• Authors:
    • Munier-Jolain, N. M.
    • Kurstjens, D. A. G.
    • Colbach, N.
    • Dalbies, A.
    • Dore, T.
  • Source: European Journal of Agronomy
  • Volume: 32
  • Issue: 3
  • Year: 2010
  • Summary: Because of environmental and health safety issues. it is necessary to develop strategies that do not rely on herbicides to manage weeds. Introducing temporary grassland into annual crop rotations and mechanical weeding are the two main features that are frequently used in integrated and organic cropping systems for this purpose. To evaluate the contribution of these two factors in interaction with other cropping system components and environmental conditions, the present study updated an existing biophysical model (i.e. ALOMYSYS) that quantifies the effects of cropping system oil weed dynamics. Based oil previous experiments, new sub-models were built to describe the effects on plant survival and growth reduction of mechanical weeding resulting from weed seedling uprooting and covering by soil, and those of grassland mowing resulting from tiller destruction. Additional modifications described the effect of the multiyear crop canopy of grassland on weed survival, growth, development and seed return to the soil. The improved model was used to evaluate the weed dynamics over 27 years in the conventional herbicide-based cropping system most frequently observed in farm Surveys (i.e. oilseed rape/winter wheat/winter barley rotation with Superficial tillage) and then to test prospective non-chemical scenarios. Preliminary simulations tested a large range of mechanical weeding and mowing strategies, varying operation frequencies, dates and, in the case of mechanical weeding, characteristics (i.e. tool, working depth, tractor speed). For mechanical weeding soon after sowing, harrowing was better than hoeing for controlling weed seed production. The later the operation, the more efficient the hoeing and the less efficient the harrowing. Tractor speed had little influence. Increasing tilling depth increased plant mortality but increased weed seed production because of additional seed germination triggering by the weeding tool. Decreasing the interrow width for hoeing was nefarious for weed control. The best combinations were triple hoeing in oilseed tape and sextuple harrowing in cereals. The best mowing strategy was mowing thrice, every 4-6 weeks, starting in mid-May. The best individual options were combined, simulated over 27 years and compared to the herbicide-based reference system. If herbicide applications were replaced solely by mechanical weeding, blackgrass infestation Could not be satisfactorily controlled. If a three-year lucerne was introduced into the rotation, weed infestations were divided by ten. Replacing chisel by mouldboard ploughing before winter wheat reduced weed infestations at short, medium and long term to a level comparable to the herbicide-based reference system. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Țărau, D.
    • Borza, I.
    • Dicu, D.
  • Source: Research Journal of Agricultural Science
  • Volume: 42
  • Issue: 3
  • Year: 2010
  • Summary: Studies were conducted on a cambic cernosiom, with a medium content of clay, dominant in the Prodagro West Arad agro-centre and representative for a large surface in the Banat-Crisana Plain, on the Arad cadasiral territory, Romania. The experimental factors considered include: soil work system; foliar phyto-sanitary treatment; classical system; and no-till system. From the geomorphological point of view, the perimeter on which the experiments are located belongs to the large physical-geographic unity called the Vinga High Plain. Relief present itself as a succession of high plain, almost even, with altitudes between 95-200 m, separated by wide valleys, rather deep, collected quite in exclusivity by Berecsau river (and less by Mires river). The zone between the rivers are well individuated in 5 steps layed in fan shape: Seceani (180 m), Alios (160 m), Vinga (150 m), Calacea (130 m), Satchinez (100 m) realized by Mires river at different geological moments an partly tectonically influenced. Hydrographically, the perimeter where the experiment is placed belongs to the hydrographic basin of Mires river which flows at approximately 2-3 km north from this. The pedophreatic levels are at 5.1-10 m depth (they do not interfere in the pedogenesis processes) in flat areas and between 1.5-3.0 m depth in the valleys. For wheat, the production was between 3613-4817 kg/ha, the highest production of 4817 kg/ha, being registered in the no-till system, treated and the lowest of 3613 kg/ha in the no-till system . For maize the obtained production had values of 3658-5680 kg/ha, the highest production of 5680 kg/ha, being registered in classic system treated and the lowest of 3658 kg/ha in no-till system untreated.
