and 100 kg K 2O/ha. With soil cultivation and N fertilization treatments, winter wheat yield varied between 2.5 and 6.0, while maize yield ranged from 6 to 10 t/ha. The influence of the annual circumstances (mostly rainfall) on the yields was measurable and from time to time statistically significant. The different amounts of N fertilizer significantly increased the yields of maize and wheat. The highest increases were found in the case of N 1 and N 2 treatments. The maximum yields of maize and wheat were obtained with the 200-250 kg N/ha doses. On the average of years, the largest weed cover (28%) was recorded in the no-tillage treatment, while the ploughing system was the least weedy (10-15%).
  • Authors:
    • Di Tizio, A.
    • Campiglia, E.
    • Mancinelli, R.
    • Marinari, S.
  • Source: Applied Soil Ecology Volume 46, Issue 1, September 2010, Pages
  • Volume: 46
  • Issue: 1
  • Year: 2010
  • Summary: Carbon sequestration in soil is an important means for reducing net emissions of CO(2) into the atmosphere. We hypothesized that organic cropping systems (ORG) would reduce soil CO(2) emission and increase C storage compared to conventional cropping systems (CONV). The objectives of this study were to: (i) analyze the ORG and CONV systems in terms of soil CO(2) emission and soil C balance and (ii) establish if the soil in the ORG and CONV systems represents a source or a sink of C. A3-year crop rotation (durum wheat-Triticum durum Desf., tomato - Licopersicum esculentum Mill., and pea - Pisum sativum L) was carried out in both cropping systems, but the crop rotation was implemented with common vetch (Vicia sativa L.) before tomato planting and sorghum (Sorghum bicolor (L) Moench.) before pea sowing and both green manured only in the ORG system. It was found that the soil CO(2) emission rate at peak times (in spring or at the end of summer - beginning of autumn) in the ORG system was higher than the CONV system. The peak of CO(2) was attributed to the fact that at this time the soil temperature and the relative soil water content (RWC) were probably in the optimal range for soil respiration (17.2 degrees C and 36.4% of RWC) and the difference between ORG and CONV was probably due to the green manuring of the cover crops in the ORG system. However, even if the cropping systems had a temporary impact on the rate of soil CO(2) emissions, the soil C output calculated as the average of cumulative CO(2) emission over the 3-year period did not show significant differences between the ORG and CONV systems (8.98 Mg C-CO(2) ha(-1) vs. 8.06 Mg C-CO(2) ha(-1)). On the other hand, the C input in the ORG system was higher than in the CONV (9.46 Mg C ha(-1) vs. 5.57 Mg C ha(-1)) as well as the C input/output ratio (1.10 vs. 0.72). The 3-year average of TOC content and C stock were higher in the ORG than in the CONV system (1.24% vs. 1.10% and 27.4 Mg C ha(-1) vs. 23.9 Mg C ha(-1), respectively). However, the decrease of TOC and C stock over 3 years period suggested that further studies over a longer period are needed to verify if C limitation for soil microbial growth and nitrogen limitation for crop growth in the organic system could hinder soil C accumulation over a longer period. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Vigil, M. F.
    • Benjamin, J. G.
    • Mikha, M. M.
    • Nielson, D. C.
  • Source: Soil Science Society of America journal
  • Volume: 74
  • Issue: 5
  • Year: 2010
  • Summary: The predominant cropping system in the Central Great Plains is conventional tillage (CT) winter wheat ( Triticum aestivum L.)-summer fallow. We investigated the effect of 15 yr of cropping intensities, fallow frequencies, and tillage (CT and no-till [NT]) practices on soil organic C (SOC) sequestration, particulate organic matter (POM), and wet aggregate-size distribution. A crop rotation study was initiated in 1990 at Akron, CO, on a silt loam. In 2005, soil samples were collected from the 0- to 5- and 5- to 15-cm depths in permanent grass, native prairie, and cropping intensities (CI) that included winter wheat, corn ( Zea mays L.), proso millet ( Panicum miliaceum L.), dry pea ( Pisum sativum L.), and summer fallow. The native prairie was sampled to provide a reference point for changes in soil parameters. The most intensive crop rotation significantly increased C sequestration compared with the other CIs where fallow occurred once every 2 or 3 yr. Legume presence in the rotation did not improve SOC sequestration relative to summer fallow. Significant amounts of macroaggregates were associated with grass and intensive cropping compared with the rotations that included fallow. Reduced fallow frequency and continuous cropping significantly increased soil POM near the surface compared with NT wheat-fallow. Macroaggregates exhibited a significant positive relationship with SOC and POM. A significant negative correlation was observed between microaggregates and POM, especially at 0- to 5-cm depth. Overall, a positive effect of continuous cropping and NT was observed on macroaggregate formation and stabilization as well as SOC and POM.
