• Authors:
    • Sweeney, D.W.
    • Kelley, K.
  • Source: Agronomy Journal
  • Volume: 99
  • Issue: 4
  • Year: 2007
  • Summary: Because of improved equipment technology, many producers in the eastern Great Plains are planting winter wheat ( Triticum aestivum L.) no-till (NT) into previous crop residues, but management of fertilizer N and P remains critical. This field study was conducted from 1998 through 2003 in southeastern Kansas on a Parsons silt loam soil (fine, mixed, thermic, Mollic Albaqualf). The objectives were to determine effects and interactions of previous crop [corn, Zea mays L.; grain sorghum, Sorghum bicolor (L.); and soybean, Glycine max (L.) Merr.], preplant placement method of liquid N-P fertilizer [subsurface-knife (KN), surface-band (SB), and surface-broadcast (BC)], and fertilizer N rate (22, 45, 90, and 134 kg N ha -1) on NT winter wheat yield, yield components, and nutrient uptake in a 2-yr cropping rotation. Wheat yields averaged 3.73, 3.56, and 2.97 Mg ha -1 following soybean, corn, and grain sorghum, respectively. However, as fertilizer N rate increased, yield differences between previous crops decreased. Grain yields also were influenced by placement of N-P fertilizer, averaging 3.68 Mg ha -1 for KN, 3.40 Mg ha -1 for SB, and 3.19 Mg ha -1 for BC. Plant and grain N responses indicated that grain yield differences were primarily related to greater immobilization of both fertilizer and soil N following grain sorghum, compared with soybean and corn, and to better utilization of KN N-P than surface-applied. Fertilizing with greater N rates applied as a subsurface band, especially if following grain sorghum, may be necessary to maximize NT wheat yield potential in the eastern Great Plains.
  • Authors:
    • Lemke, R.
    • Malhi, S.
  • Source: Soil & Tillage Research
  • Volume: 96
  • Issue: 1/2
  • Year: 2007
  • Summary: An 8-yr (1998-2005) field experiment was conducted on a Gray Luvisol (Boralf) soil near Star City, Saskatchewan, Canada, to determine the effects of tillage (no-tillage - NT and conventional tillage - CT), straw management (straw retained - R and straw not retained - NR) and N fertilizer (0, 40, 80 and 120 kg N ha -1, except no N to pea ( Pisum sativum L.) phase of the rotation) on seed and straw yield, mass of N and C in crop, organic C and N, inorganic N and aggregation in soil, and nitrous oxide (N 2O) emissions for a second 4-yr rotation cycle (2002-2005). The plots were seeded to barley ( Hordeum vulgare L.) in 2002, pea in 2003, wheat ( Triticum aestivum L.) in 2004 and canola ( Brassica napus L.) in 2005. Seed, straw and chaff yield, root mass, and mass of N and C in crop increased with increasing N rate for barley in 2002, wheat in 2004 and canola in 2005. No-till produced greater seed (by 51%), straw (23%) and chaff (13%) yield of barley than CT in 2002, but seed yield for wheat in 2004, and seed and straw yield for canola in 2005 were greater under CT than NT. Straw retention increased seed (by 62%), straw (by 43%) and chaff (by 12%) yield, and root mass (by 11%) compared to straw removal for barley in 2002, wheat in 2004, and seed and straw yield for pea in 2003. No-till resulted in greater mass of N in seed, and mass of C in seed, straw, chaff and root than CT for barley in 2002, but mass of N and C were greater under CT than NT for wheat in 2004 and for canola in 2005 in many cases. Straw retention had greater mass of N and C in seed, straw, chaff and root in most cases compared to straw removal for barley in 2002, pea in 2003 and wheat in 2004. Soil moisture content in spring was higher under NT than CT and with R than NR in the 0-15 cm depth, with the highest moisture content in the NT + R treatment in many cases. After eight crop seasons, tillage and straw management had no effect on total organic C (TOC) and N (TON) in the 0-15 cm soil, but light fraction organic C (LFOC) and N (LFON), respectively, were greater by 1.275 Mg C ha -1 and 0.031 Mg N ha -1 with R than NR, and also greater by 0.563 Mg C ha -1 and 0.044 Mg N ha -1 under NT than CT. There was no effect of tillage, straw and N fertilization on the NH 4-N in soil in most cases, but R treatment had higher NO 3-N concentration in the 0-15 cm soil than NR. The NO 3-N concentration in the 0-15, 15-30 and 30-60 cm soil layers increased (though small) with increasing N rate. The R treatment had 6.7% lower proportion of fine (38.0 mm) dry aggregates, and 4.5 mm larger mean weight diameter (MWD) compared to NR treatment. This suggests a lower potential for soil erosion when crop residues are retained. There was no beneficial effect of elimination of tillage on soil aggregation. The amount of N lost as N 2O was higher from N-fertilized (580 g N ha -1) than from zero-N (155 g N ha -1) plots, and also higher in CT (398 g N ha -1) than NT (340 g N ha -1) in some cases. In conclusion, retaining crop residues along with no-tillage improved some soil properties and may also be better for the environment and the sustainability of high crop production. Nitrogen fertilization improved crop production and some soil quality attributes, but also increased the potential for NO 3-N leaching and N 2O-N emissions, especially when applied in excess of crop requirements.
