scholarly journals Environmental advantages of binary mixtures of Trifolium incarnatum and Lolium multiflorum over individual pure stands

2012 ◽  
Vol 59 (No. 1) ◽  
pp. 22-28 ◽  
Author(s):  
B. Kramberger ◽  
A. Gselman ◽  
M. Podvršnik ◽  
J. Kristl ◽  
M. Lešnik

To investigate the environmental advantages of using grass-clover binary mixtures over pure stands as winter cover crops, a serial of five field experiments (each designed as randomized complete blocks with four replicates) was carried out in eastern Slovenia. Trifolium incarnatum L. and Lolium multiflorum Lam. were sown in late summer as pure stands and binary mixtures. Pooled data calculated from all the experiments revealed that the soil mineral N in spring and accumulation of N by plants decreased with decreasing proportion of T. incarnatum in the binary mixtures, while the C:N ratio of cover crop organic matter increased. C accumulation was the highest when the seeding ratio of the binary mixture of T. incarnatum and L. multiflorum was 50:50. In the C and N environmentally sustainable management efficiency coefficients, three important traits of winter cover crops for environmental pro-tection were given equal importance (low soil mineral N content in spring, high C accumulation in plants, and high N accumulation in plants). The coefficient was higher for binary mixtures of T. incarnatum and L. multiflorum than for pure stands of these crops, proving the complex environmental advantages of binary mixtures over pure stands.

1995 ◽  
Vol 124 (1) ◽  
pp. 1-9 ◽  
Author(s):  
G. S. Francis ◽  
R. J. Haynes ◽  
P. H. Williams

SUMMARYTwo field experiments at Canterbury, New Zealand during 1991–93 investigated the effect of the timing of ploughing a 4-year-old ryegrass/white clover pasture and the effect of two winter cover crops on subsequent N mineralization, nitrate leaching and growth and N uptake of the following wheat crops.Net N mineralization of organic N (of plant and soil origin) increased with increased fallow period between ploughing and leaching. The total amount of N accumulated in the profile by the start of winter ranged from 107 to 131 and from 42 to 45 kg N/ha for fallow treatments started in March and May respectively. Winter wheat (planted in May) had no effect on mineral N contents by the start of winter, whereas greenfeed (GF) oats (planted in March) significantly reduced the mineral N content in one year.Cumulative leaching losses over the first winter after ploughing-in pasture varied markedly between years in relation to rainfall amount and distribution. Leaching losses were greater from the March fallow (72–106 kg N/ha) than the May fallow treatments (8–52 kg N/ha). Winter wheat did not reduce leaching losses in either year. GF oats did not reduce losses in 1991/92, but losses in 1992/93, when major drainage events occurred late in the winter, were only c. 40% of those under fallow.Incorporation of a large amount (> 7 t/ha dry matter) of pasture or GF oat residue in spring depressed yield and total N uptake of the following spring wheat, largely due to net N immobilization which could be overcome by the application of fertilizer N.First-year treatments had very little residual effect in the second year. Leaching losses over the second winter (mean 142 kg N/ha) were largely unaffected by the extent of first year leaching losses. Second year leaching losses were greater than first year losses, probably due to the greater amount of mineral N at depth in the soil before the start of the second winter.


2008 ◽  
Vol 59 (12) ◽  
pp. 1156 ◽  
Author(s):  
A. Gselman ◽  
B. Kramberger

Winter cover crops are beneficial, especially legumes that can supply nitrogen (N) to the next crop. The purpose of this study, involving separate experiments carried out at 2 different locations in north-eastern Slovenia, was to determine the most appropriate sowing time (early, early autumn SD1; late, mid autumn SD2; very late, late autumn SD3) for winter legumes (Trifolium subterraneum L., T. incarnatum L., T. pratense L., and Vicia villosa Roth) for the optimal yield of beneficial dry matter and soil N cycling. The control treatment used Lolium multiflorum Lam. For legume cover crops in SD1, from 915.0 (T. subterraneum) to 2495.0 (V. villosa) kg herbage dry matter yield (HDMY)/ha, 52.3 (T. pratense) to 148.4 (T. incarnatum) kg accumulated N (AN)/ha, and 14.5 (T. pratense) to 114.5 (T. incarnatum) kg symbiotically fixed N (Nsymb)/ha was obtained to the end of autumn. Until the spring ploughing-in, which was before maize sowing, legume cover crops in SD1 yielded 1065.0 (T. subterraneum) to 4440.0 (T. incarnatum) kg HDMY/ha, 74.9 (T. subterraneum) to 193.0 (V. villosa) kg AN/ha, and 4.7 (T. subterraneum) to 179.0 (V. villosa) kg Nsymb/ha. All parameters in SD2 were significantly lower than in SD1, whereas the SD3 sowing was not suitable for the legumes. The benefits of legume winter cover crops with regard to symbiotic N fixation were achieved only by early sowing; however, the amount of soil mineral N in late autumn and in early spring was decreased under L. multiflorum more than under the legumes.


1995 ◽  
Vol 125 (1) ◽  
pp. 61-68 ◽  
Author(s):  
M. F. Allison ◽  
H. M. Hetschkun

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.


