• Authors:
    • Hoshino, Y.
    • Hirata, T.
    • Sarwar, A.
    • Araki, H.
  • Source: Acta Horticulturae
  • Issue: 950
  • Year: 2012
  • Summary: As asparagus plants are grown for a long period after transplanting, it is not possible to plow the field for soil improvement. Recently, because of global warming, establishment of new cropping system with carbon sequestration in soil has been expected. Cover crops provide a large amount of organic matter into the soil in many cropping. The effects of living mulch of cover crops on weed control and carbon storage were evaluated in the asparagus field planted for more than 16 years at the Experimental Farm of Hokkaido University, Sapporo, Japan. Wheat 'Hokushin' and 'Mulchi-mugi', barley 'Temairazu' and rye 'Kita-midori' were used as living mulch and were sown from early April to middle in May. Cropping with living mulch was repeated from 2006 to 2008. Wheat and barley continued vegetative growth because of no meeting of low temperature when they were sown in late April and May. However they were planted in early April, heading was observed in some plants. Weeds in interrow space were controlled by the emerged leaves of living mulch. Weed control ability of barley was high because of broad leaves emerged. Weed dry weight in summer reduced to 5% in barley living mulch compared with bare field when barley was planted at seeding density of 10 kg/10 a, in 2008. It reduced to 25% in wheat 'Mulch-mugi' which has tolerance to hot temperature. Heading was observed in rye even if rye was sown in May. Carbon content in the top soil with barley and rye increased 0.26-0.28% in average compared with bare field (no living mulch), however, there was no significant difference in soil carbon content among observed fields with or without cover crops. Spear yield was measured in 'Gijnlim' field, 8 years old, treated with living mulch in 2008 and significant difference was not recognized between rows with and without wheat living mulch in spring 2009.
  • Authors:
    • Bazewicz-Wozniak, M.
    • Wach, D.
  • Source: Acta Scientiarum Polonorum - Hortorum Cultus
  • Volume: 11
  • Issue: 3
  • Year: 2012
  • Summary: With the uptake of organic farming the importance of green manures increases, and the cultivation of cover crops plays an ever important role both in agriculture and in horticulture. The fertilizer value of plants cultivated for green manures is largely dependent on the biomass produced, and also the nutrients that were accumulated within it. The aim of this work is to determine the influence of weather conditions in the second half of summer on the fertilizer value of catch crops intended for cultivation of vegetables. The research included: spring rye ( Secale cereale), oats ( Avena sativa), common vetch ( Vicia sativa), white mustard ( Sinapis alba), tancy phacelia ( Phacelia tanacetifolia), buckwheat ( Fagopyrum esculentum), fodder sunflower ( Helianthus annuus). The catch crop plants, cultivated as a pre-crop for the cultivation of vegetables proved to be a rich source of organic matter and nutrients for the following crops. The course of weather had a major influence on the volume of biomass, and the chemical composition and fertilizer value of cover crops. Shortage of water and high temperatures after rainfalls, causing the formation of crust on the soil did mostly limit the growth of catch crops. The biggest biomass among the investigated catch crops was created by sunflowers, phacelia and rye, the lowest by common vetch. White mustard and sunflower provided the biggest amount of nitrogen in their role as catch crops. The sunflower proved to be a rich source of K, Ca and Mg. The most Ca was left in the field by tancy phacelia, which also proved to be a good source of K. The biomass of buckwheat provided large amounts of Mg, but it was poor in N, P and S. Rye and oats proved to be a rich sources of P, but they also contained small amount of Ca and Mg. The most sulphur was left over by the biomass of white mustard. The common vetch proved to be the most weather-sensitive of all plants. Its biomass left the least P, K, Mg and S in the field, the Ca content was also small, compared to other catch crops. Nitrogen content of dry matter of common vetch was high, but not the highest in the three year average.
  • Authors:
    • Hirata, T.
    • Komatsuzaki, M.
    • Nakamoto, T.
    • Araki, H.
