• 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:
    • Ralisch, R.
    • Nakashima, P.
    • Gasparetto, N. V. L.
    • Domingos, M. M. M.
    • Tavares Filho, J.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 33
  • Issue: 6
  • Year: 2009
  • Summary: Structural changes caused by management systems to soil can result in compaction and may change crop root development. With the aim to evaluate the effects of the farming systems on the soil structure by qualitative (cultural profile) and quantitative (soil density) methodologies, a field study was carried out in Maringa, state of Parana, Brazil (23degrees29′S, 51degrees59′W). A conventional tillage system with crop succession of corn ( Zea mays L.) and soybean ( Glycine max) and a no-till system with crop rotation of wheat ( Triticum spp.), corn ( Zea mays L.), common bean ( Phaseolus vulgaris), black oats ( Avena strigosa), and soybean ( Glycine max) established for more than 20 years were evaluated. An area under natural forest near the experimental field was evaluated as reference. After the description of the cultural (soil) profile, deformed samples were collected from the homogeneous soil volumes: two samples under forest, two samples in the no-till system and three samples in the conventional system. The physical and morphologic analyses of the soil structures of the layers 0-20 and 20-40 cm showed: (a) the two different tillage system promoted distinct depths of anthropic horizons; (b) the soil structure affected root distribution; (c) soil compaction under conventional system occurred in vertical and horizontal directions (d) soil structure was best under the no-till system; (e) the cultural profile methodology is efficient in soil morphology evaluations.
  • Authors:
    • Swanton, C. J.
    • Tardif, F.
    • Hamill, A. S.
    • Sikkema, P. H.
    • Gulden, R. H.
  • Source: Weed Science
  • Volume: 57
  • Issue: 6
  • Year: 2009
  • Summary: Glyphosate-resistant (GR) crops have been adopted rapidly since their commercial introduction, and with the increase in commercially available crops resistant to glyphosate, continuous use of the same herbicide mode of action is now possible in some crop rotations. A 6-yr study was initiated to investigate the effects of conventional herbicides compared with continuous use of gyphosate in GR or Roundup Ready corn and GR soybean in a corn-soybean and a corn-soybean-winter wheat rotation. Individual experiments were fully phased and established at three locations under conventional tillage (CT) and at two locations under no-tillage (NT). Results indicated that midseason weed ground cover was lower when weeds were controlled with glyphosate; however, in most cases, this did not result in improved corn or soybean yields. Within locations, species richness, which strongly influenced other diversity indicators, was most affected by the herbicide treatments. Including winter wheat in the crop rotation had little effect on corn and soybean weed ground cover, density, and community structure and only affected soybean yield. Moreover, no effects of herbicide system used in previous corn and soybean were observed in winter wheat, with the exception of species diversity in NT, where species diversity tended to be greater when weeds in previous corn and soybean were treated with conventional herbicides. After 6 yr, the effects of continuous use of GR crops in rotation were similar to those reported in previous Studies; however, continued monitoring and longer-term investigations of these systems are necessary to detect the early stages of development of herbicide-resistant biotypes.
  • Authors:
    • Kpomblekou-A, K.
    • Hamido, S. A.
  • Source: Soil & Tillage Research
  • Volume: 105
  • Issue: 2
  • Year: 2009
  • Summary: Increasing numbers of vegetable growers are adopting conservation tillage practices and including cover crops into crop rotations. The practice helps to increase or maintain an adequate level of soil organic matter and improves vegetable yields. The effects of the practices, however, on enzyme activities in southeastern soils of the United States have not been well documented. Thus, the objectives of the study were to investigate the effects of cover crops and two tillage systems on soil enzyme activity profiles following tomato and to establish relationships between enzyme activities and soil organic carbon (C) and nitrogen (N). The cover crops planted late in fall 2005 included black oat (Avena strigosa), crimson clover (Trifolium incarnatum L.), or crimson clover-black oat mixed. A weed control (no cover crop) was also included. Early in spring 2006, the plots were disk plowed and incorporated into soil (conventional tillage) or mowed and left on the soil surface (no-till). Broiler litter as source of N fertilizer was applied at a rate of 4.6 Mg ha(-1), triple super phosphate at 79.0 kg P ha(-1), and potassium chloride at 100 kg K ha(-1) were also applied according to soil testing recommendations. Tomato seedlings were transplanted and grown for 60 days on a Marvyn sandy loam soil (fine-loamy, kaolinitic, thermic Typic Kanhapludults). Ninety-six core soil samples were collected at incremental depths (0-5, 5-10, and 10-15 cm) and passed through a 2-mm sieve and kept moist to study arylamidase (EC 3.4.11.2), L-asparaginase (EC 3.5.1.1), L-glutaminase (EC 3.5.1.2), and urease (EC 3.5.1.5) activities. Tillage systems affected only L-glutaminase activity in soil while cover crops affected activities of all the enzymes studied with the exception of urease. The research clearly demonstrated that in till and no-till systems, L-asparaginase activity is greater (P
  • Authors:
    • Gao, H. W.
