• Authors:
    • Abreu, S. L.
    • Godsey, C. B.
    • Edwards, J. T.
    • Warren, J. G.
  • Source: Soil & Tillage Research
  • Volume: 117
  • Year: 2011
  • Summary: Intensive tillage during the last century has greatly reduced organic carbon contents of Oklahoma cropland. Increased public interest in carbon sequestration and the potential for carbon storage in no-till soils to offset CO2 emissions has brought about the need for accurate estimates of carbon sequestration in Oklahoma. Eight locations across Oklahoma were soil sampled to determine the impact of no-till farming practices on soil carbon storage. Locations consisted of side by side no-till and tilled fields sampled at four sites in each field. Samples were divided into 0–10, 10–20, 20–40, 40–70, and 70–110 cm depths and analyzed for organic carbon (OC) and total nitrogen (TN). Averaged across locations and depth, the concentration of organic carbon (OC) was 0.7 g kg−1 greater in no-till compared to tilled fields. As expected, differences between no-till and conventional till were dependent on length of time in no-till and annual precipitation. The greater the time in no-till management and the higher the annual precipitation, the greater the carbon stocks compared to conventional till fields. Despite the high degree of variation among sample locations, the mass of OC was significantly (p = 0.07), greater in the NT compared to that found in the CT fields, with the average difference being 8.6 Mg ha−1. The highest OC accumulation was observed in Miami with an average of 3.5 Mg ha−1 year−1, while at Lahoma 2 and Goodwell no accumulation of OC was observed. Eliminating tillage operations can increase OC accumulation with the presence of adequate rainfall and an extended period of time.
  • Authors:
    • Cockfield, G.
    • Maraseni, T. N.
  • Source: Agricultural Systems
  • Volume: 104
  • Issue: 6
  • Year: 2011
  • Authors:
    • Abdellaoui, Z.
    • Teskrat, H.
    • Belhadj, A.
    • Zaghouane, O.
  • Source: Options Mediterranennes
  • Issue: 96
  • Year: 2011
  • Summary: The comparative study of reduced tillage, zero tillage and conventional tillage conducted during 5 years in the sub-humid zone of Algeria showed a difference of the development of durum wheat and changes of some soil characteristics. In the first year experiment, the yield was higher in the conventional tillage compared with reduced tillage and no-tillage. After the 3rd year, better yields were obtained with no-till with a 10 q/ha rise compared with conventional tillage. This confirms that the production of wheat under no till is improved year by year. However, after the 5th year of experiment, the high soil moisture at the seeding has generated lower yields. The different tillage practices have generated differences in soil characteristics. In fact a better water retention and a better content in organic matter in the three studied layers, were observed with no till. The bulk density shows a clear variation at the surface layer (0-8 cm) with the highest density in the conventional tillage.
  • Authors:
    • Blanco-Canqui, H.
  • Source: Soil Use and Management
  • Volume: 27
  • Issue: 1
  • Year: 2011
  • Summary: Soil water repellency (SWR) is an intrinsic and dynamic soil property that can influence soil hydrology and crop production. Although several land use systems have been shown to induce water repellency in soil, the specific effects of no-till cropping on SWR are poorly understood. This article reviews the impacts of no-till on SWR and identifies research needs. No-till cropping generally induces 1.5 to 40 times more SWR than conventional tillage, depending on soil type. This may result from near-surface accumulation of hydrophobic organic C compounds derived from crop residues, microbial activity and reduced soil disturbance. While large SWR may have adverse impacts on soil hydrology and crop production, the level of SWR under no-till relative to conventional tillage may contribute to aggregate stabilization and intra-aggregate C sequestration. More research is needed to discern the extent and relevance of no-till induced SWR. This includes: (1) further assessment of SWR under different tillage systems across a wide range of soil textures and climates, (2) comparison of the various methods for measuring SWR over a range of water contents, (3) inclusion of SWR in routine soil analysis and its use as a parameter to evaluate management impacts, (4) assessment of the temporal and spatial changes in SWR under field conditions, (5) further assessment of the impacts of the small differences in SWR between no-till and conventionally tilled soils on crop production, soil hydrology and soil C sequestration, and (6) development of models to predict SWR for different tillage systems and soils.
