• Authors:
    • Marinov-Serafimov, P.
  • Source: Selskostopanska Nauka (Agricultural Science)
  • Volume: 42
  • Issue: 5
  • Year: 2009
  • Summary: During the period 2006-2008 in the experimental field of the Experimental station of soybean - Pavlikeni is displayed field trial in non-irrigated conditions for establishing the efficacy and selectivity of the herbicide Diflufenikan - 500 g/l (Pelican 50 KS) in soybean agrocenosis background in natural mixed type weediness. Results obtained may be generalized in the following more important conclusions: Herbicides Diflufenikan - 500 g/l (Pelican 50SC) has relatively high selectivity (EWRS 2-3 ball) and is suitable for treatment of soybean crops after germination before sowing at a dose of culture 125 ml/ha. Herbicide effectiveness Diflufenikan - 500 g/l (Pelican 50 KS) varies from 73 to 89% on annual dicotyledonous weeds ( S. nigrum; Amaranthus spp.). Less herbicide effect (from 25 to 50%) is established under Ch. album and the least (from 8 to 52%) in the group of weeds annual Monocotyledon ( Setaria spp., Eh. crus-galli). The increase in grain yield of soybean varies from 11.3 to 106.0% compared to the control variant (control - zero) and is in direct relation to the effect achieved in the fight against weeds.
  • Authors:
    • Pérez, R.
    • Ayuso, J. L.
    • Taguas, E. V.
    • Yuan, Y.
    • Peña, A.
  • Source: Earth Surface Processes and Landforms
  • Volume: 34
  • Issue: 5
  • Year: 2009
  • Summary: Despite the high risk of erosion in olive Orchards located in mountainous areas in Spain, little research has been carried out to account for the complexity and interaction of the natural processes of runoff and soil erosion on the catchment scale or small catchment scale. In this Study, a microcatchment of 6.7 ha in a mountainous area under no-tillage farming with hare soil was Set Up to record runoff and sediment. Soil erosion and runoff patterns were monitored Over a two-year period. Totally events were observed. The data were analysed, and then Used to calibrate the, AnnAGNPS model, which allowed Lis to complete the data period and describe the hydrological and erosive behaviour on a monthly and annual basis. A high variability in catchment responses was observed, due to differences in the storms and to the effect of the surface Soil moisture content. Maximum intensities of 10 and 30 min determined the final runoff Values while the total sediment leads were dependent on the rainfall depth. The impact of management on the reduction of porosity can explain the relationship between runoff and intensity in the microcatchment. However, the impact of the spatial scale meant that the transport of sediment required substantial rainfall depths to ensure a Continuous flew front the hillslopes. The results of the calibration (E > 0.60 and r > 0.75) on the event and monthly scale confirmed the applicability of AnnAGNPS to predict runoff and erosion in the microcatchment. The predicted average runoff coefficient was 3.3% for the study period and the total average Sediment loads, 1.3 Mg/ha/yr. Despite these low Values, the model Simulation Showed that much larger runoff coefficients and soil losses can be expected for periods with several consecutive years in which the annual rainfall depth was over 500 mm). The use of cover is recommended to prevent the high levels of erosion associated with these conditions. Copyright (C) 2009 John Wiley & Sons, Ltd,
  • Authors:
    • Miyao, G.
    • Jackson, J.
    • Mitchell, J. P.
    • Horwath, W. R.
    • Doane, T. A.
    • Brittan, K.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 85
  • Issue: 3
  • Year: 2009
  • Summary: In spite of potential benefits and positive assessments of reducing primary tillage operations, only a small part of irrigated row crops is currently managed using reduced tillage, for reasons that include concerns about its agronomic suitability for certain crop rotations. Three years of a tomato/corn rotation under standard and no-tillage management were used to understand the fate of a fertilizer and cover crop nitrogen (N) application. Uptake of both inputs was reduced under no-tillage during the year of application, in this case a tomato crop. As a result, more input N was retained in the soil in this system. The initial challenge of reduced tomato yields diminished as no-tillage management remained in place and the soil N reservoir developed. Corn production was not affected by tillage treatment. Inclusion of a legume cover crop increased the amount of fertilizer N retained in the soil over time, more so under no-tillage than under standard tillage, emphasizing the benefit of cover crops in reducing the amount of fertilizer required to maintain productivity. While acceptance of reduced tillage ultimately depends on economic performance, the results of this study support its agronomic viability for irrigated row crops.
  • Authors:
    • Durán Zuazo, V. H.
    • Rodríguez Pleguezuelo, C. R.
    • Arroyo Panadero, L.
    • Martínez Raya, A.
    • Francia Martínez, J. R.
    • Cárceles Rodríguez, B.
