• Authors:
    • Hickie, K. A.
    • James, T. A.
    • Robinson, J. L.
    • Moffitt, D. C.
    • Hays, P. D.
    • DeFauw, S. L.
    • Van Brahana, J.
    • Skinner, J. V.
    • Brauer, D. K.
    • Brye, K. R.
    • Thomas, A. L.
    • Coblentz, W. K.
    • Sauer, T. J.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 101
  • Issue: 2
  • Year: 2015
  • Summary: Optimal utilization of animal manures as a plant nutrient source should also prevent adverse impacts on water quality. The objective of this study was to evaluate long-term poultry litter and N fertilizer application on nutrient cycling following establishment of an alley cropping system with eastern black walnut (Juglans nigra L.), pecan [Carya illinoensis (Wangenh.) K. Koch], and northern red oak (Quercus rubra L.) trees and orchardgrass (Dactylis glomerata L.). One half of a 4.25-ha site in northwestern Arkansas USA received broadcast applications of 3.9-6.7 Mg ha(-1) fresh poultry litter and the other half 50-76 kg ha(-1) N as NH4NO3 fertilizer each spring from 2001 to 2008. Macronutrient (N, P, K, Ca, Mg, and S) and micronutrient (Na, Fe, Mn, Zn, and Cu) concentrations in soil, forage, and tree leaf tissue were monitored along with NO3-N in soil water and groundwater. Poultry litter application resulted in significantly increased concentrations of each macronutrient except S with increases from 6.3 (N) to 121 % (P). Nitrogen fertilizer application resulted in decreased concentrations from 2.1 (N) to 60.9 % (S) for all macronutrients except Ca. Patterns of nutrient content in forage and tree leaf tissue did not generally follow patterns of soil nutrient concentrations suggesting nutrient sufficiency in most years and that climate and plant growth had a greater effect on nutrient uptake. Soil P with litter application increased 41.3 mg kg(-1) over 7 years (from 34.1 to 75.4), which may necessitate a lower litter application rate to avoid excessive P runoff.
  • Authors:
    • Wang, X.
    • Zhang, T.
    • Liu, J.
    • Ding, C.
    • Li, X.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 1
  • Year: 2015
  • Summary: Peanut ( Arachis hypogaea L.) yield and quality are seriously compromised by consecutive monoculturing in southeastern China. This work investigated the population size and community structure of soil nematodes in 3-, 6-, and 20-yr-old peanut monoculturing systems. A grass pasture was used as the control. The results showed that continuous peanut monocropping had detrimental effects on the soil nematode abundance and functional composition compared with the control. The reductions in the abundance of total and microbivorous nematodes with increasing years of monocropping are likely to reduce bioturbation and nutrient mineralization, and an elevated abundance of plant parasitic nematodes may result in serious damage to peanut roots, thus aggravating root rot. Furthermore, the significant variations in soil nematode functional indices across the three monocropped peanut fields may produce negative effects on sustainable agroecosystems. Our study also contributes to the identification of locally applicable indicator species of soil nematodes, i.e., Tylenchus, Doryllium, and Mesorhabditis, which can be applied in the assessment of soil status within monocropped peanut fields. Our results suggest that the soil nematode community exhibits evident responses to peanut monocropping.
  • Authors:
    • Singh,R. J.
    • Ahlawat,I. P. S.