  • Source: Soil Science and Plant Nutrition
  • Volume: 58
  • Issue: 1
  • Year: 2012
  • Summary: We hypothesized that cover cropping could increase soil microbial activities under various tillage systems and that increased microbial activities would improve soil properties. Soil sampling was conducted at two fields in Japan in 2009. At the Ibaraki field (Andosol, clay loam), three tillage practices (no-tillage, plowing to 30 cm, and rotary tillage to 15 cm) and three types of winter cover cropping [bare fallow as control, hairy vetch ( Vicia villosa Roth), and rye ( Secale cereale L.)] were conducted from 2003 to 2009. At the Hokkaido field (Fluvisol, light clay), two tillage practices (autumn tillage and rotary tillage with a rotary tiller to a depth of 15 cm once in autumn and twice in a year, respectively), and four types of winter cover cropping (bare fallow, hairy vetch, bristle oat ( Avena strigosa L.), and a mixture of hairy vetch and bristle oat) were conducted from 2006 to 2009. Soil microbial activities and the fungal-to-bacterial activity ratio (F/B ratio) were estimated by the substrate-induced respiration (SIR) method with the use of selective antibiotics. At the Ibaraki field, rye cover cropping showed higher microbial SIR than bare fallow at depths of 0-30 cm and rotary tillage maintained higher microbial SIR than no-tillage or plowing at depths of 7.5-15 cm. There was no meaningful interaction effect between cover cropping and tillage on microbial SIR. At the Hokkaido field, cover cropping and tillage had only limited effects on microbial SIR. High F/B ratios (indicating fungal dominance) were recorded with the use of cover crops in both fields. Fungal SIR, estimated from the microbial SIR and F/B ratio, was closely related to the content of total soil organic carbon (SOC) and the mean weight diameter (MWD) of water-stable aggregates. Based on SOC, fungal SIR was significantly higher under rye cover cropping. The relationship between fungal SIR and MWD was affected by tillage. We conclude that rye cover cropping and rotary tillage were very effective in increasing fungal SIR, SOC, and MWD in the Ibaraki soil. Field practices that enhance fungal activities might be effective in improving certain types of arable soil.
  • Authors:
    • Szendrei, Z.
  • Source: Entomologia Experimentalis et Applicata
  • Volume: 143
  • Issue: 2
  • Year: 2012
  • Summary: Habitat diversification can influence the interactions of insects with plants and this can be used in agroecosystems for the management of pest populations. Plant diversification can be achieved through planting crops, such as trap crops, or by adjusting weed management. Aster leafhopper, Macrosteles quadrilineatus Forbes (Hemiptera: Cicadellidae), is a polyphagous species that uses cereals, vegetables, and weeds as host plants. The influence of weeds on M. quadrilineatus abundance was investigated experimentally in carrot [ Daucus carota L. cv. Canada (Apiaceae)] field plots by adjusting the level of management of two groups of weeds (broadleaf and grass) and by comparing it to weed-free plots. The preference of M. quadrilineatus for different cereal and weed species relative to carrots was tested in choice test assays. Habitat context influenced the abundance of M. quadrilineatus in the field experiments. The presence of border crops such as oat, rye, barley, wheat, and triticale did not significantly attract or repel this insect to carrot plots compared to the no-border treatment. However, spelt-bordered plots had 42% fewer M. quadrilineatus than three treatments, triticale, wheat, and barley, that had the highest insect abundance. The type of weed management affected M. quadrilineatus abundance in carrot plots, but not the frequency of herbicide application. Plots that had carrot growing with broadleaf-weeds had about 59% fewer M. quadrilineatus compared with those growing with crabgrass or carrot alone. In the greenhouse choice tests, grasses (e.g., cereals) attracted and broadleaf-weeds repelled M. quadrilineatus relative to carrots. In summary, carrot growers may be able to manage this pest by reducing the interaction of cereal cover crops with carrots and eliminating grassy weeds in commercial production fields.
  • Authors:
    • Shennan, C.
    • Muramoto, J.
    • Albano, J. P.
    • Kokalis-Burelle, N.
    • Rosskopf, E. N.
    • Butler, D. M.
  • Source: PLANT AND SOIL
  • Volume: 355
  • Issue: 1-2
  • Year: 2012
  • Summary: Anaerobic soil disinfestation (ASD) has been shown to be an effective strategy for controlling soilborne plant pathogens and plant-parasitic nematodes in vegetable and other specialty crop production systems. Anaerobic soil disinfestation is based upon supplying labile carbon (C) to stimulate microbially-driven anaerobic soil conditions in moist soils covered with polyethylene mulch. To test the effectiveness of warm-season cover crops as C sources for ASD, a greenhouse study was conducted using a sandy field soil in which several warm-season legumes and grasses were grown and incorporated and compared to molasses-amended and no C source controls. Greenhouse pots were irrigated to fill soil porosity and covered with a transparent polyethylene mulch to initiate a 3-week ASD treatment prior to planting tomatoes. Soilborne plant pathogen inoculum packets, yellow nutsedge (Cyperus esculentus L.) tubers, and Southern root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood; M.i.) eggs and juveniles were introduced at cover crop incorporation. In nearly all cases, ASD treatment utilizing cover crops as a C source resulted in soil anaerobicity values that were equal to the molasses-amended fallow control and greater than the no C source fallow control. In trial 1, Fusarium oxysporum Schlechtend.:Fr. (F.o.) survival was reduced by more than 97% in all C source treatments compared to the no C source control but there was no effect of C source in Trial 2. Carbon source treatments were inconsistent in their effects on survival of Sclerotium rolfsii Sacc. (S.r). In general, the number of M.i. extracted from tomato root tissue and root gall ratings were low in all treatments with cover crop C source, molasses C source, or composted poultry litter. Germination of yellow nutsedge tubers was highest in the no C source control (76%), lowest in the molasses control (31%), and intermediate from cover crop treatments (49% to 61%). Warm-season cover crops have potential to serve as a C source for ASD in vegetable and other crop production systems, but more work is needed to improve consistency and further elucidate mechanisms of control of soilborne plant pathogens and weeds during ASD treatment utilizing cover crops.
