• Authors:
    • Lambert, D. M.
    • Thierfelder, C.
    • Hicks, B. B.
    • Sauer, T. J.
    • O'Dell, D.
    • Logan, J.
    • Eash, N. S.
  • Source: Journal of Agricultural Science (Toronto)
  • Volume: 7
  • Issue: 3
  • Year: 2015
  • Summary: Two of the biggest problems facing humankind are feeding an exponentially growing human population and preventing the accumulation of atmospheric greenhouse gases and its climate change consequences. Refined agricultural practices could address both of these problems. The research addressed here is an exploration of the efficacy of alternative agricultural practices in sequestering carbon (C). The study was conducted in Zimbabwe with the intent to (a) demonstrate the utility of micrometeorological methods for measuring carbon dioxide (CO 2) exchange between the surface and the atmosphere in the short-term, and (b) to quantify differences in such exchange rates for a variety of agricultural practices. Four Bowen ratio energy balance (BREB) systems were established on the following agricultural management practices: (1) no-till (NT) followed by planting of winter wheat ( Triticum aestivum), (2) NT followed by planting of blue lupin ( Lupinus angustifolios L.), (3) maize crop residue ( Zea mays L.) left on the surface, and (4) maize crop residue incorporated with tillage. Over a period of 139 days (from 15 June to 31 October 2013) the winter wheat cover crop produced a net accumulation of 257 g CO 2-C m -2, while the tilled plot with no cover crop produced a net emission of 197 g CO 2-C m -2 and the untilled plot with no cover emitted 235 g CO 2-C m -2. The blue lupin cover crop emitted 58 g CO 2-C m -2, indicating that winter cover crops can sequester carbon and reduce emissions over land left fallow through the non-growing season. The micrometeorological methods described in this work can detect significant differences between treatments over a period of a few months, an outcome important to determine which smallholder soil management practices can contribute towards mitigating climate change.
  • Authors:
    • Reeve, J. R.
    • Jacobson, A. R.
    • Endelman, J. B.
    • Olsen, D. J. R.
  • Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
  • Volume: 101
  • Issue: 3
  • Year: 2015
  • Summary: Compost plays a central role in organic soil fertility plans but is bulky and costly to apply. Determining compost carryover is therefore important for cost-effective soil fertility planning. This study investigated two aspects of nutritive carryover [nitrogen and phosphorus (P)], and an indicator of non-nutritive carryover [soil organic matter (SOM)] to determine the residual effect of a one-time compost application applied at four rates in a corn-squash rotation. Crop yield was measured as an integrated carryover indicator of nutritive and non-nutritive effects. Functional groups of compost and SOM were investigated using FT-IR spectroscopy and soil organic carbon (SOC). While year to year variability was great, compost had a persistent positive effect on crop yields, evident 3 years after application with no reduction in magnitude over time. Soil nitrate was low, and additions of compost at any rate generally did not increase levels beyond the year of application, with the exception of year four. Olsen P was also low, yet was higher in amended soils than in non-amended soils 3 years after application. Pronounced polysaccharide peaks, evident in compost spectra and absent in control soil, were apparent in compost-amended soils 3 years after compost treatment and SOC was greater 2 years afterwards. Compost carryover was most pronounced in year four following the incorporation of a nitrogen-fixing cover crop. These results show that compost can influence nutritive and non-nutritive soil properties many years after incorporation, thereby reinforcing the importance of including compost in organic fertility plans despite the unpredictability of year-to-year response.
  • Authors:
    • Saenjan, P.
    • Iwai, C. B.
    • Oo, A. N.
  • Source: LAND DEGRADATION & DEVELOPMENT
  • Volume: 26
  • Issue: 3
  • Year: 2015
  • Summary: The aim of this study was to investigate the effectiveness of compost and vermicompost as soil conditioners in alleviating salt-affected soils and increasing maize productivity. A greenhouse trial, consisting of seven soil amendment treatments in a completely randomized design with three replications, was carried out at Khon Kaen University, Thailand, during the rainy season of 2011. Plant height and total dry matter of maize increased in treatments with compost and vermicompost application when compared with the control (no fertilizer) in two types of soils (saline and nonsaline) during the growing season. Soil pH and electrical conductivity in saturation paste extracts were decreased by compost and vermicompost amendments with or without earthworms when compared with unamended treatments in the saline soil. Compost and vermicompost amendments improved cation exchange capacity, soil organic carbon, total nitrogen and extractable phosphorus in both soils. These amendments also increased exchangeable K+, Ca2+ and Mg2+ while decreasing exchangeable Na+ in the saline soil, which suggested that Ca2+ was exchanged for Na+, exchangeable Na+, then leached out, and soil salinity reduced as a result. Soil microbial activities including microbial C and N and basal soil respiration were improved by the application of compost and vermicompost amendments with or without earthworms when compared with the control in both soils. This experiment showed that the compost and vermicompost were effective in alleviating salinity and improving crop growth.
