Nutrient cycling in grazed pastures. II. Further observations with [35S] gypsum

1970 ◽  
Vol 21 (2) ◽  
pp. 253 ◽  
Author(s):  
AR Till ◽  
PF May
Keyword(s):  
Nutrient Cycling ◽  
Sheep Grazing ◽  
Grazed Pastures ◽  
Grazed Pasture ◽  
Sulphur Cycle ◽  
Total Soil ◽  
Animal System ◽  
Gypsum Application

The incorporation of sulphur-35 (35S) into the wool of sheep grazing radioactive pasture was measured in two successive experiments on the same site following application of [35S]gypsum. Equilibrium between the applied sulphur and sulphur present prior to the application was established at different rates with different rainfall. After 3 years the sulphur from the original gypsum application was still being turned over in the soil-plant-animal system, there had been no change in the total soil sulphur, and a large portion of soil sulphur did not enter the sulphur cycle. A diagram of a proposed sulphur cycle in grazed pasture is given, and the assumptions made are discussed.

Nutrient cycling in grazed pastures. III. Studies on labelling of the grazed pasture system by solid [35S]gypsum and aqueous Mg35S04

1970 ◽  
Vol 21 (3) ◽  
pp. 455 ◽  
Author(s):  
AR Till ◽  
PF May
Keyword(s):  
Steady State ◽  
Nutrient Cycling ◽  
Specific Radioactivity ◽  
Sulphur Content ◽  
Sheep Grazing ◽  
Plant Materials ◽  
Grazed Pastures ◽  
Grazed Pasture ◽  
Sulphur Cycle

35S was applied to eight paddocks either onto strips that comprised 1/30 of the area of the paddock or uniformly over the paddock. It was applied as solid [35S]gypsum or aqueous Mg35SO4 at sulphur levels of either 130 mg/ha or 7.8 kg/ha. The specific radioactivity of wool grown by sheep grazing the paddocks showed that strip and uniform labelling gave similar results, that there was no retention of the applied sulphur in forms that were not eventually available to plants, and that after about 260 days the effective specific radioactivity of the cycling sulphur had approached a steady state. There were significant differences between the specific radioactivities of sulphur in phalaris and clover. The differences in the sulphur application levels produced plant materials having slightly different sulphur contents but the major changes in sulphur content were due to the natural sulphur cycle.

Nutrient cycling in grazed pastures. I. A preliminary investigation of the use of [35S] in gypsum.

1968 ◽  
Vol 19 (4) ◽  
pp. 531 ◽  
Author(s):  
PF May ◽  
AR Till ◽  
AM Downes
Keyword(s):  
Nutrient Cycling ◽  
Isotope Dilution ◽  
Plant Uptake ◽  
Specific Activity ◽  
Preliminary Investigation ◽  
Residual Value ◽  
Grazed Pastures ◽  
Initial Application ◽  
Total Soil

[35S]Gypsum was applied to six strips covering a total of approximately 1/32 of the area of a pasture grazed by sheep. The specific activity of samples of soil, plants, ingesta, faeces, and wool was measured. The results were as would be expected from uniform labelling of the whole paddock, and enabled translocation to untreated areas to be measured. They indicate that doses of the order of 1–10 mc should be detectable on paddocks up to 4 ha in area for periods of up to 1 year. When animals were put onto or removed from the treated pastures, changes in the specific activity of wool indicated that 100–150 days were required for the sulphur in the sheep and pasture to reach equilibrium. Animals continuously maintained on the pasture were still producing wool at 60% of the maximal specific activity after 600 days, which indicated a continuing recycling of the applied sulphur. From calculation of the isotope dilution it appears that only a small fraction of the total soil sulphur was available for plant uptake, and the continuing cycling of this over a period exceeding 600 days indicates a high residual value of the initial application.