  • Authors:
    • Lang, J. M.
    • Ebelhar, S. A.
    • Olson, K. R.
  • Source: Soil Science
  • Volume: 175
  • Issue: 2
  • Year: 2010
  • Summary: An 8-year cover crop study was conducted in southern Illinois to evaluate the effects of conservation tillage systems on corn and soybean yields and for the maintenance and restoration of soil organic carbon (SOC) and soil productivity of previously eroded soils. In 2001, the no-till (NT), chisel plow, and moldboard plow (MP) treatment plots, which were replicated six times in a Latin square design, were split (with cover crop and without) on sloping, moderately well-drained, moderately eroded soil. The average corn and average soybean yields were similar for NT, chisel plow, and MP systems with and without cover crops. By 2009, the tillage zone, subsoil, and rooting zone of all treatments had similar SOC on a volume basis for the cover crop treatments as for the same tillage treatment without a cover crop. However, using the baseline 2000 SOC contents only, the NT with cover crops maintained most of the SOC levels in the topsoil and subsoil during the 8-year study, when the sediment was high in SOC and retained in the upland landscape by soil conservation practices, including border and filter strips and sod waterways adjacent to the plots, with and without cover crops. Soil carbon creation retention in the upland landscape was greatest for the MP treatments when sediments were retained by the soil conservation practices, which should reduce soil erosion and sediment rich in SOC being transported by overland flow into water and the eventual release of methane and carbon dioxide to the atmosphere.
  • Authors:
    • Dagar, J. C.
    • Chaudhari, S. K.
    • Pandey, C. B.
    • Singh, G. B.
    • Singh, R. K.
  • Source: Soil & Tillage Research
  • Volume: 110
  • Issue: 1
  • Year: 2010
  • Summary: Tillage is known to reduce soil organic carbon (SOC) and increase soil N mineralization, but information on the level of tillage that increases net soil N mineralization and simultaneously maintains a considerable amount of SOC is poorly known. This study investigated the effect of four levels of tillage (15-cm deep by a local made plough) on net soil N mineralization rate (NMR), net nitrification rate (NNR), pools of NO(3)(-)-N and NH(4)(+)-N, and microbial biomass carbon (MB-C), water content of soil (WCS) and soil temperature (ST) in a Dystric fluvisols in the hot humid tropical climate of South Andaman Island of India. We hypothesized that: (1) tillage would increase NMR and reduce amount of SOC. But, these changes would depend on frequency of the tillage, i.e. greater would be the tillage frequency; higher, the NMR and decline in the amount of SOC; (2) low tillage would increase NMR, but reduce SOC nearly equal to short term zero tillage. Tillage levels included: (1) long term zero till (not tilled from 1983 to 2002; then from 2003 to 2006 crops (maize-okra rotation) were sown by dibbling, and weeds were cut and mulched), (2) frequent till (tilled three times before each crop sowing in the crop rotation from 1983 to 2002 and 2003 to 2006 as well; weeds were removed), (3)low till (not tilled from 1983 to 1999; then tilled once before each crop sowing in the crop rotation from 2000 to 2002 and weeds were removed; from 2003 to 2006 tilled like 2000-2002, but weeds were uprooted and buried in situ), and (4) short term zero till (from 1983 to 2002 tillage history was the same as in the low till; from 2003 to 2006 the crops were sown by dibbling in the crop rotation and weeds were cut and mulched in situ). Maize (Zea mays L.) was cultivated during wet season (WS, May to October) and okra (Abelmoschus esculentus L) during post-wet season (PWS, November to January) in all tillage treatments. Soils were sampled in all tillage treatments (levels) across the WS, PWS and dry (DS, February to April) seasons over