• Authors:
    • Labrecque, M.
    • Guidi, W.
    • Lockwell, J.
  • Source: PLANT AND SOIL
  • Volume: 360
  • Issue: 1-2
  • Year: 2012
  • Summary: We carried out a paired-site study (Melanic Brunisol) to assess the impact on soil carbon stocks of land-use change following establishment and multiple rotations of willows (Salix miyabeana SX67) in short-rotation coppice (SRWC). Total soil organic carbon (TSOC), hot-water extractable carbon (HWC) and amino sugars (AS) were used as main parameters of soil carbon dynamic. We found that the establishment event and 2 years of growth under SRWC did not result in any change in the TSOC pool or in the HWC pool. However, we found an increase in AS at and near the soil surface (0-20 cm) of the establishing willow plantations. We related this to the effect of the green manure applied before planting. After multiple rotations of SRWC, we found a redistribution of TSOC in the vertical profile (0-40 cm) but no TSOC difference compared to previous land-use (abandoned alfalfa crop). In the subsoil (20-40 cm), we found indications that the more labile soil organic carbon (SOC) pools were depleted (HWC and muramic acid). Willow plantations on Melanic Brunisol in southern Quebec (Canada) represent, over the long-term, a soil carbon sink when replacing a short-term no-till crop rotation. However, the conversion from abandoned alfalfa fields into SRWC does not apparently enhance soil carbon potential sequestration.
  • Authors:
    • Abbott, L. K.
    • Murphy, D. V.
    • Solaiman, Z. M.
  • Source: PLANT AND SOIL
  • Volume: 353
  • Issue: 1-2
  • Year: 2012
  • Summary: Background and aims Biochar can be produced from a wide range of organic sources with varying nutrient and metal concentrations. Before making irreversible applications of biochar to soil, a preliminary ecotoxicological assessment is desirable. Methods First, we determined the effect of biochar type and rate on early growth of wheat in a soil-less Petri dish bioassay. Second, we investigated the effect of the same biochars on seed germination and early growth of wheat in ten soils with varying texture using a glasshouse bioassay. Finally, we investigated whether these biochars had similar effects on three plant species when grown in one soil. Results Biochar type and application rate influenced wheat seed germination and seedling growth in a similar manner in both the soil-less Petri dish and soil-based bioassay. Germination and early root growth of mung bean and subterranean clover differed from that of wheat in response to the five biochars. Conclusions We recommend use of the soil-less Petri dish bioassay as a rapid and simple preliminary test to identify potential toxicity of biochars on seed germination and early plant growth prior to biochar application to soil.
  • Authors:
    • Sharma, K. L.
    • Venkateswarlu, B.
    • Ramesh, V.
    • Wani, S. P.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 43
  • Issue: 14
  • Year: 2012
  • Summary: The long-term effects of plant legume [horse gram (Macrotyloma uniflorum)] biomass incorporations were assessed in terms of carbon dioxide (CO2) emissions, soil quality parameters, and climatically influenced soil parameters in a dryland Alfisol under varying soil fertility conditions. Six selected treatments consisted of off-season legume incorporation (I) and no incorporation/fallow (F), each under three varying nitrogen and phosphorus fertilizer levels (viz., N0P0, N25P30, and N50P30). Soil moisture, soil temperature, soil surface carbon dioxide emission, soil dehydrogenases, and microbial biomass carbon (MBC) were monitored at three different crop situations [viz., Kharif period (KP), legume/fallow period (LP), and no crop period (NP)] at 14 different periods of the year. Incorporation practices resulted in greater rates of CO2 emission over fallow conditions during the Kharif and legume periods, whereas the emission rate was greater in fallow soils during the end of the legume and no crop periods. The increased rates of fertilizer doses also significantly increased the soil CO2 flux during the majority of the measurements. Beneficial effects of incorporation practices were observed in terms of high soil moisture (5-11%), low soil temperature (3-7%), and high content of MBC over without incorporations. Correlation studies indicated that the soil property MBC was found to be the greatest significant variable with CO2 emission in all the fertilizer treatments under biomass-incorporated soils. These results indicated the undesirable (in terms of CO2 fluxes) and desirable (soil biological and other parameters) effects of legume biomass incorporation and fertilizer application and their significance in improving soil quality and greenhouse gas (GHG) emissions in dryland Alfisols of semi-arid tropics.
