• Authors:
    • Gunter, C. C.
  • Source: ISHS Acta Horticulturae IV International Symposium on Ecologically Sound Fertilization Strategies for Field Vegetable Production
  • Issue: 852
  • Year: 2010
  • Summary: Efforts are being made to reduce the negative impacts that high intensity vegetable production can have on the soil. Soil nutrient removal and soil compaction due to heavy equipment can lead to long lasting problems in future production cycles. Producers are beginning to look at the beneficial effects that cover crops can have on soil tilth and fertility. Three rotational cover crop areas were established on the Southwest Purdue Agriculture Center in Vincennes, Indiana and each area was divided into four cover crop plots, no-till wheat, clover, oilseed radish and a bare ground control. Processing tomatoes, sweetcorn and snap beans were planted across the four cover crop plots within each rotational area. Two varieties of each type of vegetable were grown in each cover crop. Processing tomatoes had significantly less yield in the no-till wheat cover crop compared to the other three cover crops. There were also a higher proportion of green and turning fruit in that treatment. Snap beans showed significantly higher yields when grown in the oilseed radish and clover cover crops. Sweetcorn had significantly shorter ear length when grown in the no-till wheat cover crop. Varietal differences exist with cover crops, suggesting that some varieties perform better than others when using a specific cover crop.
  • Authors:
    • Melander, B.
    • Munkholm, L. J.
    • Hansen, E. M.
    • Olesen, J. E.
  • Source: Soil & Tillage Research
  • Volume: 109
  • Issue: 1
  • Year: 2010
  • Summary: Finding ways of reducing nitrate leaching in Northern Europe has become an extremely important task, especially under the projected climate changes that are expected to exacerbate the problem. To this end, two field experiments were established under temperate coastal climate conditions to evaluate the effect of tillage, straw retainment and cropping sequences, including cover crops, on nitrate leaching. The experiments were established in autumn 2002 on a loamy sand with 92 g clay kg(-1) and a sandy loam with 147 g clay kg(-1). The tillage treatments were stubble cultivation to 8-10 cm or 3-4 cm, direct drilling, or ploughing to 20 cm. The hypothesis was that (i) decreasing soil tillage intensity would decrease leaching compared to ploughing, (ii) leaving straw in the field would decrease leaching compared to removing straw, and (iii) a spring/winter crop rotation with catch crops would be more efficient in reducing nitrate leaching than a winter crop rotation. Overall, we were not able to confirm the three hypotheses. The effect of soil tillage on leaching might be blurred because the studied crop rotations had a high proportion of winter crops and because catch crops were grown whenever the alternative would have been bare soil in autumn and winter. The spring/winter crop rotation with catch crops was not found to be more efficient in reducing nitrate leaching than the winter crop rotation. In contrast, in a single year the winter crop rotation showed significantly lower leaching than the spring/winter crop rotations, probably due to the spring/winter crop rotation including peas, which may be considered a high-risk crop. Our study highlights that management practices that improve biomass production throughout the year are crucial in order to tighten the nitrogen cycle and thereby reduce nitrate leaching. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Reddy, P. R. R.
    • Veeranna, G.
    • Rao, L. J.
  • Source: Journal of Research ANGRAU
  • Volume: 38
  • Issue: 3/4
  • Year: 2010
  • Summary: Maize ( Zea mays) is one of the important cereal crops cultivated in India. Its area is expanding fast in Andhra Pradesh. Plant density in corn, varies with soil, rainfall, hybrid, planting pattern and field preparation (Olson and Sander, 1988). Of late, Zero tillage maize, after kharif rice is gaining popularity among the farming community in Andhra Pradesh. In zero tillage, after harvesting kharif rice, maize seeds will be dibbled under optimum moisture condition without any field preparation. Pre emergence spraying of atrazine in combination with paraquat or glyphosate is practiced to control weeds. Fertilizer application starts from 15 days after sowing in various quantities. In general, intercultivation is not practiced. The crop receives 4-6 irrigations depending on soil type.
  • Authors:
    • Kelley, J.
    • Oliver, D.
    • Gbur, E. E.
    • Brye, K. R.
    • Amuri, N.
