• Authors:
    • Afolayan, S.
    • Olorunmaiye, P.
  • Source: Notulae Scientia Biologicae
  • Volume: 4
  • Issue: 1
  • Year: 2012
  • Summary: A preliminary study was carried out to evaluate the performances of eight crops in the intercrop of citrus with arable crops at the National Horticultural Research Institute (NIHORT) Ibadan, Nigeria. Eight arable crops: maize, cucumber, sweet potato, Corchorus olitorius, large green, grain amaranth, Mucuna pruriens var. utilis, and groundnut were intercropped with young citrus trees in the early planting season of 2010 with sole citrus as control. The experiment was laid out in a completely randomized block design with three replicates. Data were collected on weed flora, weed density and weed dry weight. Results showed that the relative frequencies of weeds in all the plots were less than 4% at both 6 and 9 WAP. Gomphrena celosoides, Oldenlandia corymbosa and Tridax procumbens were most preponderant in appearing in all the plots. Tridax procumbens had a consistent relative frequency (2.34%) in all the plots except in citrus/maize plot (0.78%) at 9 WAP. Significantly lower broadleaf weed densities were obtained in citrus/sweet potato, citrus/large green, control plot and citrus/cucumber (28.67, 45.00, 50.00 and 76.33 m -2 respectively) than in citrus/groundnut plot (143.00 m -2). Similarly, significantly lower grass weed densities were produced in citrus/ Mucuna and citrus/sweet potato (0.33 m -2 each) plots than the control plot (11.33 m -2). Whereas citrus/ Corchorus plot produced significantly lower broadleaf weed dry weight (37.59 g m -2) than citrus/ Mucuna plot (126.47 g m -2) at 3 WAP, citrus/large green plot (16.15 g m -2) and citrus/groundnut plot (123.25 g m -2) followed the same trend at 6 WAP. Sedges dry weights were less than 7 g m -2 in all the plots compared with control plot.
  • Authors:
    • Jorgensen, L.
    • Nielsen, G.
    • Spliid, N.
    • Ghorbani, F.
    • Nielsen, K.
    • Rasmussen, P.
  • Source: Mycotoxin research
  • Volume: 28
  • Issue: 3
  • Year: 2012
  • Summary: Fusarium mycotoxins such as deoxynivalenol (DON) can occur in cereals conjugated to glucose and probably also to other sugars. These conjugates, which are often referred to as "masked mycotoxins", will not be detected with routine analytical techniques. Furthermore, it is suspected that the parent toxin may again be released after hydrolysis in the digestive tracts of animals and humans. Today, our knowledge of the occurrence of these compounds in cereal grains is limited. In this paper, a LC-MS/MS method for the simultaneous determination of DON, deoxynivalenol-3-beta-D-glucoside (DON-3-glucoside), 3 acetyl-DON, nivalenol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin, and T-2 toxin in naturally ( n=48) and artificially ( n=30) contaminated cereal grains (wheat, barley, oat, rye triticale) is reported. The method has also been applied to whole fresh maize plant intended for production of maize silage ( n=10). The samples were collected from the harvest years 2006-2010, The results show that DON-3-glucoside and DON co-occurred in cereal grains and, especially in several of the highly contaminated samples, the concentration of the glucoside can be relatively high, corresponding to over 37% of the DON concentration. The DON-3-glucoside levels in both the naturally and in the artificially grain inoculated with Fusarium were second only to DON, and were generally higher than those of the other tested trichothecenes, which were found at low concentrations in most samples, in many cases even below the detection limit of the method. This argues for the importance of taking DON-3-glucoside into account in the ongoing discussion within the European Community concerning exposure re-evaluations for setting changed values for the tolerable intake for DON. Our results indicate that, in the naturally contaminated grains and in the Fusarium infested cereal grains (winter and spring wheat, oat, triticale), the concentration level of DON-3-glucoside is positively correlated to the DON content. When the DON concentration is high, then the content of DON-3-glucoside will most probably also be high and vice versa.
  • Authors:
    • Jones, J.
    • Porter, C.
    • Orsini, R.
    • Seddaiu, G.
    • Roggero, P.
    • Sanctis, G.
