• Authors:
    • Morse, R. D.
    • Miyao, E. M.
    • Temple, S. R.
    • Lanini, W. T.
    • Mitchell, J. P.
    • Herrero, E. V.
    • Campiglia, E.
  • Source: California Agriculture
  • Volume: 55
  • Issue: 1
  • Year: 2001
  • Summary: The efficacy of no-till systems in conserving soil moisture and improving water infiltration under furrow irrigation was evaluated during 1997 and 1998 in California, USA. Two grass/legume mixtures, i.e. triticale/lana woolypod vetch (* Triticosecale/ Vicia dasycarpa [ V. villosa]) and rye/lana woolypod vetch ( Secale cereale/ V. dasycarpa), were used as cover cop mulches in no-till treatments, and compared with a winter fallow treatment with pre-plant herbicide (fallow +h) and a fallow control treatment with no herbicide (fallow -h). Tomato cv. Halley 3155 plants were transplanted in April 1997 and 1998, sprinkle irrigated during the first 6 weeks after transplanting, and furrow irrigated thereafter until 3 weeks before harvest. During 1997, soil water content between 0 and 78 inches did not differ among treatments, while soil water content during the 1997/98 winter was higher under the fallow +h than the cover crop treatments until cover crop termination. Soil water content of cover crop treatments in shallower soil layers (18 and 42 inches) was significantly lower than fallow treatments at the end of the winter. During the 1998 tomato crop season, soil water content between 0 and 90 inches was greater under the triticale and rye mulches than the fallow +h, beginning the 3rd week after furrow irrigations were started. Soil moisture in the shallower layers was also affected by cover crop mulches. In the 42-inch depth increment, there was significantly higher water content under the cover crops than under the fallow +h from about 1 month after the first furrow irrigation until 2 weeks before the last irrigation. Changes in soil water content during furrow irrigation under the fallow +h treatment appeared to be more pronounced than under the triticale or rye surface mulches. Soil compaction in the fallow +h treatment was higher than under the cover crop mulches for most of the 0.6-inch intervals, especially below 1 foot, but differences were significantly higher only for the 3, 3.6, 4.2, 17, 18, and 24-inch depth, but lower from the surface to 2.4 inches. Soil carbon was significantly higher (by 14 and 18%) under triticale and rye, respectively, compared with the fallow +h treatment. The number of earthworms was also higher in no-till (2.1 earthworms per square foot) than in the fallow treatments (0.6 earthworms). Tomato canopy growth did not reach 100% cover in either 1997 or 1998, while tomato plant growth, assessed by measuring the photosynthetically active radiation intercepted by the canopy, did not differ in the triticale, rye, and fallow +h system in either 1997 or 1998. Results showed that the no-till mulch system enhanced water infiltration and soil water conservation.
  • Authors:
    • Morse, R. D.
    • Miyao, E. M.
    • Temple, S. R.
    • Lanini, W. T.
    • Mitchell, J. P.
    • Herrero, E. V.
    • Campiglia, E.
  • Source: HortTechnology
  • Volume: 11
  • Issue: 1
  • Year: 2001
  • Summary: No-tillage processing tomato production in four winter cover crop-derived mulches was evaluated in 1997 and 1998 in Five Points, California, USA. The effectiveness of two medics, 'Sava' snail medic ( Medicago scutellata), and 'Sephi' barrel medic ( Medicago truncatula), and two cereal/legume cover crop mixtures, triticale/'Lana' woolypod vetch ( Triticum x Secale/ Vicia dasycarpa [ Vicia villosa]) and rye/'Lana' woolypod vetch ( Secale cereale/ V. dasycarpa), was compared with two conventionally tilled fallow controls (with and without herbicide) (fallow+h and fallow-h) in suppressing weeds and maintaining yields with reduced fertilizer inputs. The comparison was conducted as a split plot, with three N fertilization rates (0, 100, and 200 lb/acre; 0, 112, and 224 kg/ha) as main plots and cover crops and fallow controls as subplots. Tomato seedlings were transplanted 3 weeks after the cover crops had been mowed and sprayed with herbicide. There were no significant differences in weed cover in the no-till cover crop treatments relative to the fallow controls in 1997. Early season weed suppression in rye/vetch and triticale/vetch plots was similar to herbicide-treated fallow (fallow+h) in 1998, however, later in the 1998 season weed suppression was best in the fallow+h. Tissue N was highest in the fallow treatments in both 1997 and 1998. Yields were highest in the triticale/vetch and fallow and lowest in sephi treatments in 1997, but there were no differences among treatments in 1998.