  • Source: Weed Science
  • Volume: 58
  • Issue: 3
  • Year: 2010
  • Summary: Management practices and cropping systems that serve as integrated weed management practices, and at the same time can contribute to improved soil quality, will be important for the sustainability of agricultural production systems. The objective of this study was to assess weed species population density under contrasting tillage (conventional tillage [CT] and no tillage [NT]), residue burning (burn and no burn), and residue level (low and high) treatments after 5 and 6 yr of consistent management in a wheat-soybean double-crop production system. A field experiment was conducted from fall 2001 to fall 2007 in the Mississippi River Delta region of eastern Arkansas on a Calloway silt-loam. Weed assessments were conducted twice during the soybean growing season, before (early season) and after herbicide application (late season) in 2006 and 2007. Total weed density was greater under CT (513 plants m(-2)) than under NT (340 plants m(-2)) early in the growing season in 2006, but was greater under NT than CT late in the season in 2007, suggesting that the effectiveness of glyphosate on total weeds differs between CT and NT. Averaged across residue levels, grass species density was greatest in the NT burn (68 to 167 plants m(-2)) combination and lowest in the NT no-burn (41 to 63 plants m(-2)) early in the growing season in both years. Broadleaf density was greater early (200 to 349 plants m(-2)) than late (18 to 20 plants m(-2)) in the growing season under both CT and NT in 2006, but in 2007 broadleaf density did not differ by tillage treatment between seasons. Perennial weed density was greater in the burn (99 plants m(-2)) than in the no-burn (59 plants m(-2)) treatment in 2006. No tillage, no burning, and a high residue level appeared to contribute to the suppression of most weed species without reducing herbicide efficiency.
  • Authors:
    • Basso, F. C.
    • Montanari, R.
    • Passos e Carvalho, M. de
    • Andreotti, M.
    • Pariz, C. M.
    • Azenha, M. V.
    • Vercese, F.
  • Source: Ciência Rural
  • Volume: 40
  • Issue: 3
  • Year: 2010
  • Summary: The variation and the spatial dependence attributes of the following plant and soil characteristics: soyabean yield (SY) in no-till and irrigated soil; the macroporosity (MA); microporosity (MI); total porosity (TP); and bulk density (BD), in depths of 1 (0-0.10 m), 2 (0.10-0.20 m) and 3 (0.20-0.30 m), were studied in a Red Latosol of Mato Grosso do Sul, Brazil, were analysed during 2004/05, to study the variation and the linear and spatial correlations among the attributes (plant and soil) and select an index of soil physical quality with good capacity to represent the soyabean yield. A geostatistical grid to collect soil and plant data was installed, with 124 sample points, in an area of 4000 m 2. The linear relationship between soyabean yield and physical attributes of soil studied was low. So, there was a direct spatial relationship between SY and MA1 (0-0.10 m), as well as between SY and MA2 (0.10-0.20 m). The MA1 showed its best index of the soil physical quality, when it was destined to estimate the soyabean yield in no-till soil.
  • Authors:
    • Halvorson, A. D.
    • Archer, D. W.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 2
  • Year: 2010
  • Summary: Recent soil and crop management technologies have potential for mitigating greenhouse gas emissions; however, these management strategies must be profitable if they are to be adopted by producers. The economic feasibility of reducing net greenhouse gas emissions in irrigated cropping systems was evaluated for 5 yr on a Fort Collins clay loam soil (a fine-loamy, mixed, superactive, mesic Aridic Haplustalf). Cropping systems included conventional tillage continuous corn ( Zea mays L.) (CT-CC), no-till continuous corn (NT-CC), and no-till corn-bean (NT-CB) including 1 yr soybean [ Glycine max (L.) Merr.] and 1 yr dry bean ( Phaseolus vulgaris L.). The study included six N fertilization rates ranging from 0 to 246 kg ha -1. Results showed highest average net returns for NT-CB, exceeding net returns for NT-CC and CT-CC by US$182 and US$228 ha -1, respectively, at economically optimum N fertilizer rates. Net global warming potential (GWP) generally increased with increasing N fertilizer rate with the exception of NT-CC, where net GWP initially declined and then increased at higher N rates. Combining economic and net GWP measurements showed that producers have an economic incentive to switch from CT-CC to NT-CB, increasing annual average net returns by US$228 ha -1 while reducing annual net GWP by 929 kg CO 2 equivalents ha -1. The greatest GWP reductions (1463 kg CO 2 equivalents ha -1) could be achieved by switching from CT-CC to NT-CC while also increasing net returns, but the presence of a more profitable NT-CB alternative means NT-CC is unlikely to be chosen without additional economic incentives.
  • Authors:
    • Hansson, M.
    • Adler, A.
    • Bergkvist, G.
    • Weih, M.
  • Source: Weed Research
  • Volume: 50
  • Issue: 5
  • Year: 2010
  • Summary: P>Elytrigia repens (syn. Elymus repens) is a perennial grass weed that is controlled by herbicides or by tillage. Both methods are expensive and may have negative effects on the environment. Therefore, alternative methods of weed control, such as using competition from under-sown perennial forage crops, are of interest. Red fescue can be sown together with winter wheat as a non-flowering understorey crop that has its main growth during late summer and autumn. This study quantified the effect of red fescue and E. repens on wheat biomass and tested the hypothesis that under-sown red fescue reduces the amount of E. repens rhizomes and thus the need for herbicides or tillage. Two field experiments in which winter wheat, red fescue and E. repens were grown in all possible combinations were conducted between 2003 and 2005. Elytrigia repens reduced wheat biomass by 8%, while red fescue had no significant effect on wheat biomass. Red fescue reduced late autumn biomass of E. repens rhizomes by 40%. The results suggest that red fescue sown with winter wheat can reduce propagation of E. repens during summer and autumn, without a significant reduction in wheat biomass.
