scholarly journals Evaluating Cover Crop Mulches for No-till Organic Production of Onions

HortScience ◽  
2010 ◽  
Vol 45 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Emily R. Vollmer ◽  
Nancy Creamer ◽  
Chris Reberg-Horton ◽  
Greg Hoyt
Keyword(s):  
Soybean Meal ◽  
Cover Crops ◽  
Cover Crop ◽  
N Uptake ◽  
Organic Production ◽  
Weed Suppression ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
No Till

Cover crops of foxtail millet ‘German Strain R’ [Setaria italica (L.) Beauv.] and cowpea ‘Iron & Clay’ [Vigna unguiculata (L.) Walp.] were grown as monocrops (MIL, COW) and mixtures and compared with a bare ground control (BG) for weed suppression and nitrogen (N) contribution when followed by organically managed no-till bulb onion (Allium cepa L.) production. Experiments in 2006–2007 and 2007–2008 were each conducted on first-year transitional land. Mixtures consisted of cowpea with high, middle, and low seeding rates of millet (MIX-70, MIX-50, MIX-30). During onion production, each cover crop treatment had three N rate subplots (0, 105, and 210 kg N/ha) of surface-applied soybean meal [Glycine max (L.) Merrill]. Cover crop treatments COW and BG had the greatest total marketable onion yield both years. Where supplemental baled millet was applied in 2006–2007, onion mortality was over 50% in MIL and MIX and was attributed to the thickness of the millet mulch. Nitrogen rates of 105 and 210 kg N/ha increased soil mineral N (NO3– and NH4+) on BG plots 2 weeks after surface application of soybean meal each year, but stopped having an effect on soil mineral N by February or March. Split applications of soybean meal could be an important improvement in N management to better meet increased demand for N uptake during bulb initiation and growth in the spring.

The effect of winter cover crop management on nitrate leaching losses and crop growth

1998 ◽  
Vol 131 (3) ◽  
pp. 299-308 ◽  
Author(s):  
G. S. FRANCIS ◽  
K. M. BARTLEY ◽  
F. J. TABLEY
Keyword(s):  
Nitrate Leaching ◽  
Cover Crops ◽  
Dry Matter ◽  
N Uptake ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Leaching Losses ◽  
Matter Production ◽  
Fallow Soil

Two field experiments in Canterbury, New Zealand, were conducted during 1993–95 following the ploughing of temporary pasture leys. These experiments investigated the effects of cover crop management on the accumulation of soil mineral N and nitrate leaching during winter, and the growth and N uptake of the following spring cereal crop. The cover crops used were ryegrass (Lolium multiflorum L.), oats (Avena sativa L.), lupins (Lupinus angustifolius L.), mustard (Sinapis alba L.) and winter wheat (Triticum aestivum).Ploughing of temporary pasture in autumn (March) resulted in extensive net N mineralization of organic N by the start of winter (June). In fallow soil, mineral N in the profile in June ranged from 98 kg N/ha in 1993 to 128 kg N/ha in 1994. When cover crops were established early in the autumn (March) in 1993, both the above-ground dry matter production (1440–3108 kg DM/ha) and its N content (50–71 kg N/ha) were substantial by the start of winter. In 1994, establishment of cover crops one month later (April) resulted in very little dry matter production and N uptake by June. In both years, compared with fallow soil, winter wheat planted in May had little effect on soil mineral N content by the start of winter.Compared with fallow, cover crops had little effect on soil drainage over winter. Cumulative nitrate leaching losses from fallow soil were much smaller in 1993 (23 kg N/ha) than in 1994 (49 kg N/ha), mainly due to differences in rainfall distribution. Cover crops reduced cumulative nitrate leaching losses in 1993 to 1–5 kg N/ha and in 1994 to 22–30 kg N/ha. When cover crops were grazed, soil mineral N contents were increased due to the return of ingested plant N to urine patch areas of soil. Elevated soil mineral N contents under grazing persisted throughout the winter. Grazing had little effect on cumulative nitrate leaching losses, mainly because of the small amount of drainage that occurred after grazing in either year.Compared with fallow, incorporation of large amounts of non-leguminous above ground dry matter depressed the yield and N uptake of the following spring-sown cereal crop. Where cover crops were grazed, yields of the following cereal crops were similar to those for soil fallow over the winter.

Can legumes provide greater benefits than millet as a spring cover crop in southern Queensland farming systems?

