• Authors:
    • Taliaferro, C. M.
    • Kakani, V. G.
    • Zhang, H.
    • Wu, Y. Q.
    • Makaju, S. O.
    • Anderson, M. P.
  • Source: Agronomy Journal
  • Volume: 105
  • Issue: 2
  • Year: 2013
  • Summary: The maximum biomass yield of switchgrass ( Panicum virgatum L.) usually is achieved with one seasonal autumn harvest. However, information is limited on the influences of winter harvesting on annual biomass yield and on quality parameters impacting conversion into bioethanol. Accordingly, the objectives of this study were to assess: (i) yield of standing field cured biomass at monthly intervals through winter, (ii) year-round elemental composition of biomass, and (iii) associated year-round soil nutrient status. An unfertilized 'Kanlow' switchgrass planting established in 1998 was used for this study conducted from November 2007 to October 2010. The experimental treatment was monthly harvest from November to the following March and year-round monthly sampling of biomass (except April) and soil for chemical analyses. The 3-yr mean dry matter yield of winter harvests was 5.94Mg ha -1, ranging from 3.88 Mg ha -1 in the winter of 2007-2008 to 7.55 Mg ha -1 in 2009-2010. Monthly biomass yield differences were significant in Years 1 and 3 but not in Year 2. Concentrations of biomass elements and soil nutrients changed with various degrees over the 3 yr. Concentrations of ash, cell wall components, and mineral nutrients, except P, K, and S, did not change appreciably across winter months. Early winter harvests resulted in less yield loss compared to late winter harvests. These findings will be valuable in harvest management for switchgrass biomass production.
  • Authors:
    • Berns, A. E.
    • Knicker, H.
    • Panettieri, M.
    • Murillo, J. M.
    • Madejon, E.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 177
  • Year: 2013
  • Summary: The impact on soil aggregates status of two tillage practices (moldboard plowing, TT, and chisel plowing, RT) applied to a farm previously cultivated under no-tillage (NT) was studied. The experiment was carried out on a Leptic Typic Xerorthent soil at the "Las Navas" dryland experimental farm located in Jerez de la Frontera (Cadiz, SW Spain). Several organic C pools such as total organic carbon (TOC), water soluble carbon (WSC), permanganate oxidizable carbon (POxC), and microbial biomass carbon (MBC) were analyzed, together with two enzymatic activities related to soil organic matter (SOM) oxidization metabolism: dehydrogenase activity (DH) and beta-glucosidase activity (beta-Glu). 13C cross polarization magic angle spinning nuclear magnetic resonance ( 13C CPMAS NMR) spectroscopy was used to characterize the composition of the SOM and its degradation status. Two years after the implementation of the new management practices, analysis of the aggregate distribution of the topsoil (0-10 cm) showed that, even after a short term, TT enhanced aggregate disruption. The apparent reduction in soil quality of TT plots was evident from the lower contents of total organic carbon (TOC), permanganate oxidizable carbon (POxC) and microbial biomass carbon (MBC) if compared with RT and NT. Moreover, TT soil showed also a lower beta-glucosidase activity. As confirmed by 13C CPMAS NMR, the SOM of the TT fractions revealed higher alkyl C to O-alkyl ratios than their RT and NT counterparts. Also signals commonly referred to lignin structures were absent in the spectra of the TT fractions, but were still present in those of the larger fractions of the NT treatment. After a short term evaluation, RT samples did not show the same declining trend as observed for the TT treatment. For this reason, chisel plowing seems to offer a viable occasional management option when required during long-term NT.
  • Authors:
    • Vijayasankarbabu, M.
    • Balaguravaiah, G.
    • Singh, A. K.
    • Lal, R.
    • Venkateswarlu, B.
    • Kundu, S.
    • Srinivasarao, C.
    • Vittal, K. P. R.
    • Reddy, S.
