• Authors:
    • Pozo, A. del
    • Martinez G.,I.
    • Prat, C.
    • Uribe, H.
    • Valderrama V., N.
    • Zagal, E.
    • Sandoval, M.
    • Fernandez, F.
    • Ovalle, C.
  • Source: Chilean Journal of Agricultural Research
  • Volume: 71
  • Issue: 4
  • Year: 2011
  • Summary: Chilean dryland areas of the Mediterranean climate region are characterized by highly degraded and compacted soils, which require the use of conservation tillage systems to mitigate water erosion as well as to improve soil water storage. An oat ( Avena sativa L. cv. Supernova-INIA) - wheat ( Triticum aestivum L. cv. Pandora-INIA) crop rotation was established under the following conservation systems: no tillage (Nt), Nt+contour plowing (Nt+Cp), Nt+barrier hedge (Nt+Bh), and Nt+subsoiling (Nt+Sb), compared to conventional tillage (Ct) to evaluate their influence on soil water content (SWC) in the profile (10 to 110 cm depth), the soil compaction and their interaction with the crop yield. Experimental plots were established in 2007 and lasted 3 yr till 2009 in a compacted Alfisol. At the end of the growing seasons, SWC was reduced by 44 to 51% in conservation tillage systems and 60% in Ct. Soil water content had a significant (p<0.05) interaction with tillage system and depth; Nt+Sb showed lower SWC between 10 to 30 cm, but higher and similar to the rest between 50 to 110 cm except for Ct. Although, SWC was higher in conservation tillage systems, the high values on soil compaction affected yield. No tillage+subsoiling reduced soil compaction and had a significant increment of grain yield (similar to Ct in seasons 2008 and 2009). These findings show us that the choice of conservation tillage in compacted soils of the Mediterranean region needs to improve soil structure to obtain higher yields and increment SWC.
  • Authors:
    • Melero, S.
    • Panettieri, M.
    • Madejon, E.
    • Gomez Macpherson, H.
    • Moreno, F.
    • Murillo, J. M.
  • Source: Soil & Tillage Research
  • Volume: 112
  • Issue: 2
  • Year: 2011
  • Summary: Long-term no-till practices (NT) have a positive effect on recovery and improving soil fertility and decreasing soil erosion. Nevertheless, long term no-till practices may also cause some inconveniences, such as soil compaction, water infiltration and problems in seed germination. Thus, in the present work we assess the effects of the implementation (October 2008) of a traditional tillage (mouldboard ploughing) (TT) and reduced tillage (chiselling) (RT) on soil quality in a dryland calcareous soil (Leptic Typic Xerorthent) after 8 years of soil no-till management (NT) in SW Spain. The results were compared to those found under no-till. We hypothesised that C fractions and biological properties would be adequate indicators of soil quality changes. To test the hypothesis soil samples were collected at three depths (0-5, 5-10 and 10-25 cm) and in three sampling periods, after tillage and sowing (January 2009) after harvesting (June 2009) a vetch crop ( Vicia sativa, L) and after tillage and sowing (January 2010) of a wheat crop ( Triticum aestivum, L). Total organic carbon (TOC) and carbon labile fractions (active carbon (AC) and water soluble carbon (WSC)) were determined. Biological status was evaluated by the analysis of soil microbial biomass carbon and nitrogen (MBC and MBN) and enzymatic activities [dehydrogenase activity (DHA), and beta-glucosidase activity (Glu)]. The implementation of chiselling did not cause depletion in most of the studied soil properties compared to no-till in the first 5 cm of soil. However, the application of traditional tillage reduced 23% of TOC, 27% of WSC, 12% of AC, 19% of MBC, 44% of MBN, 37% of DHA and 51% of Glu in the upper layer of the soil (0-5 cm depth) with respect to no-till. Soil organic carbon and microbial parameter values decreased as depth increased, particularly in conservation tillage systems (RT and NT) in all sampling periods. Under our conditions, dryland Mediterranean areas, the mouldboard ploughing is not considered a suitable soil tillage system since it showed an early negative effect on soil organic fractions and biochemical quality. Although further studies would be necessary, the use of chiselling could be a solution in case of problems related to no-till.
  • Authors:
    • Valboa, G.
    • Favilli, F.
    • L'Abate, G.
