• Authors:
    • Lemke, R.
    • Frick, B.
    • Nagy, C. N.
    • Campbell, C. A.
    • Ulrich, D.
    • Thomas, A. G.
    • Brandt, S. A.
    • Basnyat, P.
    • Zentner, R. P.
    • Malhi, S. S.
    • Olfert, O. O.
    • Fernandez, M. R.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 26
  • Issue: 3
  • Year: 2011
  • Summary: Producers in the semi-arid Dark Brown Chernozemic (Typic Boroll) soil zone of the Canadian Prairie are contemplating changes to land-use practices, moving away from conventional high-input production systems that specialize in one or two annual grain crops to more diversified and extended cropping systems that use reduced-input and organic management practices. This study examined the economic merits of nine cropping systems, consisting of a factorial combination of three input management methods and three levels of cropping diversity. It was conducted over the 1996-2007 period on a loam soil at Scott, Saskatchewan. The input treatments were: (1) high input (HIGH), which used conventional tillage and full recommended rates of fertilizers and pesticides 'as required'; (2) reduced input (RED), which used conservation tillage and integrated weed and nutrient management practices in an effort to lower requirements for fuel, fertilizers and pesticides; and (3) organic input (ORG), which used tillage, non-chemical pest control, higher seeding rates, delayed seeding and legume crops to replenish soil nutrients. The crop diversity treatments included: (1) a fallow-based rotation with low crop diversity (LOW); (2) a diversified annual rotation of cereal, oilseed and pulse grains (DAG); and (3) a diversified rotation using annual grains and perennial forages (DAP). All crop rotations were 6 years in length. At the 2007 input costs and prices, average net returns and 12-year net present values were higher for organic than for non-organic treatments, with the ORG input/LOW crop diversity system being the most profitable (net returns=$234 ha -1 yr -1 and net present value=$1953 ha -1). Net returns averaged about 10% less for ORG/DAG compared to the most profitable system, and about 22% less for HIGH/DAG and RED/DAG (the best non-organic systems). The DAP treatments that included forage were not economically competitive with the other treatments, often producing economic losses. The relative profitability of the organic treatments was highly dependent on the existence of organic price premiums. When price premiums for organic crops were reduced to less than 70% of the 2007 levels, the organic treatments were less profitable than the comparable non-organic treatments. The organic treatments also experienced significantly lower (and often negative) net returns compared to the non-organic treatments during completion of the 3-year organic certification period. We estimated that it required 5-7 years after completion of certification for the organic treatments to break even with the comparable non-organic treatments. Thereafter the organic treatments produced consistently higher net earnings. Production costs averaged 16% lower with ORG management compared to the HIGH-input treatments, but we found little difference in total costs between the respective HIGH- and RED-input treatments. The organic treatments also displayed lower income variability than the non-organic treatments, with the ORG/LOW system being preferred by risk-averse producers, who do not subscribe to all-risk crop insurance, and with the ORG/LOW and ORG/DAG systems preferred by low and medium risk-averse producers when having the added financial protection from the Canada/Saskatchewan all-risk crop insurance program.
  • Authors:
    • Xie, J.
    • Li, L.
    • Huang, G.
    • Cai, L.
    • Luo, Z.
    • Zhang, R.
  • Source: Acta Prataculturae Sinica
  • Volume: 20
  • Issue: 4
  • Year: 2011
  • Summary: Long-term field experiments on soil physical quality in rainfed farming systems were conducted in Dingxi on the western Loess Plateau. The effects of conventional tillage and five conservation agriculture patterns [conventional tillage (T), conventional tillage with stubble incorporation (TS), no till with no stubble (NT), no till with stubble retention (NTS), conventional tillage with plastic mulching (TP) and no till with plastic mulching (NTP)] were studied. The experiment was fully-phased with two rotation sequences. Phase 1 started with field pea ( Pisum sativum) followed by spring wheat ( Triticum aestivum) (P->W) whereas phase 2 started with spring wheat followed by field pea (W->P). There were highly significant differences between the six tillage measures in soil properties including soil aggregates, available water content, water use efficiency and saturation conductivity. There were also significant differences in some soil properties including soil bulk density, total porosity, capillary porosity, non-capillary porosity, soil strength and saturation capacity. There were no significant differences in soil properties such as soil temperature and field capacity. Using the addition and multiplication method, and weighted integrated method, quantitative assessments of soil physical quality in different tillage systems were carried out. The order of soil physical quality index from high to low was NTS, NTP, NT, TS, T(TP) and TP(T) in P->W rotation, and NTS, NTP, TS, NT, TP and T in W->P rotation. The various tillage measures resulted in very different soil physical quality levels. Improved soil structure arose from tillage reduction or residue retention which improved soil structure, enhanced water infiltration, reduced soil and water loss, and hence improved soil physical quality.
  • Authors:
    • Rasaily, R. G.
    • He, J.
    • Li, H.
    • Zhang, X.
