• Authors:
    • Daigh, A. L.
  • Source: Soil Survey Horizons
  • Volume: 52
  • Issue: 2
  • Year: 2011
  • Summary: Bioenergy cropping systems will supply 16 billion gallons of cellulosic ethanol by the year 2022 in an attempt to reduce U.S. dependence on gasoline. To obtain long-term energy security, bioenergy systems will need to be sustainable, especially with regard to soil. Corn stover, as a bioenergy feedstock, is of great interest due to its immediate availability for harvest with minimal change to current corn-grain cropping systems. However, traditional row crop agriculture of the United States Corn Belt has reduced soil organic matter contents, an indicator of soil quality, by as much as 40 to 60% over the last 150 yr. The harvest of corn stover will directly remove a portion of the soil organic matter input, thus further reducing soil organic matter contents. The reduction in soil organic matter contents produce direct and indirect consequences unfavorable to soil quality and productivity. Therefore, the harvest of corn stover as a long-term bioenergy feedstock is detrimental to soil, impacting soil structure and stability, erodibility, A horizon depth, and physicochemical properties. Perennial biofuel systems, in contrast, have the potential to add soil organic matter to the soil, thus offering long-term enhancement of soil quality, productivity, and formation.
  • Authors:
    • Li, Mei
    • Gao, XingXiang
    • Guo, Xiao
    • Sun, TingLin
    • Zhao, Wei
    • Gao, ZongJun
  • Source: Acta Prataculturae Sinica
  • Volume: 20
  • Issue: 1
  • Year: 2011
  • Summary: The effects of rotary tillage with no stubble (RT), rotary tillage with straw incorporation (RTS), no-till without stubble (NT), no-till with 6 000 kg/ha (NTS 6000), and no-till with 3 000 kg/ha (NTS 3000), on weed communities structure and species diversity was studied in field experiments using a community ecology method. Compared with RT, the NT, NTS 3000, and NTS 6000 treatments increased perennial weed species, but there was no significant difference in the species richness. NT, NTS 3000 and NTS 6000 significantly reduced the summed dominance ratio (SDR) of Lithospermum arvense, but increased the SDR of Capsella bursa-pastoris. RTS significantly reduced the SDR of L. arvense, but increased the SDR of Descurainia sophia. The species diversity of weed communities varied significantly between different tillage systems. The Bray-Curtis index and hierarchical cluster analysis classified the weed communities of different tillage systems into two categories: Category I (NT, NTS 6000 and NTS 3000) where no-till was implemented, and category II (RTS and RT) where rotary tillage was implemented. The species richness of category I was a little larger than that of category II, but the species diversity and community evenness were much larger than those of category II. However, the community dominance of category I was significantly smaller than that of category II.
  • Authors:
    • Rickman, R. W.
    • Liang, Y.
    • Albrecht, S. L.
    • Machado, S.
    • Kang, S.
    • Gollany, H. T.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 1
  • Year: 2011
  • Summary: Long-term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model and (ii) to predict the potential of no-tillage (NT) management to maintain SOC stocks while removing crop residue. Classical LTEs at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) were selected for their documented history of management practice and periodic soil organic matter (SOM) measurements. Management practices ranged from monoculture to 2- or 3-yr crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned, or harvested. Measured and CQESTR predicted SOC stocks under diverse agronomic practices, mean annual temperature (2.1-19 degrees C), precipitation (402-973 mm), and SOC (5.89-33.58 g SOC kg(-1)) at the LTE sites were significantly related (r(2) = 0.94, n = 186, P < 0.0001) with a slope not significantly different than 1. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing SOC stocks were influenced by initial SOC stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under NT are options to mitigate loss of crop residue C, as using fertilizer alone is insufficient to overcome residue removal impact on SOC stocks.
  • Authors:
    • Grebennikov, V.
    • Shipilov, I.
    • Kushch, E.
  • Source: Kormoproizvodstvo
  • Issue: 2
  • Year: 2011
  • Summary: Impacts of perennial legume-grass mixtures on regulation of soil fertility processes were studied in the Stavropol region, Russia in 2006-09. The mixtures consisted of wheat grass, sainfoin, melilot, alfalfa and bluegrass. Growth and development of roots, above-ground biomass and accumulation of organic compounds in soil were measured during the experiment. The total biomass yield of the 5-component mixture reached 9.62 t/ha at the end of the fourth year. Authors recommend this mixture for phytomelioration. The detailed data on yield dynamics of legume-grass mixtures are presented in 2 tables.
  • Authors:
    • Hammond, R.
