• Authors:
    • Solaiman,Zakaria M.
    • Anawar,Hossain M.
  • Source: Pedosphere
  • Volume: 25
  • Issue: 5
  • Year: 2015
  • Summary: Biochar addition to soil is currently being considered as a means to sequester carbon while simultaneously improving soil health, soil fertility and agronomic benefits. The focus of this special issue is on current research on the effects of biochar application to soil for overcoming diverse soil constraints and recommending further research relating to biochar application to soil. The biochar research has progressed considerably with important key findings on agronomic benefits, carbon sequestration, greenhouse gas emissions, soil acidity, soil fertility, soil health, soil salinity, etc., but more research is required before definitive recommendations can be made to end-users regarding the effects of biochar application across a range of soils, climates and land management practices.
  • Authors:
    • Thomas,B. W.
    • Sharifi,M.
    • Whalen,J. K.
    • Chantigny,M. H.
  • Source: Soil Science Society of America Journal
  • Volume: 79
  • Issue: 5
  • Year: 2015
  • Summary: Manuring soil alters mineralizable N pools and organic matter fractions, but the magnitude is manure-type and soil-texture specific, complicating prediction of N mineralization. Our objective was to determine the responses of residual soil mineralizable N parameters to manure-type and evaluate their relationships to initial organic C and N fractions, C/N ratios, and mineral N concentrations in sandy loam and silty clay soils after three annual spring applications of manure. Manure types were liquid swine manure (LSM), liquid dairy cattle manure (LCM), or solid poultry manure (SPM), all applied at 90 kg available N ha-1 yr-1. Mineral fertilizer (NPK) and a zero-N control (CTL) were also included. Composite soil samples collected (0-to 20-cm depth) before manure application were aerobically incubated at 25°C for 48 wk. Both soils mineralized N linearly over 48 wk (r2 = 0.96-0.99) and the silty clay soil did not converge to nonlinear, first-order kinetics. Pool I (N mineralized in first 2 wk) was the only mineralizable N pool affected by manure-type, which was depleted by SPM in the sandy loam and increased by LCM in the silty clay. Salt extractable organic N was significantly correlated to Pool I in both soil textures. Only Pool I was significantly correlated with N mineralized over 48 wk in the sandy loam and silty clay soils (r = 0.92 and 0.64, respectively). Overall, readily mineralizable N (Pool I) was the most sensitive and robust indicator of mineralizable N after three annual manure applications to agricultural soils from a humid temperate region. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved.
  • Authors:
    • Bailey,Rebecca R.
    • Butts,Thomas R.
    • Lauer,Joseph G.
    • Laboski,Carrie A. M.
    • Kucharik,Christopher J.
    • Davis,Vince M.
  • Source: Weed Science
  • Volume: 63
  • Issue: 4
  • Year: 2015
  • Summary: Nitrous oxide (N2O) is a potent greenhouse gas with implication for climate change. Agriculture accounts for 10% of all greenhouse gas emissions in the United States, but 75% of the country's N2O emissions. In the absence of PRE herbicides, weeds compete with soybean for available soil moisture and inorganic N, and may reduce N2O emissions relative to a weed-free environment. However, after weeds are killed with a POST herbicide, the dead weed residues may stimulate N2O emissions by increasing soil moisture and supplying carbon and nitrogen to microbial denitrifiers. Wider soybean rows often have more weed biomass, and as a result, row width may further impact how weeds influence N2O emissions. To determine this relationship, field studies were conducted in 2013 and 2014 in Arlington, WI. A two-by-two factorial treatment structure of weed management (PRE + POST vs. POST-only) and row width (38 or 76 cm) was arranged in a randomized complete block design with four replications. N2O fluxes were measured from static gas sampling chambers at least weekly starting 2 wk after planting until mid-September, and were compared for the periods before and after weed termination using a repeated measures analysis. N2O fluxes were not influenced by the weed by width interaction or width before termination, after termination, or for the full duration of the study at P <= 0.05. Interestingly, we observed that POST-only treatments had lower fluxes on the sampling day immediately prior to POST application (P = 0.0002), but this was the only incidence where weed influenced N2O fluxes, and overall, average fluxes from PRE + POST and POST-only treatments were not different for any period of the study. Soybean yield was not influenced by width (P = 0.6018) or weed by width (P = 0.5825), but yield was 650 kg ha(-1) higher in the PRE + POST than POST-only treatments (P = 0.0007). These results indicate that herbicide management strategy does not influence N2O emissions from soybean, and the use of a PRE herbicide prevents soybean yield loss. Nomenclature: Soybean; Glycine max (L.) Merr.