  • Authors:
    • Greaver, T. L.
    • Compton, J. E.
    • Hu, S. J.
    • Liu, L. L.
    • Qiao, C. L.
    • Li, Q. L.
  • Source: GLOBAL CHANGE BIOLOGY
  • Volume: 21
  • Issue: 3
  • Year: 2015
  • Summary: Anthropogenic activities, and in particular the use of synthetic nitrogen (N) fertilizer, have doubled global annual reactive N inputs in the past 50-100 years, causing deleterious effects on the environment through increased N leaching and nitrous oxide (N 2O) and ammonia (NH 3) emissions. Leaching and gaseous losses of N are greatly controlled by the net rate of microbial nitrification. Extensive experiments have been conducted to develop ways to inhibit this process through use of nitrification inhibitors (NI) in combination with fertilizers. Yet, no study has comprehensively assessed how inhibiting nitrification affects both hydrologic and gaseous losses of N and plant nitrogen use efficiency. We synthesized the results of 62 NI field studies and evaluated how NI application altered N cycle and ecosystem services in N-enriched systems. Our results showed that inhibiting nitrification by NI application increased NH 3 emission (mean: 20%, 95% confidential interval: 33-67%), but reduced dissolved inorganic N leaching (-48%, -56% to -38%), N 2O emission (-44%, -48% to -39%) and NO emission (-24%, -38% to -8%). This amounted to a net reduction of 16.5% in the total N release to the environment. Inhibiting nitrification also increased plant N recovery (58%, 34-93%) and productivity of grain (9%, 6-13%), straw (15%, 12-18%), vegetable (5%, 0-10%) and pasture hay (14%, 8-20%). The cost and benefit analysis showed that the economic benefit of reducing N's environmental impacts offsets the cost of NI application. Applying NI along with N fertilizer could bring additional revenues of $163 ha -1 yr -1 for a maize farm, equivalent to 8.95% increase in revenues. Our findings showed that NIs could create a win-win scenario that reduces the negative impact of N leaching and greenhouse gas production, while increases the agricultural output. However, NI's potential negative impacts, such as increase in NH 3 emission and the risk of NI contamination, should be fully considered before large-scale application.
  • Authors:
    • Verhulst, N.
    • Luna-Guido, M.
    • Navarro-Noya, Y. E.
    • Bello-Lopez, J. M.
    • Ramirez-Villanueva, D. A.
    • Govaerts, B.
    • Dendooven, L.
  • Source: APPLIED SOIL ECOLOGY
  • Volume: 90
  • Year: 2015
  • Summary: Agricultural practices affect the bacterial community structure in soil. It was hypothesized that agricultural practices would also affect the bacteria involved in the degradation of crop residue. Soil was sampled from four different agricultural practices, i.e. conventional agriculture on the flat or on beds, or conservation agriculture on the flat or on beds. Cultivating crops on the flat is done traditionally, but cultivating crops on beds was introduced so as to avoid water logging during the rainy season and its potential negative effect on yields. Soil from these four treatments was amended in the laboratory with maize residue (Zea mays L.) or its neutral detergent fibre (NDF) fraction, mostly consisting of (hemi) cellulose, and incubated aerobically for 14 days. Maize residue was applied to soil as it is left in the field in conservation agriculture and NDF was added to study which bacteria were favoured by application of (hemi) cellulose. Soil was incubated aerobically while the carbon mineralization and the bacterial population were monitored. On the one hand, the relative abundance of phylotypes belonging to bacterial groups that preferred low nutrient environments was higher in soil with conservation agriculture (e.g. Acidobacteria 17.6%, Planctomycetes 1.7% and Verrucomicrobia 1.5%) compared to conventional practices (Acidobacteria 11.8%, Planctomycetes 0.9% and Verrucomicrobia 0.4%). On the other hand, the relative abundance of phylotypes belonging to bacterial groups that preferred nutrient rich environments, such as Actinobacteria, showed an opposite trend. It was 11.9% in conservation agriculture and 16.2% in conventional practices. The relative abundance of Arthrobacter (Actinobacteria) and Bacillales more than doubled when maize residue was applied to soil compared to the unamended soil and that of Actinomycetales when maize or NDF was applied. Application of organic material reduced the relative abundance of a wide range of bacterial groups, e.g. Acidobacteria, Bacteroidetes, Planctomycetes and Verrucomicrobia. It was found that application of organic material favoured the same bacterial groups that were more abundant in the soil cultivated conventionally while it reduced those that were favoured in conservation agriculture.
  • Authors:
    • Al-Kaisi, M. M.
    • Tenesaca, C. G.