  • Source: International Agricultural Engineering Journal
  • Volume: 20
  • Issue: 2
  • Year: 2011
  • Summary: Due to the problem of residues blocking and seriously damaged bed shape during the planting of wheat in maize stubble coverage fields under the condition of permanent raised beds in irrigated agricultural region of Northwest China, the throwing stubble and renovating the bed type no-till planter for wheat was designed. This paper mainly analyzed the reshaping plough, moving cutter and throwing stubble device. Furthermore, the key parameters were analyzed and determined. The field experiment showed that through adopting the anti-blocking principle that combined moving cutter and throwing stubble device and residue-cutting by knife type opener, the machine could solve the residue and weed blocking problem effectively. It also has a good performance of passing and cutting stubble, and renovating the beds. The seeding and fertilizing depths acquired by the planter were 47.2 mm and 85.6 mm, respectively, which indicates the planter could meet the requirements of wheat no-tillage planting in permanent raised beds farming system in agricultural region of Northwest China.
  • Authors:
    • Li, Z.
    • Liu, W. Z.
    • Zhang, X. C.
    • Chen, J.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 10
  • Year: 2011
  • Summary: Trends and uncertainty of the climate change impacts on hydrology, soil erosion, and wheat production during 2010-2039 at El Reno in central Oklahoma, USA, were evaluated for 12 climate change scenarios projected by four GCMs (CCSR/NIES, CGCM2, CSIRO-Mk2, and HadCM3) under three emissions scenarios (A2, B2, and GGa). Compared with the present climate, overall t-tests ( n=12) show that it is almost certain that mean precipitation will decline by some 6% (>98.5% probability), daily precipitation variance increase by 12% (>99%), and maximum and minimum temperature increase by 1.46 and 1.26 degrees C (>99%), respectively. Compared with the present climate under the same tillage systems, it is very likely (>90%) that evapotranpiration and long-term soil water storage will decease, but runoff and soil loss will increase despite the projected declines in precipitation. There will be no significant changes in wheat grain yield. Paired t-tests show that daily precipitation variance projected under GGa is greater than those under A2 and B2 ( P=0.1), resulting in greater runoff and soil loss under GGa ( P=0.1). HadCM3 projected greater mean annual precipitation than CGCM2 and CSIRO ( P=0.1). Consequently, greater runoff, grain yield, transpiration, soil evaporation, and soil water storage were simulated for HadCM3 ( P=0.1). The inconsistency among GCMs and differential impact responses between emission scenarios underscore the necessity of using multi-GCMs and multi-emission scenarios for impact assessments. Overall results show that no-till and conservation tillage systems will need to be adopted for better soil and water conservation and environmental protection in the region during the next several decades.
  • Authors:
    • Shen, Y.
    • Wang, X.
    • Zheng, L.
  • Source: Acta Prataculturae Sinica
  • Volume: 20
  • Issue: 4
  • Year: 2011
  • Summary: The research presented crop yield, phosphorus dynamic for a wheat-soybean rotation systems affected by tillage management: conventional tillage (t), tillage+ stubble retention (ts), no-till (nt), no-till+stubble retention (nts) in the Loess Plateau. Results showed that ten years tillage management implementation did not carry a yield penalty for winter wheat, soybean yield had a positive response to conservation tillage. Soil phosphorus content increased with the increasing of rotation sequences. Both total phosphorus and available phosphorus contents were increased at top 0-5 cm. Stubble retention increase crop phosphorus uptake, P contents in soybean grain under nts and ts treatment were 111% and 82% higher than that under t treatment. The results provide a local agricultural implement provides certain theoretical guidance.
  • Authors:
    • Ferrari, J. V.
    • Furlani Junior, E.
    • Ferrari, S.
    • Pereira, G. A.
  • Source: SEMINA-CIENCIAS AGRARIAS
  • Volume: 32
  • Issue: 4
  • Year: 2011
  • Summary: Nitrogen application on the cover and the maintenance of straw, conducted by direct seeding, should meet the needs of agriculture and promote soil conservation. This study evaluates the effect of pre-sowing nitrogen application in cotton crops and cover crops by direct seeding, on the development and yield of cotton. It was conducted in the municipality of Selviria-MS during the agricultural years 2005/06, 2006/07 and 2007/08. The experimental design used was a randomized block design consisting of three cover crops (forage turnip, black oat and white oat) and four nitrogen doses (0, 30, 60 and 90 kg of N ha -1) in pre-sowing of cotton. In April 2006, April 2007 and April 2008, the assessments of plant development and also harvesting of the experimental plots of cotton cultivars were conducted. The results showed that after planting the cover crops, the yield and development and the heights of cotton plants increased with the use of pre-sowing N of 90 kg ha -1, also showing that the forage turnip is a coverage plant that provides increased cotton.
  • Authors:
    • Muchaonyerwa, P.
    • Chiduza, C.
    • Murungu, F. S.
