• Authors:
    • Gibson,Lance R.
    • Singer,Jeremy W.
    • Blaser,Brock C.
  • Source: Crop Science
  • Volume: 52
  • Issue: 1
  • Year: 2012
  • Summary: Frost-seeding red clover (Trifolium pratense L.) into winter cereals is an efficient establishment method, although performance under contrasting soil management practices remains unclear. Wheat and intercropped red clover productivity were evaluated in intensive tillage (IT), moderate tillage (MT), and no tillage (NT) with and without compost amendment in a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.]-winter wheat (Triticum aestivum L.) and red clover rotation between 2005 and 2010. Wheat yields were not affected by tillage system and averaged 3.80 Mg ha(-1) but were 10% higher in compost amended soil compared to no compost. Red clover plant density and dry matter (DM) at cereal grain harvest averaged 127 plants m(-2) and 32 g m(-2) and were not affected by tillage or amendment treatments. Maximum wheat canopy light interception was attained in late May to early June and ranged from 84 to 91% and typically exceeded 77% light interception for at least 22 d. Red clover root DM increased on average 378% between wheat harvest and 40 d after harvest compared with a 64% average increase in red clover root length. Red clover shoot: root averaged 8.5 at wheat harvest compared with 11.2 40 d after wheat harvest. Producers using this wheat and red clover intercrop should expect no difference in wheat yield or red clover productivity when using IT, MT, or NT.
  • Authors:
    • Carr, P. M.
    • Anderson, R. L.
    • Lawley, Y. E.
    • Miller, P. R.
    • Zwinger, S. F.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 27
  • Issue: Special Issue 01
  • Year: 2012
  • Summary: The use of killed cover crop mulch for weed suppression, soil erosion prevention and many other soil and crop benefits has been demonstrated in organic no-till or zero-till farming systems in eastern US regions and in Canada. Implements have been developed to make this system possible by terminating cover crops mechanically with little, if any, soil disturbance. Ongoing research in the US northern Great Plains is being conducted to identify cover crop species and termination methods for use in organic zero-till (OZ) systems that are adapted to the crop rotations and climate of this semi-arid region. Current termination strategies must be improved so that cover crop species are killed consistently and early enough in the growing season so that subsequent cash crops can be grown and harvested successfully. Delaying termination until advanced growth stages improves killing efficacy of cover crops and may provide weed-suppressive mulch for the remainder of the growing season, allowing no-till spring seeding of cash crops during the next growing season. Excessive water use by cover crops, inability of legume cover crops to supply adequate amounts of N for subsequent cash crops and failure of cover crops to suppress perennial weeds are additional obstacles that must be overcome before the use of killed cover crop mulch can be promoted as a weed control alternative to tillage in the US northern Great Plains. Use of vegetative mulch produced by killed cover crops will not be a panacea for the weed control challenges faced by organic growers, but rather one tool along with crop rotation, novel grazing strategies, the judicious use of high-residue cultivation equipment, such as the blade plow, and the use of approved herbicides with systemic activity in some instances, to provide organic farmers with new opportunities to incorporate OZ practices into their cropping systems. Emerging crop rotation designs for organic no-till systems may provide for more efficient use of nutrient and water resources, opportunities for livestock grazing before, during or after cash crop phases and improved integrated weed management strategies on organic farms.
  • Authors:
    • Duke, J. M.
    • Borchers, A. M.
    • Johnston, R. J.
    • Absetz, S.
  • Source: Ecological Economics
  • Volume: 74
  • Year: 2012
  • Summary: This paper describes the results of a choice experiment measuring social benefits for sustainable management practices and agricultural land preservation. Sustainable management is conceptualized with three illustrative practices that impact water quality, carbon sequestration, and soil erosion: fertilizing with a broiler litter product, expanding riparian buffers, and no-till cropping. Data for a choice experiment are collected using a mail survey of residents living near a large, unpreserved agricultural parcel in an urban-influenced area of Delaware. Results identify substantial benefits for land preservation, the use of broiler litter, and riparian buffers but not for conservation tillage. Results also suggest that the estimated household benefits of all three sustainable management practices combined are similar in magnitude to the benefits from land preservation alone. Based on model results, policy and future research may wish to examine possibilities for subsidizing sustainable management practices in urban-influenced areas as a more cost-effective means of providing benefits similar to those realized through land preservation.
