• Authors:
    • Salmond, G.
    • Swan, L.
  • Source: Australian Cottongrower
  • Volume: 26
  • Issue: 3
  • Year: 2005
  • Summary: In a field in Australia, the influence of growing different rotation crops on the level of Fusarium oxysporum f.sp. vasinfectum (Fov) in the soil was monitored over three years in a summer field crop rotation experiment. In the 2001-02 and 2002-03 seasons of the trial, the same crop was grown on the same plot. The maize plots were a forced fallow during 2002-03. In 2003-04, the entire trial was oversown with cotton cv. Nu Emerald RR. Mung bean plots were replanted with Sicot 14B six weeks later. In glasshouse pot trials, soil naturally infested with Fov was used to examine different rotation options over five crop cycles with cotton oversown across all treatments in the final cycle. In the field, significantly more cotton plants survived until maturity following a bare fallow rotation compared to cotton plants grown following either maize, cotton or sorghum crops. The greatest percentage of cotton plant death and severity of disease in cotton occurred where soyabean or mung bean crops had previously been grown. In the glasshouse, rotation cycles that included a fallow treatment either one or two crops before growing cotton generally resulted in less severe Fusarium wilt (lower MDI) compared to cycles where a fallow treatment was not included occurred early in the cycle. Crops with larger root systems (sunflower, broccoli, lucerne, maize, sorghum) had more disease (higher MDI) in the following cotton compared to crops with smaller root systems (fallow, chickpea, field pea, millet, pigeon pea), after these crops had been grown for four continuous cycles, reflecting the role of residue and organic matter in pathogen survival and disease incidence. Fov has been isolated from mature plants growing in these pot trials including sunflower (5%); maize (4%); sorghum (3%) (roots only); mung bean (24%); field pea (20%); vetch (20%); pigeon pea (12%); chickpea (4%); and lucerne (4%) (stems and roots). Further research into rotation options and the roles of crop residue, organic matter and green manuring of crops in relation to pathogen survival are discussed.
  • Authors:
    • Scott, A. W.,Jr.
    • Westphal, A.
  • Source: Crop Science
  • Volume: 45
  • Issue: 1
  • Year: 2005
  • Summary: Rotylenchulus reniformis Linford & Oliveira is increasing in incidence in cotton-growing areas throughout the southern USA east of New Mexico. Cotton (Gossypium hirsutum L.) cultivars resistant to R. reniformis are currently unavailable. Management depends on a crop sequence with nonhosts of the nematode. In South Texas, the sequence of cotton with grain sorghum [ Sorghum bicolor (L.) Moench] or corn ( Zea mays L.) has become a standard practice. To improve farm efficiency, the implementation of rotation crops that are economically superior to grain sorghum is desirable. Eighteen cultivars of soybean [ Glycine max (L.) Merr.] were tested in nonfumigated and in fumigated sandy loam soil infested with R. reniformis to evaluate nematode resistance of soybean under field conditions. Shank application of 1,3-dichloropropene at a 38-cm depth reduced R. reniformis population densities at the 15- to 60-cm depth compared with preseason counts. The effect of each soybean cultivar on the growth and yield of a subsequent cotton crop was compared with the impact of grain sorghum and fallow. High-yielding cultivars of soybean (HY574, Padre, DP7375RR, and NK83-30) with reniform nematode-suppressing potential were identified among cultivars within maturity groups 5, 6, 7, and 8. In contrast, cotton yields following the susceptible cultivars Santa Rosa-R, Vernal, and DP6880RR were on average 25% lower than those following grain sorghum. The enrichment of cotton sequences with reniform nematode-resistant soybean cultivars is viable when the proper cultivars are chosen, whereas the use of reniform nematode-susceptible soybean cultivars is discouraged. The effective use of R. reniformis-resistant soybean cultivars to manage R. reniformis in cotton will depend on a number of additional economic parameters not studied in these experiments.
  • Authors:
    • Chattopadhyay, N.