    • Liu, L. J.
    • Li, H. W.
    • Wang, Q. J.
    • He, J.
  • Source: Soil & Tillage Research
  • Volume: 104
  • Issue: 1
  • Year: 2009
  • Summary: In the annual double cropping areas of North China Plain, low crop yield and water availability are the main limiting factors to crop production. Conservation tillage has been proposed to improve water conservation and sustain soil productivity. The objectives of the study were to compare conservation tillage (CT) with conventional tillage (CV) under the current double cropping system of corn-winter wheat in the Hebei, North China Plain. The field study consisted of eight conservation tillage treatments and two conventional tillage treatments, with different surface ground cover (0%, 50% and 100%). The tillage treatments consisted of no-till, subsoiling, rototilling and plowing. The CT treatments maintained soil temperatures that were approximately 0.4degreesC greater during cold condition and about 0.5degreesC lower during warm condition at 5 and 10 cm soil depths than the CV treatments, respectively. The greatest differences were achieved by the double no-till system with 100% residue cover treatment in terms of soil temperature and crop growth. Winter wheat yield and water use efficiency (WUE) were improved by 6.7% and 30.1% with CT compared to the CV treatments, and for corn, 8.9% and 6.8%, respectively. We conclude that conservation tillage for the annual double cropping system is feasible, and the double no-till with 100% residue cover is the most effective way of improving crop yields and WUE on the North China Plain.
  • 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:
    • Steinbach, H. S.
    • Alvarez, R.
  • Source: Soil & Tillage Research
  • Volume: 104
  • Issue: 1
  • Year: 2009
  • Summary: The Argentine Pampas is one of the most important cropping regions of the World. Limited tillage systems, and specially no-till, had widespread in recent years, occupying actually around 70% of the surface devoted to annual crops. We review results produced in field experiments installed along the Pampas to determine the effect of the adoption of these tillage systems on some soil properties and crops yield. It was performed a meta-analysis of data from experiments where plow tillage (mouldboard plow), reduced tillage (chisel plow, disk plow or harrow disk) and no-till were compared. Treatments effects were contrasted by paired t-tests between groups of paired data. Soil bulk density and cone penetration resistance of the 0-20 cm layer were higher under limited tillage systems than under plow tillage. Increases of bulk density under no-till in comparison to plow tillage were generally small, averaging 4%, but cone penetration increased by 50% in many soils. The increase of bulk density was greater in soils of initial low bulk density. Neither bulk density increases nor cone penetration changes reached critical threshold for roots development. Aggregate stability and water infiltration rate were higher in soils subjected to limited tillage systems than under plow tillage. The improvement of aggregate stability was higher in poorer structured soils, with an average increase of 70% under no-till in relation to plow tillage. Under no-till infiltration rate doubled in average that of plow tillage. Soil water content during the critical periods of sowing and flowering was generally greater under limited tillage but, conversely, nitrate nitrogen levels were greater in plow tillage. Higher soil water content under no-till in relation to plow tillage may satisfied the evapotranspiration demand of 1-3 days of crops during the critical flowering period, being nitrate nitrogen in average 21 kg ha -1 lower under no-till. Soybean ( Glycine max (L.)-Merr.) yield was not affected by tillage system, meanwhile wheat ( Triticum aestivum L.) and corn ( Zea mays L.) yields were lower under reduced tillage and no-till than under plow tillage without nitrogen fertilization. Wheat and corn no-till yields were 10-14% lower that yields under plow tillage as a mean. When fertilizers were applied, wheat and corn yield differences between tillage treatments generally disappeared. The adoption of limited tillage systems in the Pampas leads to soil improvement but also generates the necessity of increase nitrogen fertilizers utilization to sustain yields of graminaceus crops.
  • Authors:
    • Smith, H. J.
    • Trytsman, G.
    • Bloem, J. F.
