Urea applied as a foliar spray or in granular form to subtropical dairy pastures of kikuyu (Cenchrus clandestinus) and Italian ryegrass (Lolium multiflorum) in eastern Australia

2020 ◽  
Vol 71 (12) ◽  
pp. 1067
Author(s):  
William J. Fulkerson ◽  
Nathan Jennings

The nitrogen-use efficiency (NUE) of a fertiliser has implications for pasture growth and the environment. This study aimed to compare application of urea as a foliar spray or in granular form, to kikuyu (Cenchrus clandestinus (Hochst. ex Chiov.) Morrone) and short-rotation ryegrass (Italian ryegrass, Lolium multiflorum Lam.) pastures in the subtropical dairy region of eastern Australia. The first experiment was a replicated grazing study on a site with a high plant-available soil N (75 mg nitrate-N/kg). The granular rate of urea was 46 kg N/ha.month equivalent, and the foliar spray rate was 40% of the granular rate. Pasture growth rate (51 DM/ha.day with foliar spray vs 45 kg DM/ha.day with granules) and pasture consumed (4942 vs 4382 kg DM/ha) were not significantly different between treatments. However, over the 8 months of the study, soil nitrate-N levels fell from 75 to 22 mg/kg on the foliar plots but only fell to 60 mg/kg on the granular plots. The second experiment was a replicated plot-cut experiment on a site with a low plant-available soil N (8.7 mg nitrate-N/kg). The NUE for kikuyu grass was similar for all treatments with a mean of 14.8 kg DM/kg N for the four foliar treatments (high and low, with and without wetting agent) and 17.4 kg DM/kg N for the granular treatment. The NUE for the ryegrass was also similar for all treatments, with a mean of 13.2 kg DM/kg N for the foliar treatments and 15.8 kg DM/ha for the granular treatment. A third experiment, evaluating absorption of foliar-sprayed urea over time, found that >80% of the urea applied to kikuyu was absorbed by 7 h; for ryegrass, the amount absorbed was only ~45% but increased to ~75% if wetting agent was included. We suggest that the lack of benefit in NUE achieved by applying urea as a foliar spray, which contrasts with results from studies in temperate dairy farm systems, is primarily associated with the substantially lower tiller density and hence the smaller canopy area for absorption of the foliar spray by the new regrowth shoots post-grazing.


2005 ◽  
Vol 45 (1) ◽  
pp. 21 ◽  
Author(s):  
K. F. Lowe ◽  
W. J. Fulkerson ◽  
R. G. Walker ◽  
J. D. Armour ◽  
T. M. Bowdler ◽  
...  

Dairy farms in subtropical Australia use irrigated, annually sown short-term ryegrass (Lolium multiflorum) or mixtures of short-term ryegrass and white (Trifolium repens) and Persian (shaftal) (T. resupinatum) clover during the winter–spring period in all-year-round milk production systems. A series of small plot cutting experiments was conducted in 3 dairying regions (tropical upland, north Queensland, and subtropical southeast Queensland and northern New South Wales) to determine the most effective rate and frequency of application of nitrogen (N) fertiliser. The experiments were not grazed, nor was harvested material returned to the plots, after sampling. Rates up to 100 kg N/ha.month (as urea or calcium ammonium nitrate) and up to 200 kg N/ha every 2 months (as urea) were applied to pure stands of ryegrass in 1991. In 1993 and 1994, urea, at rates up to 150 kg N/ha.month and to 200 kg N/ha every 2 months, was applied to pure stands of ryegrass; urea, at rates up to 50 kg N/ha.month, was also applied to ryegrass–clover mixtures. The results indicate that applications of 50–85 kg N/ha.month can be recommended for short-term ryegrass pastures throughout the subtropics and tropical uplands of eastern Australia, irrespective of soil type. At this rate, dry matter yields will reach about 90% of their potential, forage nitrogen concentration will be increased, there is minimal risk to stock from nitrate poisoning and there will be no substantial increase in soil N. The rate of N for ryegrass–clover pastures is slightly higher than for pure ryegrass but, at these rates, the clover component will be suppressed. However, increased ryegrass yields and higher forage nitrogen concentrations will compensate for the reduced clover component. At application rates up to 100 kg N/ha.month, build-up of NO3–-N and NH4+-N in soil was generally restricted to the surface layers (0–20 cm) of the soil, but there was a substantial increase throughout the soil profile at 150 kg N/ha.month. The build-up of NO3–-N and NH4+-N was greater and was found at lower rates on the lighter soil compared with heavy clays. Generally, most of the soil N was in the NO3–-N form and most was in the top 20 cm.



