• 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:
    • Wu,Shuang-Ye
  • Source: Web Of Knowledge
  • Volume: 132
  • Issue: 4
  • Year: 2015
  • Summary: Using the US collection from the Global Historical Climatology Network Daily (GHCN-D) precipitation data for the contiguous United States (CONUS), this study examines the changing characteristics of precipitation during 1951-2013. In addition to mean precipitation, all precipitation events are divided into three categories: light, moderate, and heavy based on percentile thresholds. The historical trends are established for precipitation total, frequency and intensity, as well as for total and frequency of different intensity categories. Results show that from 1951 to 2013, mean precipitation increased at 1.66 % per decade, a higher rate than previous estimates. About one third of the increase is attributed to frequency change, whereas the other two thirds are attributed to an intensity increase. There was a slight decrease in light precipitation, a small increase in moderate precipitation, and much higher increase for heavy precipitation. Spatially, eastern and northern parts of the CONUS experienced higher rates of increase, whereas western regions experienced less increase. A statistically significant positive correlation exists between mean precipitation and precipitation change, suggesting the wet regions experienced more precipitation increase than dry regions. Seasonally, precipitation increased most for the fall, less in other seasons. Particularly, there were significant decreasing trends in summer precipitation for many parts of western and central CONUS. Regional frequency analysis is used to examine the change in extreme precipitation events with return intervals longer than a year. Results show that extreme precipitation events increased for most of the CONUS with the exception of the west region. These changes were a result of both a shift in the mean state and the shape of the precipitation data distribution.
  • 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:
    • Blanco-Canqui,H.
    • Shaver,T. M.
    • Lindquist,J. L.
    • Shapiro,C. A.
    • Elmore,R. W.
    • Francis,C. A.
    • Hergert,G. W.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Cover crops (CCs) can provide multiple soil, agricultural production, and environmental benefits. However, a better understanding of such potential ecosystem services is needed. We summarized the current state of knowledge of CC effects on soil C stocks, soil erosion, physical properties, soil water, nutrients, microbial properties, weed control, crop yields, expanded uses, and economics and highlighted research needs. Our review indicates that CCs are multifunctional. Cover crops increase soil organic C stocks (0.1-1 Mg ha -1 yr -1) with the magnitude depending on biomass amount, years in CCs, and initial soil C level. Runoff loss can decrease by up to 80% and sediment loss from 40 to 96% with CCs. Wind erosion potential also decreases with CCs, but studies are few. Cover crops alleviate soil compaction, improve soil structural and hydraulic properties, moderate soil temperature, improve microbial properties, recycle nutrients, and suppress weeds. Cover crops increase or have no effect on crop yields but reduce yields in water-limited regions by reducing available water for the subsequent crops. The few available studies indicate that grazing and haying of CCs do not adversely affect soil and crop production, which suggests that CC biomass removal for livestock or biofuel production can be another benefit from CCs. Overall, CCs provide numerous ecosystem services (i.e., soil, crop-livestock systems, and environment), although the magnitude of benefits is highly site specific. More research data are needed on the (i) multi-functionality of CCs for different climates and management scenarios and (ii) short- and long-term economic return from CCs.
  • Authors:
    • Fariaszewska,A.
    • Staniak,M.
