Comparative productivity of irrigated short-term ryegrass (Lolium multiflorum) pasture receiving nitrogen, grown alone or in a mixture with white (Trifolium repens) and Persian (T. resupinatum) clovers

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.

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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

Crop and Pasture Science ◽

10.1071/cp20193 ◽

2020 ◽

Vol 71 (12) ◽

pp. 1067

Author(s):

William J. Fulkerson ◽

Nathan Jennings

Keyword(s):

Lolium Multiflorum ◽

Foliar Spray ◽

Italian Ryegrass ◽

Wetting Agent ◽

Soil N ◽

Granular Form ◽

Nitrate N ◽

Eastern Australia ◽

Canopy Area ◽

A Site

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.

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Short-term effects of manipulating the source:sink ratio of white clover (Trifolium repens) plants on export of carbon from, and morphology of, developing leaves

Physiologia Plantarum ◽

10.1034/j.1399-3054.1990.800216.x ◽

1990 ◽

Vol 80 (2) ◽

pp. 262-266 ◽

Cited By ~ 1

Author(s):

D. F. Chapman ◽

M. J. Robson ◽

R. W. Snaydon

Keyword(s):

White Clover ◽

Trifolium Repens ◽

Short Term ◽

Short Term Effects

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Comparison of rotations in which barley for grain follows woollypod vetch or forage barley

The Journal of Agricultural Science ◽

10.1017/s0021859600080011 ◽

1987 ◽

Vol 108 (3) ◽

pp. 609-615 ◽

Cited By ~ 12

Author(s):

I. Papastylianou ◽

Th. Samios

Keyword(s):

Grain Yield ◽

Dry Matter ◽

Nitrogen Concentration ◽

N Balance ◽

Dry Matter Yield ◽

Soil N ◽

Fertilizer N ◽

Total Soil ◽

Using Data ◽

Total Soil N

SummaryUsing data from rotation studies in which barley or woollypod vetch were included, both cut for hay and preceding barley for grain, it is shown that forage barley gave higher dry-matter yield than woollypod vetch (3·74 v. 2·92 t/ha per year). However, the latter gave feedingstuff of higher nitrogen concentration and yield (86 kg N/ha per year for vetch v. 55 kg N/ha per year for barley). Rainfall was an important factor in controlling the yield of the two forages and the comparison between them in different years and sites. Barley following woollypod vetch gave higher grain yield than when following forage barley (2·36 v. 1·91 t/ha). Rotation sequences which included woollypod vetch had higher output of nitrogen (N) than input of fertilizer N with a positive value of 44–60 kg N/ha per year. In rotations where forage barley was followed by barley for grain the N balance between output and input was 5–6 kg N/ha. Total soil N was similar in the different rotations at the end of a 7-year period.

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Effects of humic substances from composted or chemically decomposed poplar sawdust on mineral nutrition of ryegrass

The Journal of Agricultural Science ◽

10.1017/s0021859699007492 ◽

2000 ◽

Vol 134 (3) ◽

pp. 259-267 ◽

Cited By ~ 15

Author(s):

R. A. BIDEGAIN ◽

M. KAEMMERER ◽

M. GUIRESSE ◽

M. HAFIDI ◽

F. REY ◽

...

Keyword(s):

Humic Substances ◽

Lolium Multiflorum ◽

Initial Mixture ◽

Chemical Oxidation ◽

P Uptake ◽

Organic Fertilizers ◽

Short Term ◽

Manganese Uptake ◽

Total P ◽

Poplar Sawdust

Two organic fertilizers were prepared from the same initial mixture of poplar sawdust, blood and flour either by composting in a reactor or by chemical oxidation. Both processes resulted in loss of c. 30% of the organic matter. Composting required 90 days in comparison to only a few hours with chemical oxidation. Extraction of the organic residues with 1 N KOH gave solutions containing 24·6 and 15·1 g/l of humic substances respectively. These humic solutions were applied to pot-grown Lolium multiflorum Lam. at 4 and 10 mg carbon per pot to assess the short-term uptake of macro and microelements by the plants. When the plants were short of phosphorus, the humic substances from the chemically decomposed sawdust supplied at 10 mg C per pot improved total P uptake and yield. Humic substances also increased copper and manganese uptake, and by enhancing root development, also improved nitrogen uptake and biomass yield.