  • Source: Pedosphere
  • Volume: 19
  • Issue: 4
  • Year: 2009
  • Summary: Sloping and mountainous olive production systems are widespread, occupying large parts of the Mediterranean landscape prone to water erosion. Soil erosion, runoff, and soil water content patterns over a three-year period were monitored in erosion plots on a mountainside with rainfed olive (Olea europaea cv. Picual) trees under: 1) non-tillage with barley strips of 4 m width (BS); 2) non-tillage with native vegetation strips of 4 m width (NVS); and 3) non-tillage without plant strips (NT). The erosion plots, located in Lanjaron (Granada, south-eastern Spain), on a 30% slope, were 192 m(2) in area. For assessing soil water dynamics in real-time and near-continuous soil water content measurements, multisensor capacitance probes were installed in the middle of plant strips and beneath the olive tree at five soil depths (10, 20, 30, 50, and 100 cm). The highest erosion and runoff rates were measured under NT, with a mean of 17.3 Mg ha(-1) year(-1) and 140.0 mm year(-1), respectively, over the entire study period. The BS and NVS with respect to the NT reduced erosion by 71% and 59% and runoff by 95% and 94%, respectively. In general, greater available soil water content was found under BS than NVS and NT, especially beneath the olive tree canopies. These results supported the recommendation of non-tillage with barley strips in order to reduce erosion and to preserve soil water for trees in traditional mountainous olive-producing areas, where orchards cover vast tracts of land.
  • Authors:
    • Albayrak, S.
    • Oz, M.
    • Bilgili, U.
    • Wietgrefe, G.
    • Tongel, O.
    • Karasu, A.
    • Sincik, M.
    • Acikgoz, E.
    • Turan, Z. M.
    • Goksoy, A. T.
  • Source: Field Crops Research
  • Volume: 110
  • Issue: 3
  • Year: 2009
  • Summary: Despite several experiments on row spacings and seeding rates of grain soybeans, limited information is available on the most suitable row spacing and seeding rate for tall and robust forage type soybeans grown for seed. The objectives of this study were to investigate seed yield, oil and protein content, and several morphological traits as affected by row spacing (20, 40, 60 and 80 cm) and seeding rate (330,000, 660,000, 990,000 and 1,320,000 seeds ha -1) in tall and robust forage type soybeans in three irrigated Mediterranean environments in Turkey in a randomized split plot design with three replications in 2004 and 2005. Row spacings had no significant effect on plant height but tall and profusely branched plants developed in wide row spacing and light seeding conditions. Seed yield responded positively and linearly to row spacing up to 60 cm and then decreased slightly in all locations. Seed yield was the highest at 990,000 seeds ha -1 seeding rate in all three locations (3072.5 kg ha -1 in Bursa LSD=214.7 kg ha -1, 3295.1 kg ha -1 in Mustafakemalpasa LSD=298.6 kg ha -1 and 3311.3 kg ha -1 in Samsun LSD=321.1 kg ha -1). Averaged across years, locations, row spacings, and seeding rates the mean seed yield was an impressive 3013.4 kg ha -1 compare with 3500.0 kg ha -1 average seed yield of grain types. Crude protein and oil content of forage type soybean were not significantly affected by row spacings and seeding rates. It was concluded that forage type soybeans can be grown for multiple purposes at the 990,000 seeds ha -1 seeding rate and 60 cm row spacings in Mediterranean environments.
  • Authors:
    • de Alba, S.
    • Benito, G.
    • Lacasta, C.
    • Alcázar, M.
    • Alba, S. de
  • Source: Advances in Geoecology or Land degradation and rehabilitation: dryland ecosystems. Papers presented at the Fourth International Conference on Land Degradation, Cartagena, Murcia, Spain, 12-17 September 2004.
  • Volume: 40
  • Year: 2009
  • Summary: In Europe, especially in the Mediterranean area, water erosion seriously affects 50% to 70% of agricultural land. However, there is a lack of field-data on water erosion rates for agricultural areas in semiarid Mediterranean climates. This paper describes an experimental field station (La Higueruela Station) for the continuous monitoring of water erosion that was set up in 1992 in central Spain (Toledo, Castilla-La Mancha). In the study area, the annual precipitation is around 450 mm with a very irregular inter-annual and seasonal distribution, which includes a strong drought in summer. The geology is characterized by non-consolidated Miocene materials, mostly arcosics. The area presents a low relief and gentle slopes, generally
  • Authors:
    • Paspatis, E.
    • Travlos, I.
    • Psomadeli, E.
  • Source: Journal of Agronomy
  • Volume: 7
  • Issue: 2
  • Year: 2008
  • Summary: Laboratory and greenhouse pot experiments were conducted to evaluate the potential usefulness of Oxalis pes-caprae L. as allelopathic ground-cover species for integrated weed management. The effects of the extracts of several tissues and the exudates from living roots of O. pes-caprae plants were tested for their allelopathic activity on several plants. Duckweed fresh weight was significantly inhibited from phytotoxic activity of petiole tissues (and secondly leaves and stems) of O. pes-caprae. For all the kinds of tissues duckweed fresh weight was reduced with increasing extract concentrations. Besides, root exudates of Bermuda buttercup caused 62, 58 and 42% inhibition of the dry biomass production of tomato, oat and lettuce plants, respectively, confirming the remarkable allelopathic activity of this weed.