  • Authors:
    • Hu, C. S.
    • Ren, T. S.
    • Du, Z. L.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 1
  • Year: 2010
  • Summary: Little information is available about their influences of conservation tillage on the distribution and storage of soil organic C (SOC) and total N in soil profiles in the North China Plain. We investigated the changes in SOC and total N as related to the shift from conventional to conservation tillage using a long-term field experiment with a winter wheat ( Triticum aestivum L.)-corn ( Zea mays L.) double cropping system. The experiment included four tillage treatments for winter wheat: moldboard plow without corn residue return (MP-R), moldboard plow with corn residue return (MP+R), rotary tillage (RT), and no-till (NT). Compared with the MP-R treatment, returning crop residue to the soil (MP+R, RT, and NT) increased SOC and total N in the 0- to 30-cm soil layer, but no distinct changes in SOC and total N concentration were observed among the four treatments at soil depths >30 cm. Compared with the MP+R treatment, the RT and NT treatments increased SOC and total N concentration significantly in the 0- to 10-cm layer but decreased SOC and total N concentration in the 10- to 20-cm layers. As a consequence, soil profile SOC and total N storage did not vary among the MP+R, RT, and NT treatments. Thus under the experimental conditions, conservation tillage (RT and NT) increased SOC and total N contents in the upper soil layers, but did not increase SOC and total N storage over conventional tillage (MP+R) in the soil profile.
  • 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:
    • 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:
    • Frederick, J. R.
    • Fortnum, B. A.
    • Bauer, P. J.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 4
  • Year: 2010
  • Summary: Longer rain-free periods are predicted to occur more often in the southeastern United States as a result of global climate change. This nonirrigated field study was conducted from 1997 through 2002, which coincided with the 1998-2002 drought that affected most of the United States. The objective was to determine the effect of rotation and tillage on cotton (Gossypium hirsutum L.) productivity. Treatments in the study were rotation [cotton rotated with corn (Zea mays L.), cotton planted after a rye (Secale cereale L.) winter cover crop, and continuous cotton with no cover crop] and tillage system (conventional tillage and conservation tillage). Two levels of aldicarb [2-methyl-2-(methylthio)propanal O-{(methylamino)carbonyl}oxime] (0 and 1.18 kg a.i. ha(-1)) were also included because of known soil management effects on thrips (Frankliniella sp.) and root-knot nematodes (Meloidigyne incognita). The predominant soil types were Bonneau loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudult) and Norfolk loamy sand (fine-loamy, kaolinitic, thermic Typic Kandiudult). Rotation did not affect cotton yield in any year. Tillage did not affect cotton yield in 1997. Conservation tillage resulted in an average 25% yield increase in cotton lint yield over conventional tillage during the 5-yr drought. Tillage and aldicarb affected both thrips and root-knot nematodes, but lack of interaction among these factors for lint yield suggested that management of these pests was not the predominant cause for the cotton yield increase with conservation tillage. Conservation tillage for cotton production could be an important method to help mitigate the effects of climate change in the region if change occurs as predicted.
  • Authors:
    • Paltridge, N.
    • Tao, J.
    • Unkovich, M.
    • Gason, A.
    • Grover, S.
    • Wilkins, J.
    • Coventry, D.
    • Tashi, N.
    • Bonamano, A.
