EFFECTS OF NITROGEN FERTlLlSER ON PRODUCTION OF MILK SOLIDS FROM GRAZED PASTURE

Author(s):  
A.M. Bryant ◽  
K.A. Macdonald ◽  
D.G. Clayton

In each of two years, eight 6.48 ha farmlets were used to assess effects of urea applications on dairy production. In the first year, 86 kg N/ha were applied in 2-3 dressings during May-August. Effects on annual milkfat and pasture production were not significant. In the second year 3-4 applications totalling 137 kg N/ha in April to September significantly increased annual milkfat and pasture production. Response in milkfat production per hectare to urea application averaged 0.22 (range - 0.16 to 0.45) and 0.25 (range - 0.1 I to 0.39) kgfat/ kgN in the first and second years respectively. These responses were not economic at present-day prices.

Author(s):  
A.D. Mackay

A grazing trial evaluated the agronomic effectiveness of 3 different types of phosphate (P) fertilisers. The same fertilisers were also evaluated in a small-plot mowing trial located within the grazing trial. In the grazing trial, which covered 35 ha of summer moist hill country, the partially acidulated phosphate rock (PAPR) and reactive phosphate rock (RPR) were as effective as superphosphate in stimulating legume and pasture production in the first year. In the second year the two slow-release materials continued to perform as well as SSP. In contrast in the mowing trial, superphosphate was more effective than RPR in the first year. This trial technique clearly underestimates the initial effectiveness of PAPR and RPR in grazed hill country. The traditional small-plot mowing trial technique, and the role of PAPR and RPR fertilisers in hill country, both need re-evaluation. Keywords hill country, superphosphate, slow release fertilisers, mowing trials, grazed pasture


1955 ◽  
Vol 6 (4) ◽  
pp. 553 ◽  
Author(s):  
RC Rossiter ◽  
PG Ozanne

A 2-year field experiment is described, in which an annual-type pasture was grown on a soil of lateritic origin with various initial rates of rock phosphate and superphosphate. The soil was acutely deficient in plant-available phosphorus at the outset. Application of superphosphate led to the expected increases in total pasture production, but rock phosphate also gave substantial yield increases, even during the first season. Differential species effects were noted; subterranean clover (Trifolium subterraneum L.) and cape-weed (Cryptostemma calendula Druce) responded about equally to superphosphate, but the clover responded to rock phosphate to a greater extent than did cape-weed. Both relative efficiency for total plant growth and percentage utilization of applied phosphorus were much higher with the soluble phosphatic fertilizer than with rock phosphate, especially in the first year. However, phosphorus recovery from rock phosphate was as high in the second year as in the first, whereas there was a marked decrease in the second year from superphosphate.


1998 ◽  
Vol 49 (2) ◽  
pp. 225 ◽  
Author(s):  
C. J. Thomson ◽  
C. K. Revell ◽  
N. C. Turner ◽  
M. A. Ewing ◽  
I. F. Le Coultre

A long-term rotation experiment located in south-western Australia was used to measure the effect of rotation and time of germinating rains on the productivity and botanical composition of grazed annual pastures in 2 contrasting seasons in an environment with an average annual rainfall of 325 mm. The density of self-regenerating seedlings of subterranean clover (Trifolium subterraneum), capeweed (Arctotheca calendula), and grasses (Lolium rigidum, Hordeum leporinum, Bromus diandrus) was greatly increased (approx. 3 times the density) when there was a second year of pasture after crop compared with the first year after crop. The lower plant density resulted in first-year pastures having only about 33% of the autumn biomass accumulation of second-year pastures. This difference in early pasture growth had no effect on total pasture production in 1992, but in 1993 total pasture production was 30% greater in second-year pastures compared with first-year pastures. Botanical composition varied between and within seasons with the percentage of subterranean clover increasing throughout the season and the percentage of capeweed decreasing throughout the season. Grasses comprised <20% of the biomass in all seasons and treatments. Production of subterranean clover seed in 1993 was higher in a 1 : 2 crop-pasture rotation than in a 1 : 1 crop-pasture rotation and direct drilling in the cropping phase increased seed set compared with conventional tillage in both 1 : 1 and 1 : 2 crop-pasture rotations. Capeweed seedlings emerged in large numbers after rainfall between February and May and subsequently showed a relative growth rate twice that of subterranean clover and the grasses, but exclusion of rainfall until June resulted in a significant reduction in the emergence of capeweed seedlings. Additionally, capeweed had a lower rate of seedling survival compared with other pasture species, and this is contrary to observations by other researchers that capeweed is highly resistant to moisture stress during early growth.