  • Source: European Journal of Agronomy
  • Volume: 40
  • Year: 2012
  • Summary: The differential impact on soil organic carbon (SOC) of applying no tillage (NT) compared to conventional tillage (CT, i.e. mouldboard ploughing), along with three rates of nitrogen (N) fertilizer application (0, 90 and 180 kg ha -1 y -1), was studied under rain-fed Mediterranean conditions in a long-term experiment based on a durum wheat-maize rotation, in which crop residues were left on the soil (NT) or incorporated (CT). Observed SOC content following 8 and 12 years of continuous treatment application was significantly higher in the top 10 cm of the soil under NT than CT, but it was similar in the 10-40 cm layer. NT grain yields for both maize and durum wheat were below those attained under CT (on average 32% and 14% lower respectively) at a given rate of N fertilizer application. Soil, climate and crop data over 5 years were used to calibrate DSSAT model in order to simulate the impact of the different management practices over a 50-year period. Good agreement was obtained between observed and simulated values for crops grain yield, above-ground biomass and observed SOC values. Results from the simulations showed that under NT the weeds growing during the intercrop fallow period made a significant contribution to the observed SOC increase. When the contribution of the weed fallow was considered, NT significantly increased SOC in the top 40 cm of the soil at an average rate of 0.43, 0.31 and 0.03 t ha -1 per year, respectively for 180, 90 and 0 kg N ha -1 year -1, within the simulated 50 years. Under CT, a significant SOC increase was simulated under N180 and a significant decrease when no fertilizer was supplied.
  • Authors:
    • Karas, J.
    • Hruskova, M.
    • Svec, I.
    • Hofmanova, T.
  • Source: Czech Journal of Food Sciences
  • Volume: 30
  • Issue: 5
  • Year: 2012
  • Summary: The baking quality in the sets of both commercial and variety wheat samples (80 and 18 items) and wheat composite flour (standard and 25 blends) was evaluated in terms of the Solvent retention capacity method (AACC 56-11). Composites were prepared from a commercial fine wheat flour and commercial bio-wholemeal flour prepared by milling of common wheat, rye, oat, barleys and corn at substitution levels of 10, 20, 30, 40, and 50%. The commercial wheat quality testing ANOVA revealed the major effect of the sample tested form; the data measured for grain and flour proved to be correlated. Besides, the harvest year affected the baking quality to a greater degree than the growing locality. Within the variety wheat set, the harvest year factor dominated over that of the wheat cultivar one with the exception of the sodium carbonate retention capacity. In the case of the wheat flour substitution by bio-cereal flour types, the added amount of the alternative flour supported only the quantitative change caused by the incorporated cereal in all four retention capacities.
  • Authors:
    • Lu, Y.
    • Zeng, L.
    • Liang, G.
    • Tian, Y.
  • Source: Acta Phytophylacica Sinica
  • Volume: 39
  • Issue: 1
  • Year: 2012
  • Summary: In order to confirm the effect of pest control using intercropping with different crops, investigation was conducted to study the population dynamics of insect pests of maize and their natural enemies in the habitat of sweet corn monoculture or intercropping with other crops (mung bean, kidney bean, sweet potato or peanut) by the method of eyeballing. Damage by Asian corn borer (ACB), Ostrinia furnacalis (Guenee) between different habitats was also be analyzed and discussed. Results indicated that the amounts of two predator groups, spiders and ladybirds, increased in sweet corn intercropping habitats significantly. Individual number of spiders in the fields when sweet corn intercropped with mung bean and number of ladybirds in habitat of sweet corn intercropped with sweet potato were over 21% and 83% respectively more than that in sweet corn monoculture. The number of Trichogramma ostriniae Pang et Chen showed no significant difference between different habitats, with the parasitic rates of ACB eggs were over 86%. No significant differences was observed in number of ACB eggs, Spodoptera litura (Fabricius) or Rhopalosiphum maidis Fitch between sweet corn monoculture and intercropping habitats. However, the ACB damage rate in sweet corn intercropping habitats was less than that in sweet corn monoculture at harvest, with the least in sweet corn intercropped with mung bean habitat, in which the number of holes and larvae was decreased by 55.72% and 76. 70% respectively. Study suggested that sweet corn intercropping with other crops could be beneficial to conservation of natural enemies and control of insect pests in some extents.
  • Authors:
    • Kaiser, D. E.
    • Sheaffer, C. C.
    • Russelle, M. P.
    • Coulter, J. A.
    • Yost, M. A.
