From the ground up - Ag news

Most regions in New Zealand have been experiencing quite challenging weather conditions in recent times – and the continued “wet” will be impacting most growing systems. Testing soil and herbage now will help guide decision-making to make the best of the season ahead.

Soil Testing
In some soils, the long wet spells may have resulted in increased leaching, causing the available nutrient pool to be depleted (e.g. K, SO4). Samples taken after prolonged wet weather may not reflect previous “monitor” samples but be more a point-in-time measure to enable any immediate short-fall of plant nutrients to be applied.

Soils that have been underwater for extended periods are temporarily anaerobic, altering their soil chemistry including pH. As well, soils where floodwater has intruded may have high silt loadings – and test results may not fit previous monitoring trends.

Even if samples are generally taken only every second or third year on a property, it may be worth taking samples this year to assess the current nutrient status - once conditions are acceptable for sample collection.

Advice should be sought from experienced and qualified advisors to guide management of paddocks to maintain them at the optimum productive state.

Soil Quality
Along with soil fertility (pH and nutrient status), soil quality can be evaluated using a combination of visual assessment and lab testing. Hill Laboratories have recently made available the Hot Water Extractable Carbon (HWEC) test which provides an indicative measure of the soil biological health. The HWEC test is a measure of the labile soil carbon pool, and has been shown to be highly correlated with the Soil Microbial Biomass.

The HWEC test can be requested on the same soil samples submitted for regular fertility monitoring. For more information, please see our Technical Note – Laboratory Tests for Soil Carbon, published on the Hill Laboratories website, or contact the laboratory.

Pasture and Feed Testing
Good pasture quality with adequate nutrient and mineral content is key to optimising livestock production through the spring period.

The variable weather conditions may have impacted on typical pasture growth patterns, and affected pasture feed value.

Testing pasture just prior to grazing, along with any supplementary feeds including crops or silage, will provide information to advisors and nutritionists for minimising metabolic disorders and maintaining good production levels and animal body condition.

Hill Laboratories have very recently adopted a more accurate Acid Detergent Fibre (ADFsq) method in the lab as well as included Lignin as a routine test in the NIR Feed Profile suite of tests. Fibre is a key nutrient for ruminants, and is generally quite low in pastures through spring.

Feed sample kits are available through merchants, vets or direct from the laboratory.

Arable & Hort. Leaf Testing
Arable and horticultural crop growth may also be impacted where wet soils have occurred for long periods – with wet soils slow to warm up and nutrient uptake affected.

Leaf testing at the appropriate growth stage can ensure the crop nutrient status is where it should be for targeted yields. Plant uptake of nutrients is affected by soil conditions – so leaf testing will be a useful tool this spring and early summer in case early intervention with applied nutrients is needed.

Hill Laboratories Crop Guides have recently been updated and describe how to leaf sample and when for a wide range of crops. These guides are available on request to the laboratory or can be found on our website.

Irrigation Water
While there will likely be little need for irrigation until late summer, it may be useful to plan to have the water source tested prior to use. Testing the source will also be important where this water is used for fertigation purposes. An Irrigation Water Profile Kit is available from the laboratory on request.