  • Authors:
    • Gruber, S.
    • Pekrun, C.
    • Möhring, J.
    • Claupein, W.
  • Source: Soil & Tillage Research
  • Volume: 121
  • Year: 2012
  • Summary: The study provides information to more reliably estimate the value of conservation tillage in a temperate climate. Tillage effects on yield and weeds were evaluated in field experiments at two sites in SW Germany between 1999 and 2010. Tillage varied at site Ihinger Hof from mouldboard plough (P), chisel plough (CP), rototiller (RTT), varying P and CP (VAR), to no tillage (NT), partially combined with stubble tillage (S). Tillage at site Meiereihof was S/P, S/CP, and NT. Crop rotations included winter wheat (WW, Triticum aestivum), triticale (TR, Triticosecale), oat (OA, Avena sativa), silage maize (SM, Zea mays) and oilseed rape (OSR, Brassica napus) at Ihinger Hof, and winter wheat, spring barley (SB, Hordeum vulgare), silage maize, sugar beets (SBE. Beta vulgaris) and faba bean (FB, Vicia faba) at Meiereihof. At Ihinger Hof, tillage had an effect on yield (P > F = 0.0049), but no effects were found on crop emergence and crop density. Tillage effects on yield were consistent across crops though differences between crops appeared to exist. The yield of S/P, the standard tillage, was 8.5 (WW), 7.7 (TR), 4.7 (OA), 18.3 (SM) and 4.1 (OSR) t DM ha(-1) at Ihinger Hof, with yield under NT always significantly lower than S/P by 7.3% on average for all crops. At Meiereihof, yields ranged from 7.2 to 8.0 (WW), 3.3 to 4.2 (SB), 19.8 to 21.5 (SM) and 3.1 to 3.2 (FB) t DM ha(-1), and 61.3 to 67.6 FM ha(-1) for SBE. Yield was reduced by 4.5% from S/P to S/CP (P > F = 0.0516), and by about 10% from S/P to NT (P > F = 0.0009). Weed density ranged between 0.5 and 44 plants m(-2) at Ihinger Hof and was higher in treatments without stubble tillage and under non-inversion tillage, though significance differed for the different classes of weeds. NT led to weed infestation about 2-20 times higher than S/P. The interaction crop x treatment indicated that factors other than tillage influenced weed infestation. It is unlikely that weed infestation and reduced yield will be problems in temperate climates if soil disturbance through tillage is reduced. Non-inversion tillage can easily replace inversion tillage, and stubble tillage can be added to primary tillage if needed to reduce weeds. Since no specific tillage method was unequivocally superior to another one, any method well suited to specific regional and farm conditions can be adopted successfully.
  • Authors:
    • Hansen, N. C.
    • Allen, B. L.
    • Baumhardt, R. L.
    • Lyon, D. J.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: The Great Plains region of the United States is an area of widespread dryland crop production, with wheat being the dominant crop. Precipitation in the region ranges from 300 to 500 mm annually, with the majority of precipitation falling during hot summer months. The prevailing cropping system is a two-year rotation of wheat and summer fallow. The adoption of no-till practices has resulted in greater precipitation storage and use efficiency, which has led to greater cropping intensity, higher productivity, more diverse crop rotations, and improvements in soil properties. In Colorado, for example, a no-till rotation of winter wheat-maize-fallow increased total annualized grain yield by 75% compared to winter wheat-summer fallow. Soil erosion was reduced to just 25% of that from a conventional tillage wheat-summer fallow system. The primary challenge with reducing fallow frequency is the increase in yield variability and risk of crop failure. Improved approaches for choosing crop or fallow are being developed based on soil water content and forecasted weather. Development of alternative crops, crop rotations, and integrated livestock systems that are sustainable from both economic and ecological perspectives is an on-going effort. Other research is addressing adaptation of cropping practices to climate change and the potential for dryland biomass crop production for the developing biofuel industry.