  • Authors:
    • Chauhan,Y. S.
    • Thorburn,P.
    • Biggs,J. S.
    • Wright,G. C.
  • Source: Research Article
  • Volume: 66
  • Issue: 11
  • Year: 2015
  • Summary: With the aim of increasing peanut production in Australia, the Australian peanut industry has recently considered growing peanuts in rotation with maize at Katherine in the Northern Territory - a location with a semi-arid tropical climate and surplus irrigation capacity. We used the well-validated APSIM model to examine potential agronomic benefits and long-term risks of this strategy under the current and warmer climates of the new region. Yield of the two crops, irrigation requirement, total soil organic carbon (SOC), nitrogen (N) losses and greenhouse gas (GHG) emissions were simulated. Sixteen climate stressors were used; these were generated by using global climate models ECHAM5, GFDL2.1, GFDL2.0 and MRIGCM232 with a median sensitivity under two Special Report of Emissions Scenarios over the 2030 and 2050 timeframes plus current climate (baseline) for Katherine. Effects were compared at three levels of irrigation and three levels of N fertiliser applied to maize grown in rotations of wet-season peanut and dry-season maize (WPDM), and wet-season maize and dry-season peanut (WMDP). The climate stressors projected average temperature increases of 1°C to 2.8°C in the dry (baseline 24.4°C) and wet (baseline 29.5°C) seasons for the 2030 and 2050 timeframes, respectively. Increased temperature caused a reduction in yield of both crops in both rotations. However, the overall yield advantage of WPDM increased from 41% to up to 53% compared with the industry-preferred sequence of WMDP under the worst climate projection. Increased temperature increased the irrigation requirement by up to 11% in WPDM, but caused a smaller reduction in total SOC accumulation and smaller increases in N losses and GHG emission compared with WMDP. We conclude that although increased temperature will reduce productivity and total SOC accumulation, and increase N losses and GHG emissions in Katherine or similar northern Australian environments, the WPDM sequence should be preferable over the industry-preferred sequence because of its overall yield and sustainability advantages in warmer climates. Any limitations of irrigation resulting from climate change could, however, limit these advantages.
  • Authors:
    • Mango, N.
    • Nyamangara, J.
    • Nyamugafata, P.
    • Dunjana, N.
    • Gwenzi, W.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Crop water productivity is often regarded as indicating the water use efficiency of crops, an important aspect, particularly under erratic rainfall conditions. This study investigated the effects of cattle manure and mineral-N fertilizer application on maize ( Zea mays L.) water productivity (MWP) on clay and sandy soils in a smallholder farming area of Zimbabwe. Four fields previously exhibiting heterogeneous fertility were managed under the following treatments: control (no amendment) and cattle manure (5, 15, and 25 Mg ha -1)+100 kg ha -1 mineral-N fertilizer for 7 yr. Thereafter, the effects of fertility treatment on MWP were expressed as actual maize grain yield produced per unit of seasonal transpiration modeled using AquaCrop. Furthermore, the relationship of MWP to physical soil properties was determined using principal component analysis. The MWP significantly ( P<0.05) improved with an increase in cattle manure plus mineral-N fertilizer application over control on both soils ranging between 0.5 and 1.7 kg m -3 and between 0.24 and 1.1 kg m -3 on clay and sandy soils, respectively. The MWP was significantly correlated ( P<0.05) with the steady-state infiltration rate on the clay soil and with soil organic C on the sandy soil. We concluded that cattle manure and mineral-N fertilizer application is key to MWP improvement in rainfed smallholder cropping systems and is closely coupled with improvements in physical soil properties on clay soil than sandy soil. Therefore, the observations attest to the importance of site-specific management that could contribute to efficient resource use in resource-constrained farming areas.
  • Authors:
    • Steffens, D.
    • Azam, F.
    • Koyro, H. W.
    • Haider, G.
    • Muller, C.