  • Authors:
    • Kochsiek, A. E.
    • Knops, J. M. H.
    • Walters, D. T.
    • Arkebauer, T. J.
  • Source: Agricultural and Forest Meteorology
  • Volume: 149
  • Issue: 11
  • Year: 2009
  • Summary: The litter carbon (C) pool of a single litter cohort in an agroecosystem is the difference between net primary productivity and decomposition and comprises 11-13% of the total C pool (litter and soil 0-15 cm depth) post-harvest. This litter-C pool is highly dynamic and up to 50% can be decomposed in the first 12 months of decomposition. Thus, understanding litter-C dynamics is key in understanding monthly and annual total ecosystem carbon dynamics. While the effects of management practices such as irrigation and fertilization on productivity are well understood, the effects on decomposition are less studied. While irrigation and fertilization increase productivity, this will only lead to increased litter-C residence time and litter-C pool accretion if these techniques do not also result in equivalent or greater increases in decomposition. Management could potentially have impacts on litter-C accretion by increasing litter inputs, changing plant-C allocation, plant tissue quality, or decomposition rates. We examined carbon loss of one annual cohort of maize litter using in situ nylon litter bags for 3 years in three no-till fields with differing management regimes: irrigated continuous maize with a pre-planting fertilization application and two fertigation events, irrigated maize-soybean rotation with the same fertilization regime as the irrigated continuous maize management regime, and rainfed maize-soybean rotation with a single pre-planting fertilization event. We addressed the effects of these different management regimes on net primary productivity and litter inputs, litter nitrogen (N) concentrations and carbon quality measures, plant C allocation, decomposition rates and the potential changes in the overall litter-C balance. We found that irrigation/fertigation management increased litter inputs, led to changes in plant tissue quality, had no effect on carbon allocation, and increased decomposition rates. This balance of both greater litter inputs and outputs of C from the irrigated management regimes led to a similar litter-C balance for this litter cohort in the irrigated and rainfed management regimes after 3 years of decomposition. Our data clearly show that merely increasing litter-C inputs through irrigation/fertigation practices is not sufficient to increase litter-C residence time because decomposition rates also increase. Therefore, close monitoring of decomposition rates is essential for understanding litter-C pool dynamics.
  • Authors:
    • Abrol, V.
    • Sankar, G.
    • Singh, B.
    • Sharma, P.
  • Source: Indian Journal of Agricultural Sciences
  • Volume: 79
  • Issue: 11
  • Year: 2009
  • Summary: A Field experiment was conducted during 2005-06 and 2006-07 at Dryland Research Sub Station, Dhiansar to study the influence of tillage and mulching practices on crop productivity, economics and soil properties of maize-wheat system under rainfed situation. Four different tillage methods, viz conventional, minimum, no tillage and raised bed were used in the main plots and four different mulch materials, viz straw, polyethylene, soil mulch including no mulch were used in the sub-plots. Tillage practices significantly influenced the yield of maize and wheat. Grain yield of maize and wheat was statistically at par in conventional and minimum tillage system and significantly higher than no tillage system in both the years. Mulching also resulted in increased in yield. Significantly higher mean grain yield of maize (1.91 tonnes/ha) and wheat (0.63 tonnes/ha) was recorded from polyethylene mulch, followed by straw mulch (1.77 tonnes/ha, 0.61 tonnes/ha) respectively. Minimum tillage and polyethylene mulch or straw mulch conserve more moisture and infiltration rate than other tillage methods and mulch application. The highest mean net returns (Rs 10 078) and benefit:cost ratio (1.28) was obtained with minimum tillage and lowest with conventional tillage (Rs 8 631 0.90). Minimum tillage in conjunction with polyethylene mulch or straw mulch was economically profitable and improve, the crop production and soil quality for maize-wheat sequence in rainfed condition.
  • Authors:
    • Peeyush, S.
    • Vikas, A.
    • Shankar, G.
  • Source: Research on Crops
  • Volume: 10
  • Issue: 3
  • Year: 2009
  • Summary: A field experiment was conducted during 2005-06 and 2006-07 at Dryland Research Sub-Station, Dhiansar to study the influence of tillage and mulching management on soil physical and chemical properties and crop yield on maize-wheat system under rainfed situations. Maize and wheat yield was statistically at par in conventional and minimum tillage and significantly higher over control. Increase in bulk density was higher in conventional tillage as compared to the minimum tillage. Reduction in infiltration rate was 17.24% higher in conventional tillage than minimum tillage. Minimum tillage improved the net return, benefit:cost ratio as well as fertility status. Application of plastic mulch resulted in maximum grain yield, infiltration rate and nutrient status than no mulch.