    • Das, H. P.
  • Source: Advances in Indian entomology: productivity and health (a silver jubilee supplement)
  • Volume: 1
  • Issue: 3
  • Year: 2005
  • Summary: Every year crops (such as rice, cotton, pigeon pea, sorghum, soyabean, groundnut, sugarcane and vegetables) are being damaged by pests and diseases. Due to lack of proper operational forecasting system for the incidences of pests and diseases, it becomes difficult to adopt efficient plant protection measures at the right time. It has been established with fair degree of accuracy that climate/weather plays major role in the incidences of pests and diseases. Thus, there is a tremendous scope of utilizing meteorological parameters for the advance information of the occurrences of the pests and diseases and ultimately scheduling of prophylactive measures can be taken scientifically and judiciously. Quite a number of studies in this regards have been made in the Agricultural Meteorology Division, India Meteorological Department (Pune, Maharashtra, India). In the present paper, a comprehensive review of the work done in this division on the impact of weather on pests and diseases of crops is presented. This information will probably help the agricultural community of the country to save the crops from the infestation of pest and disease incidences.
  • Authors:
    • Linden, D. R.
    • Voorhees, W. B.
    • Hatfield, J. L.
    • Johnson, J. M. F.
    • Wilhelm, W. W.
  • Source: Agronomy Journal
  • Volume: 96
  • Issue: 1
  • Year: 2004
  • Summary: Society is facing three related issues: overreliance on imported fuel, increasing levels of greenhouse gases in the atmosphere, and producing sufficient food for a growing world population. The U.S. Department of Energy and private enterprise are developing technology necessary to use high-cellulose feedstock, such as crop residues, for ethanol production. Corn (Zea mays L.) residue can provide about 1.7 times more C than barley (Hordeum vulgare L.), oat (Avena sativa L.), sorghum [Sorghum bicolor (L.) Moench], soybean [Glycine max (L.) Merr.], sunflower (Helianthus annuus L.), and wheat (Triticum aestivum L.) residues based on production levels. Removal of crop residue from the field must be balanced against impacting the environment (soil erosion), maintaining soil organic matter levels, and preserving or enhancing productivity. Our objective is to summarize published works for potential impacts of wide-scale, corn stover collection on corn production capacity in Corn Belt soils. We address the issue of crop yield (sustainability) and related soil processes directly. However, scarcity of data requires us to deal with the issue of greenhouse gases indirectly and by inference. All ramifications of new management practices and crop uses must be explored and evaluated fully before an industry is established. Our conclusion is that within limits, corn stover can be harvested for ethanol production to provide a renewable, domestic source of energy that reduces greenhouse gases. Recommendation for removal rates will vary based on regional yield, climatic conditions, and cultural practices. Agronomists are challenged to develop a procedure (tool) for recommending maximum permissible removal rates that ensure sustained soil productivity.
  • Authors:
    • Halvorson, A. D.
    • Nielsen, D. C.
    • Reule, C. A.
  • Source: Agronomy Journal
  • Volume: 96
  • Issue: 4
  • Year: 2004
  • Summary: No-till (NT) production systems, especially winter wheat (Triticum aestivum L.)-summer crop-fallow, have increased in the central Great Plains, but few N fertility studies have been conducted with these systems. Therefore, winter wheat (W) response to N fertilization in two NT dryland crop rotations, wheat-corn (Zea mays L.)-fallow (WCF) and wheat-sorghum (Sorghum bicolor L.)-fallow (WSF), on a Platner loam (fine, smectitic, mesic Aridic Palleustoll) was evaluated for 9 yr. Five N rates, 0, 28, 56, 84, and 112 kg N ha(-1), were applied to each rotation crop. Wheat biomass and grain yield response to N fertilization varied with year but not with crop rotation, increasing with N application each year, with maximum yields being obtained with 84 kg N ha(-1) over all years. Based on grain N removal, N fertilizer use efficiency (NFUE) varied with N rate and year, averaging 86, 69, 56, and 46% for the 28, 56, 84, and 112 kg ha(-1) N rates, respectively. Grain protein increased with increasing N rate. Precipitation use efficiency (PUE) increased with N addition, leveling off above 56 kg N ha(-1). A soil plus fertilizer N level of 124 to 156 kg N ha(-1) was sufficient to optimize winter wheat yields in most years in both rotations. Application of more than 84 kg N ha(-1) on this Platner loam soil, with a gravel layer below 120 cm soil depth, would more than likely increase the amount of NO3-N available for leaching and ground water contamination. Wheat growers in the central Great Plains need to apply N to optimize dryland wheat yields and improve grain quality, but need to avoid over-fertilization with N to minimize NO3-N leaching potential.