Author(s):  
W.R. Nixon

Our objectives as farmers are to sustain a pastoral farming system that converts the optimum amount of grass grown to milk solids. The key to achieving this is by adopting the correct stocking rate. On our property,production has increased from 330 kg milkfat/ha in the first year to 430kg milkfat/ha in the second year. Conservation is not the preferred option when dealing with surpluses. A combination of supplements, nitrogen and off-farm grazing is used to make up the deficits. The absence of a mid-season slump in grass growth results in a sustained production curve through the season. This is a feature of borderdyke dairy farming. The correct stocking rate will enable costly grass surpluses and deficits to be kept to a minimum. The distribution of grass growth on our farm is what is really important, not total dry matter. The availability of crop residues and off-farm grazing in this area can be used profitably to make up feed deficits. Production Increases in the short term will come through improvements in sward composition, fertility, cow quality and irrigation. Longer term, production increases can come only through growing more grass and finding the correct blend of calving date, stocking rate and drying-off date, to utilise that grass to the optimum. Keywords: dairy farming, stocking rate, borderdyke, pasture management


1989 ◽  
Vol 40 (1) ◽  
pp. 97 ◽  
Author(s):  
SJ Blaikie ◽  
KB Kelly ◽  
WK Mason

Adding organic matter or replacing topsoil have been shown to improve the growth of pasture on areas where subsoil is exposed during landforming. Intensive experiments were carried out in each of the 1985-86 and 1986-87 irrigation seasons to examine the basis of improvements in the productivity of pastures after such amelioration. Measurements were collected during the period between two irrigations which were separated by approximately 70 mm of cumulative Class A pan evaporation. Treatments included (i) high rates of nitrogen and phosphorus (NP); (ii) NP + organic matter (OM); (iii) NP + topsoil (TS); and (iv) NP +Well watered (WW).Compared to NP, pasture production in OM and TS treatments was improved in the first year, but in the second year only the TS treatment gave significant improvement. These increases in dry matter yields were reflected in rates of leaf elongation, canopy conductance, evapotranspiration and photosynthesis that were up to 50% greater than those in WW during the first half of an irrigation cycle, but there were no differences in leaf water potential. There was a strong relationship between canopy conductance and photosynthesis, and it appears that the plants in the TS and OM treatments were responding to an improved root perception of soil water availability. It is hypothesised that this allowed them to maintain canopy conductance and therefore photosynthesis at higher levels than in NP and WW. The improved performance of the TS and OM treatments represents an increase in the productive potential of exposed subsoil areas that cannot be achieved by improving fertilizer and irrigation management alone.


Author(s):  
J.D. Morton ◽  
C.J. Roach ◽  
A.H.C. Roberts

Potassium chloride (KCl) was applied at 4 rates (0, 150, 450 and 1150 kg/ha) to pasture on closed 5 ha farmlets over 3 years, and pasture and animal production and animal health measured. Friesan, Jersey and Friesan x Jersey cows were stocked at 3.2/ha on an Egmont Allophanic soil near Hawera in South Taranaki. Average soil potassium quick test (QTK) levels were 7, 8, 10 and 12 respectively from 0, 150, 450 and 1150 kg KCl/ha. There was a small significant negative linear effect of rate of KCl application on annual pasture dry matter (DM) production averaged over three years (16864 - 18359 kg/ha). The average amount of silage conserved (1369 - 2112 kg DM/ha) was consistently greater at the highest rate of KCl. Increasing rate of KCl had no significant effect on the nutritive value of grazed pasture but resulted in increased K content of silage. There was no significant effect of KCl on milksolids (MS) production (1034 -1179 kg/ha/lactation) or reproductive performance. There was a trend for the incidence of clinical metabolic disorders (8-18%) to decrease with increasing rate of KCl but this was not significant because of the low number of cows in each herd. The results from this trial suggest that soil QTK levels above the target range for optimal pasture production of 7-10 on Allophanic soils are not associated with increased dairy production and have no adverse effect on animal health. Keywords: calcium, dairy cows, hypocalcaemia, hypomagnesaemia, magnesium, milksolids, pasture, potassium, potassium chloride


Author(s):  
J.D. Morton ◽  
A.H.C. Roberts

Mowing trials were carried out to determine the rates of fertiliser nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) and frequency of application of K for maximum pasture production on extremely infertile humped and hollowed pakihi soils in the Grey Valley (Souters and Sommervilles dairy units), and flipped soils at Cape Foulwind (Bassetts dairy unit) under high annual rainfall (2000 - 3000 mm) on the West Coast. In the first measurement year, there was no significant increase in pasture production above 480 kg N/ha, 56 kg P/ha, 360 kg K/ha and 136 kg S/ha at Souters and Bassetts and a significant increase in pasture production up to 600 kg N/ha, 56 kg P/ha, 360 kg K/ha and 140 kg S/ha at Sommervilles. In the second year, there was no significant pasture production increase above 480 kg N/ ha, 56 kg P/ha, 360 kg K/ha and 136 kg S/ha at all sites. The high N, K and S rates were required because nutrients were not being recycled through returned clippings. This situation would be similar to the early stages of dairy management on these units where only a small proportion of pasture would receive recycled nutrients through return of excreta. Over time, a larger proportion of the pasture would be affected by excreta and fertiliser nutrient requirements would be expected to decrease. There was no increase in pasture production from applying potassium chloride in more than four applications per year at Souters and Bassetts in the first year, but a significant increase in pasture production from eight compared with four applications per year at Sommervilles, where soil QT (quick test) K levels were lower than at the other two sites. Keywords: flipped, hump and hollowed, nitrogen, phosphorus, potassium, sulphur


