• Authors:
    • Costa, M.
    • Castoldi, G.
    • Pivetta, L.
    • Steiner, F.
    • Costa, L.
  • Source: Revista Brasileira de Ciencias Agrarias
  • Volume: 6
  • Issue: 3
  • Year: 2011
  • Summary: The organic carbon is a major component of the soil organic matter, and its stock is influenced by the type of management system used. This study aimed to evaluate the effect of two cropping systems, with and without cover crop rotation, associated to three fertilization sources (mineral, organic and mineral+organic) in the organic and residual carbon contents of an Oxisol, in no-tillage system. Soil samples were collected at 0.0-0.10, 0.10-0.20 and 0.20-0.40 m depth in the first, second and third years of the experiment, installed in 2006. The crops sequence in the rotation system with cover crops was oat+vetch+turnip/corn/wheat/mucuna+brachiaria+crotalaria/corn/soybean, and in the following system it was wheat/corn/wheat/soybean/corn/soybean. The organic and mineral+organic fertilizers consisted in the sole application of organic fertilizers and combined with mineral fertilizer. The organic and residual carbon contents were not affected by the different cropping systems. The organic and mineral+organic fertilizers promoted increases in the organic and residual carbon contents. The system of crop succession fertilized with mineral fertilizer resulted in higher losses of soil carbon.
  • Authors:
    • Bernardi, T.
    • Tamburini, E.
    • Castaldelli, G.
  • Source: Journal of Near Infrared Spectroscopy
  • Volume: 19
  • Issue: 3
  • Year: 2011
  • Summary: The application described in this paper addresses problems encountered during the large scale production of ethanol from renewable sources. Bioethanol can be produced from several starchy raw materials (i.e. wheat, corn, barley, rye). After hydrolysis to glucose, starch can be converted in ethanol by fermentation. The hydrolysis of starch requires a multi-phase process using different enzymes. The degree of hydrolysis is a critical parameter because it determines the physical and chemical properties of the final products. The aims of this work were to monitor the enzymatic hydrolysis of starch from rye using Fourier-transformed near infrared (FT-NIR) spectroscopy, and to identify barriers for an industrial scale application of this technology. The enzymatic hydrolysis of starch from rye was carried out in three steps, using commercially-available enzymes. A FT-NIR reflectance probe was immersed in the reactor to monitor the different phases of the hydrolysis process. The most significant parameters submitted to the NIR calibration were the percentage of dry matter (%w/v) (degreesBrix) and the concentrations of maltotriose, maltose and glucose (% w/v). PLS calibration models were built using 24 samples and spectra fordegreesBrix, 32 samples for maltotriose, and 48 samples for both maltose and glucose, respectively. The models were considered as promising in terms of the squared Pearson correlation coefficient (0.89
  • Authors:
    • Gradin, B.
    • Holm, F.
    • Stevenson, F.
    • Leeson, J.
    • Legere, A.
    • Thomas, A.
  • Source: Weed Research
  • Volume: 51
  • Issue: 1
  • Year: 2011
  • Summary: Contrasting approaches to integrated weed management (IWM) for prairie cropping systems were evaluated by measuring weed response to six IWM systems in a wheat-oilseed rape-barley-pea rotation at Saskatoon and Watrous, Saskatchewan, Canada. The six IWM systems (high herbicide/zero tillage; medium herbicide/zero tillage; low herbicide/zero tillage; low herbicide/low tillage; medium herbicide/medium tillage; no herbicide/high tillage) included various combinations of seeding rate and date, herbicide timing and rate, and tillage operations, in order to achieve similar weed management levels. Changes in weed communities were assessed over 4 years by monitoring species composition and abundance at various times during the growth season. Principal response curves indicated a gradual increase in Thlaspi arvense, Chenopodium album, Amaranthus retroflexus and Fallopia convolvulus in the no herbicide/high tillage system. Winter and early spring annuals and perennials increased in most systems, but particularly in the low herbicide/zero tillage and medium herbicide/zero tillage systems. Although five of the six IWM systems provided similar results, changes in weed communities would suggest that operations could be revised to improve the overall management of certain weed species and reduce seed return in the no herbicide/high tillage system and in systems with low herbicide inputs and zero tillage. This study confirms the potential of contrasting IWM systems under the challenging environmental conditions of the Canadian Prairies.
  • Authors:
    • Kocyigit, R.
    • Rice, C. W.