  • Source: IOBC/WPRS Bulletin
  • Volume: 64
  • Year: 2011
  • Summary: Slugs are often problems in field crops grown using conservation tillage practices in the eastern United States, as well as certain locations in the Midwest and the southern USA, as well as in Canada. Although most concern has been on corn and soybean, reports of problems from dry beans, cotton, oil-seed rape, sunflowers, winter wheat, and fall planted alfalfa are often received. Although most problems are in fields located in the original forested areas of eastern and southern USA, reports are also being received from the Great Plains' grass lands of slug issues in irrigated no-till fields. Overall, slug problems have increased in geographical area as growers in the USA and Canada have adopted conservation tillage practices. As in other areas of the world, determining new methods of slug control is of utmost importance in order to allow growers to continue using conservation tillage practices. In areas that are new to slugs, a primary concern is educating growers on IPM approaches to slug management.
  • Authors:
    • Hartman, J. C.
    • Orozco, R. A.
    • Nippert, J. B.
    • Springer, C. J.
  • Source: Biomass and Bioenergy
  • Volume: 35
  • Issue: 8
  • Year: 2011
  • Summary: Switchgrass ( Panicum virgatum L.) is a broadly adapted warm-season grass species native to most of the central and eastern United States. Switchgrass has been identified as a potential biofuel species because it is a native species that requires minimal management, and has a large potential to sequester carbon underground. Since the 1990's, switchgrass has been bred to produce cultivars with increased biomass and feedstock quality. This review addresses potential ecological consequences of widespread switchgrass cultivation for biofuel production in the central United States. Specifically, this review address the ecological implications of changing use of marginal and CRP land, impacts on wildlife, potentials for disease and invasions, and changes in soil quality through reductions in erosion, decomposition rates, and carbon sequestrations. A central theme of the review is the utility of maintaining landscape heterogeneity during switchgrass biofuel production. This includes implementing harvest rotations, no till farming, and mixed species composition. If negative ecological consequences of switchgrass cultivation are minimized, biofuel production using this species has economical and environmental benefits.
  • Authors:
    • Rangel, D.
    • Jacobson, A. R.
    • Laba, M.
    • Darnault, C.
    • Otten, W.
    • Radulovich, R.
    • Camargo, F. A. O.
    • Baveye, P. C.
  • Source: Soil Science Society of American Journal
  • Volume: 75
  • Issue: 6
  • Year: 2011
  • Summary: When the Soil Science Society of America was created, 75 yr ago, the USA was suffering from major dust storms, causing the loss of enormous amounts of topsoil as well as human lives. These catastrophic events reminded public officials that soils are essential to society's well-being. The Soil Conservation Service was founded and farmers were encouraged to implement erosion mitigation practices. Still, many questions about soil processes remained poorly understood and controversial. In this article, we argue that the current status of soils worldwide parallels that in the USA at the beginning of the 20th century. Dust bowls and large-scale soil degradation occur over vast regions in a number of countries. Perhaps more so even than in the past, soils currently have the potential to affect populations critically in several other ways as well, from their effect on global climate change, to the toxicity of brownfield soils in urban settings. Even though our collective understanding of soil processes has experienced significant advances since 1936, many basic questions still remain unanswered, for example whether or not a switch to no-till agriculture promotes C sequestration in soils, or how to account for microscale heterogeneity in the modeling of soil organic matter transformation. Given the enormity of the challenges raised by our (ab)uses of soils, one may consider that if we do not address them rapidly, and in the process heed the example of U.S. public officials in the 1930s who took swift action, humanity may not get a chance to explore other frontiers of science in the future. From this perspective, insistence on the fact that soils are critical to life on earth, and indeed to the survival of humans, may again stimulate interest in soils among the public, generate support for soil research, and attract new generations of students to study soils.
  • Authors:
    • Robertson,G. P.
    • Hamilton,S. K.
    • Jasrotia,P.
    • Bhardwaj,A. K.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 140
  • Issue: 3-4
  • Year: 2011
  • Summary: Intensively cropped agricultural production systems should be managed to improve soil quality and ecological processes and ultimately strengthen system capacity for sustained biological productivity. We examined the long-term changes (>20 years) in soil quality and productivity with incorporation of ecological management principles in a set of intensively managed row crop systems of the upper Midwest, USA. Replicated experimental treatments include corn (maize)-soybean-wheat cropping systems under four different management regimes: (a) conventional tillage and fertilizer/chemical inputs ( Conventional), (b) no tillage with conventional fertilizer/chemical inputs ( No-till), (c) conventional tillage with 30% of conventional fertilizer/chemical inputs and a leguminous cover crop ( Reduced Input), and (d) conventional tillage with no fertilizer/chemical input and a leguminous cover crop ( Organic). Effects of these treatments on soils were compared by developing a soil quality index (SQI) from 19 selected soil health indicators. An old field community maintained in early succession provided a benchmark for comparison. Reduction in tillage or fertilizer ( No-till, Reduced Input and Organic) resulted in increased SQI and improved crop production. The No-till (SQI=1.02) and Reduced Input (SQI=1.01) systems outperformed Conventional management (SQI=0.92) in nitrogen availability and use efficiency, soil stability and structure improvement, and microbial nitrogen processing. Improvements in soil quality corresponded with increased primary production and crop yield in these systems, illustrating the value of an ecologically defined SQI for assessing the long-term effects of fertility and tillage management regimes in agricultural production systems.