2017 ◽  
Vol 68 (8) ◽  
pp. 746
Author(s):  
E. M. Wunsch ◽  
L. W. Bell ◽  
M. J. Bell
Keyword(s):  
Soil Water ◽  
Cover Crops ◽  
Cover Crop ◽  
Farming Systems ◽  
N Fixation ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Legume Cover Crops ◽  
Chemical Fallow

Cover crops grown during fallows can increase organic matter inputs, improve soil surface cover to reduce erosion risk, and enhance rainfall infiltration. An experiment compared a chemical fallow control with six different cover crops terminated at either 60 or 90 days after sowing. The commercial choice of millet (Echinochloa esculenta) was compared with two summer legumes (lablab (Lablab purpureus) and soybean (Glycine max)), and three winter legumes (field pea (Pisum sativum), faba bean (Vicia faba) and common vetch (Vicia sativa)). Cover crop biomass growth, atmospheric nitrogen (N) fixation, surface residue cover, and soil water and mineral N dynamics during the growth period and subsequent fallow were measured. Soil water and N availability and yield of wheat crops following the experimental treatments were simulated over a 100-year climate record using APSIM. Both experiments and simulations found the legumes inferior to millet as spring-sown cover crops, because they were slower to accumulate biomass, required later termination and provided groundcover that was less persistent, resulting in lower soil water at the end of the fallow. After 90 days of growth, the summer legumes, lablab and soybean, produced the most biomass and fixed more N (up to 25 kg N/ha) but also extracted the most soil water and mineral N. Legume N fixation was low because of high soil mineral N status (>100 kg N/ha) and occurred only when this had been depleted. At the end of the subsequent fallow in April, soil water was 30–60 mm less and soil mineral N 80–100 kg/ha less after both millet and 90-day terminated summer legume cover crops than the chemical fallow control. Simulations predicted soil-water deficits following legume cover crops to be >50 mm in the majority of years, but soil mineral N was predicted to be lower (median 80 kg N/ha) after millet cover crops. In conclusion, monoculture legume cover crops did not provide advantages over the current commercial standard of millet, owing to less effective provision of groundcover, low N fixation and possibly delayed release of N from residues. Further work could explore how legumes might be more effectively used as cover crops to provide N inputs and soil protection in subtropical farming systems.

Investigating tarps to facilitate organic no-till cabbage production with high-residue cover crops

2018 ◽  
Vol 35 (3) ◽  
pp. 227-233 ◽  
Author(s):  
Natalie P Lounsbury ◽  
Nicholas D Warren ◽  
Seamus D Wolfe ◽  
Richard G Smith
Keyword(s):  
Biological Activity ◽  
Soil Temperature ◽  
Biomass Production ◽  
Nutrient Availability ◽  
Cover Crops ◽  
Cover Crop ◽  
Weed Suppression ◽  
Winter Rye ◽  
No Till ◽  
Crop Biomass

AbstractHigh-residue cover crops can facilitate organic no-till vegetable production when cover crop biomass production is sufficient to suppress weeds (>8000 kg ha−1), and cash crop growth is not limited by soil temperature, nutrient availability, or cover crop regrowth. In cool climates, however, both cover crop biomass production and soil temperature can be limiting for organic no-till. In addition, successful termination of cover crops can be a challenge, particularly when cover crops are grown as mixtures. We tested whether reusable plastic tarps, an increasingly popular tool for small-scale vegetable farmers, could be used to augment organic no-till cover crop termination and weed suppression. We no-till transplanted cabbage into a winter rye (Secale cereale L.)-hairy vetch (Vicia villosa Roth) cover crop mulch that was terminated with either a roller-crimper alone or a roller-crimper plus black or clear tarps. Tarps were applied for durations of 2, 4 and 5 weeks. Across tarp durations, black tarps increased the mean cabbage head weight by 58% compared with the no tarp treatment. This was likely due to a combination of improved weed suppression and nutrient availability. Although soil nutrients and biological activity were not directly measured, remaining cover crop mulch in the black tarp treatments was reduced by more than 1100 kg ha−1 when tarps were removed compared with clear and no tarp treatments. We interpret this as an indirect measurement of biological activity perhaps accelerated by lower daily soil temperature fluctuations and more constant volumetric water content under black tarps. The edges of both tarp types were held down, rather than buried, but moisture losses from the clear tarps were greater and this may have affected the efficacy of clear tarps. Plastic tarps effectively killed the vetch cover crop, whereas it readily regrew in the crimped but uncovered plots. However, emergence of large and smooth crabgrass (Digitaria spp.) appeared to be enhanced in the clear tarp treatment. Although this experiment was limited to a single site-year in New Hampshire, it shows that use of black tarps can overcome some of the obstacles to implementing cover crop-based no-till vegetable productions in northern climates.

