• Authors:
    • Syp,A.
    • Faber,A.
    • Borzecka-Walker,M.
    • Osuch,D.
  • Source: Polish Journal of Environmental Studies
  • Volume: 24
  • Issue: 5
  • Year: 2015
  • Summary: Data envelopment analysis (DEA) has been recognized as a suitable tool for efficiency assessment of the economic and environmental performance of multiple similar units in the agri-food sector. In the present study, DEA methodologies were applied to 55 winter wheat farms in three farm sizes in Poland to benchmark the level of operational efficiency for each producer. Next, the potential reduction in the consumption levels of inputs were defined, and the environmental profits linked to these reduction targets were calculating. Our results indicate that 55% of the analysed farms operated efficiently. The technical efficiency scores of inefficient farms were 0.72 for small farms and 0.84 for medium and large ones. The production of 1 kg winter wheat results with average greenhouse gas (GHG) emissions of 0.448, 0.481, and 0.411 kg CO 2 eq. per kg of grain, for small, medium, and large farms, respectively. The performed analysis shows that GHG emissions per hectare depend on farm size and ranged from 2,378 kg CO 2 eq. for the small farms to 2,759 kg CO 2 eq. for large farms. The reduction of material input in inefficient farms, converted into environmental gains, resulted in GHG emissions reduction of 25.7, 29.0, and 28.6% for small, medium, and large farms, respectively. The estimated potential reduction of global warming potential (GWP) according to the DEA for the whole sample ranged from 7 to 18%, and was dependent on farm size. The major contributor to GWP was nitrous oxide field emissions (49-52%), followed by nitrogen fertilizer (31-33%), and diesel (11-13%). Raising operational efficiency is recommended for potential environmental improvement in the surveyed region.
  • 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:
    • Trebicki,P.
    • Nancarrow,N.
    • Cole,E.
    • Bosque-Perez,N. A.
    • Constable,F. E.
    • Freeman,A. J.
    • Rodoni,B.
    • Yen,A. L.
    • Luck,J. E.
    • Fitzgerald,G. J.
  • Source: Global Change Biology
  • Volume: 21
  • Issue: 9
  • Year: 2015
  • Summary: Current atmospheric CO 2 levels are about 400 mol mol -1 and are predicted to rise to 650 mol mol -1 later this century. Although the positive and negative impacts of CO 2 on plants are well documented, little is known about interactions with pests and diseases. If disease severity increases under future environmental conditions, then it becomes imperative to understand the impacts of pathogens on crop production in order to minimize crop losses and maximize food production. Barley yellow dwarf virus (BYDV) adversely affects the yield and quality of economically important crops including wheat, barley and oats. It is transmitted by numerous aphid species and causes a serious disease of cereal crops worldwide. This study examined the effects of ambient (aCO 2; 400 mol mol -1) and elevated CO 2 (eCO 2; 650 mol mol -1) on noninfected and BYDV-infected wheat. Using a RT-qPCR technique, we measured virus titre from aCO 2 and eCO 2 treatments. BYDV titre increased significantly by 36.8% in leaves of wheat grown under eCO 2 conditions compared to aCO 2. Plant growth parameters including height, tiller number, leaf area and biomass were generally higher in plants exposed to higher CO 2 levels but increased growth did not explain the increase in BYDV titre in these plants. High virus titre in plants has been shown to have a significant negative effect on plant yield and causes earlier and more pronounced symptom expression increasing the probability of virus spread by insects. The combination of these factors could negatively impact food production in Australia and worldwide under future climate conditions. This is the first quantitative evidence that BYDV titre increases in plants grown under elevated CO 2 levels.
  • Authors:
    • Yao ChunXue
    • Joseph,S.
    • Li LianQing
    • Pan GenXing
    • Lin Yun
    • Munroe,P.
    • Pace,B.
    • Taherymoosavi,S.
    • Zwieten,L. van
    • Thomas,T.
    • Nielsen,S.
    • Ye Jun
    • Donne,S.
  • Source: Pedosphere
  • Volume: 25
  • Issue: 5
  • Year: 2015
  • Summary: Utilization of biochar at high application rates can increase soil C and crop yields, decrease greenhouse gas emissions and reduce nutrient run-off from soils. However, the high application rate of 10 t ha -1 may not return a profit to the farmer due to the high cost of biochar. In this study biochar was modified through pre-treating the biomass and post-treating with phosphoric acid, minerals and different chemical fertilisers to study the effects of two new enhanced biochar fertilisers on the yield and quality of green pepper in a field experiment with 5 fertilisation treatments and 3 replications. The two new biochar fertilisers significantly ( P<<0.05) increased the yield of green pepper (11.33-11.47 t ha -1), compared with the conventional chemical fertiliser (9.72 t ha -1). The biochar fertiliser treatments improved the vitamin C content of green pepper from 236.99 to 278.28 mg kg -1, and also significantly ( P<0.05) reduced the nitrate content from 132.32 to 101.92 mg kg -1, compared with chemical fertiliser. This study indicated that, compared to the use of conventional chemical fertiliser, all of the biochar fertiliser treatments could significantly improve the yield and quality of green pepper.