  • Source: APPLIED SOIL ECOLOGY
  • Volume: 89
  • Year: 2015
  • Summary: In-field management practices of corn cob and residue mix (CRM) as a feedstock source for ethanol production can have potential effects on soil greenhouse gas (GHG) emissions. The objective of this study was to investigate the effects of CRM piles, storage in-field, and subsequent removal on soil CO2 and N2O emissions. The study was conducted in 2010-2012 at the Iowa State University, Agronomy Research Farm located near Ames, Iowa (42.0 degrees'N; 93.8 degrees'W). The soil type at the site is Canisteo silty clay loam (fine-loamy, mixed, superactive, calcareous, mesic Typic Endoaquolls). The treatments for CRM consisted of control (no CRM applied and no residue removed after harvest), early spring complete removal (CR) of CRM after application of 7.5 cmdepth of CRM in the fall, 2.5 cm, and 7.5 cmdepth of CRM over two tillage systems of no-till (NT) and conventional tillage (CT) and three N rates (0, 180, and 270 kg N ha(-1)) of 32% liquid UAN (NH4NO3) in a randomized complete block design with split-split arrangements. The findings of the study suggest that soil CO2 and N2O emissions were affected by tillage, CRM treatments, and N rates. Most N2O and CO2 emissions peaks occurred as soil moisture or temperature increased with increase precipitation or air temperature. However, soil CO2 emissions were increased as the CRM amount increased. On the other hand, soil N2O emissions increased with high level of CRM as N rate increased. Also, it was observed that NT with 7.5 cm CRM produced higher CO2 emissions in drought condition as compared to CT. Additionally, no differences in N2O emissions were observed due to tillage system. In general, dry soil conditions caused a reduction in both CO2 and N2O emissions across all tillage, CRM treatments, and N rates.
  • Authors:
    • Ren, S.
    • Gao, W.
    • Yang, J.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 151
  • Year: 2015
  • Summary: Integrating fertilizer nitrogen with organic materials was an important management strategy for sustainable agriculture production systems in most soils low in organic matter. A 33-year-old experiment with various fertilizations in a double cropping system rotated with winter wheat (Triticum aestivum L) and maize (Zea mays L) on a fluvo-aquic soil in Tianjin was evaluated. The six treatments used were control, N, NPK, NM, NS and NGM, representing various combinations of N, P, K, organic manure (M), straw (S) and green manure (GM) fertilizer applications. The specific objective of this study was to evaluate the long-term effects of combined use of organic materials and chemical fertilizer nitrogen on crop yields, soil organic carbon (SOC) and soil total nitrogen (TN).As a result, wheat and maize yields in the plot under the N treatment decreased with time, whereas the yields increased in the plot under NM treatment for both crops. The yields in NS and NGM treatments maintained a stable and higher level. Generally, both wheat and maize yields were significantly higher in NM and NPK than those in other treatments. The SOC and TN contents with all treatments showed an increasing trend with time. Compared with the N treatment, the average SOC and TN contents were 38.0 and 17.3%, 14.2 and 6.7%, and 12.9 and 6.1% larger, respectively, for NM, NPK, and NS. In addition, the SOC contents with the five treatments (N, NGM, NS, NPK and NM) increased by 25.5, 33.1, 42.1, 69.7 and 145.6%, respectively, by 2012; for TN they increased by 6.6, 17.8, 23.2, 35.5 and 57.5.5%, respectively, above the values obtained in 1979. TN contents were significantly correlated with SOC at each treatment (P<. 0.01). Soil C/N ratios were generally around 9 to 14 during cultivate time. The average soil C/N ratio in NM was significantly higher than those in other treatments, and the soil C/N ratios among the other four treatments were not significantly different.Overall, the results suggest that organic manure along with chemical N must be used to sustain the productivity and promote C and N sequestration of wheat-maize system in the fluvo-aquic soils of the Tianjin areas.
  • Authors:
    • Lal, R.
    • Pu, C.
    • Wang, M.
    • Xue, J. F.
    • Liu, S. L.
    • Yin, X. G.
    • Zhao, X.
    • Zhang, H. L.
    • Chen, F.