  • Authors:
    • NASDA
  • Year: 2004
  • Authors:
    • Dale, B. E.
    • Kim, S.
  • Source: Biomass and Bioenergy
  • Volume: 26
  • Issue: 4
  • Year: 2004
  • Summary: The global annual potential bioethanol production from the major crops, corn, barley, oat, rice, wheat, sorghum, and sugar cane, is estimated. To avoid conflicts between human food use and industrial use of crops, only the wasted crop, which is defined as crop lost in distribution, is considered as feedstock. Lignocellulosic biomass such as crop residues and sugar cane bagasse are included in feedstock for producing bioethanol as well. There are about 73:9 Tg of dry wasted crops in the world that could potentially produce 49:1 GL year-1 of bioethanol. About 1:5 Pg year-1 of dry lignocellulosic biomass from these seven crops is also available for conversion to bioethanol. Lignocellulosic biomass could produce up to 442 GL year-1 of bioethanol. Thus, the total potential bioethanol production from crop residues and wasted crops is 491 GL year-1, about 16 times higher than the current world ethanol production. The potential bioethanol production could replace 353 GL of gasoline (32% of the global gasoline consumption) when bioethanol is used in E85 fuel for a midsize passenger vehicle. Furthermore, lignin-rich fermentation residue, which is the coproduct of bioethanol made from crop residues and sugar cane bagasse, can potentially generate both 458 TWh of electricity (about 3.6% of world electricity production) and 2:6EJ of steam. Asia is the largest potential producer of bioethanol from crop residues and wasted crops, and could produce up to 291 GL year -1 of bioethanol. Rice straw, wheat straw, and corn stover are the most favorable bioethanol feedstocks in Asia. The next highest potential region is Europe (69:2 GL ofbioethanol), in which most bioethanol comes from wheat straw. Corn stover is the main feedstock in North America, from which about 38:4 GL year -1 of bioethanol can potentially be produced. Globally rice straw can produce 205 GL of bioethanol, which is the largest amount from single biomass feedstock. The next highest potential feedstock is wheat straw, which can produce 104 GL of bioethanol. This paper is intended to give some perspective on the size ofthe bioethanol feedstock resource, globally and by region, and to summarize relevant data that we believe others will 0nd useful, for example, those who are interested in producing biobased products such as lactic acid, rather than ethanol, from crops and wastes. The paper does not attempt to indicate how much, if any, of this waste material could actually be converted to bioethanol.
  • Authors:
    • Guzha, A. C.
  • Source: Soil & Tillage Research
  • Volume: 76
  • Issue: 2
  • Year: 2004
  • Summary: Conservation of soil water is an important management objective for crop production in the semi-arid tropics where droughts are persistent. Identification of the best tillage methods to achieve this objective is thus imperative. The integrated effects of conservation tillage on soil micro topography and soil moisture on a sandy loam soil were evaluated. The field experiment consisted of five tillage treatments, namely tied ridging (TR), no till (NT), disc plough (DP), strip catchment tillage (SCT) and hand hoe (HH). Data measured in the field included soil moisture content, surface roughness, infiltration and sorghum grain yield. A depth storage model was used to estimate depression storage TR treatment and the higher the surface roughness, the greater the depression storage volume. Regression analysis showed that random roughness decreased exponentially with increase in cumulative rainfall. Higher moisture contents were associated with treatments having higher depressional storage. Infiltration rate was significantly higher in the tilled soils than the untilled soils. The DP treatment had the highest cumulative infiltration while NT had the lowest. The Infiltration model which was fitted to the infiltration data gave good fit. Grain yield was highest in TR and least in NT, whereas DP and HH had similar yields.