  • Authors:
    • Beach,R. H.
    • Cai,Y.
    • Thomson,A.
    • Zhang,X.
    • Jones,R.
    • McCarl,B. A.
    • Crimmins,A.
    • Martinich,J.
    • Cole,J.
    • Ohrel,S.
    • Deangelo,B.
    • McFarland,J.
    • Strzepek,K.
    • Boehlert,B.
  • Source: Environmental Research Letters
  • Volume: 10
  • Issue: 9
  • Year: 2015
  • Summary: Increasing atmospheric carbon dioxide levels, higher temperatures, altered precipitation patterns, and other climate change impacts have already begun to affect US agriculture and forestry, with impacts expected to become more substantial in the future. There have been numerous studies of climate change impacts on agriculture or forestry, but relatively little research examining the long-term net impacts of a stabilization scenario relative to a case with unabated climate change. We provide an analysis of the potential benefits of global climate change mitigation for US agriculture and forestry through 2100, accounting for landowner decisions regarding land use, crop mix, and management practices. The analytic approach involves a combination of climate models, a crop process model (EPIC), a dynamic vegetation model used for forests (MC1), and an economic model of the US forestry and agricultural sector (FASOM-GHG). We find substantial impacts on productivity, commodity markets, and consumer and producer welfare for the stabilization scenario relative to unabated climate change, though the magnitude and direction of impacts vary across regions and commodities. Although there is variability in welfare impacts across climate simulations, we find positive net benefits from stabilization in all cases, with cumulative impacts ranging from $32.7 billion to $54.5 billion over the period 2015-2100. Our estimates contribute to the literature on potential benefits of GHG mitigation and can help inform policy decisions weighing alternative mitigation and adaptation actions. © 2015 IOP Publishing Ltd.
  • Authors:
    • Wang, Z.
    • Wang, S.
    • Li, M.
    • Chen, H.
    • Wang, X.
    • Tian, X.
    • Liu, T.
    • Chen, Y.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Revealing the response of cereal yield and water use efficiency (WUE) to water management practices is crucial for achieving high and stable grain yields in drylands. A 3-yr field study was conducted to develop a high-yield, water-saving cultivation strategy for winter wheat in the Loess Plateau of China. The study's treatments included (i) a control (CK), that is, no mulch or fertilizer, (ii) nitrogen and phosphorus fertilizers (NP), (iii) plastic film mulch plus fertilizers (NP+PF), (iv) straw mulch plus fertilizers (NP+S), and (v) plastic film combined with straw mulch plus fertilizers (NP+PF+S). The results indicated that, compared with CK, the NP treatment improved the grain yield (112%) and WUE (96%) of winter wheat but resulted in a 12% reduction in soil water storage after the jointing stage. With the NP+S treatment, there was no difference recorded in grain yield, yield components, or WUE of winter wheat (relative to the NP treatment). With the NP+PF treatment, there was a 53% increase in grain yield, a 46% increase in WUE, and a 21% increase in soil water storage after jointing compared to the NP treatment. The plastic film could also modify soil temperature, resulting in maximized soil water retention. Additionally, the NP+PF and NP+PF+S treatments resulted in similar results. Taking into account agricultural, environmental, and economic factors, in addition to optimal fertilization (NP), plastic film mulch is the recommended practice for maximum yield and water retention in tablelands, whereas plastic film combined with straw mulch is recommended in terraces.
  • Authors:
    • Garcia,G. A.
    • Dreccer,M. F.
    • Miralles,D. J.
    • Serrago,R. A.
  • Source: Global Change Biology
  • Volume: 21
  • Issue: 11
  • Year: 2015
  • Summary: Warm nights are a widespread predicted feature of climate change. This study investigated the impact of high night temperatures during the critical period for grain yield determination in wheat and barley crops under field conditions, assessing the effects on development, growth and partitioning crop-level processes driving grain number per unit area (GN). Experiments combined: (i) two contrasting radiation and temperature environments: late sowing in 2011 and early sowing in 2013, (ii) two well-adapted crops with similar phenology: bread wheat and two-row malting barley and (iii) two temperature regimes: ambient and high night temperatures. The night temperature increase (ca. 3.9°C in both crops and growing seasons) was achieved using purpose-built heating chambers placed on the crop at 19:000 hours and removed at 7:00 hours every day from the third detectable stem node to 10 days post-flowering. Across growing seasons and crops, the average minimum temperature during the critical period ranged from 11.2 to 17.2°C. Wheat and barley grain yield were similarly reduced under warm nights (ca. 7% °C -1), due to GN reductions (ca. 6% °C -1) linked to a lower number of spikes per m 2. An accelerated development under high night temperatures led to a shorter critical period duration, reducing solar radiation capture with negative consequences for biomass production, GN and therefore, grain yield. The information generated could be used as a starting point to design management and/or breeding strategies to improve crop adaptation facing climate change.