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Influence of Tobacco Plant on Macronutrient Levels in Sandy Soils

Agronomy ◽

10.3390/agronomy10030418 ◽

2020 ◽

Vol 10 (3) ◽

pp. 418 ◽

Cited By ~ 1

Author(s):

Jacob Lisuma ◽

Ernest Mbega ◽

Patrick Ndakidemi

Keyword(s):

Tobacco Plant ◽

Sandy Soils ◽

Soil N ◽

Sand Soil ◽

Calcium Ammonium Nitrate ◽

Loamy Sand Soil ◽

Nicotiana Tabacum L ◽

Before And After ◽

Tobacco Cultivation ◽

Nitrogen Phosphorus

Tobacco (Nicotiana tabacum L.) is associated with great uptake of soil macronutrients. Following the need to understand the macronutrients levels before and after tobacco cultivation, research was conducted in loamy sand soil of Sikonge, Urambo, and sand soil of Tabora, Tanzania. The initial macronutrients levels in the soil were compared with those measured after unfertilized and fertilized tobacco. Results showed that unfertilized tobacco plant influences the increase of nicotine to the rhizosphere, the macronutrients Ca (135%) > N (25%), decrease in the order of S (81%) > P (49%) > Mg (12%) > K (11%). The sole effect of nitrogen–phosphorus–potassium (NPK) and calcium–ammonium–nitrate (CAN) 27% fertilizers increased further nicotine, Ca (25%) > N (20%) > S (8%) > Mg (4%) > P (3%), and decreased K (3%) in the rhizosphere. Both tobacco plant and NPK + CAN fertilizers on the rhizosphere increased Ca (193%) > N (50%) and decreased S (80%) > P (48%) > K (14%) > Mg (8%). Leaf concentrations in fertilized tobacco increased Ca (197%) > K (28%) > P (27%) > S (26%) > N (18%) > Mg (12%). Therefore, tobacco plant increases soil N and Ca but decreases P, K, Mg, and S.

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LEAF TOTAL NITROGEN CONCENTRATION AS AN INDICATOR OF NITROGEN STATUS FOR PLANTLETS AND YOUNG PLANTS OF EUCALYPTUS CLONES

Revista Brasileira de Ciência do Solo ◽

10.1590/01000683rbcs20140689 ◽

2015 ◽

Vol 39 (4) ◽

pp. 1127-1140 ◽

Cited By ~ 4

Author(s):

Eric Victor de Oliveira Ferreira ◽

Roberto Ferreira Novais ◽

Bruna Maximiano Médice ◽

Nairam Félix de Barros ◽

Ivo Ribeiro Silva

Keyword(s):

Total Nitrogen ◽

Block Design ◽

Nitrogen Concentration ◽

Soil N ◽

Total N ◽

Chlorophyll Meter ◽

N Concentration ◽

Total Nitrogen Concentration ◽

N Status ◽

Leaf N

The use of leaf total nitrogen concentration as an indicator for nutritional diagnosis has some limitations. The objective of this study was to determine the reliability of total N concentration as an indicator of N status for eucalyptus clones, and to compare it with alternative indicators. A greenhouse experiment was carried out in a randomized complete block design in a 2 × 6 factorial arrangement with plantlets of two eucalyptus clones (140 days old) and six levels of N in the nutrient solution. In addition, a field experiment was carried out in a completely randomized design in a 2 × 2 × 2 × 3 factorial arrangement, consisting of two seasons, two regions, two young clones (approximately two years old), and three positions of crown leaf sampling. The field areas (regions) had contrasting soil physical and chemical properties, and their soil contents for total N, NH+4-N, and NO−3-N were determined in five soil layers, up to a depth of 1.0 m. We evaluated the following indicators of plant N status in roots and leaves: contents of total N, NH+4-N, NO−3-N, and chlorophyll; N/P ratio; and chlorophyll meter readings on the leaves. Ammonium (root) and NO−3-N (root and leaf) efficiently predicted N requirements for eucalyptus plantlets in the greenhouse. Similarly, leaf N/P, chlorophyll values, and chlorophyll meter readings provided good results in the greenhouse. However, leaf N/P did not reflect the soil N status, and the use of the chlorophyll meter could not be generalized for different genotypes. Leaf total N concentration is not an ideal indicator, but it and the chlorophyll levels best represent the soil N status for young eucalyptus clones under field conditions.

