• Authors:
    • Avcioglu, R.
    • Soya, H.
    • Demiroglu, G.
    • Kir, B.
  • Source: Turkish Journal of Field Crops
  • Volume: 15
  • Issue: 2
  • Year: 2010
  • Summary: This study was conducted in the experimental fields of Field Crops Department of Agriculture Faculty in Ege University, Bornova, Izmir-TURKEY under Mediterranean environmental conditions in the years, 2003-2009. Three legumes (Medicago satire, Lotus corniculatus and Trifolium resupinatum) and four grasses (Bromas inermis, Festuca erundinaceae, Dactylis glomerate and Arrhenatherum elatius) with Sanguisorha minor were sown in rows 15 cm apart and tested for some yield and quality characteristics under cattle grazing regime. Medicago satire and Festuca erundinaceae were the permanent and most successful legume and grass in the mixture in terms of botanical composition and cover traits throughout the experimental years. With respect to dry matter and crude protein yield characteristics, same components of the mixture also performed very well and have been evaluated as recommendable for all resembling Mediterranean environments. It was also suggested that Lotus corniculatus and Arrhenatherum elatius, both exhibiting stable and sustainable dry matter and crude protein yield contribution to overall performances of the sward, should be included in this type of Mediterranean pasture mixture. The general performance of this rotation pasture mixture was quite sustainable and suggested to utilize the sward economically for another couple of years.
  • Authors:
    • Di Tizio, A.
    • Campiglia, E.
    • Mancinelli, R.
    • Marinari, S.
  • Source: Applied Soil Ecology Volume 46, Issue 1, September 2010, Pages
  • Volume: 46
  • Issue: 1
  • Year: 2010
  • Summary: Carbon sequestration in soil is an important means for reducing net emissions of CO(2) into the atmosphere. We hypothesized that organic cropping systems (ORG) would reduce soil CO(2) emission and increase C storage compared to conventional cropping systems (CONV). The objectives of this study were to: (i) analyze the ORG and CONV systems in terms of soil CO(2) emission and soil C balance and (ii) establish if the soil in the ORG and CONV systems represents a source or a sink of C. A3-year crop rotation (durum wheat-Triticum durum Desf., tomato - Licopersicum esculentum Mill., and pea - Pisum sativum L) was carried out in both cropping systems, but the crop rotation was implemented with common vetch (Vicia sativa L.) before tomato planting and sorghum (Sorghum bicolor (L) Moench.) before pea sowing and both green manured only in the ORG system. It was found that the soil CO(2) emission rate at peak times (in spring or at the end of summer - beginning of autumn) in the ORG system was higher than the CONV system. The peak of CO(2) was attributed to the fact that at this time the soil temperature and the relative soil water content (RWC) were probably in the optimal range for soil respiration (17.2 degrees C and 36.4% of RWC) and the difference between ORG and CONV was probably due to the green manuring of the cover crops in the ORG system. However, even if the cropping systems had a temporary impact on the rate of soil CO(2) emissions, the soil C output calculated as the average of cumulative CO(2) emission over the 3-year period did not show significant differences between the ORG and CONV systems (8.98 Mg C-CO(2) ha(-1) vs. 8.06 Mg C-CO(2) ha(-1)). On the other hand, the C input in the ORG system was higher than in the CONV (9.46 Mg C ha(-1) vs. 5.57 Mg C ha(-1)) as well as the C input/output ratio (1.10 vs. 0.72). The 3-year average of TOC content and C stock were higher in the ORG than in the CONV system (1.24% vs. 1.10% and 27.4 Mg C ha(-1) vs. 23.9 Mg C ha(-1), respectively). However, the decrease of TOC and C stock over 3 years period suggested that further studies over a longer period are needed to verify if C limitation for soil microbial growth and nitrogen limitation for crop growth in the organic system could hinder soil C accumulation over a longer period. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Moscatelli, M. C.
    • Lagomarsino, A.
    • Marinari, S.
    • Di Tizio, A.
    • Campiglia, E.
