19722015
  • Authors:
    • Luo,Y.
    • Zhou,C.
  • Source: Journal of Food, Agriculture and Environment
  • Volume: 10
  • Issue: 2
  • Year: 2012
  • Summary: Panzhuang Irrigation District is one of the Yellow River irrigation areas. The spatial and temporal distribution of water resources is severely uneven in the upper, middle and lower reaches of the irrigation district. In order to solve this problem, it is necessary to study the differences of crop water consumption (evapotranspiration-ET), irrigation amount, soil water and water use efficiency (WUE) of winter wheat, summer maize and cotton which are the main crops in the irrigation district. This paper improved calculating methods of the capillary rise and percolation of the established model. The model was then applied to the upper, middle and lower reaches of the irrigation district. Conclusions by the model simulation were as follows: (I) The model could simulate the dynamics of water balance components of wheat-maize and cotton relatively accurately in the irrigation district. (II) Winter wheat and summer maize (wheat-maize) had the highest ET in the upper reaches, followed by the middle reaches and then the lower reaches. There was almost no difference for cotton ET in the upper, middle and lower reaches. (III) Irrigation amount of wheat-maize was 225-300 mm in the upstream, 300 mm in the middle reaches, and 500 mm in the downstream. Cotton irrigation quantity was 60-150 mm in the upper and middle reaches, and 60-390 mm in the lower reaches. (IV) Soil water basically showed a decreasing trend in growth periods of wheat-maize and cotton in the middle and lower reaches, its recharge was primarily from irrigation of wheat. Combined with other references, there was a trend of soil drying in the North China Plain. (V) Mean values of water use efficiency (WUE) of winter wheat, summer maize and cotton were highest in the middle reaches and lowest in the upstream and downstream.
  • Authors:
    • Kaspar, T. C.
    • Parkin, T. B.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 6
  • Year: 2011
  • Summary: Measurements of soil CO 2 flux in the absence of living plants can be used to evaluate the effectiveness of soil management practices for C sequestration, but field CO 2 flux is spatially variable and may be affected by soil compaction and the percentage of total pore space filled with water (%WFPS). The objectives of our study were: (i) to evaluate the effect of wheel traffic compaction on CO 2 flux at two landscape positions with differing soil properties; and (ii) to examine the relationship of CO 2 flux and %WFPS under field conditions and a wide range of soil porosities. Carbon dioxide flux was measured near Ames, IA, in a no-till system without living plants using the closed chamber method on nine cylinders inserted into the soil at each measurement site and evenly spaced across three rows, an untracked interrow, and a tracked interrow. Flux, volumetric water contents, and soil temperature were measured on 12 or 13 d between day of the year (DOY) 164 and 284 in 2001, 2004, and 2005. Bulk density, soil organic C concentration, and soil texture were determined after DOY 284. On most days, CO 2 flux was less in the tracked interrow than in the row or untracked interrow positions. In all 3 yr, the cumulative flux of the tracked position was significantly less than one or both of the other positions. Landscape position did not affect the response of CO 2 flux to traffic. Percentage water-filled pore space was not a good predictor of surface CO 2 flux in the field. The effect of wheel traffic compaction on CO 2 flux should be considered when soil CO 2 flux is used to compare management practices.
  • Authors:
    • Kocyigit, R.
    • Rice ,C. W.
  • Source: Bulgarian Journal of Agricultural Science
  • Volume: 17
  • Issue: 4
  • Year: 2011
  • Summary: The soil surface CO 2 flux is the second largest flux in the terrestrial carbon budget after photosynthesis. Plant root and microbial respiration produce CO 2 in soils, which are important components of the global C cycle. This study determined the amount of CO 2 released during spring wheat ( Triticum aestivum L.) growth under no-till (NT) and conventional tillage (CT) systems. This experiment was conducted at Kansas State University North Agronomy Farm, Manhattan, KS, on a Kennebec silt loam. This study site was previously under dry land continuous corn production with NT and CT for more than 10 years. Spring wheat ( Triticum aestivum L.) was planted with two tillage systems (NT and CT) as four replicates in March. Surface CO 2 flux was measured weekly during plant growth. Soil water content at the surface (5 cm) tended to be greater in NT and decreased from planting to harvest. Soil microbial activity at the surface was usually higher in NT and decreased from planting to harvest, while activity was constant in the deeper depths. The higher microbial activity at the surface of NT occurred after 60 days of planting where soil water content was the most limiting factor on microbial activity. Soil CO 2 flux varied in response to changes in soil water content and the variation and magnitude of the increase was greater at higher soil water contents. Conventional tillage released 20% more CO 2 to the atmosphere compare to NT after 10 years in the North American Great Plains Regions.