    • Kammann, C.
  • Source: Regular Article
  • Volume: 395
  • Issue: 1/2
  • Year: 2015
  • Summary: Aims: Biochar (BC) and humic acid product (HAP) soil amendments may improve plant performance under water-limited conditions. Our aim was to investigate if BC and HAP amendments, alone or in combination, will have positive and synergistic effects. Methods: A three-factorial fully randomized study was carried out in the greenhouse for 66 days, including the factors 'BC', 'HAP' and 'water regime'. Maize ( Zea mays var. 'Amadeo' DKC-3399) was grown in pots (6 kg sandy soil pot -1) amended with/without BC (0, 1.5 and 3%; w/ w) and with/without HAP (0 or an equivalent of 8 kg ha -1). Two water regimes, limited and frequent (H 2O limit , H 2O frequ ), were applied after day 28 following seedling establishment at 60% water holding capacity (WHC). In the H 2O limit treatment, the soil water content was allowed to drop until wilting symptoms became visible (25-30% WHC) while in H 2O frequ the WHC was brought to 60% of the maximum on a daily basis Results BC but not HAP, added alone or in combination with BC, significantly increased the biomass yield and the water and N use efficiency of plants at both water regimes. The BC-mediated relative increase in the yield was equal with both watering regimes, refuting initial hypotheses. BC had generally a stimulating effect on water relations and photosynthesis, it increased the relative water content and the leaf osmotic potential, decreased the stomatal resistance and stimulated the leaf gas exchange (transpiration). Both, BC and pure HAP addition, stimulated photosynthesis by increasing the electron transport rate (ETR) of photosystem II (PSII) and of the ratio between effective photochemical quantum yield to non-photochemical quenching (Y(II)/Y(NPQ)), revealing reduced heat dissipation. Conclusions: Biochar use in poor sandy soils can improve plant growth by improving soil-plant water relations and photosynthesis under both H 2O frequ and H 2O limit conditions. HAP loading, however, did not improve the effect of biochar or vice versa.
  • Authors:
    • Wang, Z.
    • He, M.
    • Chen, X,
    • Zou, C.
    • Cui, Z.
    • Pan, J.
    • Lu, F.
    • Lu, D.
  • Source: Web Of Knowledge
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Grain yields can be limited from delayed seeding worldwide. Perhaps yield suppressions can be overcome by applying farm manure. The objective of this study was to determine the influence of manure application and sowing date on wheat ( Triticum aestivum L.) yield and population development. A field experiment was conducted over two seasons, with three sowing dates (early [ES] - 5 October; mid [M] - 10 October; late [LS] - 15 October) with or without manure application (each plot receiving same chemical N, P, and K fertilizer) in the North China Plain (NCP). Comparing early to LS, delayed sowing reduced wheat yield from 9.5 to 7.8 t ha -1. Furthermore, manure application provided a 16 and 11% yield compensation for the M and LS date treatments, respectively, but did not significantly increase yield for ES. These results were attributed to manure increasing the wheat pre-winter tiller numbers for the mid-seeding date and manure increasing the spring tiller numbers for the LS date. High tiller mortality rate of ES treatment with manure application resulted in similar spike number and wheat yield as no manure treatment. Manure application improved plant N, P, and K concentration and soil temperature at a depth of 5 cm (0.4°C for pre-winter and 0.5-0.8°C for post-stem elongation), actions that may be important for improving population development.
  • Authors:
    • Thompson, J.
    • Curan, D.
    • Hammer, G. L.
    • Sinclair, T. R.
    • Messina, C. D.
    • Oler, Z.
    • Gho, C.
    • Cooper, M.