  • Authors:
    • Barbera, V.
    • Poma, I.
    • Gristina, L.
    • Novara, A.
    • Egli, M.
  • Source: Land Degradation & Development
  • Volume: 23
  • Issue: 1
  • Year: 2012
  • Summary: A calcareous and clayey xeric Chromic Haploxerept of a long-term experimental site in Sicily (Italy) was sampled (0-15 cm depth) under different land use management and cropping systems (CSs) to study their effect on soil aggregate stability and organic carbon (SOC). The experimental site had three tillage managements (no till [NT], dual-layer [DL] and conventional tillage [CT]) and two CSs (durum wheat monocropping [W] and durum wheat/faba bean rotation [WB]). The annually sequestered SOC with W was 2.75-times higher than with WB. SOC concentrations were also higher. Both NT and CT management systems were the most effective in SOC sequestration whereas with DL system no C was sequestered. The differences in SOC concentrations between NT and CT were surprisingly small. Cumulative C input of all cropping and tillage systems and the annually sequestered SOC indicated that a steady state occurred at a sequestration rate of 7.4 Mg C ha -1 y -1. Independent of the CSs, most of the SOC was stored in the silt and clay fraction. This fraction had a high N content which is typical for organic matter interacting with minerals. Macroaggregates (>250 m) and large microaggregates (75-250 m) were influenced by the treatments whereas the finest fractions were not. DL reduced the SOC in macroaggregates while NT and CT gave rise to higher SOC contents. In Mediterranean areas with Vertisols, agricultural strategies aimed at increasing the SOC contents should probably consider enhancing the proportion of coarser soil fractions so that, in the short-term, organic C can be accumulated.
  • Authors:
    • Bates, R. T.
    • Gallagher, R. S.
    • Curran, W. S.
    • Harper, J. K.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 2
  • Year: 2012
  • Summary: Conservation tillage for corn (Zea mays L.) production has greatly reduced the soil erosion potential in these systems, but relies heavily on herbicides to manage weeds. Overreliance on herbicides can lead to the development of herbicide-resistant weed communities and increase the risk of ground and surface water contamination by residual herbicides. This study evaluates the integration of various mechanical soil/weed management implements and herbicide programs for surface residue cover, weed control, corn productivity, and economic net returns. A pre-plant vertical coulter/rotary harrow tended to control small annual weeds as well as a standard burn down herbicide program, but reduced surface residue cover by 15% compared to the no-till check treatments. The high residue rotary hoe had little effect on surface residue cover, but provided inconsistent early-season weed control. The high residue inter-row cultivator resulted in 23% residue cover compared to 50% in the no-till treatments, but reduced weed biomass by 53% without any supplemental residual herbicides and 88% with a banded residual herbicide compared to the weedy check treatment. Crop productivity and net return data suggest that integrating the vertical coulter/rotary harrow, high residue cultivator, and banded residual herbicide program could reduce herbicide ai rates by 70% and still achieve similar corn yields and economic returns as the herbicide intensive systems. Such integrated mechanical-chemical systems will increase the crop management complexity for farmers, which may hinder adoption. Soil erosion potential of the integrated systems requires further in-depth evaluation.
  • Authors:
    • Bejiga, G.
    • Khalil, Y.
    • Kumar, S.
    • Haddad, A.
    • Piggin, C.
    • Ahmed, S.