  • Source: Environmental Monitoring and Assessment
  • Volume: 187
  • Issue: 5
  • Year: 2015
  • Summary: Two of the most pressing sustainability issues are the depletion of fossil energy resources and the emission of atmospheric green house gases like carbon dioxide to the atmosphere. The aim of this study was to assess energy budgeting and carbon footprint in transgenic cotton–wheat cropping system through peanut intercropping with using 25–50 % substitution of recommended dose of nitrogen (RDN) of cotton through farmyard manure (FYM) along with 100 % RDN through urea and control (0 N). To quantify the residual effects of previous crops and their fertility levels, a succeeding crop of wheat was grown with varying rates of nitrogen, viz. 0, 50, 100, and 150 kg ha-1. Cotton + peanut–wheat cropping system recorded 21 % higher system productivity which ultimately helped to maintain higher net energy return (22 %), energy use efficiency (12 %), human energy profitability (3 %), energy productivity (7 %), carbon outputs (20 %), carbon efficiency (17 %), and 11 % lower carbon footprint over sole cotton–wheat cropping system. Peanut addition in cotton–wheat system increased the share of renewable energy inputs from 18 to 21 %. With substitution of 25 % RDN of cotton through FYM, share of renewable energy resources increased in the range of 21 % which resulted into higher system productivity (4 %), net energy return (5 %), energy ratio (6 %), human energy profitability (74 %), energy productivity (6 %), energy profitability (5 %), and 5 % lower carbon footprint over no substitution. The highest carbon footprint (0.201) was recorded under control followed by 50 % substitution of RDN through FYM (0.189). With each successive increase in N dose up to 150 kg N ha-1 to wheat, energy productivity significantly reduced and share of renewable energy inputs decreased from 25 to 13 %. Application of 100 kg N ha-1 to wheat maintained the highest grain yield (3.71 t ha-1), net energy return (105,516 MJ ha-1), and human energy profitability (223.4) over other N doses applied to wheat. Application of 50 kg N ha-1 to wheat maintained the least carbon footprint (0.091) followed by 100 kg N ha-1 (0.100). Our study indicates that system productivity as well as energy and carbon use efficiencies of transgenic cotton–wheat production system can be enhanced by inclusion of peanut as an intercrop in cotton and substitution of 25 % RDN of cotton through FYM, as well as application of 100 kg N ha-1 to succeeding wheat crop. © 2015, Springer International Publishing Switzerland.
  • Authors:
    • Marvinney,E.
    • Kendall,A.
    • Brodt,S.
  • Source: Journal of Industrial Ecology
  • Volume: 19
  • Issue: 6
  • Year: 2015
  • Summary: This is the second part of a two-article series examining California almond production. The part I article describes development of the analytical framework and life cycle-based model and presents typical energy use and greenhouse gas (GHG) emissions for California almonds. This part II article builds on this by exploring uncertainty in the life cycle model through sensitivity and scenario analysis, and by examining temporary carbon storage in the orchard. Sensitivity analysis shows life cycle GHG emissions are most affected by biomass fate and utilization, followed by nitrous oxide emissions rates from orchard soils. Model sensitivity for net energy consumption is highest for irrigation system parameters, followed by biomass fate and utilization. Scenario analysis shows utilization of orchard biomass for electricity production has the greatest potential effect, assuming displacement methods are used for co-product allocation. Results of the scenario analysis show that 1 kilogram (kg) of almond kernel and associated co-products are estimated to cause between -3.12 to 2.67 kg carbon dioxide equivalent (CO2-eq) emissions and consume between 27.6 to 52.5 megajoules (MJ) of energy. Co-product displacement credits lead to avoided emissions of between -1.33 to 2.45 kg CO2-eq and between -0.08 to 13.7 MJ of avoided energy use, leading to net results of -1.39 to 3.99 kg CO2-eq and 15.3 to 52.6 MJ per kg kernel (net results are calculated by subtracting co-product credits from the results for almonds and co-products). Temporary carbon storage in orchard biomass and soils is accounted for by using alternative global warming characterization factors and leads to a 14% to 18% reduction in CO2-eq emissions. Future studies of orchards and other perennial cropping systems should likely consider temporary carbon storage. © 2015 The Authors. Journal of Industrial Ecology, published by Wiley Periodicals, Inc., on behalf of Yale University.
  • Authors:
    • Torres,C. M. M. E.
    • Kohmann,M. M.
    • Fraisse,C. W.
  • Source: Agricultural Systems
  • Volume: 137
  • Year: 2015
  • Summary: Agriculture is an important source of greenhouse gases (GHG), especially from crop production practices and enteric fermentation by ruminant livestock. Improved production practices in agriculture and increase in terrestrial carbon sinks are alternatives for mitigating GHG emissions in agriculture. The objective of this study was to estimate GHG emissions from hypothetical farm enterprise combinations in the southeastern United States with a mix of cropland and livestock production and estimate the area of forest plantation necessary to offset these emissions. Four different farm enterprise combinations (Cotton; Maize; Peanut; Wheat+Livestock+Forest) with different production practices were considered in the study resulting in different emission scenarios. We assumed typical production practices of farm operations in the region with 100 ha of cropland area and a herd of 50 cows. GHG emissions were calculated regarding production, storage and transportation of agrochemicals (pre-farm) and farm activities such as fertilization, machinery operation and irrigation (on-farm). Simulated total farm GHG emissions for the different farm enterprise combinations and production practices ranged from 348.8 t CO 2e year -1 to 765.6 t CO 2e year -1. The estimated forest area required to neutralize these emissions ranged from 19 ha to 40 ha. In general, enterprise combinations with more intense production practices that include the use of irrigation resulted in higher total emissions but lower emissions per unit of commodity produced.