  • Authors:
    • Nord, E. A.
    • Curran, W. S.
    • Mortensen, D. A.
    • Mirsky, S. B.
    • Jones, B. P.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 5
  • Year: 2011
  • Summary: Rolled cover crop mulches can suppress weeds in subsequent cash crops, reduce the need for herbicides, and allow organic no-till cash crop establishment. This study investigated the weed suppressiveness of a cereal rye ( Secale cereale L.) cover crop mulch across varying weed seedbank density. Cereal rye was seeded at two dates in the fall and terminated at five dates in the spring to create biomass ranging from 100 to 1600 g m -2. The first three termination dates included both herbicide (glyphosate) and rolling of the rye, while later three dates were only rolled. Soybean [ Glycine max (L.) Merr.] was no-till planted after rye termination, and weed biomass and soybean yield were assessed. Spring termination date more strongly affected cereal rye biomass than fall planting date; a termination delay of 5 to 15 d compensated for a planting delay of 30 d. Weed biomass generally declined with increasing cereal rye biomass, and this relationship was stronger at higher weed seedbank densities. Supplemental weed control reduced weed biomass compared to no supplemental control and postherbicide was more effective than cultivation. While increasing cereal rye biomass was associated with a decline in soybean yield in 2009, it did not consistently impact soybean stand. Instead soybean stand establishment appeared to be impacted by high cover crop biomass and changing edaphic conditions at planting. Future research should focus on improved technology for direct seeding in high residue environments and developing longer term cropping systems less reliant on tillage and herbicides.
  • Authors:
    • Smith, D. R.
    • Gal, A.
    • Vyn, T. J.
    • Omonode, R. A.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 1
  • Year: 2011
  • Summary: Few experiments have directly compared the long-term effects of moldboard, chisel, and no-till tillage practices on N 2O emissions from the predominant crop rotation systems in the midwestern United States. This study was conducted from 2004 to 2006 on a tillage and rotation experiment initiated in 1975 on a Chalmers silty clay loam (a Typic Endoaquoll) in west-central Indiana. Our objectives were to assess (i) long-term tillage (chisel [CP], moldboard plow [MP], and no-till [NT]), rotation (continuous corn [ Zea mays L.] and corn-soybean [ Glycine max (L.) Merr.]), and rotation * tillage interaction effects on soil N 2O emission, and (ii) how soil N 2O emission is related to environmental factors during corn production under identical N fertilizer management. Seasonal N 2O emissions were measured at intervals ranging from a few days to biweekly for up to 14 sampling dates in each growing season for corn. Nitrous oxide emissions during the growing season were significantly affected by tillage and rotation but not their interaction; however, 50% of total emissions occurred shortly after N application regardless of tillage or rotation practices. Seasonal cumulative emissions were significantly lower under NT but not statistically different for CP and MP. Overall, emissions under NT were about 40% lower relative to MP and 57% lower relative to CP. Rotation corn lowered N 2O emissions by 20% relative to continuous corn. Higher N 2O emission under MP and CP appeared to be driven by soil organic C decomposition associated with higher levels of soil-residue mixing and higher soil temperatures.
  • Authors:
    • Lal, R.
    • Stavi, I.