    • Papini, R.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 140
  • Issue: 1-2
  • Year: 2011
  • Summary: Land use strongly influences soil properties and unsuitable practices lead to degradation of soil and environmental quality. The aim of this study was to assess the impact of different land uses on some chemical properties of soils developed from Pliocene clays, within hilly environments of central and southern Italy. The areas investigated are located in Vicarello di Volterra (Pisa, Tuscany), S. Quirico d'Orcia (Siena, Tuscany) and Soveria Simeri (Catanzaro, Calabria). Within each area different land uses were compared, including a natural ecosystem (Mediterranean bush), a perennial grass or pasture and an intensive crop (wheat, as monoculture or in rotation). The soils were sampled at 0.0-0.1, 0.1-0.2 and 0.2-0.4 m depth and analysed for particle size, pH, bulk density, cation exchange capacity and exchangeable cations, total organic carbon (TOC) and humified carbon (HC) concentrations, organic carbon stock and total N. The stratification ratio of soil organic carbon was calculated to characterize soil organic carbon distribution with depth. At all sites, soil under Mediterranean bush contained the largest amounts of TOC (as both concentration and stock), HC, total N and exchangeable K, together with the highest cation exchange capacity and the lowest pH values. The decrease in soil OC stock with land use change from natural to agricultural ecosystem was 65-85% to 0.1 m depth, 55-82% to 0.2 m depth and 44-76% to 0.4 m depth, with the lowest decrements for perennial grass from S. Quirico and the highest decrement for continuous wheat from Soveria Simeri. Continuous wheat cropping, based on conventional tillage, proved to be the least sustainable land use. At Soveria Simeri, the organic carbon content under pasture was not significantly larger than under wheat cultivation, probably because of grazing mismanagement; however, organic carbon under pasture was more humified. At S. Quirico, the perennial grass resulted in a significant increase in soil organic carbon at the soil surface relative to the wheat cultivation, while at Vicarello no differences were observed between alfalfa/wheat rotation and perennial grass. Our results lead to the questioning of sustainability of intensive cereal farming and uncontrolled grazing in the considered environments, emphasizing the need for greater attention to conservative land managements.
  • Authors:
    • Ryan, J.
    • Kapur, S.
    • Ibrikci, H.
    • Singh, M.
  • Source: Journal of Sustainable Agriculture
  • Volume: 35
  • Issue: 6
  • Year: 2011
  • Summary: As most of the organic carbon (C) in the biosphere resides in the soil in the form of soil organic matter (SOM), tillage practices can potentially increase C losses to the atmosphere as carbon dioxide, thus contributing to greenhouse gases that exacerbate climate change. In the past century, conventional tillage, involving plowing and secondary cultivation, has unwittingly decreased C stocks in arable soils in North America, Europe, and Australia. The information on the effects of tillage on soil C and related properties in the Mediterranean region is scant, with evidence of resilience being even rarer. While long-term trials that directly measure tillage effects are rare in the Mediterranean, the alternative is a retrospective based on soil management history. In this study of a Vertisol in southern Turkey, we sampled sections of a field that had been intensively cultivated for about 20 years and 40 years, as well as a section left undisturbed in native vegetation for 14 years following years of conventional tillage. The SOM and total nitrogen (N) values were inversely related to cultivation intensity or duration, while the highest values were from the uncultivated site. Labile biomass C and N values followed the same trends with cultivation, whereas available P increased with cultivation time; in contrast, the percentage of water-stable aggregates decreased with cultivation duration. The study showed that such clay soils show a high degree of resilience and can recover in a relatively short time period if left uncultivated or in fallow. While preservation or set aside of arable crop land is not a viable option for farmers, reducing tillage intensity is feasible. The study suggests that minimum tillage or no-till could promote resilience and mitigate the adverse soil effects of conventional tillage that have already occurred.
  • Authors:
    • Uzun, B.
    • Furat, S.
    • Canakci, M.
    • Karayel, D.
    • Topakci, M.
