Nitrate leaching under phalaris, cocksfoot, and annual ryegrass pastures and implications for soil acidification

1999 ◽  
Vol 50 (1) ◽  
pp. 55 ◽  
Author(s):  
A. M. Ridley ◽  
R. J. Simpson ◽  
R. E. White

Nitrogen uptake and nitrate (NO-3) leaching below 1.1 m was estimated under phalaris, cocksfoot, and annual ryegrass pastures and under bare fallow in a 4-year field experiment under control and high N (500 kg N/ha) treatments in north-eastern Victoria (693 mm/year rainfall for the study period). The perennial grasses, particularly phalaris, took up more N in herbage than annual ryegrass. High concentrations of NO3-N were measured at 1 m depth below all treatments, suggesting that NO3- losses from pastures have potential to contaminate streams and/or groundwater. Perennial pastures were only able to reduce NO3- leaching compared with annuals in drier than average years. Values calculated for acid addition due to NO3-leaching resulted in a net annual input of approximately 1 kmol H +/ha.year under the phalaris pasture compared with 2 kmol H +/ha.year under annual ryegrass. Adding these figures to carbon cycle addition data of 1 kmol H+/ha.year (measured in a previous study) corresponds to a lime rate of 100 and 150 kg lime/ha.year being required to stop further acidification under these pasture types. A 1 unit pH decline to 30 cm depth was estimated to take 42 years under annual pasture or 67 years under perennial grasses. Whilst perennial pastures have a role in reducing soil acidification, lime application is the most important management option in balancing soil acidification caused by agriculture.

1991 ◽  
Vol 42 (3) ◽  
pp. 391 ◽  
Author(s):  
DR Coventry ◽  
WJ Slattery

Soil pH decline and net acidification inputs were determined for a long-term crop rotation experiment at Rutherglen in north-eastern Victoria. The rotations utilized were continuous wheat (WW), a 1 : 1 wheat-lupin sequence (WL) and continuous lupins (LL), and each rotation was cropped from 1975-1989. The soil at the site had an initial pH (0.01 mol/LCaCl2) of 6.0 (0-10 cm depth), sandy loam texture, and had a past use of grape vines and then lucerne pasture. The soil pH (0-10 cm) declined for each rotation with time (1977/78-1988/89), decreasing by about 0.8 units for WW and further decreasing with the inclusion of lupin in the rotation. Compared with the WW soil, the WL soil pH was 0.7 and 0.4 units lower at 5-10 cm and 10-15 cm depth and the LL soil pH was 1.0 and 0.8 units lower at 5-10 and 10-15 cm depth. There was no difference in pH between WW and WL below 20 cm depth, but the LL soil had a significantly lower pH to 40 cm depth. Acidification rates were calculated for the period of cropping and for the 3 rotations, with rates of 3.22, 4.11 and 5.26 kmols H+/ha.yr as net acid input for WW, WL and LL rotations. These values represent a rapid rate of soil acidification. The removal of alkalinity in grain accounted for between 15-21% of the overall calculated acidification rate for the 3 rotations. Therefore, it is likely in this cropping system that the acidification largely results from progressive nitrate leaching.


2000 ◽  
Vol 51 (3) ◽  
pp. 377 ◽  
Author(s):  
G. M. Lodge

Seedlings of 3 perennial grasses, Danthonia linkii Kunthcv. Bunderra, D. richardsonii Cashmore cv. Taranna(wallaby grasses), and Phalaris aquatica L. cv. Sirosa,were each grown in replacement series mixtures with seedlings ofTrifolium repens L. (white clover),Trifolium subterraneum L. var. brachycalycinum (Katzn.et Morley) Zorahy & Heller cv. Clare (subterraneanclover), and Lolium rigidum L. (annual ryegrass). Plantswere sown 5 cm apart in boxes (45 by 29 by 20 cm) at a density of 307plants/m2. Maximum likelihood estimates were usedto derive parameters of a non-linear competition model using the dry matterweights of perennial grasses and competitors at 3 harvests, approximately 168,216, and 271 days after sowing. Intra-plant competition was examined inmonocultures of each species, grown at plant spacings of 2, 5, and 8 cm apartwith plants harvested at the above times.Competition occurred in all perennial grass–competitor mixtures, exceptin those of each perennial grass with white clover and thephalaris–subterranean clover mixture (Harvest 1) and those withD. richardsonii and phalaris grown with white clover(Harvest 2). For D. richardsonii (Harvests 1 and 2) andD. linkii (Harvest 1 only) grown with white clover andthe phalaris–subterranean clover (Harvest 1), the two species in themixture were not competing. In the phalaris–white clover mixture, eachspecies was equally competitive (Harvests 1 and 2). These differences incompetition and aggressiveness reflected differences in individual plantweights in monocultures where there was an effect (P < 0.05) of species ondry matter weight per box, but no significant effect of plant spacing.These data indicated that for successful establishment,D. richardsonii and D. linkiishould not be sown in swards with either subterranean clover or white clover,or where populations of annual ryegrass seedlings are likely to be high.Phalaris was more compatible with both white clover and subterranean clover,but aggressively competed with by annual ryegrass.