  • Source: Soil & Tillage Research
  • Volume: 109
  • Issue: 2
  • Year: 2010
  • Summary: The scientific literature regarding the use of C and N mineralization kinetics as a tool to highlight the effects of different cropping systems on soil C and N release is scarce. In this study we aimed to assess the effectiveness of these parameters in evaluating soil C and N potential release in organic (ORG) and conventional (CONV) three-year cropping systems. A long-term field study was established in 2001 at the University of Tuscia experimental farm (Viterbo, Italy) in a randomized block design. The soil is classified as Typic Xerofluvent or Dystric Fluvisol. In the CONV system the Good Agricultural Practice is adopted, whereas the ORG system is managed following the Regulation 2092/91/EEC. Both systems had a three-year crop rotation (pea - Pisum sativum L.; durum wheat - Triticum durum Desf.; tomato - Licopersicum esculentum Mill.). One of the main differences between the two systems is the soil N fertilization program: organic fertilizers (Guano: 6% N, 32% organic carbon and DIX10: 10% N, 42% organic carbon, both produced by Italpollina. Italy) and mineral nitrogen fertilizers (NH(4)NO(3)) were applied to ORG and CONV fields.respectively. Moreover, the rotation in the ORG system included common vetch (Vicia sativa L) and sorghum (Sorghum vulgare L) as green manure crops. Our results supported the hypotheses in that the two systems differed significantly on potentially mineralizable C (C(o)) in 2008 and on potentially mineralizable N (N(o)) as nitrate form (N(0)-NO(3)(-)) in 2006 (318 mu g C-CO(2) g(-1) 28 d(-1) vs. 220 mu g C-CO(2) g(-1) 28 d(-1); 200 mu g N-NO(3)(-) g(-1) vs. 149 mu g N-NO(3)- g(-1) in ORG and CONV, respectively). The reduction of N(o) in soil during the crop rotation period could reflect the N microbial immobilization since a negative correlation between microbial biomass N:total N ratio and No as ammonium form (N(0)-NH(4)(+))(P < 0.001) as well as a positive correlation between N0-NH4+ and C:N ratio of microbial biomass (P < 0.05) were observed. Moreover, a lower potential mineralization rate of N was observed in soil with Guano (25%) than in soil with DIX10 (35%); nevertheless the former fertilizer might cover a longer period of crop N demand as a more gradual release of N0 was observed. In this work we demonstrated that the use of mineralization kinetics parameters can offer a potential to assess the mineralization–immobilization processes in soils under different climatic and management conditions. Moreover, they can be used to evaluate the most suitable N release pattern of organic fertilizers used in various cropping systems.
  • Authors:
    • Marinov-Serafimov, P.
  • Source: Selskostopanska Nauka (Agricultural Science)
  • Volume: 43
  • Issue: 2
  • Year: 2010
  • Summary: The study was conducted during 2005-2007 at the experimental field of Experimental stations in soybeans - Pavlikeni without irrigated conditions in secondary leaching on black earth in order to establish the possibility of an alternative control against weeds in soybean ( Glycine max [L.] Merr.) using allelopathic-mulching crop-oats. Relations between the two plant species, soybean-barley were followed in two factors: Factor A - the quantity of oats in the rate of propagation rate: a 1 - (Control manual removal of weeds, soybean monoculture) a 2 - (Control without manual removal of weeds, soybean monoculture) a 3 - 12%; a 4 - 25% and a 5 - 50%. Factor B - duration of the development of soybeans to emergence (VE): b 1 - flowering (R 2), b 2 - pod formation (R 4) and b 3 - technical ripeness (R 8). It was found that the use of oats as allelopathic-mulching culture in soy reduces the rate of sowing weed infestans from 33.0 to 66.0% and the cumulative amount of fresh and dry biomass (from 12.0 to 68.0%) of the group of late spring weeds, a disproportionate amount of the increased propagation norm; Weed suppression resolution allelopathic-mulching culture agrophytocenosa study is the result of limiting the density of some dicotyledonous annual weeds Amaranthus ssp., Abutilon theophrasti Medik. and Chenopodium album (L.), despite being down compensation processes in population density of Convolvulus arvensis L. uniformity in distribution of (J) - from -4.2 to -10.2; species composition (S) of weed communities is from 4 to 8 species, but in terms of their diversity (H) - from -5.9 to -21.2; complex effect of weed infestants and extent of the propagation rules of oats have a negative impact on yield of soybeans - kg/ha from 25.3 to 63.0 percent, the height of soybean flour (RCI varies from 0.11 to 0.35) and formed on fresh and dry biomass (RCI is in the range of 0.44 to 0.83) on the soybean, which can be offset by the reduced level of weed infestans in soybean agrophytotsenosis.
  • Authors:
    • Mechlia, N. B.
    • Nagaz, K.
    • Masmoudi, M. M.
