• Authors:
    • Kayisoglu, B.
    • Yalcn, H.
    • Koc, F.
    • Gonulol, E.
    • Bayhan, Y.
  • Source: Farm work science facing the challenges of the XXI century. Proceedings XXIX CIOSTA-GIGR V Congress, Krakow, Poland, 25-27 June, 2001, p. 30-35
  • Volume: 10
  • Year: 2001
  • Summary: The effect of different tillage methods on silage quality in second crop maize for silage was determined in this study. For this purpose, second crop maize was planted by using the following tillage methods: (1) Direct drilling (no-till) (DRD); (2) Heavy duty disc harrow+pneumatic precision drill (DIS); (3) Plough+disc harrow+roller+pneumatic precision drill (PLO); (4) Rotary tiller+pneumatic precision drill (ROT); (5) Tillage combination+pneumatic precision drill (TIC); and (6) Irrigation+Plough+disc harrow+roller+pneumatic precision drill (conventional) (CON). After harvesting, plant samples were filled into PVC silos (with three replication for each treatment) for fermentation and kept in these silos for 75 days. Significant statistical differences were found between treatments (tillage methods) according to pH, DM (dry matter), CA (crude ash), CF (crude fibre), WSC (water soluble carbohydrate), NH 3-N 3 and LAB (lactic acid batteries). Quality parameters in all treatments remained between the desired levels. No-tillage method with DRD and minimum tillage methods with ROT and TIC can be suggested.
  • Authors:
    • Nyakatawa,E. Z.
    • Reddy,K. C.
  • Source: Agronomy Journal
  • Volume: 92
  • Issue: 5
  • Year: 2000
  • Summary: Inadequate and less vigorous crop stand is a constraint to adoption of conservation tillage in cotton (Gossypium hirsutum L.) production. We evaluated the effects of tillage (conventional till, mulch-till, no-till), cropping system (cotton-winter fallow, cotton-winter rye, Secale cereale L.), and N source and rate (ammonium nitrate and poultry litter; 0, 100, and 200 kg N ha(-1)) on rotten seedling emergence on a Decatur silt loam soil (Typic Paleudults) in northern Alabama, from 1996 to 1998. Cotton seedling counts under no-till were 40 to 150% greater than those under conventional till at 1 and 2 d during seedling emergence. Cotton-winter rye cropping system had 14 to 50% greater seedling counts than cotton-winter fallow cropping during the first 4 d of emergence in 1998. Poultry litter source of N gave 17 to 50% greater cotton seedling counts than ammonium nitrate during the first 4 d of emergence in 1998, In all these cases, the differences progressively narrowed down by the 4th day of seedling emergence. Cotton seedling counts were significantly correlated to cotton growth parameters and lint yield, especially in the drier year (1998). These results were attributed to soil moisture conservation during seedling emergence. Our results show that conservation tillage improved cotton germination, emergence, dry matter, and lint yield. Therefore, no-till with winter rye cover cropping and poultry litter can be used for achieving early cotton seedling emergence and growth in the U.S. cotton belt where dryland cotton production systems are on the increase and safe disposal of poultry litter is becoming an environmental problem.
  • Authors:
    • Wu, J. J.
  • Source: American Journal of Agricultural Economics
  • Volume: 82
  • Issue: 4
  • Year: 2000
  • Summary: Each year, billions of dollars of public funds are expended to purchase conservation easements on farmland. One unintended impact of these programs is that they may bring non-cropland into crop production. Such a slippage effect can be caused by increased output prices and by substitution effects. This article shows that for each one hundred acres of cropland retired under the Conservation Reserve Program (CRP) in the central United States, twenty acres of non-cropland were converted to cropland. offsetting 9% and 14% of CRP water and wind erosion reduction benefits, respectively. Implications of these results for the design of conservation programs are discussed.
  • Authors:
    • Hulugalle, N. R.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 31
  • Issue: 5-6
  • Year: 2000
  • Authors:
    • Hunt, H. W.
    • Elliott, E. T.
    • Six, J.
    • Paustian, K.
