FDE applied in the correct manner can save on the fertiliser bill to the tune of $290/ha/year. The nutrient value of effluent varies greatly from farm to farm and even with a farm over the season. Therefore sampling in Spring, Summar and Autumn, in conjuction with Overseer nutrient budget modelling is recommended to estimate long term nutrients applied to effluent block.
Why sample for farm dairy effluent?
Provides an insight into the fertiliser value of your effluent
Assists in the correct calculation of land area and application rate. Inadequate land area can increase nitrate leaching, ponding of effluent, elevated pasture potassium which can induce metabolic complications in stock, and decrease the sustainability of the operation
In conjunction with Overseer nutrient budget modelling ensures land application of effluent is within maximum application rates (150-200 kg N/ha/yr) as recommended by Regional Councils. You should confirm the local maximum rates with your local authority
FDE application adds organic matter to the soil and increases earthworm activity
Which FDE analysis?
ARL offers two main analytical suites for FDE:
Where FDE is applied back onto the land the “Farm Dairy Effluent Suite” is recommended
Where FDE is treated through a two stage pond system and discharged into a receiving waterway, the “Discharge into Receiving Waterways Suite” is recommended.
Sampling of FDE being applied to the land
The nutrient value of effluent varies greatly from farm to farm and even within a farm over the season. Mineral content of FDE is likely to peak during September to October. Collecting a sample for nutrient analysis at this stage provides the optimum time to sample FDE if only sampling once a year (higher frequency of sampling is recommended)
Samples of FDE can be taken from storage ponds, dairy sumps or from the spray irrigator head. If possible sampling from the spray irrigator over a milking or period of time is recommended to obtain best representation of what is being applied
Environmental impact suite
Nutrient enrichment (eutrophication) is due to the response in water to over-enrichment by nutrients from natural and "man-made" sources. This over-enrichment leads to the growth of rooted aquatic plants at the exclusion of other plants, algal mats, and deoxygenation which in turn can lead to stress of aquatic life. The main nutrients implicated in eutrophication are phosphorus and nitrogen. Nutrient sources that can contribute to eutrophication include municipal, industrial wastewater, agricultural runoffs, and urban runoffs
Why sample for environmental impact?
To monitor the environmental impacts over time on the surrounding waterways of the operation. This testing suite monitors the main nutrients implicated in nutrient enrichment of water systems to within low levels of detection to effectively monitor any changes in nutrient levels over time
Salinity suite
Salinity is the measure of the total amount of salt in water and is measured by the conductivity of the water. Both sodium and chloride can cause potential for plant injury if in high enough concentrations in irrigation water.
Excess salinity in irrigation water can also cause excessive soil sodium levels which will lead to deterioration in soil structure.
Exploratory water wells should also be analysed for salinity to determine if water is fit to drink.
Why sample for salinity?
To assess potential for plant injury from salinity in irrigation water without incurring the full expense of selecting the “Irrigation Suite”
To assess risk of raising sodium loadings in the soil to levels where soil structure will deteriorate
To assess whether water is fit to drink (The “Domestic and Drinking Water Suite” is recommended for drinking water)
How to take water samples
Refer to the
water sampling guide for full details of how to take water samples.
For further information or to make arrangements for testing please contact our Ravensdown Customer Centre on 0800 100 123 or contact ARL directly on 0800 100 668
ARL water price list 2011.pdf