All Paddock Testing

July 2010

A new test developed at Hill Laboratories to better understand soil variances on farm

Hill Laboratories is one of NZ’s largest analytical testing laboratories. They provide a range of testing services around New Zealand covering; the environment, food and bioanalysis, microbiology, air quality, as well as horticulture and agriculture.

They have created a new testing service for farms made possible by advances in soil analysis technology and software. It’s called “All Paddock Testing”. The service is being launched at Fieldays this year, enabling farmers to make smarter, more cost effective, environmentally friendly decisions about fertiliser use.

Hill Laboratories supply a broad range of lab tests to domestic and international markets. The tests cover the environment (effluent, water, air quality), agriculture and horticulture (feed, plant and crop, compost and hydroponics, soil), food and bioanalysis (including wine and honey), microbiology (swab and surface sample testing).

They have automated a number of processes in the laboratory, working with companies to design and commission equipment that reduces the laboratory floor area required, labour units, human error and injuries, and markedly increases the number and size of samples able to be processed.

Improvements are continually being made, and one such new commission which will impact on soil testing for farmers is currently underway at the laboratory in Hamilton. A machine named RoSEE is being replaced by ASTRO.

Excerpt from the Hill Lab website:

Most NZ pastoral soils are deficient in phosphorous, sulphur and to a lesser extent, potassium and some trace elements can also be deficient. Soils under intensive cultivation may have abnormal levels of some nutrients due to previous management practices and fertiliser programmes.

Soil testing takes the guess work out of nutrient management and allows cost effective fertiliser programmes to be developed. Herbage tests of pasture complement soil tests and allow important trace elements like cobalt, selenium, copper and iodine to be adjusted for improved animal health.

Soil testing measures whether soil nutrient levels are high enough to sustain the desied level of plant growth. It indicates the existance of any deficiency, exess or imbabalance of major nutrients. It provides a scientific basis on which to assess fertiliser and lime requirements of crops, pastures and turf. An organic soil profile measures soil quality, testing soil organic matter, available nitrogen, total nitrogen and the carbon:nitrogen ratio.

Soil tests measure a fraction of the total pool of nutrients available to plants (both immediate and long term) so it is important that standard NZ methods of sampling and soil analysis are used so that results are meaningful and can be related to plant growth under NZ conditions. Single soil tests are of limited value as they are essentially snashots of what is a dynamic environment. Trends in soil test values over time give a better indication of how well (or poorly) a fertiliser programme is working. As an additional tool, plant testing complements soil testing. Plant testing measures the mineral nutrients that livestock are actually eating. It should be noted too, that factors such as soil temperature, rainfall and compaction also influence the rate of uptake of nutrients by plants.

For agricultural samples, twenty 7.5cm cores should be collected from across the area, aim for about 500g of soil. Avoid dung and urine spots and recently grazed pastures, don’t sample within 3 months of applying fertiliser or lime. For arable samples, twenty 15cm samples should be taken. Sampling at the same time of year in the same way will give better nutrient monitoring. Hill Laboratories provide Soil and Plant testing kits on request.

Currently, standard practice is to test a few paddocks and make assumptions about the remaining paddocks regarding their nutrient status based on that small sample.

The weaknesses of this approach are:

– Wasted dollars on inexact use of fertiliser,

– Insufficient or incorrect mix of fertiliser,

– Enhanced environmental risks due to leaching and run-off.

All Paddock Testing is a new service provided exclusively through Hill Laboratories. A farmer using this service gets all paddocks tested, or typically 40 to 50 samples compared to the 4 to 5 samples per farm along sampling transects traditionally employed. As a result, with the comprehensive report produced (including colour coded farm maps, depicting nutrient density gradients) farmers can optimise the fertiliser application by paddock, often for decreased cost. Included in the service is access to a password protected web service providing an interactive view of the paddock by paddock nutrient maps.

Additional benefits are improved soil nutrition in key areas and reduced farm impact on the environment.

The tests provide a greater understanding of the variability of fertility across the property and can confirm (or otherwise) whether the current monitoring regime is appropriate. It can also identify environmental “hotspots” where particular care needs to be taken.

With increased sampling, came the need to develop a method for analysing the samples that was both time and cost effective. As part of the sampling process, a motorised sampling auger was attached to an ATV and GPS enabled to record where and when core samples are taken.

In the laboratory, efficient and accurate sampling needed to be developed to cope with the increased samples. Robotics was an obvious route to take. Hill Laboratories are continuing to develop robotic testing. They use Near Infrared analysis, which is both fast and non-destructive of minerals and other soil values they test.

Tests are offered in pH, Olsen P, Cations, Volume weight, CEC, % Total base Saturation, Total Sulphur, Phosphate retention and “P Loss Index”.

The results gathered are comprehensive, and presentation of data is as important as the quality of result, for it to have the most benefit. There is a web service that has been created called IntePasture. It uses colour coding to map out the entire farm, including historic block data where appropriate. Further interpretation is given by consultants and advisers, which can take into account any other pertinent factors. This holistic approach to data interpretation makes a significant leap forward in farmers understanding their properties better and gives them the information to make better management decisions as a result.