  • Source: Biogeochemistry
  • Volume: 48
  • Issue: 1
  • Year: 2000
  • Summary: Crop-based agriculture occupies 1.7 billion hectares, globally, with a soil C stock of about 170 Pg. Of the past anthropogenic CO2 additions to the atmosphere, about 50 Pg C came from the loss of soil organic matter (SOM) in cultivated soils. Improved management practices, however, can rebuild C stocks in agricultural soils and help mitigate CO2 emissions. Increasing soil C stocks requires increasing C inputs and/or reducing soil heterotrophic respiration. Management options that contribute to reduced soil respiration include reduced tillage practices (especially no-till) and increased cropping intensity. Physical disturbance associated with intensive soil tillage increases the turnover of soil aggregates and accelerates the decomposition of aggregate-associated SOM. No-till increases aggregate stability and promotes the formation of recalcitrant SOM fractions within stabilized micro- and macroaggregate structures. Experiments using 13C natural abundance show up to a two-fold increase in mean residence time of SOM under no-till vs intensive tillage. Greater cropping intensity, i.e., by reducing the frequency of bare fallow in crop rotations and increasing the use of perennial vegetation, can increase water and nutrient use efficiency by plants, thereby increasing C inputs to soil and reducing organic matter decomposition rates. Management and policies to sequester C in soils need to consider that: soils have a finite capacity to store C, gains in soil C can be reversed if proper management is not maintained, and fossil fuel inputs for different management practices need to be factored into a total agricultural CO2 balance.
  • Authors:
    • Kwon, K. C.
    • Post, W. M.
  • Source: Global Change Biology
  • Volume: 6
  • Issue: 3
  • Year: 2000
  • Summary: When agricultural land is no longer used for cultivation and allowed to revert to natural vegetation or replanted to perennial vegetation, soil organic carbon can accumulate. This accumulation process essentially reverses some of the effects responsible for soil organic carbon losses from when the land was converted from perennial vegetation. We discuss the essential elements of what is known about soil organic matter dynamics that may result in enhanced soil carbon sequestration with changes in land-use and soil management. We review literature that reports changes in soil organic carbon after changes in land-use that favour carbon accumulation. This data summary provides a guide to approximate rates of SOC sequestration that are possible with management, and indicates the relative importance of some factors that influence the rates of organic carbon sequestration in soil. There is a large variation in the length of time for and the rate at which carbon may accumulate in soil, related to the productivity of the recovering vegetation, physical and biological conditions in the soil, and the past history of soil organic carbon inputs and physical disturbance. Maximum rates of C accumulation during the early aggrading stage of perennial vegetation growth, while substantial, are usually much less than 100 g C m-2 y-1. Average rates of accumulation are similar for forest or grassland establishment: 33.8 g C m-2 y-1 and 33.2 g C m-2 y-1, respectively. These observed rates of soil organic C accumulation, when combined with the small amount of land area involved, are insufficient to account for a significant fraction of the missing C in the global carbon cycle as accumulating in the soils of formerly agricultural land.
  • Authors:
    • Raper, R. L.
    • Runion, G. B.
    • Reeves, D. W.
    • Reicosky, D. C.
    • Prior, S. A.
  • Source: Soil & Tillage Research
  • Volume: 54
  • Issue: 3-4
  • Year: 2000
  • Summary: Recent research indicates tillage operations result in a rapid physical release of CO2 and water vapor from soil. However, effects of soil disturbance on gas fluxes during planting operations have not been adequately explored. Our objective was to measure short-term gas loss resulting from the use of different planting preparation implements on long-term residue-covered soil (no-till) on a Norfolk loamy sand (Typic Kandiudults; FAO classification Luxic Ferralsols) in east-central Alabama, USA. A crimson clover (Trifolium incarnatum L.) cover crop was killed with herbicide two weeks prior to the study. Due to dry soil conditions, 15 mm of water was applied 24 h prior to study. Gas fluxes were measured with a large canopy chamber (centered over two rows) for an integrated assessment of equipment-induced soil disturbance. Increased losses of CO2 and water vapor were directly related to increases in soil disturbance. Although these short-term C losses are minor in terms of predicting longterm C turnover in agro-ecosystems, results suggest that selecting planting equipment that maintains surface residue and minimizes soil disturbance could help to conserve soil water needed for successful seedling establishment in these coarse textured soils. Published by Elsevier Science B.V.
  • Authors:
    • Meijles, E. W.
    • van Essen, E. A.
    • Bouma, J.
    • Pulleman, M. M.