1987 ◽  
Vol 27 (5) ◽  
pp. 695 ◽  
Author(s):  
DR Coventry ◽  
JF Kollmorgen

The effects of lime, deep ripping and fertiliser treatments on the occurrence of take-all symptoms in wheat in north-eastern Victoria, was studied in a field experiment. Large wheat grain yield increases had previously been obtained at this site from both liming and deep ripping of the soil. Symptoms typical of take-all (Gaeumannomyces grarninis var. tritici) were observed on plants in all plots in the 1985 season. There were no differences in numbers of dead heads in wheat grown on unlimed soil and where the soil was treated with 0.5 and 1.0 t lime ha-l. However, 20 and 30% of the heads were dead heads where the soil was treated with 2.5 and 5.0 t lime ha-1 respectively. Plants with dead heads were severely lesioned. Where disease was most severe, 1000-grain weight was reduced. Although liming the soil increased the damage by Gaeumannomyces graminis var. tritici, and perhaps other pathogens, the overall grain yields were not reduced because of the countering effect of lime promoting yield. Lime also altered the composition of grasses in pasture plots, resulting in more brome grass and barley grass. The control of take-all by crop rotations and controlling grassy weeds in pasture could be a necessary adjunct to liming if maximum yield benefits are to be obtained.


2017 ◽  
Vol 33 (2) ◽  
pp. 233-242 ◽  
Author(s):  
L. J. Munkholm ◽  
E. M. Hansen ◽  
I. K. Thomsen ◽  
E. M. Wahlström ◽  
H. S. Østergaard

1992 ◽  
Vol 32 (8) ◽  
pp. 1061 ◽  
Author(s):  
AM Ridley ◽  
DR Coventry

Yield responses of 3 mixed grass-clover pastures [Phalaris aquatica L. cv. Sirosa (phalaris), Dactylis glomerata cv. Porto (cocksfoot), and annual grass based Trifolium subterraneum L. cv. Trikkala (subterranean clover) pastures] were measured over 5 soil pH treatments at 2 sites in Victoria. One site (Beechworth) was strongly acidic [pH(CaCl2) < 4.21 to a depth of 40 cm and contained high concentrations of soil aluminium (Al). At the other site (Lake Rowan), yield responses to lime application had been measured previously, but only in Al-sensitive wheat cultivars. At Beechworth, pasture yield responses to lime were not consistent but. when observed. occurred in autumn and winter in all 3 pasture types. Phalaris pastures showed yield increases more often than cocksfoot and annual pastures. Low magnesium and calcium concentrations may have limited dry matter production, although yields were reasonable on all treatments. Where lime was applied, growth responses may have been due to alleviation of Al toxicity. At Beechworth, pasture yield was increased where lime increased pH from 4.2 to 4.6 and decreased soil Al (measured in 10 mmol CaCl2/L) from 11 to <3 �g/g soil. Herbage manganese concentrations were not high in phalaris and subterranean clover, and cocksfoot manganese standards were not available. At Lake Rowan (pH 4.7, Al <1 �g/g), no growth responses to lime were seen in any pasture treatment, and annual grass based pastures sometimes had higher yields than phalaris and cocksfoot pastures. On strongly acidic soils such as at Beechworth, incorporation of lime prior to pasture establishment should be considered. Perennial grasses may reduce further soil degradation through acidification. Soil A1 concentrations are commonly lower in ley-cropping areas, and the inclusion of perennial grasses in ley pastures requires further evaluation.