    • Manideep, V. R.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 96
  • Issue: 1
  • Year: 2013
  • Summary: Drought stress, uncertain and variable rainfall, low soil quality and nutrient deficiencies are among principal constraints for enhancing and sustaining agronomic productivity in rainfed farming in semiarid tropical regions of India. Therefore, long-term (1985-2004) effects of cropping, fertilization, manuring (groundnut shells, GNS; farmyard manure, FYM) and integrated nutrient management practices were assessed on pod yields, nutrient status and balances for a groundnut (Arachis hypogaea) monocropping system. The five nutrient management treatments were: control (no fertilizer); 100 % recommended dose of fertilizer (RDF) (20:40:40 N, P, K); 50 % RDF + 4 Mg ha(-1) GNS; 50 % RDF + 4 Mg ha(-1) FYM and 100 % organic (5 Mg ha(-1) FYM). All treatments were replicated four times. The experiment was conducted at Anantapur district, Andhra Pradesh on an Alfisol using a Randomized Complete Block design. The gap in pod yields between control and different nutrient treatments widened with increase in duration of cultivation. Use of diverse fertilizer and manurial treatments produced significantly higher yields than control (P < 0.05). Amount and distribution of rainfall during critical growth stages was more important to agronomic yield than total and seasonal rainfall. Thus, the amount of rainfall received during pegging stage (r = 0.47; P < 0.05) and pod formation stage (r = 0.50; P < 0.05) was significantly correlated with the mean pod yields. Whereas, use of diverse fertility management practices improved nutrient status in soil profiles (N, P, K, S, Ca, Mg, Zn, Fe, Mn and B) after 20 years of cropping, yet soil available N, K and B remained below the critical limits. Long-term cultivation also caused deficiency of S, Zn and B, which limited the groundnut productivity. Crop removal of N, P and K during 20 years of cultivation was more in 50 % RDF + 4 Mg ha(-1) GNS at 523, 210 and 598 kg ha(-1), respectively. With the exception of control, there was a positive nutrient balance of NPK in all other treatments. Higher positive balance of N and K were observed in 50 % RDF + 4 Mg ha(-1) GNS (616 and 837 kg ha(-1), respectively), and those of P in 100 % RDF (655 kg ha(-1)) treatment. There was also a net depletion of available S, Zn, Cu and Mn, but a buildup of available Ca, Mg and Fe. Application of equal amount of GNS was as effective as or even better than FYM in terms of pod yields and nutrient buildup in the soil.
  • Authors:
    • Pendall, E.
    • Bell, J.
    • Tucker, C. L.
    • Ogle, K.
  • Source: Global Change Biology
  • Volume: 19
  • Issue: 1
  • Year: 2013
  • Summary: Enhanced soil respiration in response to global warming may substantially increase atmospheric CO 2 concentrations above the anthropogenic contribution, depending on the mechanisms underlying the temperature sensitivity of soil respiration. Here, we compared short-term and seasonal responses of soil respiration to a shifting thermal environment and variable substrate availability via laboratory incubations. To analyze the data from incubations, we implemented a novel process-based model of soil respiration in a hierarchical Bayesian framework. Our process model combined a Michaelis-Menten-type equation of substrate availability and microbial biomass with an Arrhenius-type nonlinear temperature response function. We tested the competing hypotheses that apparent thermal acclimation of soil respiration can be explained by depletion of labile substrates in warmed soils, or that physiological acclimation reduces respiration rates. We demonstrated that short-term apparent acclimation can be induced by substrate depletion, but that decreasing microbial biomass carbon (MBC) is also important, and lower MBC at warmer temperatures is likely due to decreased carbon-use efficiency (CUE). Observed seasonal acclimation of soil respiration was associated with higher CUE and lower basal respiration for summer- vs. winter-collected soils. Whether the observed short-term decrease in CUE or the seasonal acclimation of CUE with increased temperatures dominates the response to long-term warming will have important consequences for soil organic carbon storage.
  • Authors:
    • Zhang, X-C.
    • Zheng, Z-Q.
    • Lu, Z.-Y.
    • Lu, C.-Y.
    • Sivelli,A.
    • Li, H.-W.
    • Wang, Q-J.
    • He, J
    • Li, H.
  • Source: Soil Science
  • Volume: 178
  • Issue: 1
  • Year: 2013
  • Summary: Traditional tillage (TT) in the North China Plain has maintained grain productivity in the past 50 years. Nonetheless, it has also been a major contributor to global greenhouse gas emissions, biodiversity and soil fertility loss, soil degradation, and even desertification. Permanent raised beds (PRB) have been proposed as a viable solution to achieve sustainable farming in this plain. The effects on soil chemical properties of the PRB treatment and two other treatments, namely, no-tillage and TT treatments, were measured between 2005 and 2011 in the annual double cropping regions of the North China Plain. The soil properties significantly ( P1.35) were significantly ( P<0.05) higher than those under no-tillage and TT. In the cropping zone of PRB, the bulk density was significantly reduced by 14.4%, whereas soil organic carbon, total nitrogen, phosphorus, and potassium and available nitrogen, phosphorus, and potassium in the 0- to 10-cm soil layer were significantly increased by 24.8%, 78.8%, 121.9%, 81.8%, 46.2%, 7.0%, 2.9%, respectively, in comparison with those of TT treatments. Winter wheat and summer maize yields in PRB also underwent a slight increase. Permanent raised beds seem to be an improvement on current farming systems in the North China Plain and valuable for the sustainability of farming in this region.