  • Authors:
    • Juszczak, R.
    • Sakowska, K.
    • Uzdzicka, B.
    • Olejnik, J.
  • Source: Woda Srodowisko Obszary Wiejskie
  • Volume: 12
  • Issue: 38
  • Year: 2012
  • Summary: One of the methods to study the exchange of mass and energy between the atmosphere and the surface of various terrestrial ecosystems is direct measurement of the fluxes of greenhouse gases. Particular attention is focussed on carbon dioxide whose concentration in the atmosphere dramatically increases [Urbaniak 2006]. The paper presents results of the measurements of carbon dioxide exchange conducted on 29th of June 2011 on three experimental plots (alfalfa, winter wheat and potato crops) situated in Agricultural Experimental Station in Brody (Wielkopolskie Province) and modeled values of ecosystem respiration ( Reco ), net ecosystem exchange ( NEE) and gross ecosystem production ( GEP). Measurements were carried out by means of closed dynamic chamber system. Reco measured on 29th of June 2011 ranged from 3.61 to 16.62 mol CO 2.m -2.s -1 and measured NEE - from 4.22 to -24.08 mol CO 2.m -2.s -1. Modeled values of the ecosystem respiration ( Reco ) for particular crops obtained with the LLOYD and Taylor [1994] function did not differ from measured values by more than 4% on average. The results of NEE modeling indicate that selected model [Michaelis, Menten 1913] worked well for sites with alfalfa and winter wheat crops (mean absolute percentage error - MAPE was 25.0 and 7.3%, respectively). NEE predictions for the site with potato crop differed largely ( MAPE=98.5%) from measured values and hence there is a need for looking for a model that would consider, apart from PPFD, also other environmental factors driving photosynthesis.
  • Authors:
    • Das, S. N.
    • Venkanna, R.
    • Nikhil, G. N.
    • Swamy, Y. V.
    • Chaudhury, G. Roy
  • Source: Atmósfera
  • Volume: 25
  • Issue: 1
  • Year: 2012
  • Summary: Methane (CH4) and nitrous oxide(N2O)emission estimates were made for Vigna mango and Vigna radiata legumes. The affecting soil parameters like redox potential, soil temperature were studied to evaluate CH4 and N2O emissions. The CH4 was negative and N2O was positive for Vigna mungo, almost throughout the cropping period. The redox potential was more than +100 mV during the entire cropping period with a maximum N2O flux of 11.67 mu g m(-2) h(-1). The raise in soil temperature and the redox potential during harvest further increased the N2O flux to 18.38 mu g m(-2) h(-1). The seasonally integrated flux E((SIF)) for CH4 and N2O for Vigna mungo was calculated to be -4.06 g.m(-2) and 3.38 mg m(-2) respectively. Similarly E((SIF))values estimated for Vigna radiata cropping season were 0.009 g m(-2) and -7.6 mg m-2, whereas for the post harvesting period the fluxes were 0.02 g m(-2) and 4.06 mg m(-2) for CH4 and N2O respectively. The soil parameters like organic carbon and nutrients such as ammonia, nitrate and nitrite during the cropping season were evaluated. The emission of greenhouse gases (GHG) was also correlated to various physicochemical parameters of soil.
  • Authors:
    • Fernando, L. K.
    • Banuwa, I. S.
    • Buchari, H.
    • Utomo, M.
    • Saleh, R.