  • Authors:
    • Rhinhart, K.
    • Machado, S.
    • Ghimire, R.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Intensive cultivation of native grassland for dryland agriculture continuously depleted soil organic carbon (SOC) and nutrients. In 2010, we evaluated the influence of 80 yr of crop residue and nutrient management practices on SOC and N in 0- to 60-cm soil depth profiles in conventionally tilled winter wheat ( Triticum aestivum L.)-summer fallow (WW-SF) system. Residue and N treatments, no N addition with fall burning (FB0), spring burning (SB0), and no burning (NB0), 45 kg N ha -1 with SB (SB45) and NB (NB45), 90 kg N ha -1 with SB (SB90) and NB (NB90), manure (MN, 5.32 Mg dry mass ha -1 yr -1), and pea vines (PV, 0.99 Mg dry mass ha -1 yr -1), were in ordered arrangement, and an undisturbed grassland (GP) was used as a reference. All WW-SF treatments had less SOC and N stocks than GP. The SOC stocks were lowest under FB0 with 50% less SOC than GP. The WW-SF treatments have depleted up to 63 and 26% of SOC and N from surface soil since 1931. Fall burning and MN treatments depleted SOC at rates of 0.64 and 0.17 Mg ha -1 yr -1. Nitrogen stocks decreased at a rate of 0.02 Mg ha -1 yr -1 in FB, SB, and NB treatments, and 0.01 Mg ha -1 yr -1 in PV treatment. Reduction in tillage, application of low C/N ratio residues, and elimination of burning can improve sustainability of winter wheat production in the summer fallow region of the Pacific Northwest (PNW).
  • Authors:
    • Lin, E.
    • Ju. H.
    • Wheeler, T.
    • Li, Y.
    • Wang, H.
    • Lam, S.
    • Hao, X.
    • Han, X.
  • Source: Article
  • Volume: 209
  • Year: 2015
  • Summary: Fossil fuel combustion and deforestation have resulted in a rapid increase in atmospheric [CO 2] since the 1950's, and it will reach about 550 mol mol -1 in 2050. Field experiments were conducted at the Free-air CO 2 Enrichment facility in Beijing, China. Winter wheat was grown to maturity under elevated [CO 2] (55017 mol mol -1) and ambient [CO 2] (41516 mol mol -1), with high nitrogen (N) supply (HN, 170 kg N ha -1) and low nitrogen supply (LN, 100 kg N ha -1) for three growing seasons from 2007 to 2010. Elevated [CO 2] increased wheat grain yield by 11.4% across the three years. [CO 2]-induced yield enhancements were 10.8% and 11.9% under low N and high N supply, respectively. Nitrogen accumulation under elevated [CO 2] was increased by 12.9% and 9.2% at the half-way anthesis and ripening stage across three years, respectively. Winter wheat had higher nitrogen demand under elevated [CO 2] than ambient [CO 2], and grain yield had a stronger correlation with plant N uptake after anthesis than before anthesis at high [CO 2]. Our results suggest that regulating on the N application rate and time, is likely important for sustainable grain production under future CO 2 climate.
  • Authors:
    • Serret, M. D.
    • Garcia-Mina, J. M.
    • Zamarreno, A. M.
    • Garnica, M.
    • Aroca, R.
    • Jauregui, I.
    • Parry, M.
    • Irigoyen, J. J.
    • Aranjuelo, I.
  • Source: Article
  • Volume: 155
  • Issue: 3
  • Year: 2015
  • Summary: Although climate scenarios have predicted an increase in [CO 2] and temperature conditions, to date few experiments have focused on the interaction of [CO 2] and temperature effects in wheat development. Recent evidence suggests that photosynthetic acclimation is linked to the photorespiration and N assimilation inhibition of plants exposed to elevated CO 2. The main goal of this study was to analyze the effect of interacting [CO 2] and temperature on leaf photorespiration, C/N metabolism and N transport in wheat plants exposed to elevated [CO 2] and temperature conditions. For this purpose, wheat plants were exposed to elevated [CO 2] (400 vs 700 molmol -1) and temperature (ambient vs ambient+4°C) in CO 2 gradient greenhouses during the entire life cycle. Although at the agronomic level, elevated temperature had no effect on plant biomass, physiological analyses revealed that combined elevated [CO 2] and temperature negatively affected photosynthetic performance. The limited energy levels resulting from the reduced respiratory and photorespiration rates of such plants were apparently inadequate to sustain nitrate reductase activity. Inhibited N assimilation was associated with a strong reduction in amino acid content, conditioned leaf soluble protein content and constrained leaf N status. Therefore, the plant response to elevated [CO 2] and elevated temperature resulted in photosynthetic acclimation. The reduction in transpiration rates induced limitations in nutrient transport in leaves of plants exposed to elevated [CO 2] and temperature, led to mineral depletion and therefore contributed to the inhibition of photosynthetic activity.