  • Authors:
    • Hulugalle, N. R.
  • Source: Crop and Pasture Science
  • Volume: 64
  • Issue: 8
  • Year: 2013
  • Summary: Partial mitigation of global warming caused by accelerated emissions of greenhouse gases such as carbon dioxide may be possible by storing atmospheric carbon in soils. Carbon storage is influenced by processes and properties that affect soil aggregation, such as clay and silt concentrations and mineralogy, intensity and frequency of wet/dry cycles, and microbial activity. Microbial activity, in turn, is influenced by factors such as temperature, nutrient and water availability, and residue quality. The objective of this study was to assess the influence of average annual maximum temperature on soil carbon storage in Vertosols under cotton-based farming systems. This paper reports a re-evaluation of results obtained from a series of experiments on cotton-farming systems conducted in eastern Australia between 1993 and 2010. The experimental sites were in the Macquarie and Namoi Valleys of New South Wales, and the Darling Downs and Central Highlands of Queensland. Average soil organic carbon storage in the 0-0.6m depth was highest in a Black Vertosol in Central Queensland and lowest in a Grey Vertosol that was irrigated with treated sewage effluent at Narrabri. At other sites, average values were generally comparable and ranged from 65 to 85 t C/ha. Climatic parameters such as ambient maximum temperature, T-max, and rainfall at rainfed sites (but not irrigated sites) were also related to soil organic carbon storage. At most sites, variations in carbon storage with average ambient maximum temperature were described by Gaussian models or bell-shaped curves, which are characteristic of microbial decomposition. Carbon storage occurred at peak rates only for a very limited temperature range at any one site, with these temperatures increasing with decreasing distance from the equator. The exception was a site near Narrabri that was irrigated with treated sewage effluent, where the relationship between soil organic carbon and T-max was linear. The decrease or absence of change in soil carbon storage with time reported in many Australian studies of annual cropping systems may be due to carbon storage occurring within a limited temperature range, whereas intra-seasonal average maximum temperatures can range widely. Further research needs to be conducted under field conditions to confirm these observations.
  • Authors:
    • Finlay, L. A.
    • Weaver, T. B.
    • Hulugalle, N. R.
    • Heimoana, V.
  • Source: CROP & PASTURE SCIENCE
  • Volume: 64
  • Issue: 8
  • Year: 2013
  • Summary: Long-term studies of soil organic carbon dynamics in two- and three-crop rotations in irrigated cotton (Gossypium hirsutum L.) based cropping systems under varying stubble management practices in Australian Vertosols are relatively few. Our objective was to quantify soil organic carbon dynamics during a 9-year period in four irrigated, cotton-based cropping systems sown on permanent beds in a Vertosol with restricted subsoil drainage near Narrabri in north-western New South Wales, Australia. The experimental treatments were: cotton-cotton (CC); cotton-vetch (Vicia villosa Roth. in 2002-06, Vicia benghalensis L. in 2007-11) (CV); cotton-wheat (Triticum aestivum L.), where wheat stubble was incorporated (CW); and cotton-wheat-vetch, where wheat stubble was retained as in-situ mulch (CWV). Vetch was terminated during or just before flowering by a combination of mowing and contact herbicides, and the residues were retained as in situ mulch. Estimates of carbon sequestered by above- and below-ground biomass inputs were in the order CWV>>CW=CV>CC. Carbon concentrations in the 0-1.2m depth and carbon storage in the 0-0.3 and 0-1.2m depths were similar among all cropping systems. Net carbon sequestration rates did not differ among cropping systems and did not change significantly with time in the 0-0.3m depth, but net losses occurred in the 0-1.2m depth. The discrepancy between measured and estimated values of sequestered carbon suggests that either the value of 5% used to estimate carbon sequestration from biomass inputs was an overestimate for this site, or post-sequestration losses may have been high. The latter has not been investigated in Australian Vertosols. Future research efforts should identify the cause and quantify the magnitude of these losses of organic carbon from soil.