  • Source: Biological Nitrogen Fixation: Towards Poverty Alleviation through Sustainable Agriculture
  • Volume: 48
  • Issue: 1-3
  • Year: 2009
  • Summary: Farm lands of resource-poor communities in South Africa are depleted of nutrients due to continuous mono-cropping, limited use of fertilisers, and sometimes leaching caused by high rainfall. Despite the well-known advantages of biological nitrogen fixation (BNF) in cropping systems, less than 10% of the grain crops planted annually in these areas are legumes. Using a participatory research and development approach, resource-poor farmers were introduced to conservation agriculture (CA) practices, including BNF, that promoted zero (or reduced) tillage, increased retention of soil cover, as well as crop diversification. Because crop rotation and intercropping of legumes with cereals are known to contribute to soil fertility while enhancing food security, resource-poor fanners from various Provinces in South Africa were trained on the benefits of legume culture for eight years. As a result, these resource-poor farmers did not only get training in inoculation techniques, but were also supplied with inoculants for use on their farms. Data collected from Farmers Demonstration Trials at Belvedere, Dumbarton and Lusikisiki, showed that the grain and fodder yield of maize planted after legumes, and maize intercropped with legumes, were comparable to those of maize receiving high N fertilizer dose (i.e. 54 kg N at planting and 54 kg N as top-dressing). The same data further showed that Rhizobium inoculation, when combined with application of low levels of P and K. significantly increased crop yields within farmers' trial plots. BNF therefore offers a great opportunity for resource-poor farmers in South Africa to increase their crop yields and thus improve the quality of their livelihoods through the adoption of affordable and sustainable biological technologies that enhance soil fertility.
  • Authors:
    • Jabro, J. D.
    • Sainju, U.
    • Stevens, W. B.
    • Evans, R. G.
  • Source: Journal of Environmental Management
  • Volume: 88
  • Issue: 4
  • Year: 2008
  • Summary: Among greenhouse gases, carbon dioxide (CO 2) is one of the most significant contributors to regional and global warming as well as climatic change. A field study was conducted to (i) determine the effect of soil characteristics resulting from changes in soil management practices on CO 2 flux from the soil surface to the atmosphere in transitional land from perennial forages to annual crops, and (ii) develop empirical relationships that predict CO 2 flux from soil temperature and soil water content. The CO 2 flux, soil temperature ( Ts), volumetric soil water content (theta v) were measured every 1-2 weeks in no-till (NT) and conventional till (CT) malt barley and undisturbed soil grass-alfalfa (UGA) systems in a Lihen sandy loam soil (sandy, mixed, frigid Entic Haplustoll) under irrigated and non-irrigated conditions in western North Dakota. Soil air-filled porosity (epsilon) was calculated from total soil porosity and theta v measurements. Significant differences in CO 2 fluxes between land management practices (irrigation and tillage) were observed on some measurement dates. Higher CO 2 fluxes were detected in CT plots than in NT and UGA treatments immediately after rainfall or irrigation. Soil CO 2 fluxes increased with increasing soil moisture ( R2=0.15, P<0.01) while an exponential relationship was found between CO 2 emission and Ts ( R2=0.59). Using a stepwise regression analysis procedure, a significant multiple regression equation was developed between CO 2 flux and theta v, Ts (CO 2 flux=e -3.477+0.123T s+6.381theta v ; R2=0.68, P≤0.01). Not surprisingly, soil temperature was a driving factor in the equation, which accounted for approximately 59% in variation of CO 2 flux. It was concluded that less intensive tillage, such as no-till or strip tillage, along with careful irrigation management will reduce soil CO 2 evolution from land being converted from perennial forages to annual crops.
  • Authors:
    • Jia, H.
    • Chen, Z.
    • Ma, C.
    • Yang, Q.
    • Liu, Z.
    • Li, G.
  • Source: Nongye Jixie Xuebao = Transactions of the Chinese Society for Agricultural Machinery
  • Volume: 39
  • Issue: 11
  • Year: 2008
  • Summary: This paper describes the tillage technologies for the tillage system of soil water storage and preservation in the area of dry farming of northern China, with surface mulching, reduced-till and no-till as the core technologies, based on combined operations, to achieve the goal of soil water storage and preservation and improving soil fertility. It summarizes six innovative technologies involving the combined stalk and stubble management technology, in which the stalk and stubble of corn can be broken and partially buried in soil at one time; the universal technology for rototilling and stubble breaking, in which the two operations, can be done on the same blade rotor and disc; the strip reduced-till (no-till) precision seeding technology, in which less-tillage (or only furrowing) is needed in the seed bed; the ridging and film-side furrow sowing technology, in which the ridge is covered with the film and seeds are sowed in the furrow; the mechanical bionic resistance reduction technology, which uses the soil working tool designed based on bionics; and the no-till planting and blockage prevention technology, in which no-till planting is conducted in the residue free seed bed. It also shows the composition diagram of the farming system.