  • Authors:
    • Beres, B. L.
    • Carcamo, H. A.
    • Dosdall, L. M.
    • Yang, R. C.
    • Evenden, M. L.
    • Spaner, D. M.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 6
  • Year: 2011
  • Summary: Most semiarid regions of the northern Great Plains are prone to wheat stem sawfly (Hymenoptera: Cephidae, Cephus cinctus Norton) attack. As an alternative to the wheat ( Triticum aestivum L.)-fallow system, our objective was to determine if continuous cropping infested wheat stubble would inhibit wheat stem sawfly (WSS) emergence. Adult sawfly emergence from undisturbed stubble was compared to stubble harrowed with heavy tine or rotary drum harrows before recropping. Adult emergence from a control of "no recropping" was compared to direct seeding infested stubble with (i) air drills configured with knife-type openers spaced 23 or 30 cm apart, (ii) an air drill configured with high disturbance shovel-type sweep openers, and (iii) a low disturbance air drill equipped with disc openers. Pre-seed heavy tine harrowing reduced adult sawfly emergence but usually required a high tension setting. No-till planting into infested spring wheat stubble also lowered WSS emergence compared to leaving the field fallow. A system of heavy tine harrows and an air drill equipped with knife openers spaced 30 cm apart reduced WSS adult emergence in spring by 50 to 70%. Grain yield was optimized in spring wheat with air drills equipped with narrow knife openers; in winter wheat optimal yield was obtained with the low disturbance disc drill configurations. Our results indicate incremental benefits from continuous cropping rather than fallowing fields infested with WSS, which is a sustainable alternative to conventional tillage. A systems approach is recommended that integrates these practices with diversified nonhost crop phases and resistant cultivars.
  • Authors:
    • Shan, Y.
    • Mu, M.
    • Han, S.
    • Zhang, Y.
    • Yu, K.
  • Source: Zhongguo Shengtai Nongye Xuebao / Chinese Journal of Eco-Agriculture
  • Volume: 19
  • Issue: 4
  • Year: 2011
  • Summary: Yantai (a city in Shandong Province) is a strong base for winter wheat-maize double-copping system. A previous double-copping system experiment involving single-stem late wheat intercropped with late-maturing maize in Longkou (a county of Yantai City) yielded 22 770 kg.hm -2. Other studies have reported grain yields excess of 22 500 kg.hm -2 in North China. For various reasons, however, replicating these experiments at field scales has not been feasible. As one of the first institutions to develop super-high-yield experiments, the Grain and Food Safety Research Center of China Agricultural University was founded in July 2004 in Yantai City, Shandong Province, at where we conducted a 3-year experiment on high-yield technology system of double-cropping system. Based on weather analysis in Longkou and Laizhou Counties of Yantai City, where super-high-yield experiments were first conducted, this paper put forward a new research direction that makes rational use of the abundant light, heat and species resources in Yantai for high-yield wheat-maize double copping system. The strategy delayed the sowing time of wheat to get the effective temperature (≥16degreesC) for maize to fully exploit yield potential of longer growth period maize varieties. Two modes of double-cropping system cultivation techniques with suitable improved varieties were designed and selected. Based on the design, Longkou was best fitted for a double-copping system of mid-late wheat intercropped with mid-late maturing maize with Oct. 10 -> Oct. 10 crop-rotation periods. Laizhou, on the other hand, was best fitted for double-copping system of single-stem late wheat variety mixed with mid-late maturing maize with Oct. 15 -> Oct. 15 crop-rotation periods. Furthermore, the corresponding suitable varieties were incorporated into the experiments. The results of the double-copping system experiments were as follows: Longkou was suitable for the mid-late wheat "Liangxing 99" intercropped the mid-late maturing maize "Jinhai No. 5" of double-copping system with Oct. 10 -> Oct. 10 crop-rotation period. Laizhou was suitable for directly sowed single-stem late wheat "Liangxing 99" mixed with the mid-late maturing maize "Jinhai 607" of double copping with Oct. 15 -> Oct. 15 crop-rotation period. The results of three-year high-yield experiments in Laizhou and Longkou showed that yields were above 21 000 kg.hm -2 per year. Yields for the last year reached the expected target of 22 500 kg.hm -2. Yields for the area of 0.074 hm 2 reached 24 792.45 kg.hm -2 for the two seasons. The study showed that wheat-maize double-cropping system technology that made full use of light, heat and variety resources was more rational for Yantai, which brought local potential productivity to full realization.