  • Source: Crop & Pasture Science
  • Volume: 60
  • Issue: 7
  • Year: 2009
  • Summary: In the south of the Tibet Autonomous Region of China there is a network of valleys where intensive agriculture is practiced. Although considered highly productive by Tibetans, farm incomes in the region are low, leading to a range of government initiatives to boost grain and fodder production. However, there is limited information available on current farming practices, yields, and likely yield constraints. The present paper uses available data and farmer interviews to describe the agro-climate and current systems of crop and livestock production, and considers possible strategies to boost production. Although winters in Tibet are cold and dry, summer and autumn provide ideal conditions for crop growth. Cropping systems are characterised by heavy tillage, frequent irrigation, high seeding rates and fertiliser applications, some use of herbicides, and little stubble retention or mechanisation. Spring barley and winter wheat are the predominant crops, followed by rapeseed, winter barley, and minor fodder and vegetable crops. Average yields for the main grain crops are around 4.0 t/ha for spring barley and 4.5 t/ha for winter wheat, significantly lower than should be possible in the environment. Farmers typically keep five or six cattle tethered near the household. Cattle are fed diets based on crop residues but are generally malnourished and rarely produce beyond the needs of the family. It is suggested that research and extension in the areas of crop nutrition, weed control, irrigation, seeding technology, and crop varieties should enable significant increases in grain yield. Increases in cattle production will require increases in the supply of good quality fodder. Cereal/fodder intercrops or double crops sown using no-till seed drills might enable the production of useful amounts of fodder in many areas without jeopardising food grain supply, and allow more crop residues to be retained in fields for improved soil health.
  • 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:
    • Raper, R. L.
    • Siri-Prieto, G.
    • Reeves, D. W.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 6
  • Year: 2009
  • Summary: The use of crop rotation systems involving winter-annual grazing can help peanut (Arachis hypogaea L.) producers increase profitability, although winter-annual grazing could result in excessive soil compaction, which can severely limit yields. We conducted a 3-yr field study on a Dothan loamy sand in southeastern Alabama to develop a conservation tillage system for integrating peanut with winter-annual grazing of stocker cattle under dryland conditions. Winter-annual forages and tillage systems were evaluated in a strip-plot design, where winter forages were oat (Avena sativa L.) and annual ryegrass (Lolium mutiflorum L.). Tillage systems included moldboard and chisel plowing, and combinations of noninversion deep tillage (none, in-row subsoil, or paratill) with/without disking. We evaluated soil water content, peanut leaf stomatal conductance, plant density, peanut yield, peanut net return, and total system annual net return. Peanut following oat increased soil water extraction (15%), stands (12%), and yields (21%) compared with peanut following ryegrass. Strict no-till resulted in the lowest yields (2.29 Mg ha(-1), 42% less than the mean) and noninversion deep tillage (especially in-row subsoil) was required to maximize water use and yields with conservation tillage. Net return from annual grazing ($185 ha(-1), USD) represented 40% of the total return for the best treatment (no-tillage with in-row subsoil following oat = $462 ha(-1)). Integrating winter-annual grazing in this region using noninversion deep tillage following oat in a conservation tillage system can benefit peanut growers, allowing extra income without sacrificing peanut yields.
  • Authors:
    • Sousa, D. M. G. de
    • Rein, T. A.
  • Source: Informações Agronômicas
  • Issue: 126
  • Year: 2009
  • Summary: Soyabean monoculture with inadequate agricultural practices has resulted in losses of soil organic matter in the Brazilian cerrado, especially in sandy soils. This has led to erosion, reduced cation exchange capacity and water storage, and diminished fertilizer use efficiency. One of the ways of avoiding the loss of soil organic matter is to reduce tillage, as in the system of direct (as opposed to conventional) planting, and the use of this system is growing in the cerrado region. This paper reviews work that has been done on the correction of soil acidity and fertilizing with macronutrients in the direct planting system, both before and after crop establishment. The section on soil acidity discusses both surface (0-20 cm) and subsurface (20-60 cm) acidity, and the effects of correction with limestone or gypsum under conventional and no tillage systems, and on cotton and soyabean yields under a direct planting system. The section on fertilizers looks at the effects of liming, conventional and no tillage systems and dry farming on soil macronutrient content (with particular reference to nitrogen, phosphorus and potassium) and crop yield (with data for maize). Soil organic matter content is also compared under conventional and no tillage systems.