• Authors:
    • Negrila, E.
    • Negrila, M.
  • Source: Probleme de Agrofitotehnie Teoretica si Aplicata
  • Volume: 27
  • Issue: 2
  • Year: 2005
  • Summary: Mineral fertilizer application on crops is one of the reliable ways of increasing soil productivity, improving the yield, quality and soil fertility. The nitrogen and phosphorus long-term fertilizer application in the cambic chernozem, under non-irrigated condition at the A.R.D.S. Teleorman, Romania, caused plants and soil modifications. The annual nitrogen and phosphorus (NP) fertilizer application (in 28 years) with moderate amounts and balanced ratios resulted in a yield increase of 12-17 kg wheat/1 kg NP, 7-11 kg maize/1 kg NP, 4-6 kg sunflower/1 kg NP, the smallest increase was during the drought years. The use of coefficient depends on crop and climatic evolution. The best nitrogen and phosphorus use efficiency was with wheat, followed by maize and sunflower. During the drought years, both elements use was reduced to half. It also had a positive influence on the crude protein content (4.08% for winter wheat and 3.76% for maize), on the other quality indices: technological flour indices, macro- and microelements. The P:Zn ratio of 57-100 also indicated a good ratio between the two elements which does not lead to occurrence of Zn deficiency. The values of N:S indicated some disorders in sulfur metabolism which can generate sulfur deficiency, especially in maize. The long-term fertilizer application (1977-2000) determined the improvement in soil fertility: maintenance of the humus content, the improvement of the mobile phosphorus content, of the saturation degree in alkali up to 83% and the reaction up to 5.9 pH, without mobile aluminium and Mn coming out. The absence of nitrogen and phosphorus fertilizers during 24 years led to soil fertility, yield and yield quality reduction.
  • Authors:
    • Sullivan, D. G.
    • Balkcom, K. S.
    • Lamb, M. C.
    • Rowland, D. L.
    • Faircloth, W. H.
    • Nuti, R. C.
  • Source: Proceedings of the 27th Southern Conservation Tillage Systems Conference, Florence, South Carolina, USA, 27-29 June, 2005
  • Year: 2005
  • Summary: The interaction between reduced irrigation capacity and tillage, including the possible conservation of water with reduced tillage systems, is of vital interest to growers. A field study was initiated in the fall of 2001 to determine crop response under a simulated reduction in irrigation. Three tillage systems were replicated three times each under one of four irrigation levels (100% of a recommended amount, 66%, 33%, and 0% or dryland). Tillage systems were conventional tillage, wide-strip tillage and narrow-strip tillage. The test area was planted in triplicate, in a peanut-cotton-corn rotation, with each crop being present each year. A wheat (cv. AGS 1000) cover crop was drill-seeded each fall on conservation tillage plots. Cover crop termination was performed approximately three weeks prior to planting of each crop species. Tillage was significant for peanut yield and net return at the 0% irrigation level only. No trend in yield was evident, however, net return was consistently high with narrow-strip tillage in all years. Irrigation, at any level greater than 0%, masked tillage effects in both yield and net return. These data confirm the suitability of peanut to conservation tillage practices, including both wide- and narrow-strip tillage.
  • Authors:
    • Trein, C.
    • Herzog, R.
    • Levien, R.
  • Source: Engenharia Agricola
  • Volume: 24
  • Issue: 3
  • Year: 2004
  • Summary: To evaluate soyabean productivity on natural pasture fields, grown once with oats to produce grain and straw for soil cover, an experiment was conducted on a Typic Paleudult Soil in Eldorado do Sul, Rio Grande do Sul, Brazil. After mechanically harvesting oats, the straw was returned to plots in amounts of 0, 2, 3, 4, 5 and 6 mg/ha and were divided according to the furrow opening depth (0.06 and 0.12 m). The area was divided in 2, with and without irrigation. The volume of soil mobilized by the fertilizer furrow openers was 53% higher when the working depth reached 0.12 m compared to 0.06 m, but no difference due to the amount of cover crop residues was attained. Grain yield, crop biomass and root mass up to 0.15 cm depth did not differ with both soil working depth and crop residue cover. Irrigation increased grain yield and total biomass of soyabeans. Even without irrigation, soyabean productivity was higher than the Rio Grande do Sul State average, showing its suitability to be grown on native pastures under the no-till system.
  • Authors:
    • Rogers, G. S.
    • Little, S. A.
    • Silcock, S. J.
    • Williams, L. F.
