• Authors:
    • Tonkin, C. J.
    • Francis, R. J.
    • Dellow, J. J.
    • Mullen, C. L.
  • Source: Weed control in winter crops 2002
  • Year: 2002
  • Summary: This bulletin provides a list of the most important weeds of winter crops, and identifies the herbicides that should be used for optimum weed control in fallows, wheat, barley, oat, rye, triticale, rape, sunflower, lentil, linseed, lupin, chickpea, faba bean and field pea.
  • Authors:
    • Aroca, J. A.
    • Guerrero-Campo, J.
    • Bienes, R.
    • Nicolau, J. M.
    • Gomez, B.
    • Espigares, T.
  • Source: Man and soil at the Third Millennium. Proceedings International Congress of the European Society for Soil Conservation, Valencia, Spain, 28 March-1 April, 2000. Volume 2 2002
  • Year: 2002
  • Summary: The desertion of large agricultural lands in Mediterranean areas has important consequences on soil erosion. The aim of this study was to quantify runoff and water soil erosion evolution during the period 1994-97. Runoff and erosion were measured in erosion plots (20* 4 m). Four different treatments were applied, namely bare soil maintained with herbicide, no-tilled barley crop, spontaneous vegetation and leguminous sowing before desertion. These trials were carried out in four areas with different types of soils. The areas are located in the centre of Spain, under a Mediterranean-continental climate. In bare soils, annual runoff coefficient was higher than 10%, increasing through the time because of the soil compaction. These plots showed high soil erosion rates, between 1.3 and 28 t ha/year. Spontaneous vegetation plots produced the lowest erosion rates (from 0.0002 to 0.15 t ha/year). Annual runoff coefficient in no-tilled barley plots increased lightly through the four years, because the minimum ploughing favoured a light soil compaction. Soil erosion rate was low, ~0.3 t ha/year, showing the efficiency of this crop on erosion control. Runoff coefficient in abandoned plots (with spontaneous vegetation) and plots with leguminous sowing before desertion, decreased through the time. The lowest erosion rates were recorded when plant cover was higher than 50%, that is, from 6 months to 2.5 years after crops desertion. It is shown that in these environments soil erosion is not a continuous process, because the main water erosion measured during the four years period were produced only in two or three big storms.
  • Authors:
    • Moerkerk, M.
    • Niknam, S. R.
    • Cousens, R.
  • Source: 13th Australian Weeds Conference: weeds "threats now and forever?", Sheraton Perth Hotel, Perth, Western Australia, 8-13 September 2002: papers and proceedings 2002
  • Year: 2002
  • Summary: This paper reports on surveys of farmers' seed boxes, which were carried out in the Wimmera and Mallee regions of Victoria in 2001. From seeds ready to be sown, 160 cereal (mainly wheat and barley) and pulse samples (mainly lentils, beans and peas) were collected and the level and species of weed seed were determined. For lentils (28 samples), the seed box survey was followed up with a paddock survey at flowering and the determination of foreign seed material in the final harvested grain. A wide range of weed species was found in the farmer-retained seed. Farmer-retained seed also contained more weed seeds than certified seed. The main foreign seeds in cereals were annual ryegrass ( Lolium rigidum), volunteer canola, volunteer barley, wild oats ( Avena spp.), silver grass ( Vulpia bromoides), volunteer wheat, lesser canary grass ( Phalaris minor), brome grass ( Bromus spp.), volunteer oats and paradoxa grass ( Phalaris paradoxa). For lentils, a number of common weeds were identified which tend to persist in the cropping system and replenish the seed bank. Annual ryegrass was identified as the most problematic weed. Other weeds such as vetch ( Vicia sativa) and bedstraw ( Galium tricornutum) could become serious problems in pulses if effective management practices are not found soon.
  • Authors:
    • Brookes, G.
  • Source: Web Of Knowledge
  • Issue: Ed. 1
  • Year: 2002
  • Summary: The material contained in this book aims to bring together information about the profitability of growing different arable crops in a number of European countries. It draws on many national sources of information and brings these together in an updated form to reflect the latest harvest of 2001.
  • Authors:
    • UK, National Institute of Agricultural Botany (NIAB)
  • Source: Pocket guide to varieties of cereals, oilseeds & pulses for autumn 2002
  • Year: 2002
  • Summary: This edition presents information on the autumn sown varieties of wheat, barley, oats, triticale, rye, durum wheat, oilseed rape, linseed, peas, lupins and beans. Individual information on each variety is given, including variety notes, yield performance, relative ranking position in different environments and a summary of the important character ratings from the Recommended Lists.