  • Authors:
    • Blanco-Canqui, H.
    • Schlegel, A. J.
    • Heer, W. F.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 144
  • Issue: 1
  • Year: 2011
  • Summary: No-till (NT) farming is considered as a potential strategy for sequestering C in the soil. Data on soil-profile distribution of C and related soil properties are, however, limited, particularly for semiarid regions. We assessed soil C pool and soil structural properties such as aggregate stability and strength to 1 m soil depth across three long-term (≥21 year) NT and conventional till (CT) experiments along a precipitation gradient in the central Great Plains of the USA. Tillage systems were in continuous winter wheat ( Triticum aestivum L.) on a loam at Hutchinson and winter wheat-sorghum [ Sorghum bicolor (L.) Moench]-fallow on silt loams at Hays and Tribune, Kansas. Mean annual precipitation was 889 mm for Hutchinson, 580 mm for Hays, and 440 mm for Tribune. Changes in profile distribution of soil properties were affected by differences in precipitations input among the three sites. At Hutchinson, NT had 1.8 times greater SOC pool than CT in the 0-2.5-cm depth, but CT had 1.5 times greater SOC pool in the 5-20-cm. At Hays, NT had 1.4 times greater SOC pool than CT in the 0-2.5-cm depth. Differences in summed SOC pool for the whole soil profile (0-1 m depth) between NT and CT were not significant at any site. The summed SOC pool with depth between NT and CT were only significant above the 5 cm depth at Hutchinson and 2.5 cm depth at Hays. At Hutchinson, NT stored 3.4 Mg ha -1 more SOC than CT above 5 cm depth. At Hays, NT stored 1.35 Mg ha -1 more SOC than CT above 2.5 cm depth. Moreover, NT management increased mean weight diameter of aggregates (MWDA) by 3 to 4 times for the 0-5-cm depth at Hutchinson and by 1.8 times for the 0-2.5-cm depth at Hays. It also reduced air-dry aggregate tensile strength (TS) for the 0-5-cm depth at Hutchinson and Hays and for the 0-2.5-cm depth at Tribune. The TS ( r=-0.73) and MWDA ( r=0.81) near the soil surface were more strongly correlated with SOC concentration at Hutchinson than at Hays and Tribune attributed to differences in precipitation input. Results suggested NT impacts on increasing SOC pool and improving soil structural properties decreased with a decrease in precipitation input. Changes in soil properties were larger at Hutchinson (880 mm of precipitation) than at Hays and Tribune (≤580 mm). While NT management did not increase SOC pool over CT for the whole soil profile, the greater near-surface accumulation of SOC in NT than in CT was critical to the improvement in soil structural properties. Overall, differences in precipitation input among soils appeared to be the dominant factor influencing NT impacts on soil-profile distribution of SOC and soil structural properties in this region.
  • Authors:
    • Brito, I.
    • Carvalho, M. de
    • Goss, M. J.
  • Source: Soil Use and Management
  • Volume: 27
  • Issue: 3
  • Year: 2011
  • Summary: The potential to manage arbuscular mycorrhizal colonization within Mediterranean agricultural systems depends on the summer survival of extraradical mycelium. To investigate this further a three-stage experiment was undertaken. The first stage was the creation of two contrasting levels of extraradical mycelium development, achieved by two contrasting levels of soil disturbance (typifying full tillage and no-till). In the second stage, this differential mycelial inoculum was subjected to Mediterranean summer temperature and soil water regimes representing the post-harvest fallow. During the third stage, corresponding to the next growing season, survival was evaluated without further soil disturbance (typifying no-till conditions) using wheat as host crop. The results clearly indicate that the extraradical mycelium survived the prevailing summer conditions. The knowledge that extraradical mycelium can survive the Mediterranean summer encourages the use of tillage systems that minimize mechanical disturbance of the soil, such as no-till. The results from this study suggest that by making the appropriate choice of crops to establish a mycorrhizal-supportive rotation there can be opportunities for agro-ecosystem management to benefit from the symbiotic relationship.