  • Authors:
    • Schillinger, W. F.
  • Source: Soil Erosion Research for the 21st Century, Proc. Int. Symp. (3-5 January 2001, Honolulu, HI, USA). Eds. J.C. Ascough II and D.C. Flanagan. St. Joseph, MI: ASAE.701P0007
  • Year: 2001
  • Summary: Water runoff and soil loss from wheat fields in the inland Pacific Northwest (PNW) USA is often severe during the winter when rain or snow melt occur on frozen soils. Annual precipitation in this region varies from 150 to 600 mm and characteristically 60% occurs between November and March. Water erosion in the wheat-fallow rotation is most severe during the winter of the crop year because of the winter precipitation pattern, long steep slopes, very little ground cover from crop residue or wheat seedlings, and low water infiltration rates through frozen soil. Additional management practices are needed to combat erosion events associated with frozen soil. Research was conducted at 9 on-farm sites in eastern Washington state from 1993 to 1999 to determine the effects of subsoiling fall-sown wheat on 15 to 40% slopes prior to soil freezing on soil loss, water infiltration into the soil, and grain yield. The experimental design at each site was a randomized complete block with 6 replications of 2 treatments: subsoiled and control. Two types of subsoilers were used over the 6-yr period: (i) a 5-cm-wide shank operated 40 cm deep on the contour with shanks spaced 4 or 6 m apart to cut a continuous groove in the soil, and (ii) a rotary 'sharks tooth' implement which creates a 40 cm deep, 4-litre-capacity hole every 0.7 m 2. The sharks tooth subsoiler causes less soil disturbance and less damage to wheat plants than continuous shank channels. Results show that, when water runoff on frozen soils occurs, tillage channels or holes (i) reduce soil loss by retarding rill erosion, (ii) increase water infiltration, and (iii) do not reduce or increase grain yield. Many wheat growers have started to adopt these, or similar, soil conservation practices on their farms.
  • Authors:
    • Stout, J. E.
  • Source: Journal of Arid Environments
  • Volume: 47
  • Issue: 4
  • Year: 2001
  • Summary: Continuous measurements of dust reveal the intermittent nature of dust events within the Southern High Plains of North America. Dust events appear as sudden peaks that project outward from a much lower background dust concentration. The measured dust record appears to follow a regular annual cycle with most dust events occurring in spring and considerably fewer during other seasons. The annual dust cycle reflects seasonal changes in environmental factors such as wind speed, surface cover, and moisture conditions. Most dust events are associated with a combination of strong winds, negligible surface cover? and dry conditions, all of which occur most frequently during the spring season. Wind speed alone is found to be an imperfect indicator of dust levels in the Southern High Plains because of the moderating effects of other important environmental factors such as humidity and surface cover. However, if one limits consideration to dry and bare conditions, dust concentration exhibits a positive correlation with daily wind speeds above 4 m s(-1) and a negligible correlation for light winds.
  • Authors:
    • Williams, R. G.
    • Truman, C. C.