  • Authors:
    • Carter,D.
    • L.,Barton
    • Biswas,W. K.
  • Source: Water and Environment Journal
  • Volume: 22
  • Issue: 3
  • Year: 2008
  • Authors:
    • Barton, L.
    • Kiese, R.
    • Gatter, D.
    • Butterbach-Bahl, K.
    • Buck, R.
    • Hinz, C.
    • Murphy, D. V.
  • Source: Global Change Biology
  • Volume: 14
  • Issue: 1
  • Year: 2008
  • Summary: Understanding nitrous oxide (N2O) emissions from agricultural soils in semi-arid regions is required to better understand global terrestrial N2O losses. Nitrous oxide emissions were measured from a rain-fed, cropped soil in a semi-arid region of south-western Australia for one year on a sub-daily basis. The site included N-fertilized (100 kg N ha−1 yr−1) and nonfertilized plots. Emissions were measured using soil chambers connected to a fully automated system that measured N2O using gas chromatography. Daily N2O emissions were low (−1.8 to 7.3 g N2O-N ha−1 day−1) and culminated in an annual loss of 0.11 kg N2O-N ha−1 from N-fertilized soil and 0.09 kg N2O-N ha−1 from nonfertilized soil. Over half (55%) the annual N2O emission occurred from both N treatments when the soil was fallow, following a series of summer rainfall events. At this time of the year, conditions were conducive for soil microbial N2O production: elevated soil water content, available N, soil temperatures generally >25 °C and no active plant growth. The proportion of N fertilizer emitted as N2O in 1 year, after correction for the ‘background’ emission (no N fertilizer applied), was 0.02%. The emission factor reported in this study was 60 times lower than the IPCC default value for the application of synthetic fertilizers to land (1.25%), suggesting that the default may not be suitable for cropped soils in semi-arid regions. Applying N fertilizer did not significantly increase the annual N2O emission, demonstrating that a proportion of N2O emitted from agricultural soils may not be directly derived from the application of N fertilizer. ‘Background’ emissions, resulting from other agricultural practices, need to be accounted for if we are to fully assess the impact of agriculture in semi-arid regions on global terrestrial N2O emissions.
  • Authors:
    • Smith, R. F.
    • Koike, S. T.
    • Yokota, R.
    • Murphree, L.
    • Jackson, L. E.
    • Smukler, S. M.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 126
  • Issue: 3-4
  • Year: 2008
  • Summary: Studying the management strategies suited to large-scale organic production, particularly during the mandated 3-year transition period from conventional management, is a unique research challenge. Organic production traditionally relies on small, diverse plantings and complex management responses to cope with soil fertility and pest pressures, so research should represent decision-making options of an organic grower at the farm scale. This study analyzes crop, soil, pest and management changes during the organic transition period on two ranches (40 and 47 ha) in the Salinas Valley, California in cooperation with a large conventional vegetable producer, Tanimura and Antle, Inc. Permanent transects were established across the two ranches at the onset of adoption of organic practices, and soil and plants were sampled at harvest of almost all crops, while all management operations were recorded by the co-operator. The similar to 10 ha blocks were divided into many small plantings, and 17 different cash crop and cover crop species were planted during the transition period. Management inputs consisted of a range of organic fertilizers and amendments, sprinkler and drip irrigation, cultivation and hand-hoeing, and several types of organic pesticides. Results from the 3-year period followed these general trends: increase in soil biological indicators (microbial biomass and arbuscular mycorrhizae), low soil nitrate pools, adequate crop nutrients, minor disease and weed problems, and sporadic mild insect damage. Multivariate statistical analyses indicated that some crops and cultivars consistently produced higher yields than others, relative to the maximum yield for a given crop. Multi-factor contingency tables showed clear differences in insect and disease damage between crop taxa. Although Tanimura and Antle, Inc. used some of the principles of organic farming (e.g., crop diversity, crop rotation, and organic matter (OM) management), they also relied on substitution-based management, such as fertigation with soluble nutrients, initially heavy applications of organic pesticides, and use of inputs derived from off-farm sources. Their initial production of a large number of crop taxa in small plantings at staggered intervals proved to be an effective strategy for avoiding risks from low yields or crop failure and allowed them to move towards a smaller number of select, successful crops towards the end of the transition. This study demonstrates the feasibility of large-scale producers to transition to organic practices in a manner that was conducive to both production goals and environmental quality, i.e., increased soil C pools, low soil nitrate, and absence of synthetic pesticides. (C) 2008 Elsevier B.V. All rights reserved.