  • Source: Applied Engineering In Agriculture
  • Volume: 27
  • Issue: 2
  • Year: 2011
  • Summary: The purpose of this research was to examine the performance of a modified vacuum seeder for hill drop sowing of sesame ( Sesamum indicum L.) following wheat ( Triticum aestivum) for no-till and reduced tillage farming. Tests were conducted during the growing seasons of 2008 and 2009 in the Bati Akdeniz Agricultural Research Institute's fields in Antalya, Turkey. A fluted coulter and double disc-type furrow opener were mounted on each unit of a common vacuum seeder. A seed plate modified to achieve hill-dropping of seeds was used in the metering mechanism of the seeder. Mean plant number per hill, coefficient of variation of plant number per hill, mean hill distance, coefficient of variation of hill distance, scattering distance ratio along the length of the row, sowing depth uniformity, and percent emergence of seeds and of hills were determined. Uniformity of hill spacing obtained from no-till plots was lower than from reduced and conventional tillage plots. Treatment effects were compared for three sesame seed varieties. No-till decreased the percent emergence of both seeds and hills for all varieties. The ranges of scattering distance ration and the coefficient of variation of hill distance were within the acceptable range of variability for all the tillage systems. In order to improve the emergence of individual seeds as well as of hills for no-till sowing of sesame, a more uniform sowing depth is needed. The conventional metering system of the seeder was sufficient for hill dropping of sesame seeds, but the performance of the soil engaging parts of the seeder was not satisfactory for no-till sowing. The negative effect of a high variation in sowing depth on percent emergence of seeds was obvious for no-till conditions. The general performance of the modified vacuum seeder was satisfactory for the reduced tillage system studied.
  • Authors:
    • Sirrine, J. R.
    • Simonson, P.
    • Hoagland, L. A.
    • Darby, H.
    • Benedict, C. A.
    • Turner, S. F.
    • Murphy, K. M.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 6
  • Year: 2011
  • Summary: Hop cones grown on the female plant of the perennial crop ( Humulus lupulus L.) are an integral component of the brewing process and provide flavor, bitterness, aroma, and antimicrobial properties to beer. Demand for organically grown hops from consumers via the brewing industry is on the rise; however, due to high N requirements and severe disease, weed, and arthropod pressures, hops are an extremely difficult crop to grow organically. Currently, the majority of the world's organic hops are grown in New Zealand, while other countries, including China, are beginning to increase organic hop production. Land under organic hop production in Washington State, where 75% of the hops in the United States are grown, increased from 1.6 ha to more than 26 ha from 2004 to 2010, and other hop-producing states demonstrate a similar trend. Removing hops from the USDA Organic Exemption list in January 2013 is expected to greatly increase organic hop demand and will require corresponding increases in organic hop hectarage. Current challenges, including weed management, fertility and irrigation management, insect and disease pressures, and novel practices that address these issues will be presented. Here, we discuss current and future research that will potentially impact organic hop production in the United States.
  • Authors:
    • Torres, M. O.
    • Varennes, A. de
  • Source: Soil Use and Management
  • Volume: 27
  • Issue: 1
  • Year: 2011
  • Summary: Soil changes induced by crop rotations and soil management need to be quantified to clarify their impact on yield and soil quality. The objective of this study was to investigate the effect of continuous oat ( Avena sativa L.) and a lupin ( Lupinus albus L.)-oat rotation with and without tillage on soil enzymes, crop biomass and other soil properties In year 1, oat and lupin were grown in undisturbed plots or in plots subjected to disc tillage. Crop residues were incorporated before oat was sown in year 2 in the disc-tilled plots or remained on the soil surface of untilled plots. Soil samples were collected regularly and analysed for pH, organic C, Kjeldahl-N, mineral N, extractable P, and the enzyme activities of beta-glucosidase, cellulases, acid phosphatase, proteases, urease, and culturable bacteria and fungi. The main crop and tillage effects on soil parameters were: beta-glucosidase activity was greater after lupin than after oat, and the opposite was true for the number of culturable fungi. Organic carbon, phosphatase, cellulase and protease were greater in tilled soil than in the absence of tillage. Associations between variables that were stable over the 2 yr were those for mineral N and urease activity, cellulase activity and pH, and that of phosphatase activity and organic C. Our results contrast with most of the previous information on the effect of tillage on soil enzymes, where the activities were reported to be unchanged or decreased following tillage. This difference may be related to the small organic C content of the soil and to the fact that it was under fallow prior to the start of the experiment. In consequence, incorporation of residues would provide new sources of labile organic C for soil microbes, and result in increased enzymatic activity. The results obtained suggest that in coarse-textured soils poor in organic matter, tillage with residue conservation after a period of fallow rapidly improves several soil characteristics and should be carried out even if it were to be followed by a no-till system in the following years. This should be taken into consideration by land managers and technical advisers.
  • Authors:
    • Corp, M.
    • Wuest, S.