Nutrient cycling in grazed pastures.IV.The fate of sulphur-35 following its application to a small area in a grazed pasture

1971 ◽  
Vol 22 (3) ◽  
pp. 391 ◽  
Author(s):  
AR Till ◽  
PF May
Keyword(s):  
Nutrient Cycling ◽  
Small Area ◽  
Specific Radioactivity ◽  
Positive Evidence ◽  
Grazed Pasture ◽  
Simultaneous Measurements ◽  
Organic Sulphur ◽  
High Specific Radioactivity ◽  
Wide Range ◽  
Extractable Soil

Simultaneous measurements of sulphur content and specific radioactivity were made on soil fractions, two pasture species, and the fleece of grazing animals following the application of high specific radioactivity gypsum labelled with sulphur-35 (35S) to small randomly located sites in grazed pastures. The results show that the extractable soil sulphate was a precursor of plant sulphur and that the organic sulphur fractions in the soil were the source of replenishment of the extractable sulphate pool. Applied sulphur was shown to remain predominantly in the top 7.5 cm of the soil over a period of c. 600 days, and it was from this region that the plants drew their sulphur. The uptake of applied sulphur was initially different between plants of different species. These differences gradually decreased and finally disappeared as the applied sulphur became mixed into all soil sulphur fractions. A wide range of rates of mixing indicated that some fractions of the organic sulphur were recycling very slowly. Positive evidence of recycling of sulphur voided by the animals on the unlabelled areas of the pasture was found, and the rate of translocation of sulphur from the sites of its application to the remainder of the paddock was measured at two rates of stocking.

Viability of axillary buds of white clover (Trifolium repens) in grazed pasture

1992 ◽  
Vol 119 (3) ◽  
pp. 345-354 ◽  
Author(s):  
P. C. D. Newton ◽  
M. J. M. Hay ◽  
V. J. Thomas ◽  
H. B. Dick
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Trifolium Repens ◽  
Axillary Buds ◽  
Spring Period ◽  
Grazed Pastures ◽  
Grazed Pasture ◽  
Pattern Of Variation

SUMMARYStolon nodes of white clover were sampled monthly for 18 months from continuously grazed (set stocked) and rotationally grazed pastures in New Zealand. Both pastures were stocked at 22·5 ewes plus lambs/ha. Axillary buds were classified into viability categories using an incubation technique. On average, 54% of nodes had non-viable or dormant buds, 25% had axillary buds that were viable but non-active and 0·1% bore reproductive buds. Although 21% of buds emerged, only 8·5% of nodes bore live branches. Bud activity was strongly inhibited during the spring period of both years and this inhibition could not be removed by incubation.The greatest bud viability occurred at node 4 (from the apex) although 30–40% of the buds at this position were non-viable. This pattern of variation changed somewhat with season. Some viable buds were present at nodes more than 20 from the apex but these were of low vigour. Secondary stolons had different patterns of bud activity from those of primary stolons until they comprised more than 16 nodes.

Winter growth stimulation by gibberellin in differentially grazed pastures of Phalaris tuberosa

1964 ◽  
Vol 4 (14) ◽  
pp. 225 ◽  
Author(s):  
CN Williams ◽  
GW Arnold
Keyword(s):  
Gibberellic Acid ◽  
Growth Stimulation ◽  
Soluble Carbohydrate ◽  
Initial Increase ◽  
Subsequent Increase ◽  
Grazed Pastures ◽  
Grazed Pasture

The effect of gibberellic acid sprays on' the winter growth of two pastures of Phalaris tuberosa L. differentially grazed for a period of four years prior to the investigation, was studied. The previously lightly grazed pasture had initially approximately ten times as much soluble carbohydrate in the underground parts as the heavily grazed pasture. Both pastures responded in the same way with an initial increase in yield with gibberelin but no subsequent increase. However, regrowth from cut areas treated with gibberellin was significantly greater on the lightly grazed pasture. Since the stubble remaining after cutting was very low in chlorophyll, it is suggested that the differential regrowth might be due to the higher levels of stored carbohydrate in the lightly grazed pasture.

Effects of the composition of irrigated perennial pasture on the milk production of dairy cows and their responses to supplementation with cereal grain-based concentrates

2008 ◽  
Vol 48 (7) ◽  
pp. 866
Author(s):  
C. R. Stockdale
Keyword(s):  
Milk Production ◽  
High Energy ◽  
Grazed Pastures ◽  
Grazed Pasture ◽  
Cereal Grain ◽  
Species Groups ◽  
Metabolisable Energy ◽  
Trifolium Repens L ◽  
The Difference ◽  
Friesian Cows