Computer simulation of changes in soil mineral nitrogen and crop nitrogen during autumn, winter and spring

1987 ◽  
Vol 109 (1) ◽  
pp. 141-157 ◽  
Author(s):  
T. M. Addiscott ◽  
A. P. Whitmore
Keyword(s):  
Soil Temperature ◽  
Dry Matter ◽  
N Uptake ◽  
Sowing Date ◽  
Mineralization Rate ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Crop N Uptake

summaryThe computer model described simulates changes in soil mineral nitrogen and crop uptake of nitrogen by computing on a daily basis the amounts of N leached, mineralized, nitrified and taken up by the crop. Denitrification is not included at present. The leaching submodel divides the soil into layers, each of which contains mobile and immobile water. It needs points from the soil moisture characteristic, measured directly or derived from soil survey data; it also needs daily rainfall and evaporation. The mineralization and nitrification submodel assumes pseudo-zero order kinetics and depends on the net mineralization rate in the topsoil and the daily soil temperature and moisture content, the latter being computed in the leaching submodel. The crop N uptake and dry-matter production submodel is a simple function driven by degree days of soil temperature and needs in addition only the sowing date and the date the soil returns to field capacity, the latter again being computed in the leaching submodel. A sensitivity analysis was made, showing the effects of 30% changes in the input variables on the simulated amounts of soil mineral N and crop N present in spring when decisions on N fertilizer rates have to be made. Soil mineral N was influenced most by changes in rainfall, soil water content, mineralization rate and soil temperature, whilst crop N was affected most by changes in soil temperature, rainfall and sowing date. The model has so far been applied only to winter wheat growing through autumn, winter and spring but it should be adaptable to other crops and to a full season.The model was validated by comparing its simulations with measurements of soil mineral N, dry matter and the amounts of N taken up by winter wheat in experiments made at seven sites during 5 years. The simulations were assessed graphically and with the aid of several statistical summaries of the goodness of fit. The agreement was generally very good; over all years 72% of all simulations of soil mineral N to 90 cm depth were within 20 kg N/ha of the soil measurements; also 78% of the simulations of crop nitrogen uptake were within 15 kg N/ha and 63% of the simulated yields of dry matter were within 25 g/m2 of the amounts measured. All correlation coefficients were large, positive, and highly significant, and on average no statistically significant differences were found between simulation and measurement either for soil mineral N or for crop N uptake.

Five years of straw incorporation and its effect on growth, yield and nitrogen nutrition of sugarbeet (Beta vulgaris)

1995 ◽  
Vol 125 (1) ◽  
pp. 61-68 ◽  
Author(s):  
M. F. Allison ◽  
H. M. Hetschkun
Keyword(s):  
Field Experiments ◽  
Nitrogen Nutrition ◽  
N Uptake ◽  
Growth Yield ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Fertilizer Use ◽  
Experimental Station ◽  
Straw Incorporation

SUMMARYIn 1990–92, field experiments were performed at Broom's Barn Experimental Station to study the effect of 5 years' repeated straw incorporation on sugarbeet. Straw incorporation had no effect on plant population density. Processing quality was reduced by incorporated straw but N had a much larger effect. The effect of incorporated straw on the mineral N content of the soils and N uptake by beet was inconsistent, and this may be related to the amount of soil mineral N present when the straw was incorporated. The efficiency of fertilizer use was unaffected by straw incorporation. On Broom's Barn soils when straw was incorporated, the optimal economic N dressing was c. 120 kg N/ha, and in unincorporated plots it was c. 100 kg N/ha. At the optimal economic N rate, incorporated straw increased beet yields.

scholarly journals Greenhouse gas (N2O and CH4) fluxes under nitrogen-fertilised dryland wheat and barley on subtropical Vertosols: risk, rainfall and alternatives

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 634 ◽  
Author(s):  
Graeme D. Schwenke ◽  
David F. Herridge ◽  
Clemens Scheer ◽  
David W. Rowlings ◽  
Bruce M. Haigh ◽  
...  
Keyword(s):  
N Uptake ◽  
Nitrification Inhibitor ◽  
N2o Emission ◽  
N2o Emissions ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Before And After ◽  
Ch4 Uptake ◽  
Crop N Uptake