  • Authors:
    • Caesar-TonThat, T.
    • Sainju, U. M.
    • Wright, S. F.
    • Shelver, W. L.
    • Kolberg, R. L.
    • West, M.
  • Source: Biology and Fertility of Soils
  • Volume: 47
  • Issue: 2
  • Year: 2011
  • Summary: Little is known about the long-term tillage and cropping management effects on the microbiologically derived factors that influence macroaggregates in semi-arid soil. We tested the hypothesis that differences in macro-aggregation are due to changes in soil structure related to management treatment-induced microbiological changes. In an experiment, microbiological factors consisting of aggregate stability, glomalin, russuloid basidiomycete fungi, uronic acids, total organic C (TOC), and total N (TN) were quantified in macroaggregate-size classes ranging from 4.75 to 0.25 mm, collected at 0-5 cm depth for the following treatments: (1) 12th year of fallow phase after 11 years of conventional- and no-tilled spring wheat-fallow (CTF and NTF), (2) 12th year of lentil phase after 11 years of conventional- and no-tilled spring wheat-lentil (CTL and NTL), (3) 12 years no-tilled continuous spring wheat (NTCW), and (4) 16 years uncultivated pasture (P) used as a baseline treatment. Immunoreactive easily extractable glomalin concentration was five to six times greater under P, NTCW, or NTL in the 2.00-1.00- and 1.00-0.50-mm macroaggregate-size classes than the other treatments and these results corroborated well with the results from aggregate stability assays. Russuloid basidiomycetes were highest in all NTCW macroaggregate-size classes, suggesting that annual input of lignin-containing wheat residues may influence the growth and survival of these fungi. Uronic acid amounts were highest in P but did not differ among the other treatments. In all macroaggregate-size classes, TOC content was greater in NTCW compared to CTF, and TN was about three times higher in NTL than NTF or CTF. In conclusion, 12 years of NTCW management in semi-arid soil has resulted in higher macroaggregate stability, glomalin concentration, russuloid basidiomycete populations, and TOC in macroaggregates compared to alternate-year fallow. Lentil can be used to replace fallow in dryland wheat rotation under no-till to enhance TN content and improve soil macro-aggregation.
  • Authors:
    • VandenBygaart, A. J.
    • Zentner, R. P.
    • Lemke, R.
    • May, W. E.
    • Holzapfel, C. B.
    • Campbell, C. A.
    • Lafond, G. P.
  • Source: Canadian Journal of Plant Science
  • Volume: 91
  • Issue: 3
  • Year: 2011
  • Summary: We analyzed the agronomic data from a 50-yr crop rotation experiment being conducted on a fine-textured, thin Black Chernozem at Indian Head, Saskatchewan in Canada. Our objective was to determine how a change from conventional-till to no-till, together with an increase in N fertilizer rates recommended by the Saskatchewan Soil Testing Laboratory has affected wheat yields and N and P balance in the systems over the past 20 yr. The treatments assessed were fertilized (N-P) and unfertilized fallow-wheat ( Triticum aestivum L.) (F-W), F-W-W, and continuous wheat (ContW), and unfertilized legume green manure (LGM)-W-W and F-W-W-brome ( Bromus inermis Leyss.)/alfalfa ( Medicago sativa L.) hay (H)-H-H. On average, N applied to wheat grown on fallow was 6 kg ha -1 yr -1 from 1957 to 1989 and 57 kg ha -1 yr -1 from 1990 to 2007; for wheat grown on stubble, the N rates were 21 kg ha -1 yr -1 from 1957 to 1977 and 85 kg ha -1 yr -1 thereafter. Crops received P at 10 kg ha -1 yr -1. On average, fertilizer increased wheat yield of fallow-wheat by 31%; the hay system increased fallow-wheat yield by 26% compared with unfertilized fallow-wheat in F-W-W, and the LGM system increased it by 14%. Effects were greater on stubble crop than on fallow crop, with fertilizer increasing the yield of wheat grown on stubble in the monoculture system by 114%, the hay system increasing it by 83% and the LGM system increasing it by 37%. The legume-containing rotations increased yields by increasing the N supplying capacity of the soil with the hay system being more effective than the LGM because legumes occurred more frequently in the hay rotation (3 in 6 yr vs. 2 in 6 yr). The benefit of the legume-containing systems on wheat yield may have been restricted because this unfertilized system steadily depleted available soil P. Average annualized wheat production in F-W, F-W-W and ContW rotations was unaffected by cropping frequency for the unfertilized systems, but it was directly proportional to cropping frequency for the fertilized systems. Annualized wheat production for the LGM-W-W rotation was 18% greater than for unfertilized F-W-W, but 41% less than for the fertilized F-W-W. Annualized wheat production in the hay-containing rotation was 32% less than in the unfertilized F-W-W rotation because of the less frequent presence of wheat in the hay system. Greater rates of N fertilizer in the later years increased yields and grain N content; this resulted in less residual NO 3-N in the soil compared with previous years with lower fertilizer N. Thus, we expect there will be less likelihood of NO 3 leaching under fallow-containing systems under no-till when updated fertilizer recommendations are used compared with previous results under conventional tillage with lower rates of N applications.