  • Authors:
    • Bosch, D. D.
    • Franklin, D. H.
    • Truman, C. C.
    • Potter, T. L.
    • Strickland, T. C.
    • Hawkins, G. L.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 122
  • Year: 2012
  • Summary: Assessment of erosion impact on soil carbon and nitrogen loss and redistribution within landscapes is needed to develop estimates of soil carbon sequestration potential, soil quality management plans, and to evaluate potential for transport of sediment bound agrochemicals. We used variable intensity rainfall simulations to quantify the effects of tillage, conventional and strip, and antecedent soil water content on sediment-bound carbon and nitrogen loss from a Tifton loamy sand located in the southeastern Atlantic Coastal Plain (USA). Carbon and nitrogen loss via erosion of silt. +. clay sized versus sand sized sediment particles were quantified. Antecedent water content had no effect on mean sediment loss within tillage treatments, but losses from conventional till treatments were significantly greater than from strip till. Sediment lost as silt. +. clay was from 58 to 78% of the total under conventional and from 30 to 39% under strip tillage. The fraction of sediment lost as silt. +. clay versus sand was greater under conventional tillage than under strip tillage. Within-event sediment carbon enrichment compared to the top 2. cm of soil was 0.9-7.2 for conventional and 0.6-3.7 for strip tillage. The strip till silt. +. clay fraction had significantly higher carbon content than the strip till sand fraction and the conventional till silt. +. clay fraction. Carbon loss from treatments was directly proportional to sediment loss. However, the conventional till treatments lost 4.6-6 times more carbon from the silt. +. clay sized fraction and 1.9-4.8 times more carbon from the sand sized fraction than strip till treatments. Results suggest that the higher proportion of silt. +. clay fraction sediment loss from conventional till may deplete nitrogen enriched organic matter while decreased erosion from strip till may serve to increase retention of organic nitrogen. Findings also indicate that an approach that adjusts loss estimates of organic carbon and nitrogen by using wet-sieved subsamples for analysis followed by standardization against total bulk sediment loss accounts for introduced errors from both sub-sampling efficiency and disturbance.
  • Authors:
    • Ahuja, L. R.
    • Hatfield, J. L.
    • Ma, L.
    • Malone, R. W.
    • Heiman, P.
    • Boyle, K. P.
    • Kanwar, R. S.
  • Source: Agricultural Systems
  • Volume: 106
  • Issue: 1
  • Year: 2012
  • Summary: A 45% reduction in riverine total nitrogen flux from the 1980-1996 time period is needed to meet water quality goals in the Mississippi Basin and Gulf of Mexico. This paper addresses the goal of reducing nitrogen in the Mississippi River through three objectives. First, the paper outlines an approach to the site-specific quantification of management effects on nitrogen loading from tile drained agriculture using a simulation model and expert review. Second, information about the net returns to farmers is integrated with the nitrogen loading information to assess the incentives to adopt alternative management systems. Third, the results are presented in a decision support framework that compares the rankings of management systems based on observed and simulated values for net returns and nitrogen loading. The specific question addressed is how information about the physical and biological processes at Iowa State University's Northeast Research Farm near Nashua, Iowa, could be applied over a large area to help farmers select management systems to reduce nitrogen loading in tile drained areas. Previous research has documented the parameterization and calibration of the RZWQM model at Nashua to simulate 35 management system effects on corn and soybean yields and N loading in tileflow from 1990 to 2003. As most management systems were studied for a 6 year period and in some cases weather had substantial impacts, a set of 30 alternative management systems were also simulated using a common 1974-2003 input climate dataset. To integrate an understanding of the economics of N management, we calculated net returns for all management systems using the DevTreks social budgeting tool. We ranked the 35 observed systems in the Facilitator decision support tool using N loading and net returns and found that rankings from simulated results were very similar to those from the observed results from both an onsite and offsite perspective. We analyzed the effects of tillage, crop rotation, cover crops, and N application method, timing, and amount for the 30 long term simulations on net returns and N loading. The primary contribution of this paper is an approach to creating a quality assured database of management effects on nitrogen loading and net returns for tile drained agriculture in the Mississippi Basin. Such a database would systematically extend data from intensively monitored agricultural fields to the larger area those fields represent. Published by Elsevier Ltd.