  • Source: CLIMATIC CHANGE
  • Volume: 129
  • Issue: 1-2
  • Year: 2015
  • Summary: Climate change has been a concern of policy makers, scientists, and farmers due to its complex nature and far-reaching impacts. It is the right time to analyze the impacts of climate change and potential adaptations, and identify future strategies for sustainable development. This study assessed changes in climatic factors (e.g., temperature and precipitation) at three typical sites (i.e., Luancheng, Feixiang, and Huanghua) in the North China Plain (NCP), and analyzed adaptations of farming practices. Results indicated that the mean annual temperature followed a significant increasing trend during 1981-2011, with 0.57, 0.47, and 0.44 A degrees C decade(-1) for Luancheng, Huanghua, and Feixiang, respectively. A significant increase of 0.67, 0.53, and 0.38 A degrees C decade(-1) was observed for the winter-wheat (Triticum aestivum L.) season for Luancheng, Huanghua, and Feixiang, respectively (P < 0.05), but no significant change for the summer-corn (Zea mays L.) season for the three sites. The annual accumulated temperature (a parts per thousand yen10 A degrees C) increased significantly during 1981-2011 (P < 0.01), with 17.60, 10.49, and 14.09 A degrees C yr(-1) for Luancheng, Huanghua, and Feixiang, respectively. There was no significant increase of mean annual precipitation, which had large inter-annual fluctuations among the three sites. In addition, significant challenges lie ahead for the NCP due to climate change, e.g., increasing food grain demand, water shortages, high inputs, high carbon (C) emissions, and decreasing profits. Trade-offs between crop production, water resource conservation, and intensive agricultural inputs will inhibit sustainable agricultural development in the NCP. Farming practices have been adapted to the climate change in the NCP, e.g. late seeding for the winter-wheat, tillage conversion, and water saving irrigation. Therefore, innovative technologies, such as climate-smart agriculture, will play important roles in balancing food security and resources use, enhancing water use efficiency, reducing C emissions in the NCP. Coordinated efforts from the government, scientists, and farmers are also necessary, in response to climate change.
  • Authors:
    • Mu, J.
    • Xu, Y. H.
    • Guo, J. P.
    • Zhao, J. F.
  • Source: AGRICULTURE ECOSYSTEMS & ENVIRONMENT
  • Volume: 202
  • Year: 2015
  • Summary: To learn the effects of climate change on cultivation patterns of spring maize and its suitability will benefit the strategic decisions for future agricultural adaptation. In this paper, based on the daily data from 68 meteorological stations and 82 agro-meteorological observation stations in Northeast China between 1961 and 2010, the cultivation pattern of spring maize and its climatic suitability in Northeast China were investigated. The agricultural climatic suitability theory was applied. The specific growth phases of spring maize that were most sensitive to environmental limitations were further divided into four stages: from germination to emergence, from emergence to jointing, from jointing to tasseling, and from tasseling to maturity. The average resource suitability index ( Isr) was established to evaluate the effects. Higher values of Isr indicate a higher degree of climatic resource suitability. Over the past five decades, the northern planting boundaries of different maturities (late, medium-late, medium, medium-early and early) of spring maize varieties in Northeast China all markedly extended northward and eastward. Of all the varieties, the medium-late maturity variety had the most expanded planting area. This further illustrated the importance of promoting medium-late range heat-tolerant cultivars of spring maize in reducing the unfavorable effect of climate change in the near future in Northeast China. In addition, the most significant extension was found in the early 21st century. Moreover, the southern planting boundaries of unsuitable planting spring maize areas continually compressed northward from the Tonghe County of Heilongjiang Province (128°49′, 46°21′) to the Huma County of Heilongjiang Province (124°11′, 51°26′). Climate change affected not only the planting patterns of spring maize, but also the climatic suitability of spring maize. Significant temporal and spatial changes of Isr from 1961 to 2010 were found. The Isr showed increasing trends, which increased by 0.19 in Heilongjiang Province, 0.16 in Jilin Province and 0.12 in Liaoning Province. Spatial differences of Isr were obvious, with high values shifting northeastward over the past 50 years, indicating more efficient suitability of agricultural climatic resources in Northeast China.
  • Authors:
    • Islam, K. R.
    • Mahmood, T.
    • Bangash, N.
    • Aziz, I.
  • Source: Pakistan Journal of Botany
  • Volume: 47
  • Issue: 1
  • Year: 2015
  • Summary: There is a global concern about progressive increase in the emission of greenhouse gases especially atmosphere CO2. An increasing awareness about environmental pollution by CO2 emission has led to recognition of the need to enhance soil C sequestration through sustainable agricultural management practices. Conservation management systems such as no-till (NT) with appropriate crop rotation have been reported to increase soil organic C content by creating less disturbed environment. The present study was conducted on Vanmeter farm of The Ohio State University South Centers at Piketon Ohio, USA to estimate the effect of different tillage practices with different cropping system on soil chemical properties. Tillage treatments were comprised of conventional tillage (CT) and No-till (NT). These treatments were applied under continuous corn (CC), corn-soybean (CS) and corn-soybean-wheat-cowpea (CSW) cropping system following randomized complete block design. No-till treatment showed significant increase in total C (30%), active C (10%), and passive salt extractable (18%) and microwave extractable C (8%) and total nitrogen (15%) compared to conventional tillage practices. Total nitrogen increased significantly 23 % in NT over time. Maximum effect of no-till was observed under corn-soybean-wheat-cowpea crop rotation. These findings illustrated that no-till practice could be useful for improving soil chemical properties.