• Authors:
    • Shen, X. J.
    • Zhang, J. P.
    • Zhang, J. Y.
    • Sun, J. S.
    • Liu, H.
  • Source: Ying Yong Sheng Tai Xue Bao
  • Volume: 23
  • Issue: 2
  • Year: 2012
  • Summary: To develop a suitable tillage mode and irrigation schedule of transplanted cotton following wheat harvest under sprinkler irrigation, a field experiment was conducted to study the effects of different tillage modes (conventional tillage and no-tillage) and different irrigation schedules (45 and 22.5 mm of irrigating water quota) on the water consumption, seed yield, water use efficiency, and fiber quality of cotton. Comparing with conventional tillage, no-tillage decreased the soil evaporation among cotton plants by 20.3%. Whether with conventional tillage or with no-tillage, deficit irrigation (22.5 mm of irrigating water quota) did not affect seed yield and fiber quality, while decreased the water consumption and improved the water use efficiency. No-tillage with 22.5 mm of irrigating water quota under sprinkler irrigation not only decreased the soil evaporation effectively, but also achieved water-saving, high quality and high yield of transplanted cotton following wheat harvest.
  • Authors:
    • Soriano, M. A.
    • Santos, C.
    • Carmona, M. A.
    • Garcia-Vila, M.
    • Lorite, I. J.
  • Source: Water Resources Management
  • Volume: 26
  • Issue: 8
  • Year: 2012
  • Summary: The Local Irrigation Advisory Services (LIAS) carry out essential work to achieve an efficient use of irrigation water at field and irrigation scheme level, which is crucial in Mediterranean irrigation systems. However, it is unusual to find agronomic and economic assessments of LIAS advice. In this work, the LIAS operating in the Genil-Cabra Irrigation Scheme (southern Spain) was evaluated during the first 5 years of its advice. Acceptance by farmers of the LIAS recommendations was evaluated by using agronomic indicators, such as ARIS (Annual Relative Irrigation Supply). ARIS(LIAS) (actual irrigation applied v. recommendation of LIAS) with values ranging from about 0.23 for wheat and sunflower, and 0.94 for maize, also detecting a high variability between farmers, which indicated a scant acceptance of the LIAS recommendations. The economic evaluation of irrigation was made through two economic indicators, Irrigation Water Productivity (IWP) and Irrigation Water Benefit (IWB). IWP values varied significantly between different crops: around 0.23 a,not sign m(-3) in wheat, sunflower and maize, about 0.53 a,not sign m(-3) in cotton and sugar beet, and values higher than 2.0 a,not sign m(-3) in garlic, for optimal irrigation schedules. For IWB, trends were similar, emphasizing the low IWB values in wheat and sunflower (average values of 0.06 and 0.13 a,not sign m(-3), respectively). Consideration of these economic indicators by LIAS could not only help to obtain more suitable and economically profitable irrigation schedules, but also contribute towards a greater acceptance of advisory services by farmers, by shifting the emphasis from maximizing production to maximizing irrigation profitability.
  • Authors:
    • Thomashow, L. S.
    • Paulitz, T. C.
    • Kwak, Y. S.
    • Bonsall, R. F.
    • Parejko, J. A.
    • Mavrodi, O. V.
    • Mavrodi, D. V.
    • Weller, D. M.
  • Source: Applied and Environmental Microbiology
  • Volume: 78
  • Issue: 3
  • Year: 2012
  • Summary: Natural antibiotics are thought to function in the defense, fitness, competitiveness, biocontrol activity, communication, and gene regulation of microorganisms. However, the scale and quantitative aspects of antibiotic production in natural settings are poorly understood. We addressed these fundamental questions by assessing the geographic distribution of indigenous phenazine-producing (Phz +) Pseudomonas spp. and the accumulation of the broad-spectrum antibiotic phenazine-1-carboxylic acid (PCA) in the rhizosphere of wheat grown in the low-precipitation zone (
  • Authors:
    • Dhaka, A. K.
    • Dahiya, S. S.
    • Pannu, R. K.
    • Singh, M.