two annual cycles (2004-2005 and 2005-2006) and analyses were done for the parameters investigated. We found that WCS was the highest (44-48%) during the WS and the lowest (10-16%) during the DS, however, ST was the lowest (25.5-26.5 degrees C) during the WS and the highest (30.5-33.4 degrees C) during the DS in all tillage treatments. Across the tillage levels, NMR increased from 1.06 to 1.96 mu g g(-1), day(-1) and NNR from 1.21 to 1.88 mu g g(-1) day(-1), and pools of NO(3)(-)-N and NH(4)(-)-N from 3.98 to 11.1 mu g g(-1) and 24.76 to 42.51 mu g g(-1), respectively. The increase was, however, the highest in the frequent till and the lowest in the long term zero till treatment. The NMR and NNR were the lowest (0.53-0.93.1 mu g g(-1), day(-1) and 0.49-0.86 mu g g(-1) day(-1), respectively) during the WS and the highest (1.09-1.71 mu g g(-1) day(-1) and 1.06-1.61 mu g g(-1) day(-1)) during the PWS in all tillage treatments. The NMR was positively correlated with the MB-C in all tillage treatments. Concurrent with the increase in the NMR, the SOC declined in all tillage treatments, but the decline was the highest in the frequent till and the lowest in the long term zero till treatment. Across the tillage treatments, the MB-C was correlated to the SOC. The SOC in the low till (7. 9 mg g(-1)) treatment was nearly equal to that in theshort term zero till treatment (8.8 mg g(-1)), but NMR was higher (0.86 mu g g(-1) day(-1)) particularly during the WS when plant's demand for N is usually high. Our results supported both the hypotheses, and suggested that low tillage might be a good option for soil fertility maintenance and carbon stock build-up in the soils of the hot humid tropics. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Thierfelder, C.
    • Wall, P. C.
  • Source: Experimental Agriculture
  • Volume: 46
  • Issue: 3
  • Year: 2010
  • Summary: Conservation agriculture (CA) systems are based on minimal soil disturbance, crop residue retention and crop rotation. Although the capacity of rotations to break pest and disease cycles is generally recognized, other benefits of crop rotations in CA systems are seldom acknowledged and little understood. We monitored different conventional and CA cropping systems over the period from 2005 to 2009 in a multi-seasonal trial in Monze, southern Zambia. Both monocropped maize and different maize rotations including cotton and the green manure cover crop sunnhemp (Crotalaria juncea) were compared under CA conditions, with the aim of elucidating the effects of crop rotations on soil quality soil moisture relations and maize productivity. Infiltration, a sensitive indicator of soil quality, was significantly lower on conventionally ploughed plots in all cropping seasons compared to CA plots. Higher water infiltration rate led to greater soil moisture content in CA maize treatments seeded alter cotton. Earthworm populations, total carbon and aggregate stability were also significantly higher on CA plots. improvements in soil quality resulted in higher rainfall use efficiency and higher maize grain yield on CA plots especially those in a two- or three-year rotation. lit the 2007/08 and 2008/2009 season, highest yields were obtained from direct-seeded maize after sunnhemp, which yielded 74% and 136% more than maize in the conventionally ploughed control treatment with a continuous maize crop. Even in a two-year rotation (maize-cotton), without a legume green manure cover crop, 47% and 38% higher maize yields were recorded compared to maize in the conventionally ploughed control in the two years, respectively This suggests that there are positive effects from crop rotations even in the absence of disease and pest problems. The overall profitability of each system will, however, depend on markets and prices, which will guide the farmer's decision on which, Wally, rotation to choose,
  • Authors:
    • Scopel, E.
