The effect of nitrogen fertilizer on the seasonal production of an irrigated ryegrass-clover pasture at Badgery's Creek

1965 ◽  
Vol 5 (19) ◽  
pp. 417 ◽  
Author(s):  
FC Crofts

Nitrogen fertilizer applied as sulphate of ammonia at 23 to 92 pounds of nitrogen an acre in early spring made forage available for grazing six weeks earlier and returned 19 to 22 pounds of additional dry matter (with 14 to 19 per cent crude protein) for each pound of fertilizer nitrogen applied. However, the responses to nitrogen fertilizer became progressively less over the late spring and summer period and the responses in the autumn, when additional forage is urgently needed for winter reserves, were relatively small.

1966 ◽  
Vol 6 (20) ◽  
pp. 42 ◽  
Author(s):  
FC Crofts

Under supplementary spray irrigation at Badgery's Creek, N.S.W., it has been possible to increase the late autumn, winter, and early spring production of a clover dominant ryegrass-clover pasture by more than 3,000 lb of dry matter an acre by sod-seeding oats with nitrogen fertilizers. The oat seeding rate and the amount of nitrogen fertilizer applied at seeding are critical factors in determining the amount of additional winter forage obtained. At this stage it appears that the sod-seeding of oats at four bushels an acre with about 90 lb of nitrogen an acre in early autumn will greatly increase winter forage production under irrigation at a much lower cost than that associated with hand-feeding.


1985 ◽  
Vol 25 (3) ◽  
pp. 505 ◽  
Author(s):  
TM Davison ◽  
RT Cowan ◽  
RK Shepherd ◽  
P Martin

A 3-year experiment was conducted at Kairi Research Station on the Atherton Tablelands, Queensland, to determine the effects of stocking rate and applied nitrogen fertilizer on the pasture yield and composition, diet selection by cows, and soil fertility of Gatton panic (Panicum maximum cv. Gatton) pastures. Thirty-two Friesian cows were used in a 4x2 factorial design: four stocking rates (2.0, 2.5, 3.0 and 3.5 cows/ha), each at two rates of fertilizer application 200 and 400 kg N/ha.year. The higher rate of fertilization increased the pasture green dry matter on offer at all samplings (P < 0.01); the increase ranged from 1 106 kg/ha in summer to 548 kg/ha in spring. Green dry matter decreased ( P< 0.0 1) with increasing stocking rate, with mean yields of 3736 and 2384 kg/ha at 2.0 and 3.5 cows/ha, respectively. Weed yields increased over the 3 years at the higher stocking rates for pastures receiving 200 kg N/ha.year. The crude protein content of leaf and stem increased with increasing stocking rate and amount of applied nitrogen fertilizer. Values ranged from 12.1 to 26.5% of dry matter (DM) in leaf and from 3.7 to 13.8% DM in stem. In leaf, sodium concentration (range 0.05-0.20% DM) was increased, while phosphorus concentration (range 0.21-0.44% DM) was decreased by the higher rate of fertilizer application. Plant sodium and phosphorus levels were inadequate for high levels of milk production. Dietary leaf content and crude protein contents were consistently increased by both a reduced stocking rate, and the higher rate of fertilization. Cows were able to select for leaf and at the lowest stocking rate, leaf in the diet averaged 38%; while the leaf content of the pasture was 20%. Dietary leaf content ranged from 38 to 57% in summer and from 11 to 36% in winter. Dietary crude protein ranged from 13 to 15% in summer and from 7 to 11% in winter and was positively correlated with pasture crude protein content and dietary leaf percentage. Soil pH decreased (P<0.05) from an overall mean of 6.3 in 1976 to 6.1 at 200 N and 5.8 at 400 N in 1979. Soil phosphorus status remained stable, while calcium and magnesium levels were lower (P<0.01) after 3 years.