  • Authors:
    • Ingram, D. L.
  • Source: JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE
  • Volume: 138
  • Issue: 1
  • Year: 2013
  • Summary: The contributions of interrelated production system components of a field-grown, 2-m-tall, 5-cm-caliper Picea pungens (colorado blue spruce) in the upper midwestern (liner) and lower midwestern (finished tree) regions of the United States to its carbon footprint were analyzed using life cycle assessment protocols. The seed-to-landscape carbon footprint was 13.558 kg carbon dioxide equivalent (CO(2)e), including sequestration of 9.14 kg CO(2)e during production. The global warming potential (GWP) from equipment use was the dominant contributor to the carbon footprint of production. Seventy-six percent of the GWP investments during field production occurred at harvest. Querying the model, among other things, revealed that adding one year to the field production phase would add less than 3% to the seed-to-landscape GWP of the product. The weighted positive impact of carbon (C) sequestration during a 50-year life was 593 kg CO(2)e. After its useful life, takedown and disposal would result in emissions of 148 kg CO(2)e, resulting in a net positive, life cycle impact on atmospheric CO2 of approximate to 431 kg CO(2)e.
  • Authors:
    • Govindaraj, M.
    • Prabukumar, G.
    • Arunachalam, P.
    • Kannan, P.
  • Source: African Journal of Agricultural Research
  • Volume: 8
  • Issue: 21
  • Year: 2013
  • Summary: Atmospheric rise of CO 2, N 2O and CH 4 over years, accelerated increase in global temperature, has led to uncertainty in monsoon rainfall and also leading to recurrence of drought, which in turn is severely affecting crop productivity and livelihood security of the farmers in Semi Arid Tropics. Agriculture contributes considerable amount of CO 2, N 2O and CH 4 emission into the atmosphere through different soil and crop management practices. Nevertheless agricultural activities contribute to global warming. The medium of crop production, soil is one of the major sinks of global warming gaseous and it helps to sequester more carbon and cut the N 2O emission by adopting smart soil and crop management techniques. Biochar is one of the viable organic amendments to combat climate change and sustain the soil health with sustainable crop production. It is an anaerobic pyrolysis product derived from organic sources and store carbon on a long term basis in the terrestrial ecosystem and also capable of reducing greenhouse gases (GHG) emission from soil to the atmosphere. Biochar application improved the soil health, increase the carbon capture and storage, reduce the GHG emission and enhance the crop yield with sustained soil health, which enables to meet out the food grain needs of the ever growing population.
  • Authors:
    • Ghorbani, R.
    • Khorasani, R.
    • Mahallati, M. N.
    • Koocheki, A.
    • Khorramdel, S.
  • Source: Soil and Tillage Research
  • Volume: 133
  • Issue: October
  • Year: 2013
  • Summary: Carbon sequestration could be an effective way to reduce atmospheric carbon dioxide which is the most important greenhouse gas. Two field experiments were conducted at Agricultural Research Station of Ferdowsi University of Mashhad, Iran, during growing seasons of 2008-2009 and 2009-2010. Four treatments including two low input management systems based on application of cow manure or compost municipal made from house-hold waste, a medium input system and a high input system were applied. In low input system 30 t ha(-1) cow manure or 30 t ha(-1) compost municipal made from house-hold-waste was applied and twice hand weeding were carried out. In medium input system, 15 t ha(-1) compost, 150 kg ha(-1) urea, disking and ploughing, 1.5 l ha(-1) 2,4-D applied at five leaf stage with only one hand weeding. In high input system, management practices included twice disking, twice ploughing, 21 ha(-1) Paraquat applied after planting and 1.5 1 ha(-1) 2,4-D applied at five leaf stage. Results showed that the maximum carbon and nitrogen yields in corn residues observed in high input system (0.8 and 0.02 kg m(-2)) and its minimum were in low input system with using compost (0.5 and 0.01 kg m-2). The highest and lowest labile and recalcitrant carbon rates were observed in low input system with manure (0.92 and 1.05%) and high input system (0.06 and 0.004%), respectively. The maximum sequestered carbon obtained in low input management system with using cow manure (4.1 t ha(-1)) and the minimum sequestered carbon were in high input management system (0.01 t ha(-1)). In low input system due to slow releasing nutrients, long term crop growth and hence higher recalcitrant carbon content of the soil were enhanced which could be an indication of its potential for carbon sequestration in low input management system. (C) 2013 Published by Elsevier B.V.