  • Source: Crop Research
  • Volume: 43
  • Issue: 1/2/3
  • Year: 2012
  • Summary: The survey was conducted in Haryana state during rabi season of 2005-06 on 972 farmers in 54 villages of 16 districts with respective cropping system i. e. pearl millet-wheat, cotton-wheat and rice-wheat. The 18 farmers from each village were selected randomly covering small (4.0 ha) group of land holders. Only those farmers were selected, who had grown PBW 343 variety of wheat. The sample sizes for pearl millet-wheat, cotton-wheat and rice-wheat of all three small, medium and large farm size groups were 90, 108 and 126, respectively. Yield reported in rice-wheat system was higher than cotton-wheat and pearl millet-wheat system. Maximum yield was observed with the use of more than five bags urea/ha. Numbers of irrigations above 4 and seed rate above 100 kg/ha were also reported to increase in yield. Protein content of wheat in pearl millet-wheat system was the highest. Protein content in late sown wheat in pearl millet-wheat system was higher than cotton-wheat and rice-wheat systems. Seed rate of 100 kg/ha and nitrogen dose of five bags of urea/ha gave significantly higher protein content. Quantitative production of wheat in rice-wheat and cotton-wheat cropping systems was higher than pearl millet-wheat system but quality in terms of protein content was significantly superior to both the rice-wheat and cotton-wheat systems. Hence, export market should be developed in quality grain producing zone i. e. in pearl millet-wheat growing areas, where lower percentage of farmers use higher nitrogen doses and cultivation practices were numerically better than other cropping systems.
  • Authors:
    • Necula, D.
    • Necula, R.
  • Source: Lucrări Ştiinţifice
  • Volume: 14
  • Issue: 1
  • Year: 2012
  • Summary: Bucharest Ilfov Region Agriculture still occupies an important place, having large reserves of development, determined by soil quality, climate factors, technical equipment and materials and labor (or work within major research institutes in the field). However, productivity is lower productivity sector registered in EU countries due to insufficient technical equipment, small scale agricultural enterprises, which represent obstacles to effective development. Also, irrigation systems are underdeveloped.
  • Authors:
    • Antle, J. M.
    • Ogle, S. M.
  • Source: Climatic Change
  • Volume: 111
  • Issue: 3/4
  • Year: 2012
  • Summary: Previous research has demonstrated that soil carbon sequestration through adoption of conservation tillage can be economically profitable depending on the value of a carbon offset in a greenhouse gas (GHG) emissions market. However adoption of conservation tillage also influences two other potentially important factors, changes in soil N2O emissions and CO2 emissions attributed to changes in fuel use. In this article we evaluate the supply of GHG offsets associated with conservation tillage adoption for corn-soy-hay and wheat-pasture systems of the central United States, taking into account not only the amount of carbon sequestration but also the changes in soil N2O emission and CO2 emissions from fuel use in tillage operations. The changes in N2O emissions are derived from a meta-analysis of published studies, and changes in fuel use are based on USDA data. These are used to estimate changes in global warming potential (GWP) associated with adoption of no-till practices, and the changes in GWP are then used in an economic analysis of the potential supply of GHG offsets from the region. Simulation results demonstrate that taking N2O emissions into account could result in substantial underestimation of the potential for GHG mitigation in the central U.S. wheat pasture systems, and large over-estimation in the corn-soy-hay systems. Fuel use also has quantitatively important effects, although generally smaller than N2O. These findings suggest that it is important to incorporate these two effects in estimates of GHG offset potential from agricultural lands, as well as in the design of GHG offset contracts for more complete accounting of the effect that no-till adoption will have on greenhouse gas emissions.
  • Authors:
    • Blanco-Canqui, H.
    • Claassen, M. M.
    • Presley, D. R.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 1
  • Year: 2012
  • Summary: Impact of cover crops (CCs) on winter wheat ( Triticum aestivum L.) and grain sorghum [ Sorghum bicolor (L.) Moench] yields is not well understood. We assessed crop yield and its relationships with CC-induced changes in soil properties for a 15-yr CC experiment in wheat-sorghum rotation at 0, 33, 66, and 100 kg ha -1 of N application in south central Kansas. Hairy vetch ( Vicia villosa Roth) was used as a winter CC from 1995 to 2000, while sunn hemp (SH; Crotalaria juncea L.) and late-maturing soybean [LMS; Glycine max (L.) Merr.] were used as summer CCs in no-till from 2002 to 2008. Summer CCs increased crop yields particularly at low rates of N application. At 0 kg N ha -1, SH increased sorghum yield by 1.18 to 1.54 times, while wheat yield increased by 1.60 times in the first year (2004) after CC establishment relative to non-CC plots. At 66 kg N ha -1, SH had no effects on sorghum yield, but it increased wheat yield in 2 of 3 yr. Cover crops increased soil total N pool by 270 kg ha -1 for the 0- to 7.5-cm depth. Crop yield increased with the CC-induced decrease in soil maximum compactibility (soil's susceptibility to compaction) and soil temperature, and increase in soil aggregate stability, soil organic carbon (SOC) and total N concentration, and soil water content, particularly at 0 kg N ha -1. Principal component analysis (PCA) selected soil compactibility and total N as the best yield predictors. Inclusion of summer legume CCs in no-till fixes N, increases crop yield, and improves soil-crop relationships.
  • Authors:
    • Gibson,Lance R.
    • Singer,Jeremy W.
    • Blaser,Brock C.