  • Source: Journal of Soil and Water Conservation Society
  • Volume: 56
  • Issue: 2
  • Year: 2001
  • Summary: Runoff and sediment yields were measured from eight field plots (40 m(2)) over a three year period to determine the effect of peanut cropping practices and canopy cover conditions on runoff and sediment loss. Plots were located on a Tifton loamy sand, and were exposed to four 30 min simulated rainfall sequences (I = 63.5 mm h(-1)) four to eight times per growing season. Runoff and sediment losses were measured from four soil cover conditions: continuous fallow, bare bedded, single row peanuts (Arachis hypogea L), and twin row peanuts (2 to 4 peanut rows per 2 m wide bed). percent cover (PC) and leaf area index (LAI) increased to a maximum then leveled off as plants matured or were harvested. PC for single and twin row peanuts was related to days since planting (DSP) (r - 0.96 for single row peanuts and r = 0.98 for twin row peanuts). LAI values for single and twin row peanuts were related to PC (r = 0.98 for single row peanuts and r = 0.94 for twin row peanuts). Single and twin row peanut plots had as much as eight times less runoff and as much as 63 times less sediment loss than continuous fallow or bare bedded plots. Twin row peanut plots had as much as three times less runoff and sediment loss than single row peanut plots. Sequence-based erodibility values calculated from continuous fallow plots (K-FC) and bare bedded plots (K-BB) ranged from 4-24 (3 yr mean = 11.3, s.d. = 5.3) and 2-36 kg ha h MJ(-1) ha(-1) mm(-1) (3 yr mean = 12.9, s.d. = 11.6), respectively. Soil loss ratios (SLR) ranged from 0.001-2.61. SLRs decrease to a low for cropstage 3 when percent canopy cover was greatest (DSP = 81-107), then increased as peanut plants mature or were harvested. Results show how management practices, such as twin row peanuts, can maximize peanut canopy development early in the growing season and minimize the time in which bare soil is vulnerable to a runoff producing rainstorm, thus reducing runoff and soil loss and conserving valuable natural resources.
  • Authors:
    • Spurlock, S. R.
    • Elmore, C. D.
    • Wesley, R. A.
  • Source: Agronomy Journal
  • Volume: 93
  • Issue: 1
  • Year: 2001
  • Summary: Deep tillage (subsoiling) of clayey soils in the fall when the profile is dry is a new concept that results in increased yields and net returns from soyabean (Glycine max) grown without irrigation. Crop rotation may also result in increased crop yields. Field studies were conducted on Tunica clay (clayey over loamy, smectitic, nonacid, thermic, Vertic Haplaquept) near Stoneville, Mississippi, USA (33degrees 26′ N lat), during 1993-97, to determine the individual and combined effects of fall deep tillage and crop rotations on crop yields and net returns. Treatments included monocrop cotton (Gossypium hirsutum cultivars DES 119 and Suregrow 125), soyabean (cultivars Pioneer 9592 and DPL 3588), and grain sorghum ( Sorghum bicolor cv. Pioneer 8333), and biennial rotations of cotton with grain sorghum and soyabean with grain sorghum grown without irrigation and in either a conventional-till (CT) or deep-till (DT) production system. Yields from all cotton and soyabean crop sequences grown in the DT respectively averaged 541 kg ha -1 and 525 kg ha -1 greater than comparable cotton (2184 kg ha -1) and soyabean (2983 kg ha -1) crop sequences grown in the CT. Net returns from monocrop cotton ($552 ha -1) and soyabean ($462 ha -1) in the DT respectively averaged $392 ha -1 and $121 ha -1 more than similar crop sequences in the CT. Rotations increased cotton and soyabean yields but not net returns because of the low value of the grain sorghum component. These data indicate that fall deep tillage should be incorporated into monocrop cotton and soyabean crop sequences to maximize and stabilize net returns from these crops on Tunica clay.
  • Authors:
    • Follett, R. F.
  • Source: Soil & Tillage Research
  • Volume: 61
  • Issue: 1/2
  • Year: 2001
  • Summary: One of the most important terrestrial pools for carbon (C) storage and exchange with atmospheric CO 2 is soil organic carbon (SOC). Following the advent of large-scale cultivation, this long-term balance was disrupted and increased amounts of SOC were exposed to oxidation and loss as atmospheric CO 2. The result was a dramatic decrease in SOC. If amounts of C entering the soil exceed that lost to the atmosphere by oxidation, SOC increases. Such an increase can result from practices that include improved: (1) tillage management and cropping systems, (2) management to increase amount of land cover, and (3) efficient use of production inputs, e.g. nutrients and water. Among the most important contributors is conservation tillage (i.e., no-till, ridge-till, and mulch-tillage) whereby higher levels of residue cover are maintained than for conventional-tillage. Gains in amount of land area under conservation tillage between 1989 and 1998 are encouraging because of their contributions to soil and water conservation and for their potential to sequester SOC. Other important contributors are crop residue and biomass management and fallow reduction. Collectively, tillage management and cropping systems in the US are estimated to have the potential to sequester 30-105 million metric tonnes of carbon (MMTC) year -1. Two important examples of management strategies whereby land cover is increased include crop rotations with winter cover crops and the conservation reserve programme (CRP). Such practices enhance SOC sequestration by increasing the amount and time during which the land is covered by growing plants. Crop rotations, winter cover crops, and the CRP combined have the potential to sequester 14-29 MMTC year -1. Biomass production is increased by efficient use of production inputs. Optimum fertility levels and water availability in soils can directly affect quantity of crop residues produced for return to the soil and for SOC sequestration. Nutrient inputs and supplemental irrigation are estimated to have the potential to sequester 11-30 MMTC year -1. In the future, it is important to acquire an improved understanding of SOC sequestration processes, the ability to make quantitative estimates of rates of SOC sequestration, and technology to enhance these rates in an energy- and input-efficient manner. Adoption of improved tillage practices and cropping systems, increased land cover, and efficient use of nutrient and water inputs are examples where such information is necessary.