The northern Australian grains industry relies on nitrogen (N) fertiliser to optimise yield and protein, but N fertiliser can increase soil fluxes of nitrous oxide (N2O) and methane (CH4). We measured soil N2O and CH4 fluxes associated with wheat (Triticum aestivum) and barley (Hordeum vulgare) using automated (Expts 1, 3) and manual chambers (Expts 2, 4, 5). Experiments were conducted on subtropical Vertosol soils fertilised with N rates of 0–160kgNha–1. In Expt 1 (2010), intense rainfall for a month before and after sowing elevated N2O emissions from N-fertilised (80kgNha–1) wheat, with 417gN2O-Nha–1 emitted compared with 80g N2O-Nha–1 for non-fertilised wheat. Once crop N uptake reduced soil mineral N, there was no further treatment difference in N2O. Expt 2 (2010) showed similar results, however, the reduced sampling frequency using manual chambers gave a lower cumulative N2O. By contrast, very low rainfall before and for several months after sowing Expt 3 (2011) resulted in no difference in N2O emissions between N-fertilised and non-fertilised barley. N2O emission factors were 0.42, 0.20 and –0.02 for Expts 1, 2 and 3, respectively. In Expts 4 and 5 (2011), N2O emissions increased with increasing rate of N fertiliser. Emissions were reduced by 45% when the N fertiliser was applied in a 50:50 split between sowing and mid-tillering, or by 70% when urea was applied with the nitrification inhibitor 3,4-dimethylpyrazole-phosphate. Methane fluxes were typically small and mostly negative in all experiments, especially in dry soils. Cumulative CH4 uptake ranged from 242 to 435g CH4-Cha–1year–1, with no effect of N fertiliser treatment. Considered in terms of CO2 equivalents, soil CH4 uptake offset 8–56% of soil N2O emissions, with larger offsets occurring in non-N-fertilised soils. The first few months from N fertiliser application to the period of rapid crop N uptake pose the main risk for N2O losses from rainfed cereal cropping on subtropical Vertosols, but the realisation of this risk is dependent on rainfall. Strategies that reduce the soil mineral N pool during this time can reduce the risk of N2O loss.

Weed Control and Sweet Corn (Zea maysvar.rugosa) Response in a No-till System with Cover Crops

Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 355-361 ◽  
Author(s):  
Nilda R. Burgos ◽  
Ronald E. Talbert
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Sweet Corn ◽  
Weed Suppression ◽  
Growth And Yield ◽  
Hairy Vetch ◽  
Yellow Nutsedge ◽  
No Till ◽  
Agricultural Experiment ◽  
And Control

Studies were conducted at the Main Agricultural Experiment Station in Fayetteville and the Vegetable Substation in Kibler, Arkansas, in 1992 and 1993 on the same plots to evaluate weed suppression by winter cover crops alone or in combination with reduced herbicide rates in no-till sweet corn and to evaluate cover crop effects on growth and yield of sweet corn. Plots seeded to rye plus hairy vetch, rye, or wheat had at least 50% fewer early season weeds than hairy vetch alone or no cover crop. None of the cover crops reduced population of yellow nutsedge. Without herbicides, hairy vetch did not suppress weeds 8 wk after cover crop desiccation. Half rates of atrazine and metolachlor (1.1 + 1.1 kg ai ha−1) reduced total weed density more effectively in no cover crop than in hairy vetch. Half rates of atrazine and metolachlor controlled redroot pigweed, Palmer amaranth, and goosegrass regardless of cover crop. Full rates of atrazine and metolachlor (2.2 + 2.2 kg ai ha−1) were needed to control large crabgrass in hairy vetch. Control of yellow nutsedge in hairy vetch was marginal even with full herbicide rates. Yellow nutsedge population increased and control with herbicides declined the second year, particularly with half rates of atrazine and metolachlor. All cover crops except hairy vetch alone reduced emergence, height, and yield of sweet corn. Sweet corn yields from half rates of atrazine and metolachlor equalled the full rates regardless of cover crops.