  • Source: Crop Science
  • Volume: 52
  • Issue: 1
  • Year: 2012
  • Summary: Frost-seeding red clover (Trifolium pratense L.) into winter cereals is an efficient establishment method, although performance under contrasting soil management practices remains unclear. Wheat and intercropped red clover productivity were evaluated in intensive tillage (IT), moderate tillage (MT), and no tillage (NT) with and without compost amendment in a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.]-winter wheat (Triticum aestivum L.) and red clover rotation between 2005 and 2010. Wheat yields were not affected by tillage system and averaged 3.80 Mg ha(-1) but were 10% higher in compost amended soil compared to no compost. Red clover plant density and dry matter (DM) at cereal grain harvest averaged 127 plants m(-2) and 32 g m(-2) and were not affected by tillage or amendment treatments. Maximum wheat canopy light interception was attained in late May to early June and ranged from 84 to 91% and typically exceeded 77% light interception for at least 22 d. Red clover root DM increased on average 378% between wheat harvest and 40 d after harvest compared with a 64% average increase in red clover root length. Red clover shoot: root averaged 8.5 at wheat harvest compared with 11.2 40 d after wheat harvest. Producers using this wheat and red clover intercrop should expect no difference in wheat yield or red clover productivity when using IT, MT, or NT.
  • Authors:
    • Briedis, C.
    • Sa, J. C. de M.
    • Caires, E. F.
    • Navarro, J. de F.
    • Inagaki, T. M.
    • Boer, A.
    • Ferreira, A. de O.
    • Quadros Neto, C.
    • Canalli, L. B.
    • Santos, J. B. dos
  • Source: Soil Science Society of America Journal
  • Volume: 76
  • Issue: 1
  • Year: 2012
  • Summary: In a no-till system (NTS) on naturally acidic soils, surface liming is essential to neutralize soil acidity and increases crop productivity. As a result, the soil organic matter (SOM) pools of the soil surface layers may change, reflecting increased C inputs by crop residues. The objective of this study was to quantify changes in SOM pools and the rate of C sequestration that occur in response to surface liming in a long-term NTS experiment. The experiment was conducted in an Oxisol in southern Brazil. The treatments consisted of the application of 0 or 6 Mg ha -1 of dolomitic lime on the soil surface in 1993 and a reapplication of 0 or 3 Mg ha -1 of dolomitic lime in 2000 to plots with or without the previous lime application. Liming caused total organic C (TOC) accumulation, especially in the 0- to 2.5-cm layer. The amount of TOC stored in the 20-cm layer was 49.9, 52.9, 52.7, and 57.5 Mg ha -1 in the control, 6+0, 0+3, and 6+3 Mg ha -1 treatments, respectively. The levels of particulate organic C (POC) and mineral-associated organic C (MAOC) in the SOM were also enhanced by liming. The increase in POC was directly related ( R2=0.99, P=0.002) to the accumulation of C from crop residues, which was greater in the plots receiving lime treatment. There were positive correlations between TOC and C extractable with hot water, total polysaccharides, and labile polysaccharides. The correlation analysis also demonstrated that TOC was more tightly correlated with POC than with MAOC, indicating a greater influence of the labile fraction on the increase in TOC with surface liming.
  • Authors:
    • Chen, C. C.
    • Neill, K.
    • Burgess, M.
    • Bekkerman, A.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 2
  • Year: 2012
  • Summary: The rotational effects and economic potential of incorporating fall-seeded pea ( Pisum sativum L.) and lentil ( Lens culinaris Medik) into conventional wheat ( Triticum aestivum L.)-based cropping systems in the northern Great Plains are not well understood. Two 2-yr crop rotation experiments were conducted in central Montana to investigate how winter pea hay, lentil green manure, and lentil grain affects subsequent winter wheat yield and protein content, as well as the economic returns of the systems under no-till conditions. In Exp. 1, a winter pea hay-winter wheat (WP-WW) rotation was compared to fallow-winter wheat (FW-WW) and spring wheat-winter wheat (SW-WW) rotations. In Exp. 2, a winter lentil for green manure-winter wheat [WL(m)-WW] rotation was compared to a winter lentil grain-winter wheat [WL(g)-WW] rotation. Four different rates of N were applied to the winter and spring wheat. Winter wheat yield in the WP-WW rotation was 2193 kg ha -1, which was equivalent to the yield in the FW-WW rotation (2136 kg ha -1), and much greater than the SW-WW rotation (1155 kg ha -1). Averaged over all N rates, the WP-WW, FW-WW, and SW-WW systems had $196, $116, and $41 ha -1 net return, respectively. In Exp. 2, the WL(m)-WW rotation produced greater grain yield and protein content at lower N input levels, indicating a greater N benefit. Nevertheless, the WL(g)-WW system generated $213 ha -1 net profit while the WL(m)-WW system produced $92 ha -1. Therefore, the winter pea cover crop, used for livestock feed, improves the system profitability.