The objective of the research described here was to compare the milk production from paspalum (Paspalum dilatatum Poir.)-dominant swards with milk production from perennial ryegrass (Lolium perenne L.)–white clover (Trifolium repens L.)-dominant swards. Eight experiments were conducted over a 2-year period, during which half the cows grazed pastures that had been established for more than 15 years (old pasture) and were dominated by paspalum in summer, while the remaining cows grazed pastures sown within the previous 2–3 years (new pasture), which were dominated by temperate species. Groups of four to five lactating Friesian cows grazed either old or new pasture and were either unsupplemented or were offered ~5 kg DM/cow.day of a high energy supplement (75% barley and 25% wheat). The hypothesis was that milk production would be greater from cows grazing new pastures than old pastures (at common pasture allowances), but that marginal milk responses when cereal grain-based supplements were fed would be greater when cows grazed old pastures; this was only partially supported. Milk yields were generally greater when cows grazed new pastures, but in six out of eight experiments, the advantage was only ~1 kg milk (100 g fat plus protein)/cow or less. In these six experiments, the difference in metabolisable energy density between the pastures was 0.7 MJ/kg DM or less. When concentrates were fed to supplement grazed pasture, there were seasonal variations, but similar marginal responses in milk production were recorded on both pastures throughout the study.

scholarly journals A decision support model for fertiliser recommendations for grazed pasture

1997 ◽  
pp. 137-140
Author(s):  
A.K. Metherell ◽  
B.S. Thorrold ◽  
S.J.R. Woodward ◽  
D.G. Mccall ◽  
P.R. Marshall ◽  
...  
Keyword(s):  
Decision Support ◽  
Relative Yield ◽  
Animal Production ◽  
Nutrient Budgets ◽  
Decision Support Model ◽  
Organic S ◽  
Soil P ◽  
Grazed Pasture ◽  
Animal System ◽  
Support Software

Decision support software for the evaluation of phosphorus (P) and sulphur (S) fertiliser strategies can assist farm consultants and their clients to determine pastoral agriculture fertiliser policies. The underlying dynamic model is based on the P and S cycles in the soil-plant-animal system, including fertiliser inputs and soil- and animalmediated losses. Initial soil fertility is estimated from the Olsen P and phosphate-extractable organic S soil tests, and recent fertiliser history. In the S sub-model organic S and elemental S pools are considered. Animal production responses to fertiliser are estimated from relationships between soil P and S status, fertiliser inputs, pasture relative yield and stocking rate. Maintenance and economically optimum fertiliser strategies can be automatically calculated or the user can enter their own scenarios. Alternative fertiliser policies can be evaluated in terms of nutrient budgets, soil P and S status, pasture and animal production, and economics. Keywords: decision support, economics, fertiliser, model, phosphorus, sulphur

Nutrient cycling and losses based on a mass-balance model in grazed pastures receiving long-term superphosphate applications in New Zealand: 1. Phosphorus

1992 ◽  
Vol 119 (1) ◽  
pp. 89-109 ◽  
Author(s):  
M. L. Nguyen ◽  
K. M. Goh
Keyword(s):  
Soil Depth ◽  
Plant Litter ◽  
Balance Model ◽  
Fertilizer Plant ◽  
Rooting Zone ◽  
Grazed Pastures ◽  
Animal System ◽  
P Leaching ◽  
Soil Inorganic

SummaryPhosphorus (P) cycling and losses in irrigated, sheep-grazed pastures receiving superphosphate (SP) applications for 35 years at annual rates of 0, 188 and 376 kg/ha were studied using a massbalance approach which accounted both for P inputs to and outputs from the soil-plant-animal system. Total recoveries of applied P in the soil-plant-animal systems in the 188 and 376 kg SP/ha treatments were 94 and 83% respectively. Approximately 52–53% of the applied P was recovered in the soil within the major plant rooting zone (0–300 mm soil depth). These data suggest that P leaching losses from SP fertilizer, plant litter, root residue and sheep faeces were unlikely to occur beyond the major plant rooting zone. However, the transfer of excretal P to stock camps and the transport of P from SP fertilizer, plant litter and sheep faeces via the irrigation water along the border from the top to the bottom of the irrigated border strip accounted for less than 6% of the applied P. Superphosphate applications resulted in the accumulation of both soil inorganic and organic P fractions to a depth of 225 mm. The accumulation of soil inorganic P was most pronounced when SP was applied annually at the rate of 376 kg/ha, which was in excess of pasture P requirements.

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