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Rain on Our Parade: La Niña and the Impact of Climate Change on ‘Sunny’ Sydney

Sydney Journal ◽

10.5130/sj.v4i1.2792 ◽

2013 ◽

Vol 4 (1) ◽

pp. 141-153

Author(s):

Julia Miller

Keyword(s):

Climate Change ◽

La Niña ◽

Short Term ◽

La Nina ◽

Eastern Australia ◽

Weather And Climate ◽

Cultural Interface ◽

Established Norm ◽

Natural Climate ◽

The Impact

In 1963 Sydneysiders, having suffered four dismal summers in a row and wetter than usual weather during the 1950s, looked back to those lazy, hazy days of the summers of a distant past where the sky arched blue over the gleaming golden sand of the quintessential Australian beach. City dwellers in the dying months of 1963, worried by persistent rain and cool temperatures, concluded that soggy weather had become the established norm. More recent experiences of wet summers in Sydney have blamed this on La Niña—a short-term climate driver that brought heavy rains and flooding to many districts of eastern Australia. This article examines the impact of natural climate cycles on attitudes to weather in Sydney. It shows how an investigation of the cultural interface of weather and climate can illuminate attitudes that impact on our ability to plan for climate change into the future.

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The Brigalow Catchment Study: III. Productivity changes on brigalow land cleared for long-term cropping and for grazing

Soil Research ◽

10.1071/sr07062 ◽

2007 ◽

Vol 45 (7) ◽

pp. 512 ◽

Cited By ~ 20

Author(s):

B. J. Radford ◽

C. M. Thornton ◽

B. A. Cowie ◽

M. L. Stephens

Keyword(s):

Crop Production ◽

Clay Soil ◽

Soil Nutrient ◽

Grain Protein Content ◽

Annual Rainfall ◽

Soil N ◽

Stocking Rate ◽

Beef Production ◽

Eastern Australia ◽

Productivity Decline

Productivity of grain crops and grazed pastures inevitably declines without soil nutrient replacement and may eventually make these enterprises unprofitable. We monitored these declines in north-eastern Australia during 23 years after clearing 2 of 3 adjacent brigalow catchments, in order to define the productivity levels of developed brigalow land over time. One catchment (11.7 ha) was used for grain production and another (12.7 ha) for beef production from a sown buffel grass pasture. There was no upward or downward trend in annual rainfall amounts throughout the study period. In the cropped catchment, grain yield from 14 winter crops without added nutrients declined significantly in 20 years from 2.9 to 1.1 t/ha.year on the upper-slope clay soil (92 kg/ha.year) and from 2.4 to 0.6 t/ha.year on the Sodosol (88 kg/ha.year). Crop production per year declined by 20% between 2 successive 10-year periods. Wheat grain protein content also declined with time, falling below the critical value for adequate soil N supply (11.5%) 12 years after clearing on the Sodosol and 16 years after clearing on the clay soil. Such declines in grain quantity and quality without applied fertiliser reduce profitability. The initial pasture dry matter on offer of 8 t/ha had halved 3 years after clearing, and a decline in cattle liveweight gain of 4 kg/ha.year was observed over an 8-year period with constant stocking of 0.59 head/ha. Due to fluctuating stocking rate levels of 0.3–0.7 head/ha over the trial period, liveweight productivity trends are attributed to the multiple effects of stocking rate changes and fertility decline. The amount of nitrogen exported from the cleared catchments was 36.1 kg/ha.year in grain but only 1.6 kg/ha.year in cattle (as liveweight gain). Total soil N at 0–0.3 m declined by 84 kg/ha.year under cropping but there was no significant decline under grazing. The soil nutrients removed during grain and beef production need to be replaced in order to avert productivity decline post-clearing.

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