  • Source: AGRONOMY JOURNAL
  • Volume: 104
  • Issue: 4
  • Year: 2012
  • Summary: Compared with corn ( Zea mays L.) following corn, N guidelines for first-year corn following alfalfa ( Medicago sativa L.) in the U.S. Corn Belt suggest that N rates can be reduced by about 168 kg N ha -1 when ≥43 or 53 alfalfa plants m -2 are present at termination. These guidelines have been questioned by practitioners, however, as corn grain yields have increased. We conducted experiments at 16 locations in Minnesota to address questions regarding N availability to first-year corn after alfalfa relating to the effect of carryover fertilizer K from alfalfa and the amount and timing of alfalfa regrowth incorporation. Corn grain yield, silage yield, and fertilizer N uptake were not affected by carryover K or amount or timing of regrowth incorporation. Maximum corn grain yield ranged from 12.0 to 16.1 Mg ha -1 among locations but responded to fertilizer N at only one. At that location, which had inadequate soil drainage, the economically optimum N rate (EONR) was 85 kg N ha -1, assuming prices of US$0.87 kg -1 N and US$132 Mg -1 grain. The EONR for silage yield across 6 of 15 locations where it was measured was 40 kg N ha -1, assuming US$39 Mg -1 silage. These results demonstrate that on highly productive medium- to fine-textured soils in the Upper Midwest with ≥43 alfalfa plants m -2 at termination, first-year corn grain yield is often maximized without fertilizer N, regardless of alfalfa regrowth management or timing of incorporation, but that small N applications may be needed to optimize silage yield.
  • Authors:
    • Luo, J. F.
    • Ding, W. X.
    • Cai, Y. J.
  • Source: GEODERMA
  • Volume: 181
  • Year: 2012
  • Summary: There is a high spatial variation in N2O emission from agricultural fields and N2O emissions from fields cultivated with stalk-crops was generally measured in the interrow area. The aim of this study was to evaluate the difference in seasonal N2O emissions between interrow soil and interrow + row soil, and to understand the effect of different fertilizers on N2O emissions in a maize-cultivated sandy loam soil in the North China Plain. The experiment included five treatments: organic manure (OM), half-organic manure N plus half fertilizer N (HOM), fertilizer NPK (NPK), fertilizer NK (NK) and control (CK). Cumulative N2O emission from interrow + row soil during the maize growth season was 0.84-122 kg N ha(-1) with an average of 0.98 kg N ha(-1) in the N-fertilized treatments, significantly higher than the 0.30-0.49 kg N ha(-1) from interrow soil. However, no significant difference was observed in the CK treatment. The measurement in interrow soil underestimated N2O emissions by 44-67%. This difference mainly occurred at the two peak emission periods following fertilizer application probably due to discrepancy in soil denitrification potential. Manure application more efficiently increased difference in N2O emission between interrow soil and interrow + row soil than inorganic N fertilizer application. The higher NO concentration did not induce larger N2O emission from interrow soil in the NK treatment than in the NPK treatment, but did from interrow + row soil, resulting in greater difference in N2O emission between interrow soil and interrow + row soil. It is suggested that measuring N2O emission solely from interrow soil could underestimate seasonal N2O emissions, and partly mask the effect of N fertilizer application rates on N2O emission in a maize-cultivated soil in the North China Plain.
  • Authors:
    • Clothier, B. E.
    • Jun, G. I.
    • Young, I.
    • Huh, K. Y.
    • Kim, I.
    • Mueller, K.
    • Deurer, M.
  • Source: GEODERMA
  • Volume: 183
  • Year: 2012
  • Summary: In an organic apple (Malus domestica Borkh., Braeburn on MM.106 rootstock) orchard in New Zealand we observed that the soil's carbon concentration in 0-0.1 m depth directly below a wheel-track in the grassed alley-way was significantly higher than under the grassed tree-row. By using a literature review and direct measurements, we systematically exclude two explanations for the possible accumulation of soil carbon under the wheel-track. Firstly, we discard the possibility of higher carbon inputs to the wheel-track compared to the tree-row area. The tree-row received more carbon inputs by the regular application of compost, and the growth of roots was not impeded by compaction. Secondly, we directly measured the monthly dynamics of microbial biomass and respiration rates per unit of soil carbon over a year, and based on 3D X-ray computed tomography (CT) images we modelled the gas exchange close to water saturation. A restricted gas exchange under wet conditions would be an indication that soil carbon mineralization is reduced under wet conditions. We found that both the microbial carbon decomposition dynamics and the gas exchange under wet conditions were similar in the tree-row and under the wheel-track. The most probable explanation for the enhanced carbon sequestration under the wheel-track is a reduction in carbon losses. The water infiltration rates into the wheel-tracks were significantly smaller than in the tree-row. This means that the carbon loss with water flow in the form of dissolved carbon is probably smaller under the wheel-track Additionally, a reduction in meso- and macro-faunal activities exporting particulate organic matter from the soil volume is probable under minor compaction. We conclude that a minor compaction like under a wheel-track can be a physical protection mechanism for soil carbon. (C) 2012 Published by Elsevier B.V.
