• Authors:
    • Cantero-Martinez, C.
    • Westfall, D. G.
    • Sherrod, L. A.
    • Peterson, G. A.
  • Source: Journal of Soil and Water Conservation
  • Volume: 61
  • Issue: 2
  • Year: 2006
  • Summary: The presence of crop residue is an important component of dryland cropping systems management in the semiarid environment where soil erosion by wind is a major soil degradation process. Residue also affects precipitation capture and runoff. Long-term residue quantity dynamics of different cropping systems has not been studied in the semi-arid environment of the western Great Plains. Long-term studies were conducted in eastern Colorado, USA to determine the interaction of no-till cropping systems, soils, and climatic gradient on the production, retention, and disappearance of crop residue over a 12-year period. The cropping systems evaluated were winter wheat ( Triticum aestivum)-summer fallow (WF), winter wheat-maize ( Zea mays) or sorghum ( Sorghum bicolor)-summer fallow (WC/SF), winter wheat-maize/sorghum-millet ( Panicum miliaceum)-summer fallow (WC/SMF), and continuous cropping (CC). A soil surface residue base was achieved in a few years (four to five) and changed little over time. However, as cropping intensity increased the total crop residue retained on the soil surface increased as the proportion of fallow time decreased; a general trend was for residue levels to increase slowly. However, in the winter wheat-summer fallow system residue levels showed a trend to decrease after the initial base was achieved. Greater residue production and retention occurred on the toeslope soil position because these soils are deeper, have greater water holding capacity, and receive run-on water from upslope positions. Residue disappearance was less in the fallow period before maize planting compared to before wheat planting due to the greater fallow period, which included summer fallow in the wheat system. Residue loss was greater during the crop production periods as compared to the fallow periods. The levels of residue present on the soil surface in our intensive no-till cropping systems were generally adequate to control erosion by wind. However, at our high potential evapotranspiration site the residue levels were "marginal" for adequate wind erosion abatement, particularly in the winter wheat-summer fallow system. A combination of no-till management and increased cropping intensity (greater than winter wheat-summer fallow) is the key to sustainable production and soil conservation in this semi-arid environment.
  • Authors:
    • Gill, M.
    • Sarlach, R.
  • Source: Environment and Ecology
  • Volume: 24
  • Issue: 1
  • Year: 2006
  • Summary: The kandi region comprising 0.5 m ha (about 9.5%) of Punjab, India, is characterized undulated topography, light soil texture, heavy run off and soil erosion losses, poor moisture retentivity and devoid of easily exploitable underground water sources, and is therefore highly dependent upon seasonal south-west monsoon (July-September). It is coupled with poor infrastructure of roads and marketing, illiteracy, heavy cattle and human population pressure and agriculture adopted as subsidiary occupation. About 25-40% of the monsoon rains is lost as run off. The soils are non-saline, organic carbon averages 0.24% in loamy sand and 0.30 or more in sandy loam soils. The corresponding values of moisture retention at 1/3 bar or field capacity range from 8.1 to 15.8% and at 15 bar (permanent wilting point) from 3.7 to 4.8% in 0-180 cm soil layer of loamy sand soil and 16.2 to 21.5% and 3.7 to 7.6% respectively in sandy loam soil. In situ soil moisture conservation with the minor leveling, bunding and installation of suitable water structure helped to increase the yield of wheat [ Triticum aestivum] + gram [ Vigna mungo] by 57% and pearl millet by 25%. In light soil, green manuring during kharif gave an edge of 0.5 q/ha over the fallow fields on account of more rain water conservation and addition of green matter in soil. Mulching in standing maize [ Zea maize] in kharif helped to conserve the moisture in seed zone (0-15 cm) layer and ensured germination of succeeding wheat crop. Using the stored water in ponds during rainy season and its use as light irrigation (5 cm) at the initial moisture stress or as life saving irrigation, resulted in the better establishment of crops and increased the yield by 669 kg/ha over the controlled un-irrigated plots. Amongst the various crops, management practices conserving the soil moisture during kharif season and taking winter season crop were found promising technologies. Raya grown as an inter-rowcrop at 2.0 to 2.5 meter interval gave 2.5 q/ha seed yield. Application of fertilizer under dry land conditions seemed to be a prerequisite. It improved the above-, and below-, ground biomass and helped extend the root system to exploit water from deeper layer of soils and enabled the crop sustain the drought better and resulted in 50-70% grain yield increases in combination with fertilizer application. Under such an approach, fertilizer schedule for wheat was established at 80-40-20; N-P 2O 5-K 2O kg/ha in medium to heavy soil; and 40-20-10; N-P 2O 5-K 2O kg/ha for wheat or wheat+gram for light soils while the fodder ( kharif) and raya required just about 50 kg. N/ha.