Author(s):  
S.D. Mcbride

The effectiveness of Sechura RPR (SPR) plus sulphur (S) as a development and maintenance fertiliser was compared with superphosphate (SSP) on an irrigated grazed pasture. In 1980, SSP or SPR plus S was applied at 71 kg/ha phosphorus (P) to pastures that had not received fertiliser for 22 years, but had been recently over-drilled with ryegrass and white clover. Annual maintenance rates of 250 kg SSP/ha and 175 kg SPRjha plus S, (supplying 22 kg P/ha and 27 kg S/ha), were applied from 198 1 to 1992. In the first year the SSP treatment restored pasture production to near optimal level and this level was maintained over subsequent years with annual topdressings. In contrast, the SPR plus S treatment did not restore pasture production until the third year. In the first two years production from this treatment was only 69% and 88%. respectively, of the 250 kg/ha/year SSP treatment. From year 3, annual applications of SPR plus S maintained pasture production. In the first 3 years P concentrations of pasture topdressed with SPR were lower than those of pastures topdressed with SSP. Herbage S concentrations were adequate on both fertiliser treatments. Soil Olsen P levels rose quickly in the first year after the initial application of SSP then decreased to the same level as the SPR plus S treatment. Olsen P levels have been rising steadily since 1983, from both forms of P, indicating that 22 kg P/ha/year is above maintenance for this site. Keywords development fertiliser, irrigated pasture, maintenance fertiliser, Sechura reactive phosphate rock, superphosphate


Author(s):  
Sd Mcbride ◽  
M.L. Nguyen ◽  
D.S. Rickard

Two field-plot trials were superimposed on irrigated, sheep-grazed pastures on Lismore stony silt loam in Canterbury to investigate residual effects of previous superphosphate applications on dry matter (DM) production and herbage composition. Residual effect of phosphorus (P) in superphosphate was shown to depend upon previous application rate and number of years of superphosphate application. In contrast, residual effect of sulphur (S) in superphosphate was independent of previous application rate if superphosphate had been applied for 25 years at rates at or above the S maintenance rate. Previous applications of superphosphate at the annual rate of 376 kg/ha for 6 years failed to safeguard pasture against yield reduction even in the first year after superphosphate was discontinued. This reduction was attributed equally to both P and S deficiencies. Residual values of both P and S were more substantial in areas where superphosphate had been-applied-at--the-higher rate of 564 kg/ha for 6 years. However, these residual values were also short-lived and DM production declined by 13% in the second year after the cessation of superphosphate application. Different patterns of residual values of superphosphate were recorded on areas where superphosphate had been applied over a longer term of 25 years. Where superphosphate had been applied annually at 188 kg/ha, DM production fell by 10% in the first year after topdressing ceased. This reduction was due entirely to P deficiency affecting clover growth, while S deficiency - in both grass and clover - was not observed until the third year after topdressing ceased. On areas where superphosphate had been applied at a higher rate of 376 kg/ha for a similar period of 25 years, DM production did not decline until the second year. This initial decline was attributed to S deficiency in clover while P deficiency in grass and clover was not apparent until the 4th year after the cessation of superphosphate application. The results were used in a simple model that uses previous topdressing history to predict yield reductions if topdressing is withheld. Keywords residual effects, phosphorus, sulphur, irrigated pasture


2020 ◽  
Vol 5 (1) ◽  
pp. 74-89
Author(s):  
Hugh Crago

In a seminal 1973 paper, Robert Clark described the very different “cultures” of the first and second year students in a four year clinical psychology PhD programme. The author applies Clark’s template to his own experiences as trainee or trainer in five different counsellor education programmes, one in the US and four in Australia. Each of the programmes, to varying degrees, demonstrates key features of the pattern identified by Clark, where the first year is “therapeutic” and other-oriented, the second is “professional” and self-focused. The author concludes that all the surveyed programmes exhibited some level of “second year crisis”, in which a significant number of students felt abandoned, dissatisfied, or rebellious. The author extends and refines Clark’s developmental analogy (first year = childhood; second year = adolescence) to reflect recent neurological research, in particular, the shift from a right hemisphere-dominant first year of life, prioritising affiliative needs, to a left hemisphere-dominant second year, prioritising autonomy and control. This shift is paralleled later by a more gradual move from a protective, supportive childhood to necessary, but sometimes conflictual, individuation in adolescence. The first two years of a counsellor training programme broadly echo this process, a process exacerbated by the second year internship/placement, in which students must “leave home” and adjust to unfamiliar, potentially less nurturing, authority figures. Finally, the author suggests introducing more rigorous “academic holding” into the first year, and greater attention to “therapeutic holding” of dissident students in the second, hopefully decreasing student dropout, and achieving a better balanced training experience.


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