1998 ◽  
Vol 49 (3) ◽  
pp. 419 ◽  
Author(s):  
J. Evans ◽  
D. P. Heenan

Procedures for assessing the quantity of symbiotically fixed nitrogen (kg N/ha) in standing crops of lupin and for estimating variation of N2 fixation by lupins in different years were determined empirically and described. In standing crops, N2 fixation was estimated from crop height, plant population density, and a bioassay of soil mineral nitrogen (cereal crop N; kg N/ha). In addition it was also estimated from rainfall, sowing date, and cereal N, which consequently enabled prediction of seasonal variation in fixed N using historical rainfall data. Procedures for estimating the potential contribution of N2 fixation to soil N, and the effects of lupin and cereal N budgets on soil N balance based on differences in fixed N and grain N (grain yield×estimated grain N concentration) are also given. The collective procedures are applied to a site in south-eastern Australia and the predicted crop effects on soil N balance compared with actual field data. Perceived limitations of the procedures are discussed.



2018 ◽  
Vol 44 (2) ◽  
pp. 219-232 ◽  
Author(s):  
S.J Jang ◽  
K.R. Kim ◽  
Y.B. Yun ◽  
S.S. Kim ◽  
Y.I Kuk


Euphytica ◽  
2021 ◽  
Vol 217 (1) ◽  
Author(s):  
Wenqing Tan ◽  
Di Zhang ◽  
Nana Yuyama ◽  
Jun Chen ◽  
Shinichi Sugita ◽  
...  


2020 ◽  
pp. 1-9
Author(s):  
Keum-Ah Lee ◽  
Youngnam Kim ◽  
Hossein Alizadeh ◽  
David W.M. Leung

Abstract Seed priming with water (hydropriming or HP) has been shown to be beneficial for seed germination and plant growth. However, there is little information on the effects of seed priming with amino acids and casein hydrolysate (CH) compared with HP, particularly in relation to early post-germinative seedling growth under salinity stress. In this study, Italian ryegrass seeds (Lolium multiflorum L.) were primed with 1 mM of each of the 20 protein amino acids and CH (200 mg l−1) before they were germinated in 0, 60 and 90 mM NaCl in Petri dishes for 4 d in darkness. Germination percentage (GP), radicle length (RL) and peroxidase (POD) activity in the root of 4-d-old Italian ryegrass seedlings were investigated. Generally, when the seeds were germinated in 0, 60 and 90 mM NaCl, there was no significant difference in GP of seeds among various priming treatments, except that a higher GP was observed in seeds of HP treatment compared with the non-primed seeds when incubated in 60 mM NaCl. When incubated in 60 and 90 mM NaCl, seedlings from seeds primed with L-methionine or CH exhibited greater RL (greater protection against salinity stress) and higher root POD activity than those from non-primed and hydro-primed seeds. Under salinity stress, there were higher levels of malondialdehyde (MDA) in the root of 4-d-old Italian ryegrass seedlings, a marker of oxidative stress, but seed priming with CH was effective in reducing the salinity-triggered increase in MDA content. These results suggest that priming with L-methionine or CH would be better than HP for the protection of seedling root growth under salinity stress and might be associated with enhanced antioxidative defence against salinity-induced oxidative stress.



1989 ◽  
Vol 264 (3) ◽  
pp. 857-862 ◽  
Author(s):  
P A Gleeson ◽  
M McNamara ◽  
R E H Wettenhall ◽  
B A Stone ◽  
G B Fincher

An arabinogalactan-protein (AGP) purified from the filtrate of liquid-suspension-cultured Italian-ryegrass (Lolium multiflorum) endosperm cells by affinity chromatography on myeloma protein J539-Sepharose was deglycosylated with trifluoromethanesulphonic acid to remove polysaccharide chains that are covalently associated with hydroxyproline residues in the peptide component of the proteoglycan. The protein core, which accounts for less than 10% (w/w) of the intact proteoglycan, was purified by h.p.l.c. It has an apparent Mr of 35,000, but reacts very poorly with both Coomassie Brilliant Blue R and silver stains. Amino-acid-sequence analysis of the N-terminus of the h.p.l.c.-purified protein core and of tryptic peptides generated from the unpurified protein reveals a high content of hydroxyproline and alanine. These are sometimes arranged in short (Ala-Hyp) repeat sequences of up to six residues. Polyclonal antibodies raised against the protein core do not cross-react with native AGP, the synthetic peptide (Ala-Hyp)4, poly-L-hydroxyproline or poly-L-proline. The results suggest that the polysaccharide chains in the native AGP render the protein core of the proteoglycan inaccessible to the antibodies and that the immunodominant epitopes include domains of the protein other than those rich in Ala-Hyp repeating units.



Author(s):  
Afonso Henrique Schaeffer ◽  
Diógenes Cecchin Silveira ◽  
Otávio Augusto Schaeffer ◽  
Nadia Canali Lângaro ◽  
Leandro Vargas




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