  • Source: Geomorphology
  • Volume: 125
  • Issue: 1
  • Year: 2011
  • Summary: Erosion and deposition processes affect the physical quality of the soil. Thus, the objective of this study was to assess the effects of these processes on a long-term no-till corn agroecosystem in a humid-temperate region of the Midwest U.S. The study was conducted under on-farm conditions, in a field which experiences erosional and depositional processes. At the end of the dormant season, soil characteristics were tested for two depths (0-5 and 5-10 cm) in uneroded (UN), eroded (ER), and depositional (DP) sites. The data showed that UN and ER were characterized by the highest and lowest soil shear strength (137.3 and 78.1 KPa, respectively) and organic carbon concentration (35.6 and 30.3 g kg -1, respectively). The highest and lowest aggregate stability (85.4% and 73.6%, respectively) and mean weight diameter (2.9 and 1.6 mm, respectively) were observed in UN and DP. The highest and lowest penetration resistance (4.82 and 4.57 MPa, respectively) and bulk density (1.49 and 1.33 Mg m -3, respectively) were measured in ER and DP. An opposite trend was observed for the C:N ratio (8.2 and 9.6, respectively), and the value's color variable (4.6 and 4.9, respectively). No significant differences among the erosional phases were measured in the soil's total nitrogen concentration, hue and chroma color variables, texture, hydraulic conductivity, and intrinsic permeability. The erodibility factor was the lowest and highest in DP and ER (0.00326 and 0.00397 Mg ha h ha -1 MJ -1 mm -1, respectively), and the effect of erosional phase on this factor was close to significant. In general, the effect of erosion and deposition on soil characteristics decreased with an increase in soil depth. This study suggests that the occurrence of positive feedbacks in ER and DP have led to accelerated erosional and depositional processes and the continuous degradation of the soil quality. A range of management practices should be considered in order to mitigate these processes and reduce negative impact on crop yields in such agroecosystems.
  • Authors:
    • Stavi,I.
    • Lal,R.
    • Owens,L. B.
  • Source: Agronomy for Sustainable Development
  • Volume: 31
  • Issue: 3
  • Year: 2011
  • Summary: Contrary to earlier studies, this study suggests that even one year of tillage within a long-term no-till agroecosystem adversely affected the soil quality, with possible negative impact on crop yields. Worldwide interest in conservation tillage is increasing, because conventional tillage adversely impacts the long-term quality of the soil and its vulnerability to erosion. No-till agriculture minimizes adverse impacts of an intensive arable land use. In some cases, occasional tillage is used as a means of weed or pathogen control. Therefore, this study was conducted in eastern Ohio to examine soil quality as affected by occasional tillage, i.e. disk plowed every 3-4 years, within a long-term no-till agroecosystem. The study compared the soil characteristics between two fields, both under corn ( Zea mays L.) at the time of the study. Soil properties were studied for three depths of 0-6, 6-12, and 12-18 cm. Compared with the continuous no-till field, the field under occasional tillage had significantly higher bulk density of 1.45 versus 1.31 gcm -3, and somewhat higher soil penetration resistance of 1.77 versus 1.56 MPa. Also, compared with the no-till field, the field under occasional tillage had significantly lower water stable aggregate of 475 versus 834 gkg -1, mean weight diameter of 1.4 versus 3.4 mm, field moisture capacity of 293 versus 360 gkg -1, equilibrium infiltration rate of 2.0 versus 6.7 mm min -1, and cumulative infiltration of 353.4 versus 1,211.8 mm. The field under occasional tillage had somewhat lower soil organic carbon of 16.0 versus 19.2 gkg -1, soil water sorptivity of 16.3 versus 36.5 mm min -0.5, and transmissivity of 2.1 versus 4.9 mm min -1. The occasional tillage had no effect on the soil shear strength. In general, the effect of tillage on soil properties decreased with increase in soil depth. Also corn yields were compared between the two agroecosystems. Compared with the no-till field, the field under occasional tillage had significantly lower grain moisture content of 22.4 versus 28.2%, and somewhat lower wet stover biomass of 14.6 versus 20.2 Mg ha -1, wet corn ear yield of 10.0 versus 11.4 Mg ha -1, and dry grain yield of 8.2 versus 9.4 Mg ha -1. As contrasted with earlier studies which were conducted under controlled research plots, this study was conducted under on-farm conditions.
  • Authors:
    • Kravchenko, A. N.
    • Mokma, D. L.
    • Corbin, A. T.
    • Syswerda, S. P.
