• Authors:
    • Black, A. L.
    • Wienhold, B. J.
    • Halvorson, A. D.
  • Source: Soil Science Society of America Journal
  • Volume: 66
  • Issue: 3
  • Year: 2002
  • Summary: Soil C sequestration can improve soil quality and reduce agriculture's contribution to CO2 emissions. The long-term (12 yr) effects of tillage system and N fertilization on crop residue production and soil organic C (SOC) sequestration in two dryland cropping systems in North Dakota on a loam soil were evaluated. An annual cropping (AC) rotation [spring wheat (SW) (Triticum aestivum L.)-winter wheat (WW)-sunflower (SF) (Helianthus annuus L.)] and a spring wheat-fallow (SW-F) rotation were studied. Tillage systems included conventional-till (CT), minimum-till (MT), and no-till (NT). Nitrogen rates were 34, 67, and 101 kg N ha-1 for the AC system and 0, 22, and 45 kg N ha-1 for the SW-F system. Total crop residue returned to the soil was greater with AC than with SW-F. As tillage intensity decreased, SOC sequestration increased (NT > MT > CT) in the AC system but not in the SW-F system. Fertilizer N increased crop residue quantity returned to the soil, but generally did not increase SOC sequestration in either cropping system. Soil bulk density decreased with increasing tillage intensity in both systems. The results suggest that continued use of a crop-fallow farming system, even with NT, may result in loss of SOC. With NT, an estimated 233 kg C ha-1 was sequestered each year in AC system, compared with 25 kg C ha-1 with MT and a loss of 141 kg C ha-1 with CT. Conversion from crop-fallow to more intensive cropping systems utilizing NT will be needed to have a positive impact on reducing CO2 loss from croplands in the northern Great Plains.
  • Authors:
    • Smith, P.
    • Williams, S.
    • Schuler, J.
    • Killian, K.
    • Moore, R.
    • Foulk, R.
    • Easter, M.
    • Cipra, J.
    • Bluhm, G.
    • Paustian, K.
    • Brenner, J.
  • Source: Report to the Nebraska Conservation Partnership
  • Year: 2002
  • Summary: Land managers have long known the importance of soil organic matter in maintaining the productivity and sustainability of agricultural land. More recently, interest has developed in the potential for using agricultural soils to sequester C and mitigate increasing atmospheric carbon dioxide by adopting practices that increase standing stocks of carbon in soil organic matter and vegetation. Practices that increase the amount of CO2 taken up by plants (through photosynthesis), which then enter the soil as plant residues, tend to increase soil C stocks. Likewise, management practices that reduce the rate of decay or "turnover" of organic matter in soils will also tend to increase carbon stocks.
  • Authors:
    • Liang, B. C.
    • Zentner, R. P.
    • Sabourin, D.
    • Izaurralde, R. C.
    • Gameda, S.
    • McConkey, B. G.
    • Campbell, C. A.
  • Source: Agriculture Practices and Policies for Carbon Sequestration in Soil
  • Year: 2002
  • Authors:
    • Ulmer, M. G.
    • Cihacek, L. J.
  • Source: Agriculture Practices and Policies for Carbon Sequestration in Soil
  • Year: 2002
  • Summary: from summary: "The significance of soils in sequestering greenhouse gases and reducing global warming may be greater due to C sequestration as inorganic C. Soil IC is a sink for atmospheric CO 2 , which may be more resistant to cropping and tillage effects on sequestered soil C and is likely to persist for decades and perhaps centuries after sequestration."
  • Authors:
    • Grove, J. H.
    • Dí­az-Zorita, M.
  • Source: Soil & Tillage Research
  • Volume: 66
  • Issue: 2
  • Year: 2002
  • Summary: Surface accumulation of soil organic carbon (SOC) under conservation tillage has significant effects on stratification of other nutrients, on crop productivity and in ameliorating the greenhouse effect via atmospheric CO, sequestration. A measure of SOC stratification relative to deeper soil layers has been proposed as a soil quality index. Our objective was to determine the effects of the duration of tillage practices upon the SOC and extractable P distribution with depth in Maury silt loams (Typic Paleudalfs) at similar levels of corn (Zea mays L.) productivity without P fertilization. Soil samples (0-20.0 cm in 2.5 cm increments) were collected under moldboard tillage (MT), chisel tillage (CT) and no-tillage (NT) and in surrounding tall fescue (Festuca arundinacea L.) sods selected from three tillage experiments (1-2-, 8- and 29-year durations) in Kentucky. SOC stratification was greater under conservation tillage (CT and NT) and sods than under MT. SOC and soil-test-extractable P stratification were positively related. Increasing the duration under NT caused the thickness of C stratification to increase. In NT soils, C stratification ratio (CSR) approached CSR in the nearby long-term sods with time. Conservation tillage rapidly promoted the occurrence of CSR greater than 2 while MT always resulted in values lower than 2. The rapid initial change in CSR suggests characterization of thin soil layers (i.e. 2.5 cm depth increments) is desirable under conservation tillage. (C) 2002 Elsevier Science B.V. All rights reserved.