  • Authors:
    • Wuest, S. B.
  • Source: Applied Soil Ecology
  • Volume: 18
  • Issue: 2
  • Year: 2001
  • Summary: Dryland fanning in the Mediterranean climate of the Pacific Northwest, USA supports extremely low earthworm populations under conventional tillage. Increases in earthworm populations are being observed in fields under no-till cropping systems. A 30+ year experiment with four tillage levels in a pea (Pisum sativum L.)-winter wheat (Triticum aestivum L.) rotation was evaluated for earthworm populations and ponded infiltration rates. Where tillage has been limited to 2.5 cm depth, Apporectodea trapezoides (Duges) mean population was 25 m(-2). Plots subject to tillage by plow (25 cm depth) or chisel (35 cm depth) averaged less than 4 earthworms m-2. The shallow tillage treatment also had the highest average infiltration rate of 70 mm h(-1) compared to 36 for chisel, 27 for spring plow, and 19 mm h(-1) for fall plow treatments. The highly variable nature of earthworm counts and infiltration measurements prevented conclusive correlation between the two, but increases in both can be attributed to minimum tillage.
  • Authors:
    • Drinkwater, L. E.
    • Puget, P.
  • Source: Soil Science Society of America Journal
  • Volume: 65
  • Issue: 3
  • Year: 2001
  • Summary: Although roots are an important source of soil organic matter (SOM) and are thought to be the major constituent of the particulate organic matter (POM) fraction, few studies have documented the fate of belowground C inputs in situ. The main purpose of this experiment was to determine the fate of root-derived C vs. shoot-derived C and to identify factors contributing to any differences in the retention of aboveground vs. belowground C inputs. We labeled hairy vetch (Vicia villosa Roth subsp. villosa) in situ with 13CO2 and followed both root- and shoot-derived C in total soil organic C (SOC) and labile C pools for the first growing season following hairy vetch incorporation. At the end of the growing season, nearly one-half of the root-derived C was still present in the soil, whereas only 13% of shoot-derived C remained. A greater proportion of root-derived C was found as occluded POM and associated with the clay and silt fraction. Greater root-derived C also was retained as chloroform-extractable microbial biomass. We suggest that three different mechanisms contributed to the increased retention of root-derived C: (i) the greater biochemical recalcitrance of root litter, (ii) increased physical protection of root-derived POM within aggregates, and (iii) the continuous nature of root C inputs from exudates and fine root turnover. We conclude that shoot residues are broken down rapidly and serve as the source of N for the following cash crop, whereas the root litter is probably largely responsible for the short-term soil structural improvements associated with the use of green manures. Furthermore, on the basis of these findings, we hypothesize that the greater retention of root-derived C in the first 6 mo of decomposition will increase the persistence of this C in SOM in the long term.
  • Authors:
    • Baldock, J. A.
    • Drury, C. F.
    • Gregorich, E. G.
    • Greaves, Travis
  • Source: Canadian Journal of Soil Science
  • Volume: 81
  • Issue: 1
  • Year: 2001
  • Summary: Legume-based cropping systems could help to increase crop productivity and soil organic matter levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. To evaluate the effects of 35 yr of maize monoculture and legume-based cropping on soil C levels and residue retention, we measured organic C and 13C natural abundance in soils under: fertilized and unfertilized maize (Zea mays L.), both in monoculture and legume-based [maize-oat (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa] rotations; fertilized and unfertilized systems of continuous grass (Poa pratensis L.); and under forest. Solid state 13C nuclear magnetic resonance (NMR) was used to chemically characterize the organic matter in plant residues and soils. Soils (70-cm depth) under maize cropping had about 30-40% less C, and those under continuous grass had about 16% less C, than those under adjacent forest. Qualitative differences in crop residues were important in these systems, because quantitative differences in net primary productivity and C inputs in the different agroecosystems did not account for observed differences in total soil C. Cropping sequence (i.e., rotation or monoculture) had a greater effect on soil C levels than application of fertilizer. The difference in soil C levels between rotation and monoculture maize systems was about 20 Mg C ha-1. The effects of fertilization on soil C were small (~6 Mg C ha-1), and differences were observed only in the monoculture system. The NMR results suggest that the chemical composition of organic matter was little affected by the nature of crop residues returned to the soil. The total quantity of maize-derived soil C was different in each system, because the quantity of maize residue returned to the soil was different; hence the maize-derived soil C ranged from 23 Mg ha-1 in the fertilized and 14 Mg ha-1 in the unfertilized monoculture soils (i.e., after 35 maize crops) to 6-7 Mg ha-1 in both the fertilized and unfertilized legume-based rotation soils (i.e., after eight maize crops). The proportion of maize residue C returned to the soil and retained as soil organic C (i.e., Mg maize-derived soil C/Mg maize residue) was about 14% for all maize cropping systems. The quantity of C3-C below the plow layer in legume-based rotation was 40% greater than that in monoculture and about the same as that under either continuous grass or forest. The soil organic matter below the plow layer in soil under the legume-based rotation appeared to be in a more biologically resistant form (i.e., higher aromatic C content) compared with that under monoculture. The retention of maize residue C as soil organic matter was four to five times greater below the plow layer than that within the plow layer. We conclude that residue quality plays a key role in increasing the retention of soil C in agroecosystems and that soils under legume-based rotation tend to be more "preservative" of residue C inputs, particularly from root inputs, than soils under monoculture.