  • Source: Journal of Tropical Soils
  • Volume: 17
  • Issue: 1
  • Year: 2012
  • Summary: Although agriculture is a victim of environmental risk due to global warming, but ironically it also contributes to global greenhouse gas (GHG) emission. The objective of this experiment was to determine the influence of long-term conservation tillage and N fertilization on soil carbon storage and CO2 emission in corn-soybean rotation system. A factorial experiment was arranged in a randomized completely block design with four replications. The first factor was tillage systems namely intensive tillage (IT), minimum tillage (MT) and no-tillage (NT). While the second factor was N fertilization with rate of 0, 100 and 200 kg N ha -1 applied for corn, and 0, 25, and 50 kg N ha -1 for soybean production. Samples of soil organic carbon (SOC) after 23 year of cropping were taken at depths of 0-5 cm, 5-10 cm and 10-20 cm, while CO2 emission measurements were taken in corn season (2009) and soybean season (2010). Analysis of variance and means test (HSD 0.05) were analyzed using the Statistical Analysis System package. At 0-5 cm depth, SOC under NT combined with 200 kg N ha -1 fertilization was 46.1% higher than that of NT with no N fertilization, while at depth of 5-10 cm SOC under MT was 26.2% higher than NT and 13.9% higher than IT. Throughout the corn and soybean seasons, CO2-C emissions from IT were higher than those of MT and NT, while CO2-C emissions from 200 kg N ha -1 rate were higher than those of 0 kg N ha -1 and 100 kg N ha -1 rates. With any N rate treatments, MT and NT could reduce CO2-C emission to 65.2%-67.6% and to 75.4%-87.6% as much of IT, respectively. While in soybean season, MT and NT could reduce CO2-C emission to 17.6%-46.7% and 42.0%-74.3% as much of IT, respectively. Prior to generative soybean growth, N fertilization with rate of 50 kg N ha -1 could reduce CO2-C emission to 32.2%-37.2% as much of 0 and 25 kg N ha -1 rates.
  • Authors:
    • Roose-Amsaleg, C.
    • Garnier, J.
    • Vilain, G.
    • Laville, P.
  • Source: Web Of Knowledge
  • Volume: 92
  • Issue: 1
  • Year: 2012
  • Summary: The denitrification process and the associated nitrous oxide (N(2)O) production in soils have been poorly documented, especially in terms of soil profiles; most work on denitrification has concentrated on the upper layer (first 20 cm). The objectives of this study were to examine the origin of N(2)O emission and the effects of in situ controlling factors on soil denitrification and N(2)O production, also allowing the (N(2)O production)/(NO(3) (-)-N reduction) ratio to be determined through (1) the position on a slope reaching a river and (2) the depth (soil horizons: 10-30 and 90-110 cm). In 2009 and 2010, slurry batch experiments combined with molecular investigations of bacterial communities were conducted in a corn field and an adjacent riparian buffer strip. Denitrification rates, ranging from 0.30 mu g NO(3) (-)-N g(-1) dry soil h(-1) to 1.44 mu g NO(3) (-)-N g(-1) dry soil h(-1), showed no significant variation along the slope and depth. N(2)O production assessed simultaneously differed considerably over the depth and ranged from 0.4 ng N(2)O-N g(-1) dry soil h(-1) in subsoils (the 90-110-cm layer) to 155.1 ng N(2)O-N g(-1) dry soil h(-1) in the topsoils (the 10-30-cm layer). In the topsoils, N(2)O-N production accounted for 8.5-48.0% of the total denitrified NO(3) (-)-N, but for less than 1% in the subsoils. Similarly, N(2)O-consuming bacterial communities from the subsoils greatly differed from those of the topsoils, as revealed by their nosZ DGGE fingerprints. High N(2)O-SPPR (nitrous oxide semi potential production rates) in comparison to NO(3)-SPDR (nitrate semi potential reduction rates) for the topsoils indicated significant potential greenhouse N(2)O gas production, whereas lower horizons could play a role in fully removing nitrate into inert atmospheric N(2). In terms of landscape management, these results call for caution in rehabilitating or constructing buffer zones for agricultural nitrate removal.
  • Authors:
    • Azooz, R. H.
    • Soon, Y. K.
    • Arshad, M. A.
    • Lupwayi, N. Z.
    • Chang, S. X.
  • Source: AGRONOMY JOURNAL
  • Volume: 104
  • Issue: 3
  • Year: 2012
  • Summary: Wood ash has the properties to be an effective liming material, and research is needed to compare its effectiveness relative to agricultural lime on acidic agricultural soils. Wood ash at a calcium carbonate rate of 6.72 t ha -1 was compared with an equivalent rate of agricultural lime on a clay loam soil with an initial pH of 4.9. Replicated plots were managed under a barley ( Hordeum vulgare L.)-canola ( Brassica rapa L.)-pea ( Pisum sativum L.) rotation for 4 yr (2002-2005). Soil pH increased in the order of: wood ash=lime > control (without lime or wood ash). Available soil P increased in the order of: wood ash > lime ≥ control. The effect of wood ash and lime application on pH and available P was greatest in the 0- to 5-cm depth, less but still significant in the 5- to 10-cm depth, and not significant below 10 cm. The effect on soil aggregation was: wood ash > lime > control. Averaged over 4 yr, application of wood ash increased grain yields of barley, canola, and pea by 49, 59, and 55%, respectively, compared to a corresponding increase of 38, 31, and 49% by agricultural lime. The increase in crop yield with wood ash compared with lime is attributed partly to increased P availability in wood ash-amended plots. It is concluded that wood ash applied at rates equivalent to agricultural lime improved some soil chemical and physical properties and increased crop production relative to agricultural lime.