  • Source: Options Méditerranéennes : Série A. Séminaires Méditerranéens
  • Issue: 95
  • Year: 2010
  • Summary: Climate change scenarios predict negative impacts on agriculture in the southern Mediterranean regions. Preparedness for increasingly frequent droughts requires a good knowledge on how chronic water shortages may affect production and cropping systems. This work investigates recent variations in agricultural production and in cropping practices in Tunisia as induced by a rapidly changing environment. Using production statistics and climatic records over the period 1984-2005, our analysis shows that variation of the agricultural production could be explained by the Standardized Precipitation Index (R 2=0.45), and that resilience to drought could be evaluated in the same manner. Data from surveys was used to identify adjustments adopted by farmers under the pressure of water scarcity in semi arid (Nabeul) and arid (Medenine) environments. Contrasting changes in cropping systems seem to be taking place for both regions. Contrast is also observed between irrigation strategies adopted by farmers. In Nabeul, large citrus growers having access to water from canal tend to over irrigate whenever water is available in order to minimize risks of water delivery failure from public networks. In contrast small farmers using shallow wells in Medenine seek practices such as deficit irrigation and intercropping in order to optimize water use. It is our view that options to face drought under increasing environmental stress should have a dynamic nature integrating adaptive practices used by farmers.
  • Authors:
    • Ben-Hammouda, M.
    • Errouissi, F.
    • Moussa-Machraoui, S. B.
    • Nouira, S.
  • Source: Soil & Tillage Research
  • Volume: 106
  • Issue: 2
  • Year: 2010
  • Summary: No-tillage (NT) is becoming increasingly attractive to farmers worldwide because it clearly reduces production costs relative to conventional tillage (CT) and improves soil properties and crop yield. Currently, under semi-arid conditions in North Africa, modern no-tillage techniques are being practiced on several hectares of land. The effect of NT and CT management and crop rotation on soil properties under semi-arid Mediterranean conditions was studied, over a 4-year period at two locations in northern Tunisia. Data from a short-term (2000-2004) use of both no-tillage (NT) and conventional tillage (CT) at the ESAK (Tunisia) were used to evaluate the influence of the tillage systems on the physicochemical properties of soil at the 0-20 cm depth layers. Trial was set up in 2000, where the two tillage systems (CT and NT), and four crop types (durum wheat, barley, pea and oats) were implemented in two distinct sites close to two governorates: Kef (silt/clayey) and Siliana (sand/clay) in northwestern Tunisia. Four years after implementing the two different tillage systems, soil parameters (N, NO(3)(2-), NH(4)(+) P, P(2)O(5), K, K(2)O, SOC, SOM and CEC) were determined and comparison between the two tillage systems was made. Our results showed that after 4 years the contents of some parameters for most crop types were greater under NT than under CT at 0-20 cm depth layers, the results varied depending on crop type and site. NT significantly improved soil content especially for K, K(2)O, P(2)O(5) and N. Under NT system SOM and SOC were enhanced, but without significant results. These enhancements were accompanied by the enhancement of the CEC and the decrease of the C/N ratio. Thus the mineralization process was slightly quicker under NT. Our results also indicate that residue cover combined with no-tillage appears to improve some agronomic parameters and biomass production (grain yield). Multivariate analyses indicate that the improvement of soil properties was dependant on tillage management, sites (climate and soil type) and crop succession (species and cover residue). It must be pointed Out that a 4-year period was not sufficient to clearly establish some parameters used in the effects of the NT system on soil properties under semi-arid conditions in northwestern Tunisia. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Brennan, J. P.
    • Murray, G. M.
  • Source: Australasian Plant Pathology
  • Volume: 39
  • Issue: 1
  • Year: 2010
  • Summary: The incidence, severity and yield loss caused by 40 pathogens associated with 41 diseases of barley were assessed from a survey of 15 barley pathologists covering the winter cereal growing areas of Australia. The survey provided data on the frequency of years that each pathogen developed to its maximum extent, the proportion of the crop then affected in each growing area, and the yield loss that resulted in the affected crops with and without current control measures. These data were combined with crop production and grain quality data to estimate the value of the losses aggregated to the Northern, Southern and Western production regions. Pathogens were estimated to cause a current average loss of $252 x 10(6)/year or 19.6% of the average annual value of the barley crop in the decade 1998-99 to 2007-08. Nationally, the three most important pathogens are Pyrenophora teres f. maculata, Blumeria graminis f. sp. hordei and Heterodera avenae with current average annual losses of $43 x 10(6), $39 x 10(6) and $26 x 10(6), respectively. If current controls were not used, losses would be far higher with potential average annual losses from the three most important pathogens, P. teres f. maculata, H. avenae and P. teres f. teres, being $192 x 10(6), $153 x 10(6) and $117 x 10(6), respectively. The average value of control practices exceeded $50 x 10(6)/year for nine pathogens. Cultural methods (rotation, field preparation) were the only controls used for 14 pathogens and contributed more than 50% of the control for a further 13 pathogens. Breeding and the use of resistant cultivars contributed more than 50% of control for five pathogens and pesticides for four pathogens. The relative importance of pathogens varied between regions and zones.
  • Authors:
    • Meijide, A.