  • Source: Acta Horticulturae
  • Issue: 638
  • Year: 2004
  • Summary: A no-till system using permanent beds, permanent subsurface irrigation and organic mulches grown in situ was implemented as an alternative to conventional production in an experiment conducted in North Queensland, Australia. The system used a tropical legume, Centrosema pubescens 'Cavalcade', or the C 4 grasses Bothriochloa pertusa 'Keppel' or 'Hatch' as cover crops over summer and autumn. Cover crops were killed using glyphosate (1440 g a.i./ha) and residues were left on the soil surface. Vegetable seedlings were then planted through the mulch residues and grown using conventional agronomic techniques. Following harvest, crop residues were macerated and the following cover crop direct sown through the mulch residues. Soil from conventional production areas using polyethylene mulch had significantly lower aggregate stability than all other treatments. Soil aggregates taken from beneath cover crop mulches were more stable than aggregates under polyethylene mulch after one year under the no-till regime. Soil aggregates after three years of treatment showed similar statistical differences between the treatments. Bulk density in permanent beds under C. pubescens mulch was significantly lower than uncultivated bare soil and frequently cultivated polyethylene mulch. Soil under frequent cultivation was significantly more compacted than uncultivated bare soil. There were significantly more earthworms under C. pubescens and B. pertusa mulch than in uncultivated bare topsoil or under polyethylene mulch. No earthworms were found in any sample under polyethylene mulch. The yields of tomatoes after 5 harvests were not significantly different for conventional and no-till production.
  • Authors:
    • Kelly, K.
    • Edis, R. B.
    • Li, Y.
    • Chen, D.
    • Turner, D.
  • Source: SuperSoil: 3rd Australian New Zealand Soils Conference
  • Year: 2004
  • Authors:
    • Gibson, S. G.
    • Yarboro, W.
    • Hamrick, M.
    • Thompson, S.
    • King, R.
  • Source: Proceedings of the 26th Southern Conservation Tillage Conference for Sustainable Agriculture
  • Year: 2004
  • Summary: In addition to regular programming, County Agricultural Extension agents are asked many times to respond to questions, suggestions and concerns by their farmer clientele. In North Carolina as in other states an advisory leadership system is in place and farmers can formally and informally make suggestions and requests for on-farm demonstrational work. In many cases what the farmers are observing in their fields and/or things they have read "spark" the interactions with agents. Such has been the case in Cleveland County, NC. For example in the early continuous no-till era many area farmers were concerned about soil compaction. Measurements and simple demonstrations conducted by the Cleveland and Lincoln County agents and supported by the NCSU Soil Science Department and Cleveland County Government helped alleviate these concerns. Later as fields were in continuous no-till for 5 or more years, farmers began to notice a greater than expected development of their crops prior to major applications of fertilizer nitrogen. These observations led to a replicated test in wheat conducted by the Cleveland County Agricultural Extension agent comparing a field in a 2 year no-till wheat soybean rotation verses a nearby field in a 5 year continuous no-till wheat soybean rotation. Also a 6 year replicated test was initiated on Cleveland County owned land that had been in continuous no-till for 10 years. The test was set up as a continuous soybean corn rotation and in addition to the standard dryland portion, irrigation was used in part of the study to simulate a "good" corn year. Five nitrogen rates were used. The economics of the cost of fertilizer nitrogen was used to demonstrate that the Realistic Yield Expectation (RYE) method for determining nitrogen rates was very much applicable in continuous no-till. Both the wheat and corn tests indicated that residual soil nitrogen was indeed becoming a major factor in continuous no-till for these field crops and when farmers considered the realities of the weather very likely nitrogen rates can be reduced with confidence.
  • Authors:
    • Lal, R.
  • Source: Science
  • Volume: 304
  • Issue: 5677
  • Year: 2004
  • Summary: The carbon sink capacity of the world's agricultural and degraded soils is 50 to 66% of the historic carbon loss of 42 to 78 gigatons of carbon. The rate of soil organic carbon sequestration with adoption of recommended technologies depends on soil texture and structure, rainfall, temperature, farming system, and soil management. Strategies to increase the soil carbon pool include soil restoration and woodland regeneration, no-till farming, cover crops, nutrient management, manuring and sludge application, improved grazing, water conservation and harvesting, efficient irrigation, agroforestry practices, and growing energy crops on spare lands. An increase of 1 ton of soil carbon pool of degraded cropland soils may increase crop yield by 20 to 40 kilograms per hectare (kg/ha) for wheat, 10 to 20 kg/ha for maize, and 0.5 to 1 kg/ha for cowpeas. As well as enhancing food security, carbon sequestration has the potential to offset fossil fuel emissions by 0.4 to 1.2 gigatons of carbon per year, or 5 to 15% of the global fossil-fuel emissions.