  • Authors:
    • Waddell, J.
    • Caesar-Tonthat, T.
    • Lenssen, A.
    • Sainju, U. M.
  • Source: Soil Science Society of America Journal
  • Volume: 70
  • Issue: 2
  • Year: 2006
  • Summary: Sustainable management practices are needed to enhance soil productivity in degraded dryland soils in the northern Great Plains. We examined the effects of two tillage practices [conventional till (CT) and no-till (NT)], five crop rotations [continuous spring wheat (Triticum aestivum L.) (CW), spring wheat-fallow (W-F), spring wheat-lentil (Lens culinaris Medic.) (W-L), spring wheat-spring wheat-fallow (W-W-F), and spring wheat-pea (Pisum sativum L.)-fallow (W-P-F)], and a Conservation Reserve Program (CRP) on plant biomass returned to the soil, residue C and N, and soil organic C (SOC), soil total N (STN), and particulate organic C and N (POC and PON) at the 0- to 20-cm depth. A field experiment was conducted in a mixture of Scobey clay loam (fine, smectitic, frigid Aridic Argiustolls) and Kevin clay loam (fine-loamy, mixed, superactive, frigid Aridic Argiustolls) from 1998 to 2003 near Havre, MT. Mean annualized plant biomass returned to the soil from 1998 to 2003 was greater in W-F (2.02 Mg ha-1) than in W-L and W-W-F, regardless of tillage. In 2004, residue cover was greater in CW (60%) than in other rotations, except in W-W-F. Residue amount and C and N contents were greater in NT with CW (2.47 Mg ha-1 and 963 and 22 kg ha-1, respectively) than in NT with W-L and CT with other crop rotations. The POC at 0 to 5 cm was greater in W-W-F and W-P-F (2.1-2.2 Mg ha-1) than in W-L. Similarly, STN at 5 to 20 cm was greater in CT with W-L (2.21 Mg ha-1) than in other treatments, except in NT with W-W-F. Reduced tillage and increased cropping intensity, such as NT with CW and W-L, conserved C and N in dryland soils and crop residue better than the traditional practice, CT with W-F, and their contents were similar to or better than in CRP planting.
  • Authors:
    • Schillinger, W. F.
    • Wuest, S. B.
    • Williams, J. D.
    • Gollany, H. T.
  • Source: Soil & Tillage Research
  • Volume: 86
  • Issue: 2
  • Year: 2006
  • Summary: Water erosion and runoff can be severe due to poor infiltration through frozen soil in the dryland wheat (Triticum aestivum L.) production region of the inland Pacific Northwest (PNW), USA. For more than 70 years, farmers and researchers have used various methods of subsoiling to reduce runoff and erosion and to improve infiltration and soil moisture storage. The practice and equipment have evolved from chiseling continuous open channels across hillslopes to the rotary subsoiler that pits the soil. Farmers often subsoil wheat stubble after harvest, but do not employ this practice on newly planted winter wheat fields. These fields are especially vulnerable to erosion because of meager residue cover after a year of fallow. A 6-year field study was conducted in eastern Washington to determine the effect of rotary subsoiling in newly planted winter wheat on over-winter water storage. erosion, infiltration, and grain yield. There were two treatments, rotary subsoiling and control. The rotary subsoiler created one 40 cm-deep pit with 4 L capacity every 0.7 m(2). Natural precipitation did not cause rill erosion in either treatment because of mild winters during the study period. Net change in water stored over winter was significantly (P < 0.05) improved with rotary subsoiling compared to the control in 2 of 6 years. Grain yield was not affected by treatments in any year or when averaged over years. In 2003, we simulated rainfall for approximately 3 h at a rate of 18 mm/h on both subsoiled and control plots to determine runoff and erosion responses on frozen soils. Rotary subsoiling reduced runoff (P < 0.01) by 38%. Rotary subsoiling also significantly reduced erosion (P < 0.01) during the 20-45 min period after runoff had begun. The total quantities of eroded soils were 1.3 and 3.4 Mg/ha for the subsoiled and control treatments, respectively, with inter-rill the dominant erosion process. The average infiltration rate for the control treatment (3.3 mm/h) was half of the rate for the subsoiled treatment (6.6 mm/h), at the end of the 3 h simulation. Rotary subsoiling of newly-planted winter wheat can increase soil moisture stored over-winter and reduce runoff and soil loss on frozen soils, but the benefit of this practice for increasing grain yield has not been proven.