  • Authors:
    • Borghi, E.
    • Crusciol, C.
    • Mateus, G.
  • Source: Acta Scientiarum Agronomy
  • Volume: 29
  • Issue: 4
  • Year: 2007
  • Summary: The effects of cover plants on the performance of annual crops under no-tillage systems are not well defined yet. A field trial was carried out on a Rhodic Kandiudalf soil in Botucatu, state of Sao Paulo, Brazil, aiming to evaluate the effect of the amount of Gigante guinea sorghum straw on soybean nutrient uptake and its consequent performance of grain yield in no-tillage area. The experimental design was developed in randomized blocks with four replications. The treatments consisted of 6.1, 7.1, 19.5, 26.7, 28.1 e 30.2 ton ha -1 of guinea sorghum straw. The increase of straw provided increment of N and P plant levels until the amount of 25.0 and 17.5 ton ha -1, respectively. Thus, the highest soybean grain yields reported in soils under no-tillage systems might be related to the proper water and nutrient uptakes due to higher soil moisture availability.
  • Authors:
    • Gracia, R.
    • Lopez, M.
    • Arrue, J.
    • Moret, D.
  • Source: European Journal of Agronomy
  • Volume: 26
  • Issue: 1
  • Year: 2007
  • Summary: Winter barley is the major crop on semiarid drylands in central Aragon (NE Spain). In this study we compared, under both continuous cropping (BC) (5-6-month fallow) and a crop-fallow rotation (BF) (16-18-month fallow), the effects of three fallow management treatments (conventional tillage, CT; reduced tillage, RT; no-tillage, NT) on the growth, yield and water use efficiency (WUE) of winter barley during three consecutive growing seasons in the 1999-2002 period. Daily precipitation measurements and monthly measurements of soil water storage to a depth of 0.7 m were used to calculate crop water use (ET) and its components. The average growing season precipitation was 195 mm. Above-ground dry matter (DM) and corresponding WUE were high in years with high effective rainfalls (>10 mm day -1) either in autumn or spring. However, the highest values of WUE for grain yield were mainly produced by effective rainfalls during the time from stem elongation to harvest. Despite the similarity in ET for the three tillage treatments, NT provided the lowest DM production, corresponding to a higher soil water loss by evaporation and lower crop transpiration ( T), indicated by the lowest T/ET ratio values found under this treatment. No clear differences in crop yield were observed among the tillage treatments in the study period. On average, and regardless of the type of tillage, BF provided the highest values of DM and WUE and yielded 49% more grain than BC. These differences between cropping systems increased when water-limiting conditions occurred in the early stages of crop growth, probably due to the additional soil water storage under BF at sowing. Although no significant differences in precipitation use efficiency (PUE) were observed between BC and BF, PUE was higher under the BC system, which yielded 34% more grain than the BF rotation when yields were adjusted to an annual basis including the length of the fallow. The crop yield under BF was not dependent on the increase in soil water storage at the end of the long fallow. In conclusion, this study has shown that, although conventional tillage can be substituted by reduced or no-tillage systems for fallow management in semiarid dryland cereal production areas in central Aragon, the practice of long-fallowing to increase the cereal crop yields is not longer sustainable.
  • Authors:
    • Franti, T.
    • Mamo, M.
    • Wortmann, C.
    • Quincke, J.
    • Drijber, R.