  • Authors:
    • Campos, L. P.
    • Leite, L. F. C.
    • Maciel, G. A.
    • Iwata, B. de F.
    • Nobrega, J. C. A.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 46
  • Issue: 12
  • Year: 2011
  • Summary: The objective of this work was to evaluate the chemical attributes in a Xanthic Ferralsol under different tillage systems in the cerrado of Piaui State, Brazil. Four tillage systems were evaluated: three-year-old conventional tillage; no-tillage with three (NT3) and five years old (NT5), using millet as cover crop; and no-tillage with nine years old (NT9), of which seven years used millet as cover crop and two used forage. A native cerrado area was taken as reference. Soil samples were collected in wet and dry seasons at soil depths, 0.00-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.40 m, and analyzed for pH, Al 3+, H+Al, Ca 2+, Mg 2+, K +, sum of bases (SB), effective (t) and potential (T) cation exchangeable capacity, base (BS) and Al 3+ saturation (m%), available P and total organic carbon (TOC). The system NT9 showed the highest values of pH and lowest of Al 3+, H+Al, and m%. The highest values for Ca 2+, K, SB, t, T, V% and P, were observed under NT5 and NT9, until 0.20 m depth. The highest TOC contents were verified also under NT5 and NT9, except for 0.00-0.05 m soil depth. Organic matter accumulation associated with pasture under no-till increases TOC content at deeper soil layers in the dry period.
  • Authors:
    • Hannachi, A.
    • Touahria, O.
    • Fellahi, Z. E. A.
    • Makhlouf, M.
    • Bouzerzour, H.
    • Chennafi, H.
  • Source: Advances in Environmental Biology
  • Volume: 5
  • Issue: 10
  • Year: 2011
  • Summary: A field study was conducted during two cropping seasons (2009/10 and 2010/11) at the Institute of Field Crop-Agricultural Research Station of Setif (eastern Algeria) to compared the effect of tillage (no till and conventional tillage) and residue management (0, 30 and 60% soil cover) on the growth and grain yield of durum wheat. The cumulative growing season precipitations were 427.7 and 312.1 mm. Soil water storage to a depth of 0.4 m was higher under CT in the first year and no significant differences existed between NT and CT during the second year. Above-ground biomass was higher under CT, while grain yield, spikes m -2 and number of kernels m -2 were higher under NT. Residue rate affected positively all measured traits, suggesting the necessity to maintain residue cover to avoid reducing yield under NT management system. Averaged over residue rates, Transpiration was higher under CT than under NT, in 2009/10, but not significant difference was noted in 2010/11. The opposite was noted for evaporation. Transpiration increased as residue rates increased during both seasons. CT showed higher WUE BIO and WUE GY in the first year, while during the second year, NT expressed higher WUE BIO and WUE GY. WUE BIO and WUE GY increased as residue rate increased, during both cropping seasons. The results of the present study indicated that with adequate residue cover, no-till did not decreased grain yield, which suggested that durum wheat can be grown under NT with the expectation that gain yield will be higher or at least equal to CT grain yield.