1967 ◽  
Vol 21 (3) ◽  
pp. 587-597 ◽  
Author(s):  
D. J. Minson

1. Experiments were conducted with wether sheep in 1964 and 1965 fed pelleted or chopped mature Digitaria decubemes Stent (pangola grass) bay containing different crude protein contents. The voluntary intake of food, digestibility of dry matter and nitrogen, nitrogen retention and apparent time of retention of feed organic matter in the reticulo-rumen were measured. The different crude protein contents of the grass were obtained by applications of urea to the sward 14 and 28 days before cutting for hay in 1964 and 1965 respectively. This treatment increased the crude protein content of the dry matter from 4.9% to 8.7% in 1964 and from 3.7% to 7.2% in 1965. The size of the particles of the ground hay before pelleting is given.2. The mean voluntary intake of chopped fertilized grass was 10% and 54% greater than that of the unfertilized; the voluntary intake of pellets made from fertilized grass was 35% and 75% greater than of those made from the unfertilized grass in 1964 and 1965 respectively.3. The voluntary intake of pellets of unfertilized grass was 7% and 14% greater than that 30% greater than that of chopped fertilized grass in 1964 and 1965 respectively.4. The digestibility of the pellets was less than that of the chopped grass.5. The apparent digestibility of the feed nitrogen was increased by the fertilizer nitrogen, but grinding and pelleting had no consistent effect. Sheep eating chopped or pelleted fertilized hay were in positive nitrogen balance.6. The apparent retention time of organic matter in the reticulo-rumen was longer when the sheep were eating chopped hay than when they were eating pellets. In 1964 the apparent retention time of organic matter in the reticulo-rumen was shorter for chopped and pelleted unfertilized grass than for chopped and pelleted fertilized grass, but in 1965 the order was reversed.7. The relationship between voluntary intake, apparent retention time of organic matter in the rumen and the protein content of the food is discussed.


1984 ◽  
Vol 103 (3) ◽  
pp. 659-669 ◽  
Author(s):  
D. Reid

SummaryIn studies of the seasonal distribution of nitrogen fertilizer dressings on grassland using conventional experimental designs it is usually not possible to separate the true effects of an individual fertilizer dressing on the yield at a particular cut from the residual effects of previous dressings. An experiment is described which was designed to allow separation of the direct and residual effects, with certain restrictions, for a system involving five cuts and five possible fertilizer dressings per season on perennial ryegrass swards. From the results obtained over two harvest years on swards on two adjacent sites equations were derived relating the dry-matter and crude-protein yields of herbage to the rate of nitrogen application at five dressings in the season. Predictions of yield distribution patterns from the equations are compared with observed yields from various sequences of nitrogen dressings included in previous experiments at this Institute. Examples are also given of the prediction of sequences of nitrogen dressings required to obtain certain patterns of yield distribution.


1982 ◽  
Vol 22 (115) ◽  
pp. 100
Author(s):  
BA Rowe

Ground limestone and molybdenum were applied to well fertilized, clover based, perennial pastures established on krasnozems with a pH of 5.5 at Elliott and Central Castra in north-western Tasmania. The experiments began in 1971 and continued until June 1976 at Central Castra and April 1979 at Elliott. Limestone was applied in increments of 2.5 t/ha over several years to achieve a maximum cumulative application of 12.5 t/ha at Central Castra and 15.0 t/ha at Elliott. These broadcast applications of limestone increased the pH of the surface 75 mm of the soils by 0.1 units for each tonne of limestone applied per hectare. Large increases in soil pH were recorded in the surface 150 mm of the soils when measured 18 months after the last limestone application but the increases were small (less than 0.2 pH units) below this depth. Limestone applications totalling 7.5-15.0 t/ha significantly increased pasture dry matter yields in more than half the harvests taken in summer, autumn and early spring but not in late spring. These increases, which ranged from 200-1200 kg/ha, are of potential agricultural importance since they occurred when feed supplies often restrict production from dairy herds grazing dryland pasture in northwestern Tasmania. The factor or factors limiting production on the unlimed plots have not been identified but, contrary to previous reports, the yield increases from the limestone applications were not due to an increase in the availability of molybdenum associated with the increase in soil pH.


1992 ◽  
Vol 119 (3) ◽  
pp. 373-381 ◽  
Author(s):  
A. Lloyd

SUMMARYForty-one experiments were carried out in England and Wales between 1983 and 1985 to compare ammonium nitrate and urea as N top dressings for multicut silage.The results showed that relative dry matter yields from the two fertilizers differed considerably between sites. However, compared with ammonium nitrate, there was a mean yield decrease with urea of 2% at the first cut and 5% at the second cut. Mean herbage N contents and apparent N recoveries were lower with urea than with ammonium nitrate at both the first and second cuts. It appeared, at least for first-cut dressings applied in early spring, that urea effectiveness increased with the amount of rain falling within 3 days of fertilizer application. The effect was much less obvious at the second cut.Urea effectiveness was not markedly reduced on soils of high pH or light texture, where higher ammonia volatilization losses might have been expected.