  • Source: Agronomy Journal
  • Volume: 99
  • Issue: 4
  • Year: 2007
  • Summary: Soil organic carbon (SOC) accumulation occurs mostly in the top 5 cm of soil with continuous no-till (NT) while SOC losses often occur at deeper depths. We hypothesize that one-time tillage conducted once in >10 yr to mix the high SOC surface layer with deeper soil will not result in large SOC losses following tillage with a net positive gain in SOC eventually. Two experiments in long-term NT fields were installed under rainfed corn ( Zea mays L.) or sorghum [ Sorghum bicolor (L.) Moench.] rotated with soybean [ Glycine max (L.) Merr.] in eastern Nebraska. Tillage treatments were applied in the spring or fall and included: NT, disk, chisel with 10-cm wide twisted shanks, moldboard plow (MP), and mini-moldboard plow (miniMP). A portable infrared gas analyzer was used to monitor CO 2 flux immediately following tillage. Effect of tillage on profile distribution of total and labile (particulate and oxidizable) SOC was determined. At 24 to 32 mo following tillage, SOC mass was determined for depths of 0 to 5, 5 to 20, and 20 to 30 cm. Some tillage operations effectively redistributed total and labile SOC with little increase in CO 2 flux compared with NT. Total and labile SOC concentrations were reduced by 24 to 88% in the 0- to 2.5-cm depth and increased by 13 to 381% for the 5- to 10-cm depth for the various tillage operations. Moldboard plowing caused the greatest redistribution of SOC. On an equivalent soil mass basis, tillage did not cause significant losses of total or labile SOC between tillage and planting of the next crop or by 24 to 32 mo after tillage. Stratification of SOC in long-term NT soil could be reduced most effectively by means of one-time MP tillage without increased loss of labile SOC.
  • Authors:
    • Garcia, J.
    • Drijber, R.
    • Franti, T.
    • Mamo, M.
    • Wortmann, C.
    • Quincke, J.
  • Source: Agronomy Journal
  • Volume: 99
  • Issue: 4
  • Year: 2007
  • Summary: Continuous no-till (NT) has numerous benefits, including improved soil aggregate stability in the surface soil and increased rate of water infiltration, but accumulation of soil P at the soil surface with NT can increase P concentration in runoff. We hypothesized that occasional one-time tillage of NT land, conducted once in 10 or more years, can reduce P runoff and improve crop yields without reducing soil aggregation or increasing runoff. Research was conducted in long-term NT fields under rainfed corn [ Zea mays (L.)] or sorghum [ Sorghum bicolor (L.) Moench.] rotated with soybeans [ Glycine max (L.) Merr.] at two locations in eastern Nebraska. Tillage treatments were applied in the spring or fall and included continuous NT, tandem disk (disk), chisel with 10-cm-wide twisted shanks, moldboard plow (MP), and mini-moldboard plow (miniMP). Subplots had either 0 or 87.4 kg P ha -1 applied as composted feedlot manure before tillage. Yield and yield components were measured for 2 and 3 yr after the spring and fall one-time tillage, respectively. In Year 2 or 3 after tillage, soil sorptivity, field-saturated infiltration rate, runoff volume, runoff P loss, and soil aggregate stability were determined. Yield was not affected by the tillage * compost interaction, but was increased by compost application at one location and sorghum yield was affected by tillage treatments at the second location. Grain yield was never significantly more or less with one-time tillage as compared with NT. Soil aggregate stability was not affected by tillage treatments. Sorptivity and infiltration were increased with MP tillage compared with NT at one location but reduced at the other. One-time MP tillage reduced dissolved P loss at both locations and total phosphorus (TP) loss at one location. The benefit of one-time MP tillage in terms of reduced dissolved reactive P loss in runoff was positive with no negative effect on soil aggregate stability but no gain in yield.
  • Authors:
    • Avila, A.
    • Spera, S.
    • Tomm, G.
    • Santos, H.
  • Source: Bragantia
  • Volume: 66
  • Issue: 2
  • Year: 2007
  • Summary: The effects of soil management systems and crop rotations were assessed from 1997 to 2003, in Passo Fundo, Rio Grande do Sul State, Brazil. Four soil management systems (no-tillage, minimum tillage, conventional tillage using disc plough, and conventional tillage using mouldboard plough) and three crop rotation systems (system I (wheat/soyabean), system II (wheat/soyabean and common vetch/maize or sorghum), and system III (wheat/soyabean, common vetch/maize or sorghum and white oats/soyabean)) were compared. The main plot consisted of soil management systems, while the split-plots consisted of crop rotation systems. Energy conversion (energy available/energy consumed) and balance (energy available-energy consumed) during the seven-year period is presented. No-tillage resulted in higher energy conversion and balance (72.44 and 190 766 MJ/ha) than minimum tillage (64.06 and 167 349 MJ/ha), conventional tillage using disc plough (54.35 and 134 982 MJ/ha), and conventional tillage using mouldboard (52.02 and 128 159 MJ/ha), respectively. Wheat in crop rotations presented higher energy efficiency than that in monoculture. Maize had the highest energy efficiency among the crops.