2010 ◽  
Vol 7 (3) ◽  
pp. 279 ◽  
Author(s):  
P. M. Kopittke ◽  
F. P. C. Blamey ◽  
R. A. Kopittke ◽  
C. J. Asher ◽  
N. W. Menzies

Environmental context.High concentrations of Ni in soil may occur either naturally or as a result of human activities. We used a sand culture system to investigate the suitability of seven perennial grasses for the revegetation of Ni-contaminated sites. This study provides information on the toxic effects of Ni on plant growth and gives consideration to the health of animals consuming these plants, thereby increasing the accuracy of risk assessments. Abstract.Although grasses are commonly used to revegetate disturbed areas, comparatively little is known regarding the tolerance of perennial grasses to toxic levels of trace metals. A sand culture experiment was conducted to investigate the tolerance of seven perennial grasses to high concentrations of Ni. The activity of Ni2+ in solution that resulted in a 50% reduction in shoot growth ranged from 50 µM for Sabi grass (Urochloa mosambicensis (Hack.) Dandy cv. Saraji) to 13 µM for curly Mitchell grass (Astrebla lappacea (Lindl.) Domin). In most grasses, growth in the high-Ni2+ treatments resulted in shoot Ni concentrations at or above the toxicity threshold for consumption by cattle (100 µg Ni g–1). Based upon their tolerance to Ni, and the extent to which they translocate Ni to the shoots, Sabi grass, signal grass (Brachiaria decumbens Stapf. cv. Basilisk) and buffel grass (Cenchrus ciliaris (L.) cv. Biloela) appear well suited for the phytostabilisation of Ni-contaminated sites in subtropical and tropical regions.


2006 ◽  
Vol 27 ◽  
pp. 139-147 ◽  
Author(s):  
KR Pandey

Some experiments were conducted in field conditions at Rampur, Nepal between 2001 and 2003 to assess the potential of wheat straw management with grain and green manure legumes in the lowland areas on soil N dynamics, crop yields and systems’ N balances. Two levels of wheat straw incorporation (0 and 2 Mg ha-1) with four types of land management (bare fallow control, mucuna, mungbean and maize) treatments were randomly allotted in the 10 m2 plots in the fields. When the land was left bare during the transition season, Nmin was initially building up of 50-80 kg of nitrate-N and subsequently lost by nitrate leaching and denitrification, resulting in low N uptake of rice. The application of wheat straw during DWT significantly reduced soil Nmin at the same rate as soil microbial biomass-N increased and resulted in <1 kg ha-1 of nitrate leaching and minimal nitrous oxide emissions from the soil. Growing cover crops during transition period reduced leaching losses by half and nitrous oxide emissions by two thirds of those in the bare fallow control, and BNF-N additions by legumes ranged from 27 to 56 kg ha-1. Depending on the type of legume, this resulted in increased crop N uptake and grain yield. The lower N benefits were associated with the grain legume because about 50% of the N assimilation was removed by grain harvest, while the high benefits were obtained with green manures. When DWT is sufficiently long, the cultivation of legumes appears economically and ecologically beneficial and should be encouraged. Combinations of straw amendment and green manure use during DWT provide the largest benefits in terms of grain yield, and N balance with possible long-term benefits for system’s productivity. Key words: Soil, nutrient management, lowland rice J. Inst. Agric. Anim. Sci. 27:139-147 (2006)


1994 ◽  
Vol 45 (5) ◽  
pp. 1077 ◽  
Author(s):  
AM Ridley ◽  
RJ Simpson

Studies in the field and in a rhizotron were conducted to examine the root growth of Phalaris aquatica L. (phalaris), Dactylis glomerata L. (cocksfoot) and Lolium rigidum Gaudin (annual ryegrass). Root and tiller development of the perennial grasses in autumn was also studied. In the field, annual ryegrass developed a more extensive surface rooting system than phalaris and cocksfoot by spring in a favourable season. Early root development of annual ryegrass was poor where the first rains of the season did not occur until winter. Growth rates of annual ryegrass roots at depth were similar to phalaris in mid spring in the rhizotron. Phalaris had a higher proportion of live roots than cocksfoot prior to the first autumn rain. Cocksfoot did not regenerate a substantial new root system until it developed secondary tillers, about a month after initial rains. Collectively, these studies indicated that the seasonal development and extent of the root systems of cocksfoot and phalaris were different.


Sign in / Sign up

Export Citation Format

Share Document