  • Authors:
    • Kushnak, G. D.
    • Riveland, N.
    • Eckhoff, J. L.
    • Wichman, D. M.
    • Carlson, G. R.
    • Kephart, K. D.
    • Cook, C. R.
    • Stougaard, R. N.
    • Berg, J. E.
    • Nash, D. L.
    • Bruckner, P. L.
  • Source: Crop Science
  • Volume: 46
  • Issue: 3
  • Year: 2006
  • Summary: MT1159CL (Reg. No. CV-992, PI 641221) hard red winter wheat ( Triticum aestivum) was developed by Montana Agricultural Experiment Station and released in September 2004, for its tolerance to imazamox herbicide, adaptation to dryland production in central and south-central Montana, and improved milling and bread baking qualities relative to other available Clearfield winter wheat cultivars. This double-haploid line developed using the wheat * maize hybridization method from the cross FS2/Tiber (PI 517194) has moderate resistance to stripe rust ( Puccinia striiformis f.sp. tritici).
  • Authors:
    • Barker-Reid, F.
    • Gates, W. P.
    • Eckard, R. J.
    • Wilson, K.
    • Baigent, R.
    • Galbally, I. E.
    • Meyer, C. P.
    • Weeks, I. A.
  • Source: 4th International Symposium on non-CO2 Greenhouse Gases
  • Year: 2005
  • Authors:
    • Paustian, K.
    • Breidt, F. J.
    • Ogle, S. M.
  • Source: Biogeochemistry
  • Volume: 72
  • Issue: 1
  • Year: 2005
  • Summary: We conducted a meta-analysis to quantify the impact of changing agricultural land use and management on soil organic carbon (SOC) storage under moist and dry climatic conditions of temperate and tropical regions. We derived estimates of management impacts for a carbon accounting approach developed by the Intergovernmental Panel on Climate Change, addressing the impact of long-term cultivation, setting-aside land from crop production, changing tillage management, and modifying C input to the soil by varying cropping practices. We found 126 articles that met our criteria and analyzed the data in linear mixed-effect models. In general, management impacts were sensitive to climate in the following order from largest to smallest changes in SOC: tropical moist>tropical dry>temperate moist>temperate dry. For example, long-term cultivation caused the greatest loss of SOC in tropical moist climates, with cultivated soils having 0.58 ± 0.12, or 58% of the amount found under native vegetation, followed by tropical dry climates with 0.69 ± 0.13, temperate moist with 0.71 ± 0.04, and temperate dry with 0.82 ± 0.04. Similarly, converting from conventional tillage to no-till increased SOC storage over 20 years by a factor of 1.23 ± 0.05 in tropical moist climates, which is a 23% increase in SOC, while the corresponding change in tropical dry climates was 1.17 ± 0.05, temperate moist was 1.16 ± 0.02, and temperate dry was 1.10 ± 0.03. These results demonstrate that agricultural management impacts on SOC storage will vary depending on climatic conditions that influence the plant and soil processes driving soil organic matter dynamics.
  • Authors:
    • Ahuja, L. R.
    • Westfall, D. G.
    • Peterson, G. A.
    • Sherrod, L. A.