  • Authors:
    • Lupwayi, N.
    • Haq, A.
    • Arshad, M.
    • Soon, Y.
  • Source: Soil & Tillage Research
  • Volume: 95
  • Issue: 1/2
  • Year: 2007
  • Summary: Information on which management practices can enhance soil organic matter (SOM) content and quality can be useful for developing sustainable crop production systems. We tested the influence of 12 years of no-till (NT) versus conventional tillage (CT), and four crop sequences on the organic C pools of a Grey Luvisolic sandy loam soil in northwestern Alberta, Canada. The crop sequences were: continuous wheat ( Triticum aestivum L.), field pea ( Pisum sativum L.)-wheat-canola ( Brassica rapa L.)-wheat, red clover ( Trifolium pratense L.) green manure-wheat-canola-wheat/red clover and fallow-wheat-canola-wheat. Soil samples from 1992, when the study was initiated, and 1996, 2000 and 2004 were analysed for total organic C (TOC), the light fraction (LF) and its C content, and water-soluble and mineralizable C. Total organic C in the top 15 cm of soil was higher in the red clover rotation than either the pea or fallow rotation by 1996. The tillage effect became significant only in 2004 with NT having a higher TOC than CT. The LF dry matter (DM) increased from 6.9 g kg -1 soil in 1992 to a range of 10-13 g kg -1 in 2000 and 2004. It was higher under NT than CT in 2 of 3 years and in the red clover rotation than the pea or fallow rotation in 1 of 3 years. The LF C content exhibited a similar trend as LF DM. The water-soluble and mineralizable C pools were not affected by tillage but decreased with time. Among crop rotations, the red clover rotation tended to result in higher levels of hot water-soluble and mineralizable C. It is concluded that tillage had a greater influence than crop rotation on the LF DM and LF C (as indicators of C storage), whereas the converse effect applied to mineralizable C and, to a lesser degree, hot water-soluble C (as indicators of SOM quality).
  • Authors:
    • Rice, C. W.
    • Boyles, S. B.
    • Williams, J. R.
    • Pendell, D. L.
    • Nelson, R. G.
  • Source: Review of Agricultural Economics
  • Volume: 29
  • Issue: 2
  • Year: 2007
  • Summary: This study examines the economic potential of using either no-tillage or conventional tillage with either commercial nitrogen or cattle manure to sequester soil in continuous corn production. This research uses stochastic efficiency with respect to a function to determine the preferred production systems under various risk preferences and utility-weighted certainty equivalent risk premiums to determine the carbon credit values needed to motivate adoption of systems, which sequester higher levels of carbon. The results indicate that no-tillage and cattle manure increase carbon sequestration. Carbon credits or government program incentives are not required to entice risk-averse managers to use no-tillage, but are required to encourage manure use as a means of sequestering additional carbon even at historically high nitrogen prices. New environmental rules for confined animal feeding operations may increase the demand for land to apply manure as a primary nutrient source and participation in the Environmental Quality Incentives Program, Conservation Security Program, and a carbon credit market to obtain payments to offset some or all of the costs of manure application.
  • Authors:
    • Burmester, C.
    • Reeves, D. W.
    • Motta, A. C. V.
    • Feng, Y.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 38
  • Issue: 19-20
  • Year: 2007
  • Summary: The impact of conservation tillage, crop rotation, and cover cropping on soil-quality indicators was evaluated in a long-term experiment for cotton. Compared to conventional-tillage cotton, other treatments had 3.4 to 7.7 Mg ha(-1) more carbon (C) over all soil depths. The particulate organic matter C (POMc) accounts for 29 to 48 and 16 to 22% of soil organic C (SOC) for the 0- to 3- and 3- to 6-cm depths, respectively. Tillage had a strongth influence on POMc within the 0- to 3-cm depth, but cropping intensity and cover crop did not affect POW A large stratification for microbial biomass was observed varing from 221 to 434 and 63 to 110 mg kg(-1) within depth of 0-3 and 12-24 cm respectively. The microbial biomass is a more sensitive indicator (compared to SOC) of management impacts, showing clear effect of tillage, rotation, and cropping intensity. The no-tillage cotton double-cropped wheat/soybean system that combined high cropping intensity and crop rotation provided the best soil quality.