1955 ◽  
Vol 46 (3) ◽  
pp. 267-286 ◽  
Author(s):  
W. Holmes ◽  
D. S. MacLusky

1. An experiment is described which lasted for 5 years and in which a comparison was made of twelve grasses or grass mixtures under different fertilizer nitrogen treatments and also when grown with clover. The herbage was cut 4–6 times in each season. Adequate amounts of mineral fertilizers (280–340 lb. K2O and about 100 lb. P2O5 per acre per annum), and the following nitrogen treatments were applied: (1) no nitrogen, no clover, (2) grass sown with clover, (3) 140–208 lb. nitrogen per acre per annum in four to six equal dressings, (4) 350–416 lb. nitrogen per acre per annum in five and six equal dressings.In 1951, 1952 and 1953 the clover dominant swards (treatment 2) were split between the following treatments; (X) as (3) above, (Y) 35 lb. nitrogen per acre in spring and again in late summer, (Z) no nitrogen as (2) above.2. The average yields for the 4 years were 2180, 5940 and 8300 lb. dry matter per acre, and 290, 850 and 1460 lb. crude protein per acre for treatments 1, 3 and 4. With treatment 2 the average yields were 2830 lb. dry matter and 400 lb. crude protein in 1949 and 4270 lb. dry matter and 820 lb. crude protein in 1950. An approximate average yield for the 4 years from treatment 2 was 4630 lb. dry matter and 860 lb. crude protein. In 1951–3 average yields for treatments 2X, 2Y and 2Z were, 7240, 6340 and 5750 lb. dry matter and 1240, 1180 and 1100 lb. crude protein per acre.3. There were considerable differences between grasses in nitrogen response and compatibility with clover. The highest yields with fertilizer nitrogen were given by cocksfoot strains, but, in the presence of clover, ryegrass and timothy strains gave the highest yields. There were also differences between strains within each species.4. Mean crude protein contents were, for treatments 1, 3 and 4, 13·3, 14·3 and 17·6%, and for treatments 2X, 2Y and 2Z in 1951–3, 17·2, 18·6 and 19·1%. Differences between species were significant in only a few instances.5. The distribution of yield over the season was most regular with treatment 4. Cocksfoot species gave the least variable yields from cut to cut, while those from timothy and ryegrass swards were the most variable.6. Treatments 3 and 4 maintained a high proportion of sown grasses in the swards. In treatment 2 the clover percentage rose to a high level by 1950. A high percentage was maintained under treatment 2Z in 1951–3. Treatment 2Y depressed the clover content in some grasses, and treatment 2X further depressed it in those grasses. A fairly high clover content was maintained, however, even with treatment 2X with some timothy strains and meadow fescue.7. The mineral fertilizers applied maintained the soil analysis at a satisfactory level.8. The results are discussed with special reference to the relative merits of fertilizer nitrogen and clover nitrogen and to the differences between species and strains.


1970 ◽  
Vol 74 (2) ◽  
pp. 227-240 ◽  
Author(s):  
D. Reid

SUMMARYA series of twenty-one nitrogen fertilizer rates ranging from 0 to 800 lb nitrogen/acre (897 kg/ha)/annum was applied on a pure S. 23 perennial ryegrass sward and on an S. 23 ryegrass sward containing S. 100 white clover. Total yields of herbage dry matter and crude protein from both swards at all the nitrogen rates were determined each year by cutting the herbage five times at approximately the same stage of growth on each occasion. Four-parameter growth curves relating herbage yield to nitrogen rate were fitted to the data, and are presented for the first 3 years of the experiment. On the pure-grass sward the response of dry-matter yield to nitrogen rate was almost linear between the 0 and 300 lb nitrogen/acre (336 kg/ha) rates, then it decreased steadily, becoming non-significant about the 500 lb/acre (560 kg/ha) rate. In contrast the response of crude-protein yield was virtually linear from the 0 to the 600–700 lb nitrogen/acre (673–785 kg/ha) rates. The inclusion of white clover in the sward increased the yields of dry matter and crude protein at the low nitrogen rates, but decreased the responses, with the result that the yields and responses of the grass + clover sward were not significantly different from those of the pure-grass sward at nitrogen rates above about 300 lb/ acre (336 kg/ha). In terms of profitability at present fertilizer prices the optimum nitrogen rate for dry-matter production on both swards was estimated to be 400–450 lb/ acre (448–504 kg/ha), whereas that for crude-protein production was greater than 600 lb/acre (673 kg/ha). The value of clover in a sward receiving nitrogen fertilizer is discussed.