  • Source: Agronomy Joural
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Yield loss due to water deficit is ubiquitous in maize ( Zea mays L.) production environments in the United States. The impact of water deficits on yield depends on the cropping system management and physiological characteristics of the hybrid. Genotypic diversity among maize hybrids in the transpiration response to vapor pressure deficit (VPD) indicates that a limited-transpiration trait may contribute to improved drought tolerance and yield in maize. By limiting transpiration at VPD above a VPD threshold, this trait can increase both daily transpiration efficiency and water availability for late-season use. Reduced water use, however, may compromise yield potential. The complexity associated with genotype * environment * management interactions can be explored in a quantitative assessment using a simulation model. A simulation study was conducted to assess the likely effect of genotypic variation in limited-transpiration rate on yield performance of maize at a regional scale in the United States. We demonstrated that the limited-transpiration trait can result in improved maize performance in drought-prone environments and that the impact of the trait on maize productivity varies with geography, environment type, expression of the trait, and plant density. The largest average yield increase was simulated for drought-prone environments (135 g m -2), while a small yield penalty was simulated for environments where water was not limiting (-33 g m -2). Outcomes from this simulation study help interpret the ubiquitous nature of variation for the limited-transpiration trait in maize germplasm and provide insights into the plausible role of the trait in past and future maize genetic improvement.
  • Authors:
    • Ahmad, R.
    • Zahir, Z. A.
    • Khalid, M
    • Aon, M
  • Source: Article
  • Volume: 52
  • Issue: 3
  • Year: 2015
  • Summary: In calcareous soils, the effects of biochar characteristics on maize growth are least understood. In a laboratory study, citrus peel biochar (CPB) and green waste biochar (GWB) were produced by slow pyrolysis at 300°C with 20 min residence time. Electrical conductivity, pH, ash, and nutrients i.e. N, P, K, Ca, Mg, S, Zn and Mn content in GWB were greater than CPB. Citrus peel biochar had wider C:N, C:P and C:S ratios than GWB. Efficacy of these biochars was tested for maize growth and nutrient uptake, and chemical properties of calcareous soil. Maize hybrid (Syngenta-6621) was grown in a greenhouse pot trial by using calcareous soil amended either with CPB or GWB at application rates of 0.0, 0.5, 1.0, 1.5 and 2.0% (w/w) along with NPK fertilizers. Our results revealed that increasing rates of CPB, effectively improved maize plant height; fresh and dry weight; chlorophyll content and photosynthetic rate; and N, P and K uptake. At varying GWB application rates, maize fresh and dry weight; and N and P uptake was improved. Regarding plant growth and nutrient uptake, the overall response of CPB was better than GWB. At 2.0% application rate, CPB resulted better fresh weight (19%), dry weight (24%), plant height (20%), N uptake (42%), P uptake (36%) and K uptake (30%), than from the treatment having same rate of GWB. Due to biochar addition, the highest percentage of N and P recovery (5.3 and 6.6%, respectively) was obtained at 2.0% CPB application rate, while the highest K recovery (9.8%) was obtained at CPB application rate of 0.5%. At 2.0% application rate, CPB decreased soil pH up to 7.96 and increased soil organic carbon up to 1.25%, and GWB increased soil electrical conductivity up to 1.45 dS m -1. Conclusively, CPB produced at 300°C pyrolysis temperature with 20 min residence time, could be effectively used at the rate of 2.0%, for improving maize growth and nutrient uptake, and chemical characteristics of calcareous soil.
  • Authors:
    • Ju, X.
    • Norse, D.
  • Source: Article
  • Volume: 209
  • Year: 2015
  • Summary: China's successful achievement of food security in recent decades has resulted in serious damage to the environment upstream of the agricultural sector, on farm and downstream. The environmental costs of this damage are not only agro-ecosystem function and the long-term sustainability of food production, but also bio-physical including human health with impacts at all levels from the local to the global, and with economic loss estimates ranging from 7 to 10% of China's agricultural gross domestic product (GDP). This paper presents a systematic analysis of the causes and impacts of these environmental costs for China's cropping systems and crop-based livestock systems, and focuses on the nitrogen management. Since the 1980s most of the environmental costs have been related to the intensification of first grain production stimulated by high nitrogen fertilizer and irrigation subsidies, and then vegetable production and fruit trees, with the overuse and misuse of synthetic nitrogen fertilizer and manure being the dominant cause of eutrophication, soil acidification and high greenhouse gas emissions. However, during the last 10 years or so the expansion of intensive livestock production has become a serious cause of direct and indirect air and water pollution and is destined to be the main agricultural threat to China's environment in the long-term unless a holistic strategy for sustainable intensification is adopted for the next and future 5 Year Plans. This strategy should focus on improving nutrient management to limit nitrogen overuse, which is now the main cause of the economic losses from agriculture's damage to the environment.