  • Authors:
    • Riedell, W. E.
    • Pikul, J. L.
    • Archer, D. W.
  • Source: Soil & Tillage Research
  • Volume: 67
  • Issue: 1
  • Year: 2002
  • Summary: Ridge tillage (RT) has been proposed as an economically viable conservation tillage alternative for row crop production; however the long-term economic viability of RT in the northern Corn Belt of the USA is largely unknown. Economic returns, risk and input use were compared for RT and conventional tillage (CT) in a corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) rotation with high, medium and low nitrogen treatments. The analysis was based on 10 years of experimental data from Brookings, SD on a Barnes clay loam (US soil taxonomy: fine-loamy, mixed, superactive, frigid Calcic Hapludoll; FAO classification: Chernozem). Economic returns were significantly higher at the highest nitrogen treatment levels. Highest average net returns to land and management were $ 78 per hectare for RT at the high nitrogen treatment level (RT-H) followed by $ 59 per hectare for CT at the high nitrogen treatment level (CT-H). Risk, measured as the standard deviation of net returns, was the lowest for CT at the medium nitrogen treatment level (CT-M) followed by RT-H and CT-H. However, net returns were substantially lower under CT-M at $ 32 per hectare. Average yields and average operating costs were not significantly different for RT-H and CT-H. Reduced equipment operating costs for CT-H were offset by increased herbicide costs for RT-H. Equipment ownership costs were significantly lower for RT-H than CT-H. There were no significant differences in fertilizer use for RT and CT. Pesticide use was significantly higher for RT-H than CT-H. Fuel use was 18-22% lower and labor use was 24-27% lower for RT-H than CT-H. Despite continued low adoption rates for RT in the northern Corn Belt, our analysis shows that RT is an economically viable alternative to CT.
  • Authors:
    • Kennedy, G. G.
    • Barbercheck, M. E.
    • Walgenbach, J. F.
    • Hummel, R. L.
    • Hoyt, G. D.
    • Arellano, C.
  • Source: Environmental Entomology
  • Volume: 31
  • Issue: 1
  • Year: 2002
  • Summary: Populations of endemic soil entomopathogens (nematodes and fungi) were monitored in vegetable production systems incorporating varying degrees of sustainable practices in Fletcher, NC. Two tillage types (conventional plow and disk versus conservation tillage), two input approaches (chemically versus biologically based), and two cropping schedules (continuous tomato versus 3-yr rotation of corn, cucumber, cabbage, and tomato) were employed in large plots from 1995 to 1998. A Galleria mellonella (L.) trap bioassay was used to identify and monitor activity of Steinernema carpocapsae, Heterorhabditis bacteriophora, Beauveria bassiana, and Metarhizium anisopliae populations during the vegetable growing season (April-September). Seasonal detection of entomopathogens was significantly higher in conservation compared with conventional tillage systems. The strip-till operation did not affect levels of detection of S. carpocapsae. Pesticide use significantly reduced detection of entomopathogenic fungi. Type of ground cover significantly affected temperature in the upper 12 cm of soil; highest soil temperatures were observed under black plastic mulch and bare ground, whereas lowest temperatures were observed under rye mulch and clover intercrop. The high soil temperatures associated with certain ground covers may have reduced entomopathogen detection or survival. Although type of tillage appeared to be the primary factor affecting survival of endemic soil entomopathogens in our system, other factors, such as pesticide use and type of ground cover, can negate the positive effects of strip-tillage.
  • Authors:
    • Hoyt, G. D.
    • Walgenbach, J. F.
    • Hummel, R. L.
    • Kennedy, G. G.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 93
  • Issue: 1-3
  • Year: 2002
  • Summary: Populations of foliar insect pests and natural enemies were monitored in vegetable production systems incorporating varying degrees of sustainable practices in Fletcher, NC, USA. Two types of tillage (conventional plow and disk, strip-tillage), two input approaches (chemically-based, biologically-based) and two cropping schedules (continuous tomato (Lycopersicon esculentum Mill.), 3-year rotation of corn (Zea mays L.), cucumber (Cucumis sativus L.) and tomato) were employed from 1995 to 1998. Tomato pest pressure was relatively low in all years, resulting in a limited impact of production systems on potato aphid, Macrosiphum euphorbiae (Thomas) (Homoptera: Aphididae), and its associated parasitoids and predators. Thrips (Frankliniella spp. (Thysanoptera)) populations were significantly higher in the biological input treatments in 3 of 4 years. Lepidopterous (primarily Helicoverpa zea Boddie (Lepidoptera: Noctuidae)) damage on tomato was significantly higher in biological treatments in all years, damage by thrips and pentatomids (Hemiptera: Pentatomidae) increasing each year in the continuous tomato crop schedule. Most insect populations were significantly influenced by type of insecticide input or ground cover. Few population measurements were affected by tillage type. Foliar insect problems in commercial vegetable production may be associated predominantly with insecticide input (i.e. more damage with biologically based insecticides) and use of intercropping (i.e. more damage in systems with living mulch); however, the long term effects of tillage and crop rotation remain to be seen. (C) 2002 Elsevier Science B.V. All rights reserved.