  • Authors:
    • Tenuta, M.
    • Sparling, B.
    • Bell,L. W.
    • Entz, M. H.
  • Source: Web Of Knowledge
  • Volume: 158
  • Year: 2012
  • Summary: Soil carbon stocks are useful indicators of both C sequestration capacity and sustainability of agricultural systems. Yet, most investigations have only studied the effects of agricultural management on soil carbon in surface layers (<0.3 m). Current soil organic carbon (SOC), total soil nitrogen (TN) and plant available phosphorus (P Olsen) to a depth of 1.2 m was measured at two long-term (9 and 18 years) farming systems experiments in southern Manitoba, Canada. Both experiments compared an annual-crop rotation, an alfalfa ( Medicago sativa L.)/crop rotation and re-established perennial grassland. At one site the two cropping systems were managed conventionally as well as in adherence to organic farming guidelines, but without manure additions. Due to higher net primary productivity and higher carbon inputs, particularly below ground, SOC stocks (0-120 cm) were 21-65 t C ha -1 higher under the re-established grassland than cropping systems at the clay soil site after 18 years, but not at the site with sandy loam soil after 9 years. On the clay soil, 30-40% of the additional C in the soil profile under the re-established grassland was found below 30 cm indicating the capacity of deep plant roots to sequester C in the sub-soil. Using alfalfa cut for hay in crop rotations did not increase SOC or N stocks compared to annual crop rotations, but plant-available P concentrations were depleted, especially under organic management. SOC was 25-30 t C ha -1 lower under organic than conventionally managed cropping systems, due to lower inputs of plant C (0.8 t C ha -1 yr -1) over the life of the experiment. This highlights that without additional C inputs organic management can reduce SOC compared to conventional cropping systems unless C inputs are maintained which may require manure or compost additions.
  • Authors:
    • Jensen, C. R.
    • Jacobsen, S. -E
    • Liu, F.
  • Source: Field Crops Research
  • Volume: 128
  • Year: 2012
  • Summary: The aim of the present review is to highlight the possibilities of a sustainable crop production in the arid Mediterranean region, which is predicted to suffer from increasingly severe droughts in the future due to climate changes, in addition to increased problems with soil salinity and increased temperatures. Annual rainfall in the region varies between 300 and 1000 mm, covering arid, semi-arid and wet ecosystems. As stress factors often act together, it is important sometimes to focus on multiple stresses affecting the crop, instead of looking at the individual stress separated from the rest. The rainfed farming systems are the most important in the Mediterranean countries. The question is if we can overcome mild to medium level of abiotic stresses by agronomic means. It might be done by using different crops of increased drought and salinity tolerance, and utilizing their stress adaptation mechanisms to optimize crop productivity. However supplemental irrigation used as deficit irrigation has the potential to overcome periods of low rainfall or high temperatures. It is suggested that improvements in crop production may arise from several strategies such as early sowing enabled by minimum tillage, increased use of organic manure, and an efficient weed control. Further, crop rotations will play an important role in improving weed control, minimizing disease risk, and increasing nitrogen availability. Introduction of drought and salt tolerant crop species as quinoa, amaranth and Andean lupin may result in more resilient crop rotations and high value cash crop products. Genotypic increases may arise from selection for early vigour, deep roots, increased transpiration efficiency, improved disease resistance, and high assimilate storage and remobilization. A range of crop and management strategies might be combined for a specific target environment in order to optimize crop productivity. These combinations can then be used as a guidance to future decision support systems for crop production at limited water supply under arid Mediterranean conditions. (C) 2011 Elsevier B.V. All rights reserved.