Review of Experiments with Nitrogen Fertiliser on Pastures in Victoria

Year of study:

pre-1987

Lead organisation & Collaborators:

Department of Agriculture and Rural Affairds

Contact:

Dairy Research Institute, Ellinbank

 Best available science assessment:

Overall Score: 27

Overall rating: High

Objectives

Conceptual model

Study design

Soil analysis

Production & financial

Method reporting

Data analysis

Results reporting

Publication

4

4

3

3

2

3

2

3

3

Project details

Objectives:

Results from about 600 trials investigating the effects of N fertiliser on Victorian pastures over the past 50 years have been collected and reviewed. The review sought to quantify the magnitude of pasture responses to fertiliser and interactions with various management treatments.

Hypotheses:

The review considers a variety of effects of N fertilizers. In relation to soil pH, the hypothesis under consideration was that nitrogen fertilizers have affect on soil acidity.

Basis of trial:

Nitrogen fertilisers have an effect on soil acidity.

Location details:

Trial site details:

Over 600 trials, occurring over the 50 years prior to publication (in 1987) were compiled to inform this review.

Pre-trial management:

Not specified

Trial management:

Not specified

 

Reportage:

How results have been reported:

Technical Report

Research Report series No 54, December 1987

How a copy of any relevant reports can be obtained:

DPI Knowledge Resource Centre

Level of review of results:

Internal technical review

Results:

Summary of key findings of trial:

Athough there is nearly always increased growth with increased N fertilizer, the magnitude of responses and the interactions with various management treatments have been variable.

Average growth responses are 10kg DM/kg N. Marginal Reponses and average responses decline as the rate of N decreases.

Variation in soil pH with time and management influence:

One set of trials investigated the effect of six N fertilizers (applied at 112 kg N / ha / year for four years in an unspecified location.

Fertilizer

pH (0 -75 mm)

pH (75 – 150 mm)

Control

7.4

8

Sodium Nitrate

7.6

8.1

Potassium Nitrate

7.4

8

Calcium ammonium nitrate

7.3

8

Nitrophoska red

7

7.8

Urea

6.9

7.9

Ammonium Sulphate

6.4

7.7

The results confirmed other findings ammonium sulphate is the only commonly used fertilizer likely to significantly increase soil acidity

Variation in productivity/ profitability with time & management influence:

Average growth responses were 10kg DM / kg N and the proportion of clover in pasture falls.

Experimental Design:

Treatments:

Various treatments

Trial design/layout:

Distribution of Nitrogen trials (1932-1985)

East Gippsland 33
Central Gippsland 27
West Gippsland 69
South Gippsland 49
Central 48
Central Highlands 45
South West 50
Western District 42
Goulburn Valley 128
North East 51
TOTAL 550

Soil Sampling:

Not specified

pH tests were reviewed.

Plant and/or animal production measurements:

Average growth responses by pasture were reviewed (DM /kg N applied). Clover cover also reviewed as a function of N application (kg N/ha), and the effects on N fertilization in spring on seed yields for perennial grasses.

Cost and value of production:

Fertilizer

Cost ($/tonne)

Urea

304

Foliar Spray

419

Ammonium Sulphate

264

Ammonium Nitrate

335

Calcium Ammonium Nitrate

220

Sodium Nitrate

537