Dynamics of nitrogen capture without fertilizer: the baseline for fertilizing winter wheat in the UK

2001 ◽  
Vol 136 (1) ◽  
pp. 15-33 ◽  
Author(s):  
R. SYLVESTER-BRADLEY ◽  
D. T. STOKES ◽  
R. K. SCOTT
Keyword(s):  
Winter Wheat ◽  
N Uptake ◽  
Soil Horizon ◽  
Soil N ◽  
Soil Mineral N ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Mineral N ◽  
Fertilizer Use ◽  
The Uk

Experiments at three sites in 1993, six sites in 1994 and eight sites in 1995, mostly after oilseed rape, tested effects of previous fertilizer N (differing by 200 kg/ha for 1993 and 1994 and 300 kg/ha for 1995) and date of sowing (differing by about 2 months) on soil mineral N and N uptake by winter wheat cv. Mercia which received no fertilizer N. Soil mineral N to 90 cm plus crop N (‘soil N supply’; SNS) in February was 103 and 76 kg/ha after large and small amounts of previous fertilizer N respectively but was not affected by date of sowing. Previous fertilizer N seldom affected crop N in spring because sowing was too late for N capture during autumn, but it did affect soil mineral N, particularly in the 60–90 cm soil horizon, presumably due to over-winter leaching. Tillering generally occurred in spring, and was delayed but not diminished by later sowing. Previous fertilizer N increased shoot survival more than it increased shoot production. Final shoot number was affected by previous fertilizer N, but not by date of sowing. Overall, there were 29 surviving tillers/g SNS.N uptakes at fortnightly intervals from spring to harvest at two core sites were described well by linear rates. The difference between sowings in the fitted date with 10 kg/ha crop N was 1 month; these dates were not significantly affected by previous fertilizer. N uptake rates were increased by both previous fertilizer N and late sowing. Rates of N uptake related closely to soil mineral N in February such that ‘equivalent recovery’ was achieved in late May or early June. At one site there was evidence that most of the residue from previous fertilizer N had moved below 90 cm by February, but N uptake was nevertheless increased. Two further ‘satellite’ sites behaved similarly. Thus at 14 out of 17 sites, N uptake until harvest related directly and with approximate parity to soil mineral N in February (R2 = 0·79), a significant intercept being in keeping with an atmospheric contribution of 20–40 kg/ha N at all sites.It is concluded that, on retentive soils in the UK, SNS in early spring was a good indicator of N availability throughout growth of unfertilized wheat, because the N residues arising from previous fertilizer mineralized before analysis, yet remained largely within root range. The steady rates of soil mineral N recovery were taken as being dependent on progressively deeper root development. Thus, even if soil mineral N equated with a crop's N requirement, fresh fertilizer applications might be needed before ‘equivalent recovery’ of soil N, to encourage the earlier processes of tiller production and canopy expansion. The later process of grain filling was sustained by continued N uptake (mean 41 kg/ha) coming apparently from N leached to the subsoil (relating to previous fertilizer use) as well as from sources not related to previous fertilizer use; significant net mineralization was apparent in some subsoils.

No-till seeded spinach after winterkilled cover crops in an organic production system

2014 ◽  
Vol 30 (5) ◽  
pp. 473-485 ◽  
Author(s):  
Natalie P. Lounsbury ◽  
Ray R. Weil
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Spinacia Oleracea ◽  
Management Strategies ◽  
Field Work ◽  
Early Spring ◽  
Organic Production ◽  
No Till ◽  
Winter Cover ◽  
Winter Cover Crops

AbstractOrganic no-till (NT) management strategies generally employ high-residue cover crops that act as weed-suppressing mulch. In temperate, humid regions such as the mid-Atlantic USA, high-residue winter cover crops can hinder early spring field work and immobilize nutrients for cash crops. This makes the integration of cover crops into rotations difficult for farmers, who traditionally rely on tillage to prepare seedbeds for early spring vegetables. Our objectives were to address two separate but related goals of reducing tillage and integrating winter cover crops into early spring vegetable rotations by investigating the feasibility of NT seeding spinach (Spinacia oleracea L.), an early spring vegetable, into winterkilled cover crops. We conducted a four site-year field study in the Piedmont and Coastal Plain regions of Maryland, USA, comparing seedbed conditions and spinach performance after forage radish (FR) (Raphanus sativus L.), a low-residue, winterkilled cover crop, spring oat (Avena sativa L.), the traditional winterkilled cover crop in the area, a mixture of radish and oat, and a no cover crop (NC) treatment. NT seeded spinach after FR had higher yields than all other cover crop and tillage treatments in one site year and was equal to the highest yielding treatments in two site years. Yield for NT spinach after FR was as high as 19 Mg ha−1 fresh weight, whereas the highest yield for spinach seeded into a rototilled seedbed after NC was 10 Mg ha−1. NT seeding spring spinach after a winterkilled radish cover crop is feasible and provides an alternative to both high-residue cover crops and spring tillage.

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