  • Source: ACTA Scientiarum Polonorum Agricultura
  • Volume: 14
  • Issue: 4
  • Year: 2015
  • Summary: The aim of the study was to assess the effects of water deficit on yield, leaf area and fluorescence chlorophyll parameters of forage grasses. The pot experiment was conducted in 2013 in IUNG-PIB's greenhouse in Pulawy. Nine cultivars of five species ( Lolium perenne, Lolium multiflorum, Festuca pratensis, Festuca arundinacea and Festulolium braunii) were investigated in well-watered conditions (70% field water capacity) as well as in a short-term drought stress conditions (40% field water capacity). The study showed, that dry matter of yield, chlorophyll fluorescence parameters: quantum of photosynthetic yield efficiency ( Fv/Fm ratio) and performance index ( PI) and leaf area were significantly lower in drought stress than under well-watered conditions in all cultivars in each regrowth. The data demonstrated the highest yield decrease for F. arundunacea cv. Barolex in the first, for L. perenne cv. Melluck and Meltador in the second and for F. braunii cv. Felopa in the third regrowth. The hybrid F. braunii was characterized by the lowest yield reduction and PI parameter in first and second regrowth. Based on the yield average, short drought resistance of different species was in the following order: F. pratensis > F. braunii-L. multiflorum > F. arundinacea > L. perenne. There was a significant relationship between dry matter yield and leaf area, and also between dry matter yield and fluorescence chlorophyll parameters.
  • Authors:
    • Lupwayi, N.
    • Blackshaw, R.
    • Li, L
    • Pearson, D.
    • Larney, F.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Dry bean ( Phaseolus vulgaris L.) production on the Canadian prairies has traditionally used wide rows, inter-row cultivation, and undercutting at harvest. Recent breeding efforts have produced cultivars with more upright growth which are better suited to solid-seeded narrow-row production systems. A 12 yr (2000-2011) study compared conservation (CONS) and conventional (CONV) management for dry bean in 3- to 6-yr rotations. The CONS rotations included reduced tillage, cover crops, feedlot manure compost, and solid-seeded narrow-row dry bean. Effects of CONS management on plant density were inconsistent with some years showing lower density when seeded into high-residue conditions. On average, there was a 3 d maturity advantage with CONS (103 d) vs. CONV (106 d) management. The CONS rotations showed significantly higher mean incidence (19%) of white mold [ Sclerotinia sclerotiorum (Lib.) de Bary] than CONV rotations (6%). Averaging across 12 yr, there was no significant rotation effect on yield ( P=0.19) showing that CONS production performed as good as CONV production. In the last 2 yr (2010-2011) of the study, in an attempt to reduce harvest losses, CONS dry bean was undercut rather than direct combined. This led to significantly higher (25%) yield with CONS (3311 kg ha -1) vs. CONV management (2651 kg ha -1). Our results provide incentive for more rapid adoption of conservation-oriented soil and crop management practices for dry bean production on the Canadian prairies, including narrow rows, reduced tillage, cover crops, and feedlot manure compost addition.
  • Authors:
    • Tanaka, D.
    • Nichols, K.
    • Schmer, M.
    • Archer, D.
    • Hendrickson, J.
    • Liebig, M.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Cover crops can expand ecosystem services, though sound management recommendations for their use within semiarid cropping systems is currently constrained by a lack of information. This study was conducted to determine agroecosystem responses to late-summer seeded cover crops under no-till management, with particular emphasis on soil attributes. Short-term effects of late-summer seeded cover crops on soil water, available N, near-surface soil quality, and residue cover were investigated during three consecutive years on the Area IV Soil Conservation Districts Research Farm near Mandan, ND. Mean aboveground cover crop biomass was highly variable across years (1430, 96, and 937 kg ha -1 in 2008, 2009, and 2010, respectively), and was strongly affected by precipitation received within 14 d following cover crop seeding. During years with appreciable biomass production (2008 and 2010), cover crops significantly reduced available N in the 0.9-m depth the following spring ( P=0.0291 and 0.0464, respectively). Cover crop effects on soil water were subtle, and no differences in soil water were found between cover crop treatments and a no cover crop control before seeding cash crops the following spring. Late-summer seeded cover crops did not affect near-surface soil properties or soil coverage by residue. Soil responses to late-summer seeded cover crops did not differ between cover crop mixtures and monocultures. Late-summer seeded cover crops may enhance ecosystem services provided by semiarid cropping systems through biomass production and N conservation, though achieving these benefits in a consistent manner appears dependent on timely precipitation following cover crop seeding.
  • 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.