  • Authors:
    • Lal, R.
  • Source: Environment International
  • Volume: 30
  • Issue: 7
  • Year: 2004
  • Summary: This manuscript is a synthesis of the available information on energy use in farm operations, and its conversion into carbon equivalent (CE). A principal advantage of expressing energy use in terms of carbon (C) emission as kg CE lies in its direct relation to the rate of enrichment of atmospheric concentration of CO2. Synthesis of the data shows that estimates of emissions in kg CE/ha are 2-20 for different tillage operations, 1-1.4 for spraying chemicals, 2-4 for drilling or seeding and 6-12 for combine harvesting. Similarly, estimates of C emissions in kg CE/kg for different fertilizer nutrients are 0.9-1.8 for N, 0.1-0.3 for P2O5, 0.1-0.2 for K20 and 0.03-0.23 for lime. Estimates of C emission in kg CE/kg of active ingredient (a.i.) of different pesticides are 6.3 for herbicides, 5.1 for insecticides and 3.9 for fungicides. Irrigation, lifting water from deep wells and using sprinkling systems, emits 129±98 kg CE for applying 25 cm of water and 258±195 for 50 cm of water. Emission for different tillage methods are 35.3 kg CE/ha for conventional till, 7.9 kg CE/ha for chisel till or minimum till, and 5.8 kg CE/ha for no-till method of seedbed preparation. In view of the high C costs of major inputs, sustainable management of agricultural ecosystems implies that an output/input ratio, expressed either as gross or net output of C, must be >1 and has an increasing trend over time.
  • Authors:
    • Mosier, A. R.
    • Burke, I. C.
    • Kaye, J. P.
    • Guerschman, J. P.
  • Source: Ecological Applications
  • Volume: 14
  • Issue: 4
  • Year: 2004
  • Summary: Land-use change is an important driver of soil-atmosphere gas exchange, but current greenhouse-gas budgets lack data from urban lands. Field comparisons of urban and non-urban ecosystems are required to predict the consequences of global urban-land expansion for greenhouse-gas budgets. In a rapidly urbanizing region of the U.S. Great Plains, we measured soil-atmosphere exchange of methane (CH 4) and nitrous oxide (N 2O) for one year in replicated ( n=3) urban lawn, native shortgrass steppe, dryland wheat-fallow, and flood-irrigated corn ecosystems. All soils were net sinks for atmospheric CH 4, but uptake by urban, corn, and wheat-fallow soils was half that of native grasslands (-0.300.04 g C.m -2.yr -1 [mean1 Se]). Urban (0.240.03 g N.m -2.yr -1) and corn (0.200.02 g N.m -2.yr -1) soils emitted 10 times more N 2O to the atmosphere than native grassland and wheat-fallow soils. Using remotely sensed land-cover data we calculated an upper bound for the contribution of lawns to regional soil-atmosphere gas fluxes. Urban lawns occupied 6.4% of a 1578-km 2 study region, but contribute up to 5% and 30% of the regional soil CH 4 consumption and N 2O emission, respectively, from land-use types that we sampled. Lawns that cover small portions of the landscape may contribute significantly to regional soil-atmosphere gas exchange.
  • Authors:
    • Kumpawat, B. S.
  • Source: Indian Journal of Agronomy
  • Volume: 49
  • Issue: 1
  • Year: 2004
  • Summary: A field experiment was carried out under irrigated condition on fixed site during 1986-2001 at Dryland Farming Research Station, Arjia, Bhilwara, Rajasthan, to find out the effect of integrated nutrient supply system in maize ( Zea mays L.)-Indian mustard [ Brassica juncea (L.) Czernj. & Cosson] cropping system. The highest mustard-equivalent yield (24.88 q/ha) was recorded with the application of 100% recommended N in the rainy season through FYM and 100% recommended NP in the winter season through inorganic fertilizers. Maximum net monetary returns (Rs 15,537/ha), benefit:cost ratio (2.07) and agronomic efficiency (16.1) were obtained from the treatment consisting of 50 and 100% recommended NP through fertilizers to maize and mustard respectively. Amount of available phosphorus increased over initial value when organic manures and crop residues were incorporated. Organic carbon status declined in the control, while there was build up in organic source-incorporated plots.