  • Source: Crop Management
  • Issue: December
  • Year: 2011
  • Summary: Millions of acres of cropland with as low as 6 inches annual precipitation are used for production of winter wheat ( Triticum aestivum L.) in the Pacific Northwest of the USA. Despite soil conservation advances, soil erosion continues to be a problem. This on-farm study analyzed seed-zone soil water under farmer-implemented fallow tillage practices to find out if very low-disturbance systems are possible. A low-disturbance, wide-blade undercutter sweep treatment was similar or superior to the farmer's more intensive conventional tillage system. A subsequent test at four paired no-till-conventionally-tilled summer-fallow sites demonstrated that a single pass of an undercutter sweep in the no-till field could preserve seed-zone moisture comparable to the more intensive multiple-pass conventional tillage. Despite conventional wisdom, summer-fallow soil mulches do not need to be finely pulverized or repeatedly tilled to be effective.
  • Authors:
    • Brennan, E. B.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 5
  • Year: 2011
  • Summary: Winter cover crops can add soil organic matter, improve nutrient cycling, and suppress weeds in organic vegetable systems. A 2-yr study was conducted on organic farms in Salinas and Hollister, CA, to evaluate the effect of seeding rate (SR) and planting arrangement on cover crop density, ground cover, and cover crop and weed dry matter (DM) with a mixed cover crop. The mix contained legumes (35% Vicia faba L., bell bean; 15% Vicia dasycarpa Ten., woolypod vetch; 15% Vicia benghalensis L., purple vetch; and 25% Pisum sativum L., pea) and 10% oat (Avena sativa L.) by seed weight. Three SRs (112, 224, and 336 kg ha(-1)) and two planting arrangements (one-way versus grid pattern) were evaluated. Planting arrangement had no effect on the variables measured. When weeds were abundant, weed DM declined linearly with increasing SR from approximately 300 kg ha(-1) at the low SR to <100 kg ha(-1) at the high SR. Increasing SR increased oat and legume DM early in the season, but did not affect final cover crop DM that ranged from 7 to 12 Mg ha(-1). Year affected final cover crop DM production at both sites. The legume DM portion of the total cover crop declined through the season but varied between sites and year, probably due to soil and climatic differences. Higher SRs may be cost effective because weed control is expensive and cover crop seed is a relatively small component of cover cropping costs in this region.
  • Authors:
    • Radicetti, E.
    • Mancinelli, R.
    • Campiglia, E.
    • Marinari, S.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 89
  • Issue: 3
  • Year: 2011
  • Summary: There is not sufficient knowledge concerning the risks involved in NO 3-N leaching in relation to the use of cover crops and mulches. A 2 year field experiment was carried out in a pepper ( Capsicum annuum L.) crop transplanted into different soil management treatments which involved the addition of mulch of three different types of winter cover crops (CC) [hairy vetch ( Vicia villosa Roth.), subclover ( Trifolium subterraneum L.), and a mixture of hairy vetch/oat ( Avena sativa L.)], and an un-mulched plot. At the time of CC conversion into mulch, the hairy vetch/oat mixture accumulated the highest aboveground biomass (5.30 t ha -1 of DM), while hairy vetch in pure stand accumulated the highest quantity of N (177 kg ha -1) and showed the lowest C/N ratio (12). The marketable pepper yield was higher in mulched than in conventional (on average 33.5, 28.9, 27.7 and 22.2 t ha -1 of FM for hairy vetch, subclover, hairy vetch/oat mixture, and conventional, respectively). Generally, the NO 3-N content of the soil was minimum at CC sowing, slightly higher at pepper transplanting and maximum at pepper harvesting (on average 15.2, 16.8, and 23.3 mg NO 3-N kg -1 of dry soil, respectively). The cumulative leachate was higher during the CC period (from October to April) than the pepper crop period (from April to September), on average 102.1 vs 66.1 mm over the years, respectively. The cumulative NO 3-N leached greatly depended on the type of mulch and it was 102.3, 95.3, 94.7, and 48.2 kg ha -1 in hairy vetch, subclover, hairy vetch/oat mixture, and conventional, respectively. A positive linear correlation was found between the N accumulated in the CC aboveground biomass and the NO 3-N leached during pepper cultivation ( R2=0.87). This research shows that winter legume cover crops, especially hairy vetch in pure stand, converted into dead mulch in spring could be used successfully for adding N to the soil and increasing the yield of the following pepper crop although the risks of N losses via leaching could be increased compared to an un-mulched soil. Therefore when leguminous mulches are used in the cultivation of a summer crop, appropriate management practices of the system, such as a better control of the amount of irrigation water and the cultivation of a graminaceous or a cruciferous catch crop after the harvesting of the summer crop, should be adopted in order to avoid an increase in NO 3-N leaching.