    • Triomphe, B.
    • Tourdonnet, S. de
    • de Tourdonnet, S.
  • Source: Proceedings of a symposium on Innovation and Sustainable Development in Agriculture and Food, Montpellier, France, 28 June to 1st July 2010
  • Year: 2010
  • Summary: No-tillage techniques and conservation agriculture (CA), based on minimal soil disturbance, the maintenance of plant cover and a diversification of rotations and intercropping, are developing rapidly in both the North and South. The emergence of these techniques often involves an original process of innovation based on continuous and adaptive learning within innovative socio-technical networks, which overturn the traditionally linear process of innovation design and transfer. Changes in the functioning of the agrosystem associated with CA are likely to supply ecosystem services, but the difficult implementation of these techniques may decrease the performance of the agrosystem, in particular by increasing dependence on pesticides. The general objective of the PEPITES project is to generate knowledge concerning ecological processes, technical and social innovation processes and their interactions, for the evaluation and design of more sustainable technical and support systems. We are working towards this objective by constructing an interdisciplinary approach combining biophysical sciences, cropping system and production system agronomy and the sociology of innovation, in partnership with professionals in four study terrains: conventional field crops in France, organic farming in France and small-scale family farms in Brazil and Madagascar. After one year of operation, we present here the progress made towards answering the questions posed in this project, in terms of the positioning of research with respect to two key questions: first concerning the construction of an interdisciplinary approach in partnership to assist the innovation process and the generation of knowledge, and second the construction of an approach for comparing terrains in the North and South.
  • Authors:
    • Demuzere, M.
    • Gillijns, K.
    • Diels, J.
    • Govers, G.
    • Van den Putte, A.
  • Source: European Journal of Agronomy
  • Volume: 33
  • Issue: 3
  • Year: 2010
  • Summary: Many strategies exist to combat soil degradation through erosion and compaction on agricultural fields. One of these strategies is conservation agriculture (CA). Reduced or no-tillage techniques, together with crop residue management and crop rotation are the pillars of CA. The term reduced tillage covers a range of tillage practices but it never involves inverting the soil. In this way, soil disturbance is minimised and crop residues are left on the soil. Studies in many European countries have shown that CA can indeed be very effective in combating soil erosion. However, soil and water conservation do not appear as main drivers in farmers' decisions to shift or not to CA. Economic factors tend to be more important, but there are a lot of uncertainties on this domain. Studies show that production costs are mostly reduced, mainly by reduced fuel costs. Although many European studies have investigated the effect of reduced soil tillage on crop yields, a lot of uncertainties still exist. Most of the studies only cover a small range of field experiments, in one region. We present a meta-regression analysis (47 European studies, 563 observations) that compares crop yields under conventional tillage (CT), reduced tillage (RT) and no-tillage (NT) techniques. We analysed the possible influence on the relative yield ((RT or NT)/CT) of crop type, tillage depth, crop rotation, climate, CT yield and length of application of RT or NT. Our analysis shows that, while the introduction of conservation tillage in Europe may indeed have some negative effect on yields, these effects can be expected to be limited: the overall average reduction we found was ca. 4.5%. NT reduces crop yield on average with 8.5%. However, RT leads to a reduction in crop yields for maize and winter cereals only. By applying a linear mixed model, the importance of tillage depth and crop type as classification effects could be confirmed. Surprisingly, no-tillage did perform worse under drier climatic conditions. Negative effects such as an increased prevalence of pests and a lower quality of seed placement seem to outweigh possible gains due to increased water availability. On clay and sandy soils, however, this negative effect of no-tillage is counteracted, and all conservation tillage techniques perform better under drier climatic conditions. Another important finding is that, in cereals only rotations, relative yields under conservation tillage tend to decrease with time. Our analysis shows that conservation tillage is certainly a viable option for European agriculture from the viewpoint of agricultural productivity. Potential negative effects on agricultural productivity can be strongly reduced by applying sufficiently deep tillage and using a crop rotation including crops other than cereals. (C) 2010 Elsevier B.V. All rights reserved.