  • Authors:
    • Hoyt, G. D.
    • Walgenbach, J. F.
    • Hummel, R. L.
    • Kennedy, G. G.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 93
  • Issue: 1-3
  • Year: 2002
  • Summary: Populations of epigeal arthropods were monitored in vegetable production systems under varying degrees of sustainable agricultural practices in Fletcher, NC (USA). Two tillage types (conventional plow and disk, strip-tillage (ST)), two input approaches (chemically based, biologically based) and two cropping schedules (continuous tomato Lycopersicon esculentum Mill., 3-year rotation of sweet corn [Zea mays L.]/cabbage [Brassica oleracea L.], cucumber [Cucumis sativus L.]/cabbage and tomato) were employed from 1995-1998. A second study with tomatoes was performed in 1997-1998 to separate effects of pesticide use, intercropping and herbicide application. Pitfall traps (48-h sample period) were used at similar to25-day intervals to monitor relative activity of carabid beetles (Coleoptera: Carabidae), staphylinid (Coleoptera: Staphylinidae) beetles and lycosid spiders (Araneidae: Lycosidae). Carabids and lycosids appeared to be more active in systems with ground cover. Trap catches of carabid species were not significantly affected by insecticide input, but trap catches of lycosids were lower in plots with conventional insecticide use. No consistent effect of tillage was found over time, although Scarites spp. were more active in minimally disturbed habitats in 1998. Two distinct patterns of seasonal activity were observed for carabid beetles and lycosid spiders. Ground cover generally enhanced abundance of carabids and lycosids, while tillage type, pesticide use and crop rotation had different effects. (C) 2002 Elsevier Science B.V. All rights reserved.
  • Authors:
    • Ulrich, D.
    • Brandt, S. A.
    • Malhi, S. S.
    • Lemke, R.
    • Gill, K. S.
  • Source: Journal of Plant Nutrition
  • Volume: 25
  • Issue: 11
  • Year: 2002
  • Summary: Cropping systems can influence the accumulation and distribution of plant nutrients in the soil profile, which can affect their utilization efficiency by crops and pollution potential in the environment. A field experiment was conducted on a Dark Brown loam soil at Scott, Saskatchewan, Canada to assess the effects of input level, cropping diversity and crop phase on the accumulation and distribution of nitrate-nitrogen (N) and extractable phosphorus (P) in the soil profile at the end of 1995 to 2000 growing seasons. The 54 treatments were combinations of three input levels (organic-ORG, reduced-RED and high-HIGH), three cropping diversities (low diversity-LOW, diversified annual grains-DAG, and diversified annual and perennials-DAP), and six crop phases chosen from fallow (tillage-fallow or chemfallow), green manure [lentil-Lens culinaris Medicus or sweet clover-Melilotus officinalis (L.) Lam], spring wheat (Triticum aestivum L.), canola (Brassica napus L. and Brassica rapa L.), fall rye (Secale cereale L.), field pea (Pisum sativum L.), spring barley (Hordeum vulgare L.), flax (Linum usitatissimum L.), oats (Avena sativa L.), and bromegrass (Bromus inermis Leyss), alfalfa (Medicago sativa Leyss) mixture hay. Soil was sampled from the 0-15, 15-30, 30-60, and 60-90cm depths in each crop phase from 1995 to 2000, with additional depths 90-120, 120-150, 150-180, 180-210, and 210-240cm taken from the wheat phase in 2000. In general, there were greater amounts of nitrate-N with HIGH input compared to ORG or BID inputs, especially under LOW diversity. The nitrate-N in various soil depths suggested some downward movement of nitrate-N to the deeper soil depths when HIGH input was compared to ORG input. In LOW cropping diversity, green manure or fallow usually had more nitrate-N in soil than other crop phases. In DAG and DAP cropping diversities, nitrate-N varied with crops and on average it had maximum concentration after wheat or canola in DAG and after hay followed closely by wheat in DAP. The ORG input level had greater nitrate-N than RED or HIGH inputs in some instances, most likely due to relatively low extractable P in soil for optimum crop growth under ORG input. Extractable P in the 0-15 and 15-30 cm soil depths tended to be greater under HIGH or RED inputs compared to the ORG input level in many cases. In summary there was no consistent effect of cropping diversity on extractable P in soil under ORG input, but LOW diversity tended to show more extractable 13 compared to DAG and DAP diversities in some cases of RED and HIGH inputs. The green manure/fallow, HIGH input and LOW diversity treatments tended to result in higher nitrate-N and extractable P levels compared to the corresponding treatments, and the effects were more pronounced on nitrate-N than extractable P and in shallow compared to deeper soil layers.