    • Sanz-Cobena, A.
    • Sanchez-Martin, L.
    • Quemada, M.
    • Vallejo, A.
  • Source: European Journal of Soil Science
  • Volume: 61
  • Issue: 5
  • Year: 2010
  • Summary: The aim of this study was to evaluate the pattern of nitrous oxide (N 2O) and methane (CH 4) fluxes, and leaching losses of nitrate (NO 3-) and dissolved organic C (DOC), during a fallow-onion crop-fallow cycle in a Mediterranean area. The importance of the fallow (intercrop) period and the type of fertilizer were also evaluated. Goat and chicken manure (M) from an organic farm, digested pig slurry (DPS) and urea (U) were applied at a rate of 110 kg N ha -1 and compared with a zero N treatment (Control). The crop period contributed more than each fallow period to the total N 2O emission (ranging from 70 to 85% of the total emission, depending on the treatment). The variability of rainfall during fallow periods affected N 2O emissions, with the highest fluxes observed in the second fallow, which was the wetter. Negative net fluxes of N 2O (0 to -0.4 mg N 2O-N m -2 day -1) were mainly observed during the irrigation period and in fallow periods. The type of fertilizer had no effect on N 2O fluxes, but influenced the CH 4 oxidation. The largest CH 4 emission was from the manure treatment (2.4 mg CH 4-C m -2 day -1) during the irrigation period. The lowest NO 3- but highest DOC leaching rates were measured during the second fallow period from the manure treated plots (0.2 kg NO 3--N ha -1 and 3.9 kg C ha -1), which also had the highest drainage. The use of OM, therefore, seems to be a suitable method to reduce the environmental impacts associated with N leaching as well as increase the potential to denitrify NO 3- in groundwater.
  • Authors:
    • Belina, K.
    • Baumgartner, K.
    • Steenwerth, K.
    • Veilleux, L.
  • Source: Weed Science
  • Volume: 58
  • Issue: 3
  • Year: 2010
  • Summary: This research compared effects of the weed control practice, soil cultivation, and the conventional practice, glyphosate application on weed seedbank, in a vineyard system. The experiment was conducted in a commercial wine-grape vineyard in the Napa Valley of northern California from 2003 to 2005. The annual treatments were "winter-spring glyphosate," "spring cultivation," "fall-spring cultivation," and "fall cultivation-spring glyphosate," and were applied "in-row," under the vine. Composition of the weed seedbank collected in 2002 before treatment establishment did not differ among treatments. After 3 yr of weed treatments, detrended correspondence analysis indicated that the composition of spring cultivation and winter-spring glyphosate tended to differ from each other, but the remaining two treatments showed little differentiation. As determined by linear discriminant analysis, the specific weed species were associated with seedbanks of certain treatments. These were Carolina geranium, annual bluegrass, brome grasses, California burclover, and scarlet pimpernel, which do not pose problems with regard to physical aspects of grape production. Although 'Zorro' rattail fescue was ubiquitous among treatments, its distribution between depths in the cultivated treatments indicated that tillage provided some homogenization of seedbank along the vertical soil profile. The seedlings from the seedbank study were not congruent with those measured aboveground in the field, suggesting that both treatment and microclimatic effects in the field may have influenced germination, and thus, aboveground composition.
  • Authors:
    • Kapur, B.
    • Kanber, R.
    • Unlu, M.
  • Source: African Journal of Biotechnology
  • Volume: 9
  • Issue: 30
  • Year: 2010
  • Summary: Lysimeters are considered the standard for evapotranspiration (ET) measurements. However, these units are often not replicated and are few in number at any given location. The Bowen ratio-energy balance (BREB) is a micrometeorological method often used to estimate ET because of its simplicity, robustness, and cost. In this paper, ET of irrigated soybean ( Glycine max L.) was directly measured by weighing lysimeter and estimated by BREB method over a growing season in a semi-arid climate of eastern Mediterranean region. The study was conducted in Adana-Turkey during the summer of 2009 on a 0.12 ha area with a weighing lysimeter (2.0*2.0*2.5 m) located in the center of the field completely covered by well watered soybean where the prevailing direction of the wind and the upwind fetch was about 60 m. Cumulative evapotranspiration totals from the lysimeter and BREB methods were 354 and 405 mm, respectively. The BREB method showed a good performance for daily ET estimation when compared to values measured by lysimeter. This method, with a root mean square error (RMSE) of 0.79 mmd -1 and a 0.96 index of agreement, over-estimates lysimetric measurements by 15%. The BREB method also performs well compared with lysimetric measurements for hourly ET, but produces overestimation of 14% with RMSE of 0.128 mmh -1, and a 0.92 index of agreement.