  • Authors:
    • Finlay, L. A.
    • Hulugalle, N. R.
    • Weaver, T. B.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 27
  • Issue: 2
  • Year: 2012
  • Summary: Cover crops in minimum or no-tilled systems are usually killed by applying one or more herbicides, thus significantly increasing costs. Applying herbicides at lower rates with mechanical interventions that do not disturb or bury cover crop residues can, however, reduce costs. Our objective was to develop a management system with the above-mentioned features for prostrate cover crops on permanent beds in an irrigated Vertisol. The implement developed consisted of a toolbar to which were attached spring-loaded pairs of parallel coulter discs, one set of nozzles between the individual coulter discs that directed a contact herbicide to the bed surfaces to kill the cover crop and a second set of nozzles located to direct the cheaper glyphosate to the furrow to kill weeds. The management system killed a prostrate cover crop with less trafficking, reduced the use of more toxic herbicides, carbon footprint, labor and risk to operators. Maximum depth of compaction was more but average increase was less than that with the boom sprayer control.
  • Authors:
    • Takebe, M.
    • Karasawa, T.
  • Source: Plant and Soil
  • Volume: 353
  • Issue: 1-2
  • Year: 2012
  • Summary: Aims A field experiment was conducted where maintenance of indigenous arbuscular mycorrhizal (AM) fungal populations was attempted using AM host cover crops arranged temporally or spatially during growth of nonmycorrhizal crops. Methods To arrange AM hosts temporally, sunflower or oat was grown as a cover crop after non-host cropping (cabbage) or fallowing. In order to arrange AM hosts spatially, red clover, white clover or vetch was intercropped during growth of non-host cabbage. Results The AM colonization and growth of maize with previously introduced sunflower or oat were much greater than those without introduction of cover crops or those with introduction of non-host cover crops. The AM colonization and yield of winter wheat grown after cabbage with AM host intercropping were greater than those after cabbage only cropping, suggesting that arrangement of AM hosts between cabbage rows is effective for maintaining the AM fungal population in soil during non-host cropping. Conclusions Mycorrhizal hosts cropped after or during non-host cropping is an effective means to increase indigenous AM fungal populations. The results show that AM colonization, P uptake and productivity of crops after cultivation of nonmycorrhizal crops can be improved by arranging AM hosts temporally or spatially as cover crops.
  • Authors:
    • Singer, J. W.
    • Moorman, T. B.
    • Parkin, T. B.
    • Jaynes, D. B.
    • Kaspar, T. C.
  • Source: Agricultural Water Management
  • Volume: 110
  • Year: 2012
  • Summary: Much of the NO3 in the riverine waters of the upper Mississippi River basin in the United States originates from agricultural land used for corn (Zea mays L) and soybean (Glycine max [L] Merr.) production. Cover crops grown between maturity and planting of these crops are one approach for reducing losses of NO3. In this experiment, we evaluated the effectiveness of oat (Avena sativa L.) and rye (Secale cereale L.) cover crops in reducing NO3 concentrations and loads in subsurface drainage water. The oat fall cover crop was broadcast seeded into living corn and soybean crops before harvest in late August or early September and was killed by cold temperatures in late November or early December The rye winter cover crop, which had already been used annually for four years, was planted with a grain drill after corn and soybean harvest, overwintered, grew again in the spring, and was killed with herbicides before main crop planting. These treatments were evaluated in subsurface-drained field plots with an automated system for measuring drainage flow and collecting proportional samples for analysis of NO3 concentrations from each plot. The rye winter cover crop significantly reduced drainage water NO3 concentrations by 48% over five years, but this was less than the 58% reduction observed in its first four years of use. The oat fall cover crop reduced NO3 concentrations by 26% or about half of the reduction of the rye cover crop. Neither cover crop significantly reduced cumulative drainage or nitrate loads because of variability in cumulative annual drainage among plots. Both oat and rye cover crops are viable management options for significantly reducing NO3 losses to surface waters from agricultural drainage systems used for corn and soybean production. Published by Elsevier B.V.