    • Mnkeni, P. N. S.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 89
  • Issue: 1
  • Year: 2011
  • Summary: Increasing land degradation has prompted interest in conservation agriculture which includes growing cover crops. Besides providing soil cover, decaying cover crops may release substantial amounts of nutrients. Decomposition, N and P release from winter cover crops [grazing vetch ( Vicia darsycarpa), forage peas ( Pisum sativum) and oats ( Avena sativa)] were assessed for suitability in a cropping system found in the smallholder irrigation sector of South Africa. Nitrogen and P contribution to maize growth by cover crop residues was also estimated. Decrease in mass of cover crop residues was highest in grazing vetch (7% remaining mass after 124 days) followed by forage peas (16%) and lastly oats (40%). Maximum net mineralized N and P were higher for grazing vetch (84.8 mg N/kg; 3.6 mg P/kg) than for forage peas (66.3 mg N/kg; 2.7 mg P/ha) and oats (13.7 mg N/kg; 2.8 mg P/kg). Grazing vetch and forage pea residues resulted in higher N contribution to maize stover than oat residues. Farmers may use grazing vetch for improvement of soil mineral N while oats may result in enhancement of soil organic matter and reduction land degradation because of their slow decomposition. Terminating legume cover crops a month before planting summer crops synchronizes nutrient release from winter-grown legume cover crops and uptake by summer crops.
  • Authors:
    • Wang, R.
    • CHEN-Zhi
    • Sun, Y.
    • Zhao, Y.
  • Source: Journal of Northwest A & F University - Natural Science Edition
  • Volume: 39
  • Issue: 4
  • Year: 2011
  • Summary: Objective: The paper uncovered the wheat and potato strip intercropping farmland's resistance effects to wind erosion in the agro-pastoral ectone in order to provide theoretical foundation and techonological direction. Method: Based on agro-pastoral mixed areas of Yinshan Mountain in Inner Mongolia, soil-erosion testing experiments were conducted on three stubble coverage farmland (wheat stubble coverage, coverage 65% and 76%, stubble height 20 cm and 30 cm; naked oats stubble coverage, coverage 90%, stubble height 30 cm) under 5 scheduled velocities (6, 9, 12, 15 and 18 m/s) by means of the movable wind tunnel and its suited velocity and sand sampling equipments. The author analyzed the change disciplinarian of the surfaces' aerodynamic roughness and wind erosion amount with the increasing distance of tested points (3, 3.75, 4.5, 5.25 and 6 m) from wind tunnel experiment section entrance (Simulating conservation tillage farmland's stubble widths). Result: The roughness of three kinds of surface showed early increasing and subsequent decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities and the majority reached the max when the distance was 5.25 m; The wind erosion amount revealed rapid decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities, the decreasing trend of wind erosion amount was gentle when the distance reached 5.25 m. Conclusion: Conservation tillage farmland's stubble height and vegetation coverage increase anti-wind erosion significantly. Anti-wind erosion effect of conservation tillage farmland tends to be more steady and significant when conservation tillage farmland effective width reaches 5.25 m.
  • Authors:
    • Navarrete, L.
    • Kozak, M.
    • Hernandez Plaza, E.
    • Gonzalez-Andujar, J. L.
  • Source: Agriculture, Ecosystems and Environment
  • Volume: 140
  • Issue: 1-2
  • Year: 2011
  • Summary: This study investigated whether the choice of a tillage system (no-tillage, minimum tillage or traditional tillage) affected weed diversity in a 23 years cereal-leguminous rotation system in Spain. Weed diversity was assessed using common diversity indices: species richness, Shannon's index and Pielouis evenness. Linear mixed-effects models were employed to compare the tillage systems. It was found that after 23 years no large differences between tillage systems have arisen related to weed diversity. Only minimum tillage appeared to support, on average, more species than the two other tillage systems. Richness, Shannon diversity index and evenness varied largely through the years in all tillage systems but this variation was not related to type of crop sown (cereal or leguminous). Our results highlight that conservation tillage practices did not represent any concern for weed diversity conservation in cereal-leguminous rotations in the conditions of central Spain.
  • Authors:
    • José-María, L.
    • Sans, F. X.
  • Source: Weed Research
  • Volume: 51
  • Issue: 6
  • Year: 2011
  • Summary: Weed seedbanks are a reserve of weed diversity and can contribute to the prediction of future weed problems in arable fields. Managing seedbanks should therefore help in optimising biodiversity and controlling weed infestations. This study assessed the effects of management system (organic vs. conventional) and landscape complexity on seedbank size and species richness at the edges and centres of Mediterranean dryland cereal fields and examines the relationship between specific management practices and seedbanks. Field edges and organic fields had more species-rich, denser seedbanks than field centres and conventional fields, and landscape complexity had a limited effect on arable seedbanks. Accordingly, the promotion of low-intensity farming practices regardless of landscape complexity, especially at field edges, would be an effective measure for conservation purposes in Mediterranean agroecosystems. Nevertheless, the high seed density of organic seedbanks reveals the need for more effective seedbank management. The analysis of the effects of specific management practices highlights the importance of cleaning crop seeds properly to reduce seedbank size and using complex rotations, especially as this tends to conserve species richness while reducing seed abundance.