  • Authors:
    • Sojka, R. E.
    • Bjorneberg, D. L.
    • Aase, J. K.
  • Source: Transactions of the ASAE
  • Volume: 44
  • Issue: 3
  • Year: 2001
  • Summary: Zone subsoiling on irrigated land has been successfully used to improve potato ( Solanum tuberosum) yield and quality. Zone subsoiling under furrow irrigation may disrupt water flow and influence infiltration and soil erosion. We hypothesized that zone subsoiling, done appropriately, will maintain integrity of irrigation furrows, improve small grain (barley) and dry bean ( Phaseolus vulgaris) growth and yield, and not adversely affect water flow, infiltration, or erosion on furrow-irrigated soils. The experiment, which started in 1995, was conducted at the USDA-ARS Northwest Irrigation and Soils Research Laboratory in Kimberly, Idaho, USA. The soil is a Portneuf silt loam (coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcids). Tillage treatments were disc, disc+paratill, paratill, and no-till. There were no differences in water infiltration, runoff, or soil erosion among treatments. Bulk density differences among treatments were largest at the 0.15 to 0.20-m depth, and bulk density was ~16 to 18% greater on disc and no-till treatments than on paratill treatments. The highest frequency of low cone index (CI) values belonged to paratill treatments (65 to 80% frequency of CI values less than 2 MPa); the lowest frequency of low CI values belonged to no-till treatment (20% frequency less than 2 MPa). Cone index versus bulk density relationships depended on soil water content with a slope of 5.81 (r 2=0.70) in the wetter year of 1997, and 2.90 in the drier year of 1995 (r 2=0.60). Subsoiling can be accomplished on furrow-irrigated lands with no adverse effects on runoff, infiltration, and erosion, but under our conditions did not improve crop growth and yield.
  • Authors:
    • Khosla, R.
    • Alley, M. M.
    • Davis, P. H.
  • Source: Agronomy Journal
  • Volume: 92
  • Issue: 2
  • Year: 2000
  • Summary: Grain sorghum [Sorghum bicolor (L.) Moench] is grown in rotation with wheat (Triticum aestivum L.) and soybean [Glycine mar (L.) Merr.] in the mid-Atlantic Sufficient data on N fertilization of sorghum are not available for this region. Our objective was to evaluate the influence of multi-rate N fertilization on dryland sorghum. Treatments consisted of factorial combinations of four starter-band N rates (11, 34, 56, and 78 kg N ha(-1)) and four sidedress N rates (0, 45, 90, and 134 kg N ha(-1)). A broadcast treatment of 67 kg N ha(-1) at planting was also included. Starter-band was applied 5 cm to the side and below the seed. Sidedress was applied 35 days after emergence at the eight-leaf growth stage. Grain yield ranged from 1.7 to 11.9 Mg ha(-1) over eight site-years and was responsive and nonresponsive to N applications on four sites each. Nonresponsiveness was either due to high levels (>85 kg N ha(-1)) of residual soil mineral N, or severe water stress conditions. Our results indicate that production of sorghum on soils testing high in mineral N (50 kg N ha(-1) in the surface 0.3 m) at planting should not receive any starter-band N in conjunction with sidedress N application of 130 kg N ha(-1) for optimum economic return to N fertilization. For soils testing low in mineral N, 40 kg N ha(-1) starter-band in conjunction with 130 kg N ha(-1) sidedress N should optimize the sorghum yields in most situations.
  • 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.