  • Authors:
    • Everts, K.
    • Sardanelli, S.
    • Kratochvil, R.
    • Gallagher, E.
  • Source: Agronomy Journal
  • Volume: 96
  • Issue: 5
  • Year: 2004
  • Summary: Root-knot ( Meloidogyne incognita) and lesion ( Pratylenchus penetrans) nematodes are important pathogens that cause yield and quality losses for most vegetable and field crops in Maryland, USA when they exceed certain threshold levels and if control measures are not applied. Chemical nematicides are the primary control tactic, but their use is both costly and raises environmental concerns. This study was conducted from 2000 to 2002 to evaluate the efficacy of crop rotation and other cultural practices for management of southern root-knot nematodes (RKNs) and lesion nematodes. Three nonhost crops, a RKN-resistant soyabean ( Glycine max) cultivar, and poultry litter/tillage (Year 1) and fallow (Year 2) were used as summer rotation crops/management options following production of nematode-susceptible crops on 2 sites in Dorchester County, Maryland, on Downer and Hammonton sandy loam soils (coarse-loamy, siliceous, mesic Typic and Aquic Hapludults), respectively. Sorghum sudangrass ( Sorghum bicolor * Sorghum arundinaceum var. sudanense), grown annually as a green manure crop following a nematode-susceptible crop, potato ( Solanum tuberosum) or cucumber ( Cucumis sativus), reduced the RKN population as effectively as the control treatment (soyabean cultivar with no known RKN resistance and one nematicide application). Sorghum sudangrass and poultry litter/tillage/fallow were equally effective in managing the lesion nematode population. Annual inclusion of these practices was necessary to maintain the reduced population levels that were attained for these 2 nematode species. Finally, either summer or early-autumn sampling dates were determined to be more effective than a midspring sampling date for identifying threshold levels of these 2 pests.
  • Authors:
    • Rogers, H.
    • Runion, G.
    • Torbert, H.
    • Prior, S.
  • Source: Environmental Management
  • Volume: 33
  • Issue: Supplement 1
  • Year: 2004
  • Summary: Elevated atmospheric CO 2 concentration can increase biomass production and alter tissue composition. Shifts in both quantity and quality of crop residue may alter carbon (C) and nitrogen (N) dynamics and management considerations in future CO 2-enriched agroecosystems. This study was conducted to determine decomposition rates of the legume soybean [ Glycine max (L.) Merr.] and nonlegume grain sorghum [ Sorghum bicolor (L.) Moench.] residue produced under two levels of atmospheric CO 2 (ambient and twice ambient) on a Blanton loamy sand (loamy siliceous, thermic, Grossarenic Paleudults) in Auburn, Alabama, USA, managed using no-till practices. At maturity, harvested plants were separated into component parts for dry weight determination and tissue analysis. Mass, C, and N losses from residues were determined using the mesh bag method. Biomass production was significantly greater for soybean compared to sorghum and for elevated versus ambient CO 2-grown plants. The CO 2 level had little affect on the C/N ratio of residue (probably because the tissue used was senesced). Elevated CO 2 concentration did not affect percent residue recovery; however, greater biomass production observed under elevated CO 2 resulted in more residue and C remaining after overwintering. The higher total N content of soybean residue, particularly when grown under elevated CO 2, indicated more N may be available to a following crop with lower N inputs required. Results suggest that in a high CO 2 environment, greater amounts of residue may increase soil C and ground cover, which may enhance soil water storage, improve soil physical properties, and reduce erosion losses.