  • Authors:
    • Eleto Torres,Carlos M. M.
    • Kohmann,Marta M.
    • Fraisse,Clyde W.
  • Source: Agricultural Systems
  • Volume: 137
  • Year: 2015
  • Summary: Agriculture is an important source of greenhouse gases (GHG), especially from crop production practices and enteric fermentation by ruminant livestock. Improved production practices in agriculture and increase in terrestrial carbon sinks are alternatives for mitigating GHG emissions in agriculture. The objective of this study was to estimate GHG emissions from hypothetical farm enterprise combinations in the southeastern United States with a mix of cropland and livestock production and estimate the area of forest plantation necessary to offset these emissions. Four different farm enterprise combinations (Cotton; Maize; Peanut; Wheat + Livestock + Forest) with different production practices were considered in the study resulting in different emission scenarios. We assumed typical production practices of farm operations in the region with 100 ha of cropland area and a herd of 50 cows. GHG emissions were calculated regarding production, storage and transportation of agrochemicals (pre-farm) and farm activities such as fertilization, machinery operation and irrigation (on-farm). Simulated total farm GHG emissions for the different farm enterprise combinations and production practices ranged from 348.8 t CO(2)e year(-1) to 765.6 t CO(2)e year(-1). The estimated forest area required to neutralize these emissions ranged from 19 ha to 40 ha. In general, enterprise combinations with more intense production practices that include the use of irrigation resulted in higher total emissions but lower emissions per unit of commodity produced. (C) 2015 Elsevier Ltd. All rights reserved.
  • Authors:
    • Gul,S.
    • Whalen,J. K.
    • Thomas,B. W.
    • Sachdeva,V.
    • Deng HongYuan
  • Source: Agriculture, Ecosystems and Environment
  • Volume: 206
  • Year: 2015
  • Summary: Soil microbial communities are responsive to biochar amendments. As the residence time of biochar in soil is expected to be hundreds to thousands of years, the changes in microbial community structure and functions could persist for a long period of time. Given that biochar is being applied as a soil amendment in many parts of the world, the long-term consequences for soil microbial communities need to be considered. The objective of this review is to document how biochar creates new habitats and changes the soil environment for microorganisms, which may lead to changes in microbial abundance, community structure and activities. Our meta-analysis revealed that slow pyrolyzed biochars produced from various feedstocks at temperatures from 300°C to 600°C consistently increased some physico-chemical properties (i.e., pH, cation exchange capacity and aggregation) and microbial parameters (i.e., abundance and community structure of microorganisms) in a vast number of soils during short (≤90 days) laboratory incubations and longer (1-3 years) field studies. The biochar-mediated changes in soil physico-chemical and biological properties appeared to be a function of soil texture and biochar type based on its feedstock and production temperature, which determines key biochar characteristics such as surface area, porosity and pH. Biochars derived from manure or crop residue feedstocks tend to promote microbial abundance more than wood-derived biochars. Biochars derived from wood and other lignocellulosic-rich feedstocks tend to exhibit beneficial effects on soil microbial abundance later (≥60 days) than biochars from manure or crop residue feedstocks. Coarse textured soils tend to have less aggregation, lower microbial biomass and lower enzyme activities when amended with slow pyrolyzed biochars produced at high temperatures (>600°C), but these biochars did not affect the physico-chemical and biological properties of clayey soils. Further research is needed to evaluate the magnitude of biochar influence on soil microbial abundance and activities considering (1) the biochar particle size, surface area, porosity, nutrient content and pH, and (2) the soil organic matter (SOM) content and microbial abundance of the soil matrix. Once the microbial activities in the biochar-soil system are understood, they can be manipulated through organic and inorganic fertilizer applications to sustain or improve agricultural crop production.
  • Authors:
    • Lee,Hyunok
    • Sumner,Daniel A.
  • Source: Climatic Change
  • Volume: 132
  • Issue: 4
  • Year: 2015
  • Summary: This article establishes quantitative relationships between the evolution of climate and cropland using daily climate data for a century and data on allocation of land across crops for six decades in a specific agro-climatic region of California. These relationships are applied to project how climate scenarios reported by the Intergovernmental Panel on Climate Change would drive cropland patterns into 2050. Projections of warmer winters, particularly from 2035 to 2050, cause lower wheat area and more alfalfa and tomato area. Only marginal changes in area were projected for tree and vine crops, in part because although lower, chill hours remain above critical values.