  • Authors:
    • Wang, J. Y.
    • Yan, X. Y.
    • Gong, W.
  • Source: PLANT AND SOIL
  • Volume: 353
  • Issue: 1-2
  • Year: 2012
  • Summary: Background and Aims Previous studies have clearly shown substantial increases of soil organic carbon (SOC) in agricultural soils of Yellow River reaches. Those soils did not receive organic fertilizer input, but did receive chemical fertilizer inputs. Thus, to investigate the hypothesis that the observed SOC increases were driven by chemical fertilizer additions, a maize pot experiment was conducted using a Fluvisol that developed under C-3 vegetation in the Yellow River reaches. Methods Using the natural C-13 abundance method we calculated the SOC renewal ratio (C-renewal), and separated total soil organic carbon (TOC) into maize-derived soil organic carbon (SOCmaize) and original soil organic carbon (SOCoriginal). Carbon dioxide fluxes and microbial biomass carbon (MBC) were determined by closed chamber method and fumigation-extraction method, respectively. The experiment included five treatments: (1) NPK: application of chemical fertilizer NPK; (2) NP, application of chemical fertilizer NP; (3) PK: application of chemical fertilizer PK; (4) NK, application of chemical fertilizer NK; and (5) CK: unfertilized control. Results Fertilization increased maize biomass (including grain, straw and root), TOC, C-renewal, SOCmaize, maize-derived carbon (MDC: including SOCmaize, and root and stubble biomass carbon) and MBC, and these values among the treatments ranked NPK>NP>PK>NK>CK. The C-renewal was 5.548.50% across the treatments. Fertilization also increased soil CO2 emission (including root respiration and SOCoriginal decomposition), while the SOCoriginal decomposition during the maize growing season only amounted to 74.0-93.4 and 33.5-46.1% of SOCmaize and MDC among the treatments, respectively. Thus input was larger than export, and led to SOC increase. Maize grain and straw biomass were positively and significantly correlated with soil delta C-13, TOC, C-renewal, SOCmaize, MDC and MBC. Conclusions The study suggests that chemical fertilizer application could increase C-renewal by increasing crop-derived C and accelerating original SOC decomposition, and that as long as a certain level of crop yield or aboveground biomass can be achieved, application of chemical fertilizer alone can maintain or increase SOC level in Fluvisol in the Yellow River reaches.
  • Authors:
    • Canellas, L. P.
    • Aguiar, N. O.
    • Garcia, C.
    • Hernandez, T.
    • Perez-Alfocea, F.
    • Navarro, E. C.
    • Martim, S. A.
    • Jindo, K.
  • Source: PLANT AND SOIL
  • Volume: 353
  • Issue: 1-2
  • Year: 2012
  • Summary: Background and aims Besides general effect of organic residues on soil quality and plant crop, hormonal direct effect on plant growth by extracted humic acids of organic materials is interesting and profitable theme. In the present work, we studied on direct interaction between humic acid and root growth, depending on different origin of organic materials. Methods All extracted humic acids of four organic materials (sewage sludge, compost sewage sludge, municipal solid waste, compost municipal solid waste) were characterized chemically by elemental analyses, ion pair chromatography (ICP), size exclusion chromatography (HPSEC), solid-state nuclear magnetic resonance (C-13-CPMAS-NMR) and quantification of IAA. Later, different morphological effects on maize (principal root growth, lateral root growth, root area, root mitosic site, root dry weight and H+-ATPase activity of plasma membrane) were analyzed. Results All humic acids samples promoted root growth and proton pump activity in maize vesicles, especially those composted samples, which contained more carboxylic groups and had a more hydrophobic character, produced preferentially morphological and biochemical effects. Conclusion The conformational dynamics of humic hydrophobic associations in the rhizosphere may release auxin-like plant growth promoters and enhance plant biochemical activities. These organic wastes represent a renewable source of humic acid for use as plant root promoter.