  • Source: Soil & Tillage Research
  • Volume: 121
  • Year: 2012
  • Summary: Conservation agriculture is becoming popular due to its potential for enhanced productivity and cost savings among small scale farmers in developing countries. The International Center for Agricultural Research in Dry Areas is promoting conservation cropping systems that involve cereal-legume rotation in West Asia and North Africa region. Studies were made on the impact of long-term rotation trial on diseases of chickpea and lentil as well as the evaluations of lentil genotypes for their reactions to Fusarium wilt and downy mildew under two tillage practices. In the long-term rotation trials, the two season results showed no significant differences between tillage practices, crops and planting dates and their interactions in affecting mean percent cyst nematode disease. The mean cyst nematode disease incidence ranged from 7.3% on early planted lentil on CT to 14.5% in late planted chickpea on ZT. Tillage practices significantly ( P≤0.05) affected Ascochyta blight incidence but not its severity. The incidence ranged from 4% to 22.5% under early planted chickpea on both tillage practices. Moreover, the mean severity ranged from 3.2 to 5.5 rating in early planted CT and ZT, respectively. The combined analysis showed significant differences ( P≤0.05) among genotypes but not their interactions with tillage for Fusarium wilt and downy mildew reactions. All the genotypes showed less than 10% Fusarium wilt mortality indicating high levels of resistance. The mean downy mildew severity ranged from 1.3 in ILL-7991 to 2.6 rating in ILL6994. This study showed that both soil borne and foliar diseases could be a problem in conservation cropping system and continuous monitoring of diseases is essential to prioritize management practices in relation to conservation agriculture in Mediterranean type environments. Moreover, cool-season legume genotypes with disease resistance and high yield can be developed under conservation agriculture that could also serve traditionally tilled production systems.
  • Authors:
    • Bergheaud, V.
    • Benoit, P.
    • Alletto, L.
    • Coquet, Y.
  • Source: Pest Management Science
  • Volume: 68
  • Issue: 4
  • Year: 2012
  • Summary: BACKGROUND: Sorption largely controls pesticide fate in soils because it influences its availability for biodegradation or transport in the soil water. In this study, variability of sorption and desorption of isoxaflutole (IFT) and its active metabolite diketonitrile (DKN) was investigated under conventional and conservation tillage. RESULTS: According to soil samples, IFT KD values ranged from 1.4 to 3.2 L kg -1 and DKN KD values ranged from 0.02 to 0.17 L kg -1. Positive correlations were found between organic carbon content and IFT and DKN sorption. IFT and DKN sorption was higher under conservation than under conventional tillage owing to higher organic carbon content. Under conservation tillage, measurements on maize and oat residues collected from the soil surface showed a greater sorption of IFT on plant residues than on soil samples, with the highest sorbed quantities measured on maize residues ( KD ~45 L kg -1). Desorption of IFT was hysteretic, and, after five consecutive desorptions, between 72 and 89% of the sorbed IFT was desorbed from soil samples. For maize residues, desorption was weak (
  • Authors:
    • Albuquerque, J.
    • Picolla, C.
    • Mafra, A.
    • Andrade, A.
    • Bertol, I.
  • Source: Ciencia Rural
  • Volume: 42
  • Issue: 5
  • Year: 2012
  • Summary: Suitable soil management is one of the bases for sustainability in agricultural systems. The study aimed to evaluate chemical properties of a Humic Dystrudept for 12 years under two tillage systems, with crops rotation and succession. The experiment was carried out in Lages, SC, under conventional tillage (CT) and no-till (NT), with rotation (r) and succession (s) cropping systems, using crop sequences of beans-fallow-maize-fallow-soybean in CTr; maize-fallow in CTs; beans-oats-maize-fodder radish-soybean-vetch in NTr; and maize-vetch in NTs. The experimental design was completely randomized with four replicates. The soil samples were collected in the layers 0-2.5, 2.5-5, 5-10 and 10-20 cm. The variables assessed were total organic carbon (TOC), calcium, magnesium, exchangeable aluminum, phosphorus, potassium, total nitrogen (TN) and water pH. The no-tillage system increased TOC and nutrient levels in comparison with conventional tillage, especially in the surface soil layer. Maize and vetch crop succession had higher TOC and TN contents in the surface soil layer compared to crop rotation under no-tillage.