  • Authors:
    • Dabney,S. M.
    • Delgado,J. A.
    • Reeves,D. W.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 32
  • Issue: 7-8
  • Year: 2001
  • Summary: This article reviews literature about the impacts of cover crops in cropping systems that affect soil and water quality and presents limited new information to help fill knowledge gaps. Cover crops grow during periods when the soil might otherwise be fallow. While actively growing, cover crops increase solar energy harvest and carbon flux into the soil, providing food for soil macro and microrganisms, while simultaneously increasing evapotranspiration from the soil. Cover crops reduce sediment production from cropland by intercepting the kinetic energy of rainfall and by reducing the amount and velocity of runoff. Cover crops increase soil quality by improving biological, chemical and physical properties including: organic carbon content, cation exchange capacity, aggregate stability, and water infiltrability. Legume cover crops contribute nitrogen (N) to subsequent crops. Other cover crops, especially grasses and brassicas, are better at scavenging residual N before it can leach. Because growth of these scavenging cover crops is usually N limited, growing grass/legume mixtures often increases total carbon inputs without sacrificing N scavenging efficiency. Cover crops are best adapted to warm areas with abundant precipitation. Water use by cover crops can adversely impact yields of subsequent dryland crops in semiarid areas. Similarly, cooler soil temperatures under cover crop residues can retard early growth of subsequent crops grown near the cold end of their range of adaptation. Development of systems that reduce the costs of cover crop establishment and overcome subsequent crop establishment problems will increase cover crop utilization and improve soil and water quality.
  • Authors:
    • Morse, R. D.
    • Miyao, E. M.
    • Temple, S. R.
    • Lanini, W. T.
    • Mitchell, J. P.
    • Herrero, E. V.
    • Campiglia, E.
  • Source: HortTechnology
  • Volume: 11
  • Issue: 1
  • Year: 2001
  • Summary: No-tillage processing tomato production in four winter cover crop-derived mulches was evaluated in 1997 and 1998 in Five Points, California, USA. The effectiveness of two medics, 'Sava' snail medic ( Medicago scutellata), and 'Sephi' barrel medic ( Medicago truncatula), and two cereal/legume cover crop mixtures, triticale/'Lana' woolypod vetch ( Triticum x Secale/ Vicia dasycarpa [ Vicia villosa]) and rye/'Lana' woolypod vetch ( Secale cereale/ V. dasycarpa), was compared with two conventionally tilled fallow controls (with and without herbicide) (fallow+h and fallow-h) in suppressing weeds and maintaining yields with reduced fertilizer inputs. The comparison was conducted as a split plot, with three N fertilization rates (0, 100, and 200 lb/acre; 0, 112, and 224 kg/ha) as main plots and cover crops and fallow controls as subplots. Tomato seedlings were transplanted 3 weeks after the cover crops had been mowed and sprayed with herbicide. There were no significant differences in weed cover in the no-till cover crop treatments relative to the fallow controls in 1997. Early season weed suppression in rye/vetch and triticale/vetch plots was similar to herbicide-treated fallow (fallow+h) in 1998, however, later in the 1998 season weed suppression was best in the fallow+h. Tissue N was highest in the fallow treatments in both 1997 and 1998. Yields were highest in the triticale/vetch and fallow and lowest in sephi treatments in 1997, but there were no differences among treatments in 1998.