    • Robertson, G. P.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 1
  • Year: 2011
  • Summary: Soil C sequestration research has historically focused on the top 0 to 30 cm of the soil profile, ignoring deeper portions that might also respond to management. In this study we sampled soils along a 10-treatment management intensity gradient to a 1-m depth to test the hypothesis that C gains in surface soils are offset by losses lower in the profile. Treatments included four annual cropping systems in a corn ( Zea mays)-soybean ( Glycine max)-wheat ( Triticum aestivum) rotation, perennial alfalfa ( Medicago sativa) and poplar ( Populus * euramericana), and four unmanaged successional systems. The annual grain systems included conventionally tilled, no-tillage, reduced-input, and organic systems. Unmanaged treatments included a 12-yr-old early successional community, two 50-yr-old mid-successional communities, and a mature forest never cleared for agriculture. All treatments were replicated three to six times and all cropping systems were 12 yr post-establishment when sampled. Surface soil C concentrations and total C pools were significantly greater under no-till, organic, early successional, never-tilled mid-successional, and deciduous forest systems than in the conventionally managed cropping system ( p≤0.05, n=3-6 replicate sites). We found no consistent differences in soil C at depth, despite intensive sampling (30-60 deep soil cores per treatment). Carbon concentrations in the B/Bt and Bt2/C horizons were lower and two and three times more variable, respectively, than in surface soils. We found no evidence for C gains in the surface soils of no-till and other treatments to be either offset or magnified by carbon change at depth.
  • Authors:
    • Wilhelm, W. W.
    • Varvel, G. E.
  • Source: Soil & Tillage Research
  • Volume: 114
  • Issue: 1
  • Year: 2011
  • Summary: Emphasis and interest in carbon (C) and nitrogen (N) storage (sequestration) in soils has greatly increased in the last few years, especially C with its' potential to help alleviate or offset some of the negative effects of the increase in greenhouse gases in the atmosphere. Several questions still exist with regard to what management practices optimize C storage in the soil profile. A long-term rainfed study conducted in eastern Nebraska provided the opportunity to determine both the effects of different tillage treatments and cropping systems on soil N and soil organic C (SOC) levels throughout the soil profile. The study included six primary tillage systems (chisel, disk, plow, no-till, ridge-till, and subtill) with three cropping systems [continuous corn (CC), continuous soybean (CSB), and soybean-corn (SB-C)]. Soil samples were collected to a depth of 150-cm in depth increments of 0-15-, 15-30-, 15-30-, 30-60-, 60-90-, 90-120-, and 120-150-cm increments and composited by depth in the fall of 1999 after harvest and analyzed for total N and SOC. Significant differences in total N and SOC levels were obtained between tillage treatments and cropping systems in both surface depths of 0-15-, 15-30-cm, but also in the 30-60-cm depth. Total N and SOC accumulations throughout the profile (both calculated by depth and for equivalent masses of soil) were significantly affected by both tillage treatment and cropping system, with those in no-till the greatest among tillage treatments and those in CC the greatest among cropping systems. Soil N and SOC levels were increased at deeper depths in the profile, especially in those tillage systems with the least amount of soil disturbance. Most significant was the fact that soil N and SOC was sequestered deeper in the profile, which would strongly suggest that N and C at these depths would be less likely to be lost if the soil was tilled.
  • Authors:
    • Wu, Z. J.
    • Zhu, A. N.
    • Chen, L. J.
    • Chen, Z. H.
    • Wang, J. B.
  • Source: Plant, Soil and Environment
  • Volume: 57
  • Issue: 6
  • Year: 2011
  • Summary: The effects of tillage and residue input amounts on soil phosphatase (alkaline phosphomonoesterase ALP, acid phosphomonoesterase ACP, phosphodiesterase PD, and inorganic pyrophosphatase IPP) activities and soil phosphorus (P) forms (total P, organic P, and available P) were evaluated using soils collected from a three-year experiment. The results showed that no-till increased soil total and organic P, but not available P as compared to conventional tillage treatments. Total P was increased as inputs of crop residue increased for no-till treatment. There were higher ALP and IPP activities in no-till treatments, while higher PD activity was found in tillage treatments and tillage had no significant effect on ACP activity. Overall phosphatase activities increased with an increase of crop residue amounts. Soil total P was correlated negatively with PD activity and positively with other phosphatase activities. Organic P had a positive correlation with ACP activity, but a negative correlation with PD activity. Available P had no significant correlation with phosphatase activities. Our data suggests that no-till and residue input could increase soil P contents and enhance the activities of phosphatase.