  • Source: BULGARIAN JOURNAL OF AGRICULTURAL SCIENCE
  • Volume: 17
  • Issue: 4
  • Year: 2011
  • Summary: The soil surface CO 2 flux is the second largest flux in the terrestrial carbon budget after photosynthesis. Plant root and microbial respiration produce CO 2 in soils, which are important components of the global C cycle. This study determined the amount of CO 2 released during spring wheat ( Triticum aestivum L.) growth under no-till (NT) and conventional tillage (CT) systems. This experiment was conducted at Kansas State University North Agronomy Farm, Manhattan, KS, on a Kennebec silt loam. This study site was previously under dry land continuous corn production with NT and CT for more than 10 years. Spring wheat ( Triticum aestivum L.) was planted with two tillage systems (NT and CT) as four replicates in March. Surface CO 2 flux was measured weekly during plant growth. Soil water content at the surface (5 cm) tended to be greater in NT and decreased from planting to harvest. Soil microbial activity at the surface was usually higher in NT and decreased from planting to harvest, while activity was constant in the deeper depths. The higher microbial activity at the surface of NT occurred after 60 days of planting where soil water content was the most limiting factor on microbial activity. Soil CO 2 flux varied in response to changes in soil water content and the variation and magnitude of the increase was greater at higher soil water contents. Conventional tillage released 20% more CO 2 to the atmosphere compare to NT after 10 years in the North American Great Plains Regions.
  • Authors:
    • Olson, B. L.
    • Schlegel, A. J.
    • Holman, J. D.
    • Maxwell, S. R.
  • Source: Crop Management
  • Issue: June
  • Year: 2011
  • Summary: A common crop rotation in the west-central Great Plains is no-till winter wheat-corn-fallow. Because most of the corn produced is herbicide-tolerant, volunteer corn in fallow is not controlled with glyphosate. This study evaluated the impact of volunteer corn on soil moisture storage in fallow and the succeeding winter wheat crop across three locations in western Kansas from 2008 to 2010. Volunteer corn reduced available soil water at wheat planting in 8 out of 9 site years. On average, available soil water was reduced by 1 inch for each 2,500 volunteer corn plants per acre. Volunteer corn water use reduced wheat tillers in half of the site years. Similarly, volunteer corn reduced wheat yields in half of the site years, and yields fell 1 bu/acre for every 500 volunteer corn plants per acre. When wheat yields were above 70 bu/acre or below 35 bu/acre, other factors affected wheat yield more than the preceding volunteer corn population or available soil water at wheat planting.
  • Authors:
    • Vanotti, M. B.
    • Matheny, T. A.
    • Stone, K. C.
    • Hunt, P. G.
    • Szogi, A. A.
    • Busscher, W. J.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 22
  • Year: 2011
  • Summary: The wastewater from swine production facilities has been typically managed by treatment in anaerobic lagoons followed by land application. However, there have been considerable advances in superior treatment technologies. Wastewater from one of these technologies was effective for subsurface drip irrigation of bermudagrass. The objectives of this experiment were to assess accumulation of soil nitrogen and carbon along with grain yield, dry-matter accumulation, and plant nitrogen accumulation of soybean [ Glycine max (L) Merr., cv.] and wheat [ Triticum aestivum (L), cv.] when supplementally irrigated with treated swine effluent via subsurface drip irrigation (SDI). The soil series was Autryville loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudults). Its low unsaturated hydraulic conductivity of 0.00170.0023 mm h -1 caused problems with water movement to either the soil surface or laterally to adjoining soybean and wheat roots. This condition contributed to complete crop failure in soybean in 2 years and generally poor yields of wheat. In a good rainfall year, the soybean yield was somewhat satisfactory and benefited from the supplemental irrigation. In that year, nonirrigated and irrigated soybean mean yields were 1.55 versus 1.98 Mg ha -1, respectively. The mean yield of wheat was only 1.06 Mg ha -1, and it was not affected by irrigation. The means for soil nitrogen and carbon in the 0- to 15-cm depth were 414 and 5,679 mg kg -1, respectively, and they were not affected by the water treatments. Thus, neither soil conditions nor soybean/wheat production were greatly enhanced by the SDI system.
  • Authors:
    • Lenssen, A. W.
    • Sainju, U. M.
    • Jabro, J. D.