  • Authors:
    • Muirhead, B.
    • Nelson, P. N.
    • Bass, A. M.
    • Agegnehu, G.
    • Wright,Graeme
    • Bird,Michael I.
  • Source: Article
  • Volume: 213
  • Year: 2015
  • Summary: This study investigated the effects of biochar and compost, applied individually or together, on soil fertility, peanut yield and greenhouse gas (GHG) emissions on a Ferralsol in north Queensland, Australia. The treatments were (1) inorganic fertilizer only (F) as a control; (2) 10 t ha(-1) biochar + F (B +F); (3) 25 t compost +F (Com +F) ha-1; (4) 2.5t B ha(-1) + 25 t Com ha-1 mixed on site +F; and (5) 25 t ha(-1) cocomposted biochar-compost + F (COMBI + F). Application of B and COMBI increased seed yield by 23% and 24%, respectively. Biochar, compost and their mixtures significantly improved plant nutrient availability and use, which appeared critical in improving peanut performance. Soil organic carbon (SOC) increased from 0.93% (F only) to 1.25% (B amended), soil water content (SWC) from 18% (F only) to over 23% (B amended) and CEC from 8.9 cmol(+)/kg (F only) to over 103 cmol(+)/kg (organic amended). Peanut yield was significantly positively correlated with leaf chlorophyll content, nodulation number (NN), leaf nutrient concentration, SOC and SWC for the organic amendments. Fluxes of CO2 were highest for the F treatment and lowest for the COMBI treatment, whereas N2O flux was highest for the F treatment and all organic amended plots reduced N2O flux relative to the control. Principal component analysis indicates that 24 out of 30 characters in the first principal component (PRIN1) individually contributed substantial effects to the total variation between the treatments. Our study concludes that applications of B, Cam, B +Com or COMBI have strong potential to, over time, improve SOC, SWC, soil nutrient status, peanut yield and abate GHG fluxes on tropical Ferralsols. Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserved.
  • Authors:
    • Wu, J.
    • Liu, J.
    • Zhou, G.
    • Jiang, P.
    • Chang, S. X.
    • Li, Y.
    • Zhang, J.
    • Shen, Z.
  • Source: Plant and Soil
  • Volume: 376
  • Issue: 1-2
  • Year: 2014
  • Summary: The impact of understory vegetation control or replacement with selected plant species, which are common forest plantation management practices, on soil C pool and greenhouse gas (GHG, including CO2, CH4 and N2O) emissions are poorly understood. The objective of this paper was to investigate the effects of understory vegetation management on the dynamics of soil GHG emissions and labile C pools in an intensively managed Chinese chestnut (Castanea mollissima Blume) plantation in subtropical China. A 12-month field experiment was conducted to study the dynamics of soil labile C pools and GHG emissions in a Chinese chestnut plantation under four different understory management practices: control (Control), understory removal (UR), replacement of understory vegetation with Medicago sativa L. (MS), and replacement with Lolium perenne L. (LP). Soil GHG emissions were determined using the static chamber/GC technique. Understory management did not change the seasonal pattern of soil GHG emissions; however, as compared with the Control, the UR treatment increased soil CO2 and N2O emissions and CH4 uptake, and the MS and LP treatments increased CO2 and N2O emissions and reduced CH4 uptake (P < 0.05 for all treatment effects, same below). The total global warming potential (GWP) of GHG emissions in the Control, UR, MS, and LP treatments were 36.56, 39.40, 42.36, and 42.99 Mg CO2 equivalent (CO2-e) ha(-1) year(-1), respectively, with CO2 emission accounting for more than 95 % of total GWP regardless of the understory management treatment. The MS and LP treatments increased soil organic C (SOC), total N (TN), soil water soluble organic C (WSOC) and microbial biomass C (MBC), while the UR treatment decreased SOC, TN and NO3 (-)-N but had no effect on WSOC and MBC. Soil GHG emissions were correlated with soil temperature and WSOC across the treatments, but had no relationship with soil moisture content and MBC. Although replacing competitive understory vegetation with legume or less competitive non-legume species increased soil GHG emissions and total GWP, such treatments also increased soil C and N pools and are therefore beneficial for increasing soil C storage, maintaining soil fertility, and enhancing the productivity of Chinese chestnut plantations.