  • Source: Soil Science Society of America Journal
  • Volume: 69
  • Issue: 5
  • Year: 2005
  • Summary: Previous studies of no-till management in the Great Plains have shown that increased cropping intensity increased soil organic carbon (SOC). The objectives of this study were to (i) determine which soil C pools (active, slow, and passive) were impacted by cropping intensity after 12 yr of no-till across potential evapotranspiration (PET) and slope position gradients; (ii) relate C pool sizes to the levels found in total SOC; and (iii) determine C pool sizes relative to C levels found in a grass treatment (G). Cropping systems were wheat (Triticum aestivum)-fallow (WIT), wheat-corn (Zea mays L.)-fallow (WCF), wheat-corn-millet (Panicum miliaceum)-fallow (WCMF), and continuous cropping (CC) at three PET sites in Colorado. Active C (Soil microbial biomass C [SMBC]); and slow pool C (particulate organic matter C; POM-C) increased as cropping intensity increased, dependent on PET. Passive C (mineral associated organic C [MAOC]) was strongly influenced by a site-by-slope position interaction but not by cropping system. Toeslope soils had 35% higher POM-C compared with summits and sideslopes. All C pools were strongly correlated with total SOC, with the variability decreasing as C pool turnover time increased. Carbon pool sizes in cropping systems relative to levels found in G were independently influenced by cropping system. The highest were found in the CC system, which had 91, 78, and 90% of the amounts of C found in the perennial G system in the active, slow, and passive C pools, respectively.
  • Authors:
    • Johnsen, T. N.
    • McLain, J. E. T.
    • Emmerich, W.
    • Martens, D. A.
  • Source: Soil & Tillage Research
  • Volume: 83
  • Issue: 1
  • Year: 2005
  • Summary: Agriculture in the southwestern USA is limited by water supply due to high evaporation and limited seasonal precipitation. Where water is available, irrigation allows for production of a variety of agricultural and horticultural crops. This review assesses the impacts of agriculture on greenhouse gas emission and sequestration of atmospheric C in soils of the hot, dry region of the southwestern USA. In Texas, conservation tillage increased soil organic C by 0.28 Mg C ha(-1) year(-1) compared with more intensive tillage. Conversion of tilled row crops to the conservation reserve program or permanent pastures increased soil organic C by 0.32 +/- 0.50 Mg C ha(-1) year(-1). Soil organic C sequestration was dependent on rotation, previous cropping, and type of conservation tillage employed. Relatively few studies have interfaced management and C cycling to investigate the impacts of grazing management on soil organic C, and therefore, no estimate of C balance was available. Irrigated crop and pasture land in Idaho had soil organic C content 10-40 Mg C ha(-1) greater than in dryland, native grassland. Soil salinity must be controlled in cropland as soil organic C content was lower with increasing salinity. Despite 75% of the region's soils being classified as calcic, the potential for sequestration of C as soil carbonate has been only scantly investigated. The region may be a significant sink for atmospheric methane, although in general, trace gas flux from semiarid soils lacks adequate characterization. Agricultural impacts on C cycling will have to be better understood in order for effective C sequestration strategies to emerge. Published by Elsevier B.V.
  • Authors:
    • Duvick, D. N.
    • Rosegrant, Mark
    • Derner, Justin D.
    • Schuman, Gerald E.
    • Verchot, Louis
    • Steinfeld, Henning
    • Gerber, Pierre
    • De Freitas, Pedro Luiz
    • Lal, Rattan
    • Desjardins, Raymond L.
    • Dumanski, Julian
  • Source: Advances in Agronomy
  • Volume: 86
  • Year: 2005
  • Summary: Maize (Zea mays L.) yields have risen continually wherever hybrid maize has been adopted, starting in the U.S. corn belt in the early 1930s. Plant breeding and improved management practices have produced this gain jointly. On average, about 50% of the increase is due to management and 50% to breeding. The two tools interact so closely that neither of them could have produced such progress alone. However, genetic gains may have to bear a larger share of the load in future years. Hybrid traits have changed over the years. Trait changes that increase resistance to a wide variety of biotic and abiotic stresses (e.g., drought tolerance) are the most numerous, but morphological and physiological changes that promote efficiency in growth, development, and partitioning (e.g., smaller tassels) are also recorded. Some traits have not changed over the years because breeders have intended to hold them constant (e.g., grain maturity date in U.S. corn belt). In other instances, they have not changed, despite breeders' intention to change them (e.g., harvest index). Although breeders have always selected for high yield, the need to Select Simultaneously for overall dependability has been a driving force in the selection of hybrids with increasingly greater stress tolerance over the years. Newer hybrids yield more than their predecessors in unfavorable as well as favorable growing conditions. Improvement in the ability of the maize plant to overcome both large and small stress bottlenecks, rather than improvement in primary productivity, has been the primary driving force of higher yielding ability of newer hybrid.