  • Source: Soil Science Society of America Journal
  • Volume: 64
  • Issue: 2
  • Year: 2000
  • Summary: A regional survey of management and crop type and soil organic matter (SOM) content was conducted in one soil series in the Netherlands (loamy, mixed, mesic, Fluventic Eutrudept). The objective was to determine the effects of land use history on SOM contents in a prime agricultural soil, using available soil survey information and statistical analyses. Soil organic matter content is a relatively stable, integrating soil characteristic that reflects long-term land use and is an important indicator of soil quality. The SOM contents and information about past land use were obtained from 45 fields. Land use history was expressed in terms of (i) tillage; (ii) crop type; and (iii) use of chemical fertilizers, (iv) manure, and (v) biocides, for six successive periods (63-31, 31-15, 15-7, 7-3, 3-1, and 1-0 yr before sampling). Only four land use types occurred: conventional-arable, conventional-grass, organic-arable, and organic-grass. The SOM contents ranged between 17 and 88 g kg-1. Regression models of the actual SOM content as a function of crop type and management in the different periods showed that SOM contents were increased under long-term grass or, to a lesser extent, by organic farming, when compared with conventional-arable use. The regression model depends on the nature of land use history in any particular region and on the length of the selected periods, but it provides an easy method to predict SOM content as a function of management in a given soil series. The method can be an alternative to simulation modeling in situations where detailed data records from long-term field experiments are not available.
  • Authors:
    • Rhoton, F. E.
  • Source: Soil Science Society of America Journal
  • Volume: 64
  • Issue: 2
  • Year: 2000
  • Summary: The number of growing seasons required for no-till practices to improve soil properties should be considered before changing management systems. To evaluate this time factor, an 8-yr tillage study was conducted on a Grenada silt loam (fine-silty, mixed, active, thermic Glossic Fragiudalfs) using cotton (Gossypium hirsutum L.), grain sorghum [Sorghum bicolor (L.) Moench]-corn (Zea mays L.), and soybean [Glycine max (L.) Merr.]-wheat (Triticum aestivum L.) as test crops. Soil samples were characterized for soil organic matter (SOM), pH, exchangeable Ca and Mg, extractable P, K, Fe, Mn, Cu, and Zn, aggregate stability (AS), water dispersible clay (WDC), total clay (TC), and modulus of rupture (MR) at time 0, 4, and 8 yr. Within 4 yr, no-till (NT) resulted in statistically significant (P less than or equal to 0.05) differences compared to conventional tillage (CT). The surface 2.5 cm of the NT treatments had higher levels of SOM, exchangeable Ca, and extractable P, Mn, and Zn, but lower extractable K, Fe, and Cu. Tillage had no effect on exchangeable Mg and pH. No-till also resulted in higher AS, and lower MR, WDC, and TC in the top 2.5 cm, relative to CT. The differences in soil properties between tillage treatments were essentially independent of crop. Instead, the results are controlled by relative amounts of SOM and clay, and the extent to which these properties change with time. Undoubtedly, NT practices ran improve several fertility and erodibility-related properties of this soil within 4 yr, and-enhance its sustainability.
  • Authors:
    • TCG
    • Teasdale,John R.
    • Rosecrance,R. C.
    • Coffman,Charles B.
    • Starr,J. L.
    • Paltineanu,I. C.
    • Lu,Y. C.
    • Watkins,B. K.
  • Source: American Journal of Alternative Agriculture
  • Volume: 15
  • Issue: 2
  • Year: 2000
  • Summary: Sustainable production systems are needed to maintain soil resources and reduce environmental contamination on erodible lands that are incompatible with tillage-intensive operation. A long-term cropping systems comparison was established at Beltsville, Maryland, on a site with 2 to 15% slope to evaluate the efficacy of sustainable strategies compatible with reduced-tillage systems. All systems followed a 2-year rotation of corn the first year and winter wheat followed by soybean the second year. Treatments included (1) no-tillage system with recomended fertilizer and herbicide inputs, (2) crownvetch living mulch system with similar inputs to the no-tillages system, (3) cover crop system including a hairy vetch cover crop before corn and a wheat cover crop before soybean with reduced fertilizer and herbicide inputs, (4) manure systemd including crimson clover green manure plus cow manure for nutrient sources, chisel plow/disk for incorporatin manure and rotary hoe plus cultication for weed control. Results from the initial 4 years demonstrated the relative productivity of these systems. Corn yields were similar in the no-tillage and cover crop systems in each year. both systems average 7.8 Mg ha-1 compared to 5.7 Mg ha-1 in both the croen vetch and manure systems. Wheat yields were highest in the manure system in the first 2 years and in the crown vetch system in the last 2 years. Soybean yields were highest in the cover crop system in all years. The manure system usually had lower yields than the highest yielding system, partly because of competitions from uncontrolled weeds. Several measures of the efficience of grain production were evaluated. The no-tillage system produced the most grain per total vegetative biomass throughout the rotation. The cover crop system produced the most grain per unit of external N input and, along with the no-tillage system, had the highest corn water-use efficiency. The cover crop system also recycled the most vegetative residues and nutrients of all systems. No single system perfomed best according to all measures of comparison, suggesting that trade-offs will be required when choosing production systems.