HortScience ◽  
2010 ◽  
Vol 45 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Emily R. Vollmer ◽  
Nancy Creamer ◽  
Chris Reberg-Horton ◽  
Greg Hoyt

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.


1996 ◽  
Vol 36 (5) ◽  
pp. 581 ◽  
Author(s):  
J Evans ◽  
NA Fettell ◽  
GE O'Connor

Grain legume-cereal rotations are unsustainable on acid soils because they promote acidification of surface soil through nitrate leaching. Two field experiments were conducted on red, clay-loams in the cropping zone of central western New South Wales to determine whether soil mineral N concentrations during crop growth are higher under pea than barley, and whether the nitrate concentration under pea crops can be decreased by ammending soil with cereal straw before sowing.Significantly higher mineral N, particularly nitrate, was found under pea than under barley, as early as 6 weeks following autumn sowing, and also in spring. The pea effect represented an increase of up to 23 kg N/ha of mineral N (0-30 cm). It is proposed that the source of higher nitrate concentration under pea may be residual soil nitrate not utilised by pea, or nitrate derived from the mineralisation of pea roots or exudate. The increase in soil nitrate during pea growth contributes to greater postharvest soil mineral N and higher wheat yields after pea, but also increases the risk of soil acidification. Soil ammendment with cereal straw was partially effective in reducing nitrate concentration under pea, but a more effective treatment is required.


1998 ◽  
Vol 131 (3) ◽  
pp. 299-308 ◽  
Author(s):  
G. S. FRANCIS ◽  
K. M. BARTLEY ◽  
F. J. TABLEY

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.


Soil Research ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 695 ◽  
Author(s):  
WM Strong ◽  
JE Cooper

Nine field experiments were conducted in 1978, 1981 and 1982 to evaluate applications of anhydrous ammonia (AA) or urea applied during the fallow period (January-May) for winter cereal crops. Following fertilizer application, soil was sampled using a stratified soil coring procedure to determine the rate of transformation of applied N to nitrate (nitrification), the quantity of N remaining in mineral forms (NH4+NO3 and NO2), and the movement of applied N into the subsoil. Nitrification of applied N was usually quite rapid in moist soil, particularly with early application (January, February or March when mean soil temperature was >20�C. Very similar rates of nitrification (0.6-4.7 kg N ha-1 day-1) were found for AA and urea applications in May 1982. Extreme drying of soil following N application reduced nitrification to a very low rate in May 1982 (0.6 kg N ha-1 day-1) and to an undetectable level in January 1981. In moist soil in February 1978, AA applied at 56 kg N ha-1 was nitrified completely after 11 days and the 112 kg N ha-1 rate was estimated to have nitrified completely in about 12 days. Also, AA applied to moist soil in May 1978 was estimated to have nitrified completely in about 28 and 42 days for 56 and 112 kg N ha-1 rates, respectively. Low recovery of early applied N as soil mineral N in June 1981 was associated with very heavy rain received during the latter part of the fallow period (March-May). Soil erosion on sloping sites and on a level site was a likely cause for the very low recovery (<47% that of a May application) of January-applied N, and some movement of mineral N below 0.2 m was also evident. Low recovery in fertilized soil (0.2 m) at the level sites was due to a large proportion of mineral N moving into the subsoil (below 0.9 m at one site). Also, prolonged periods of waterlogging during April probably promoted some loss of N due to denitrification, thus resulting in reduction in soil mineral N levels. Low recoveries of early applied N in mineral forms at the end of relatively drier fallows in 1978 and 1982 were also associated with soil saturating rainfall during the latter part of the fallow period. Where wheat crops responded to applied N, January or February applications were less effective than May applications to increase yield and N content of grain.


2017 ◽  
Vol 68 (8) ◽  
pp. 746
Author(s):  
E. M. Wunsch ◽  
L. W. Bell ◽  
M. J. Bell

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.


2018 ◽  
Vol 53 (8) ◽  
pp. 909-917 ◽  
Author(s):  
Fábio Henrique Krenchinski ◽  
Victor José Salomão Cesco ◽  
Danilo Morilha Rodrigues ◽  
Leandro Paiola Albrecht ◽  
Katle Samaya Wobeto ◽  
...  

Abstract: The objective of this work was to evaluate the effect of winter cover crop species on the agronomic performance of soybean (Glycine max) cropped in succession, under a no-tillage system. The study was conducted during three crop seasons (2011/2012, 2012/2013, and 2013/2014), with the following cover crops: white oat (Avena sativa), black oat (Avena strigosa), ryegrass (Lolium multiflorum), vetch (Vicia sativa), forage radish (Raphanus sativus), the intercrop black oat + forage radish, and wheat (Triticum aestivum) as the standard management. Forage radish and the intercrop black oat + forage radish provided greater soil cover rates after 30 days of planting, as well as dry matter production in the three crop seasons. After 45 and 90 days from desiccation, however, white oat and ryegrass showed the highest soil cover rate. Black oat and the intercrop black oat + forage radish provided higher soybean yield than the standard management with wheat, in the 2012/2013 and 2013/2014 crop seasons. Winter cover crops can significantly affect soybean yield in succession, and black oat and the intercrop black oat + forage radish stand out for this purpose.


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