1954 ◽  
Vol 45 (2) ◽  
pp. 129-140 ◽  
Author(s):  
W. Holmes ◽  
D. S. Maolusky

1. A small-scale plot experiment which had been carried out from 1947 to 1949 (Holmes, 1951) to study the effect of massive dressings of nitrogen, with and without phosphate and potash, on the yield of a ryegrass dominant sward was continued in 1950–2. A 4 × 4 Graeco-Latin square was used.The nitrogen treatments applied each year were:(1) no nitrogenous fertilizer, (2) 260 lb., (3) 520 lb. and (4) 416 lb. (312 lb. in 1951) nitrogen per acre per annum applied in four or five equal dressings, one for each cut. Treatments 1, 2 and 3 were cut each time they reached the long leafy stage (8–11 in. in height), treatment 4 was cut when 13–16 in. in height.The mineral treatments were (A) no mineral fertilizer, (B) 336–538 lb. K2O per acre per annum depending on nitrogen treatment, (C) 120–180 lb. P2O5 per acre per annum, (D) treatments B and C combined. Mineral applications were applied in four or five dressings each year, one for each cut.2. Applications of phosphate did not affect the yield or protein content of the herbage, but yields were severely restricted in the absence of potash. Where potash was applied the yields under each nitrogen treatment were maintained or increased over the 6-year period. Average yields of dry matter for the 6-year period when potash was present were 4760, 8050, 9620 and 9320 lb. per acre per annum for treatments 1, 2, 3 and 4. Without potash the corresponding average yields were 3980, 5610, 5190 and 5100 lb. Average crude protein yields with potash were 710, 1410, 1990 and 1640 lb. per acre per annum and without potash 550, 1090, 1190 and 1020 lb.3. The presence of potash resulted in earlier growth in each season through the maintenance of the earlier vigorous grasses in the sward. Although the growth curve was variable with treatment 1, treatments 2, 3 and 4 gave nearly uniform distribution of herbage production over the season.4. The weighted mean contents of crude protein for each year ranged from 13·9% for treatment 1 to 20·6% for treatment 3 when potash was given and from 12·9% for treatment 1 to 23·6% for treatment 3 when potash was absent. There was a gradual increase in protein content at the later cuts in each season, but the range was less where nitrogen was applied.5. The efficiency of utilization of fertilizer nitrogen was calculated. When the yield was compared with that of a no-clover sward the average response was 15·6, 10·8 and 11·8 lb. dry matter per lb. of nitrogen applied for treatments 2, 3 and 4 respectively. In terms of crude protein the percentage recovery was 53, 44 and 42 respectively. When the yields were compared with those of the clovery swards the nitrogen recovery figures were reduced by about one-third.6. The botanical composition of the plots was determined by the nitrogen and potash treatments. Where both were adequate a vigorous sward of ryegrass and timothy was maintained. Where nitrogen was absent but potash present a clovery sward developed. In the absence of potash with or without nitrogen the better grasses declined and were replaced by poor grasses.7. Provided potash was applied there were no marked changes in the soil analysis.8. The results are discussed with particular reference to the maintenance of high grass yields and the relative roles of clover and fertilizer nitrogen.


1997 ◽  
Vol 48 (6) ◽  
pp. 811 ◽  
Author(s):  
A. R. Lawson ◽  
P. W. G. Sale ◽  
K. B. Kelly

A field experiment was carried out to investigate whether changes in winter and post-winter defoliation frequency would increase the white clover content of an irrigated perennial ryegrass–white clover pasture in northern Victoria. Pastures defoliated every 4 weeks during winter had higher white clover growing point (stolon apices with at least 2 nodes) density at the end of winter than pastures defoliated every 8 weeks or those receiving a single defoliation after 16 weeks, but these differences did not affect the clover content in the spring. Reasons for this are suggested. Pastures defoliated at 8-week intervals in winter were the most productive over winter{early spring. Less frequent defoliation (4 v. 2 weeks) during the post-winter, September–May period reduced white clover growing point and perennial ryegrass tiller densities. However, the white clover growth rate during this period was increased by less frequent defoliation, whereas the ryegrass growth rate was reduced, resulting in an increase of 10% in the white clover content, and a 1·9 t dry matter (DM)/ha increase in total DM produced. This higher clover content and pasture yield during spring–autumn with less frequent defoliation has important implications for the management of irrigated perennial pastures for the dairy industry in northern Victoria.


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