    • Evans, R. G.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 18
  • Year: 2011
  • Summary: We evaluated the effect of no tillage (NT) and conventional tillage (CT) on soil penetration resistance (PR), bulk density (BD), gravimetric moisture content (MC), and saturated hydraulic conductivity (Ks) during the fallow phase of a spring wheat-fallow rotation. The study was conducted on two soils mapped as Williams loam at the Froid and Sidney sites. Soil measurements were made on 19 May, 23 June, and 4 August 2005 at the Froid site and on 6 June and 8 July 2005 at the Sidney site. Tillage had no effect on either soil properties except on the PR at Sidney. However, soil PR, MC, and BD varied significantly with depth regardless of tillage and location. Further, soil PR and MC varied with the date of sampling at both locations, and PR generally increased with decreased MC at all soil depths. Soil Ks was slightly influenced by tillage at both locations.
  • Authors:
    • Sarauskis, E.
    • Karayel, D.
  • Source: Žemės Ūkio Inžinerija, Mokslo Darbai
  • Volume: 43
  • Issue: 3
  • Year: 2011
  • Summary: Seed placement uniformity and failure to establish a uniform plant stand are critical problems associated with no-tillage production of maize ( Zea mays L.) following wheat ( Triticum aestivum). The objective of this research was to evaluate the effect of different downforces (680, 880, 1150 and 1400 N) on performance of disc furrow openers and determine the optimum downforce for modified precision seeder equipped with single or double disc-type openers. The study was conducted in two different field conditions (field I and field II). The soil of field I and II were clay-loam and loamy, respectively. Seed spacing uniformity, sowing depth uniformity, mean emergence time and percentage of emergence were determined. Sowing depth and seed spacing uniformity, mean emergence time and percentage of emergence of both furrow openers were increased as a result of increasing downforce for both fields. The downforce of modified conventional precision seeder should be greater than 880 N for more precise no-till sowing using with single and double disc furrow openers for clay-loam and loamy soils.
  • Authors:
    • Zhang, F. S.
    • Sun, J. H.
    • Li, L.
  • Source: Soil Science and Plant Nutrition
  • Volume: 57
  • Issue: 1
  • Year: 2011
  • Summary: Intercropping two species at different growth stages is common in temperate and tropical areas. An apparent recovery of growth is observed in late-maturing species after early-maturing species have been harvested, but the mechanism remained unclear. This study tested the hypothesis that the roots of late-maturing species occupy greater below-ground space at later growth stages. The monolith method was employed to investigate the spatial and temporal distribution of maize grown alone (no interspecific interactions), maize intercropped with wheat (asymmetric interspecific facilitation before wheat harvesting), and maize intercropped with faba bean (symmetric interspecific facilitation) on August 8, September 2 and September 30, after harvesting of wheat (July 15) or faba bean (August 2). The results show that maize intercropped with wheat occupied more below-ground space at late growth stages than at early growth stages when the two crops grew at the same time, thus supporting our hypothesis. Furthermore, we also found that interspecific interactions during the co-growth stage of the two species led to a longer root life span in both maize intercropped with wheat and faba bean compared to the maize grown alone. The findings may partly explain the recovery of late-maturing species found in intercropping systems between two crop species with different growth stages and the complementary effect on the relationship between plant biodiversity and productivity.
  • Authors:
    • Trond M. Henriksen, T. M.
    • Anne-Kristin Løes, A.-K.
    • Sjursen, H.
    • Ragnar Eltun, R.
  • Source: Acta Agriculturae Scandinavica, Section B - Soil & Plant Science
  • Volume: 61
  • Issue: 2
  • Year: 2011
  • Summary: By restricted access to manure, nitrogen (N) supply in organic agriculture relies on biological N-fixation. This study compares grain yields after one full-season green manure (FSGM) to yields with repeated use of a green-manure catch crop. At two sites in south-eastern Norway, in a simple 4-year rotation (oats/wheat/oats/wheat), the repeated use of ryegrass, clover, or a mixture of ryegrass and clover as catch crops was compared with an FSGM established as a catch crop in year 1. The FSGM treatments had no subsequent catch crops. In year 5, the final residual effects were measured in barley. The yield levels were about equal for grains with no catch crop and a ryegrass catch crop. On average, the green-manure catch crops increased subsequent cereal yields close to 30%. The FSGM increased subsequent cereal yields significantly in two years, but across the rotation the yields were comparable to those of the treatments without green-manure catch crop. To achieve acceptable yields under Norwegian conditions, more than 25% of the land should be used for full-season green manure, or this method combined with green-manure catch crops. The accumulated amount of N in aboveground biomass in late autumn did not compensate for the N removed by cereal yields. To account for the deficiency, the roots of the green-manure catch crops would have to contain about 60% of the total N (tot-N) required to balance the cereal yields. Such high average values for root N are likely not realistic to achieve. However, measurement of biomass in late autumn may not reflect all N made available to concurrent or subsequent main crops.