Rural Diary October

Rural Diary October 2019

PGG Wrightson's monthly technical guide to assists farmers with planning on-farm activities, to maximise productivity and grow their business.

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Knowing your soil type

This is the second article of a three-part series that takes a closer look at New Zealand soils. Soil underpins all agricultural activity, so understanding the soil you farm is important. This month, I will focus on four distinct soils that are well known to farmers, and explain how they are different to each other.

There are actually 15 main soil types in New Zealand, called soil orders, and within each order there are soil groups and sub-groups. So altogether, there are more than a thousand different soils. This level of detail can be somewhat daunting, so, to simplify from a practical agricultural point of view, all of these soils are grouped into four larger soil types, categorised according to the parent materials from which they have formed. These parent materials determine the natural fertility and how they respond to the different nutrients applied to the soil. These four generic soil types are Ash, Sedimentary, Pumice and Peat/Organic soils.

Ash soils

Ash soils are found mostly in the western, central and upper/mid North Island. They are made up of iron rich volcanic ash and are some of the oldest soils found in New Zealand. They are predominantly used for highly productive dairy and horticultural systems, such as those found in Taranaki, Waikato and Bay of Plenty. Ash soils generally have good soil structure, large organic matter content and deep topsoil.  In relative terms (compared to the other three soils), ash soils can retain large amounts of phosphorus.

Sedimentary soils

Sedimentary soils cover the vast majority of New Zealand and have a wide range of land uses. This wide coverage means there are many different soil orders, with different soil properties, within the sedimentary group. All sedimentary soils are formed from quartz-rich sedimentary parent material, such as greywacke, schist and granite. These sedimentary rocks are formed by the accumulation or deposition of small particles and subsequent cementation of mineral or organic particles on the floor of oceans which are then uplifted above the ocean over millions of years. Compared to the other three soils, sedimentary soils can have naturally high reserves of potassium.

Pumice soils

Pumice soils cover a large area of the central plateau of the North Island. They are dominated by pumice that is high in volcanic glass. Most of the pumice in these soils originated from the powerful Taupō eruption 1,800 years ago. Many pumice soils are extensively used for commercial forestry. They were unsuitable for pastoral farming until the cobalt deficiency was found and managed. Pumice soils generally have naturally low fertility. However, with the addition of fertiliser they can become productive pastoral soils.

Peat soils or organic soils

Organic soils cover only a small portion of the country, with the largest occurrence in the Waikato. Organic soils are generally located in wetlands, and are formed from the decomposed remains of wetland plants or forest litter. Organic soils are generally wet and naturally acidic with low soil nutrient levels. However, when drained and well fertilised they can become very productive. 
Keep an eye out in next month’s Rural Diary where I will finish this three-part series with advice on how to manage each of these four generic soil types.

For more information on your property’s soil type or to arrange soil testing, talk to your local PGG Wrightson Technical Field Representative.

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Win the war on buttercup and dock

Over time, established perennial pastures can become overrun with weeds and reduce pasture production if left unchecked. 

Dry summers, wet winters, insect attacks, poor fertility and over-grazing can cause the death of desirable pasture plants, thus creating gaps for weeds to colonise. These weeds compete for light, space, moisture and nutrients. For the good of the longevity and quality of pasture, these weeds should be controlled.

As I walk pastures around the country in the early spring, I notice more and more pastures infested with weeds, such as buttercup and dock. These two weeds can cause a large amount of competition to perennial pastures and, if left unchecked, they force you to have to renew your pasture earlier than desired due to poor performance.

Most people forget they have these two weeds until they see paddocks covered in yellow buttercup flowers or tall ugly dock seed-heads standing above the grazing platform. By then it is too late to do anything effective about them and stay relatively clover safe.

Normally, the best time to use broad spectrum herbicides such as 2,4-D for weed control in established pasture is during autumn and early winter, but for these two weeds 2,4-D is not the correct product. Early spring when weeds are actively growing is the best time for some other selective chemistry. A range of herbicides are available for use in established pasture and, if used correctly, they should give a high level of weed control, with no damage to pasture grasses and minimal damage to clover species. 

The timing of the sprays are when soils have just started to warm up and you see the first signs of buttercup flowers or, if you have docks, when the first new spring leaves start to unroll. Sometimes there has to be a compromise between these two spray periods.

When using herbicides, the clover content of the pasture has to be taken into account as this affects your product selection and timing. If the clover content is low or non-existent, more robust chemistry can be used. This helps kill the toughest of weeds and unfortunately any clover, but is still safe on grasses and the clover can always be added back in at a later date. If there is a good amount of clover, use “softer chemistry” that is either safe or less damaging to clovers. There can be some pasture growth suppression if conditions are warm at the time of spraying, so don’t delay spraying too late into spring. 

Get in touch with your local PGG Wrightson Technical Field Representative to walk your paddocks and help you with your herbicide management plan and product choice for spring.


Top Tips:

  • Walk your paddocks and identify weed species.

  • If targeting buttercup, dock or both, refine your product selection and time appropriately.

  • Spray buttercup once you start seeing yellow flowers, usually from mid-late September to early November.

  • Spray dock when you see the first new leaves unroll, don’t spray too early. 

  • Base product selection on target weed species, and ensure it is appropriate for clover sensitivity.

  • There can be some pasture growth suppression where clover tolerant products are used, but pasture production recovers in the absence of the weeds.

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Managing worm burdens in reared calves

Scouring can be a common problem around weaning in calves, but it is not always due to worms.

The weaning process needs to be managed well to reduce potential problems as the calf transitions from a milk fed diet onto a forage based one involving the rapid development of the rumen. If this transitional phase is done poorly, then parasites create concerns. 

It is recommended that milk intake is reduced and meal intake is increased over a period of up to six weeks. This allows the rumen and intestines to adjust to the new feed source and reduces incidences of coccidiosis and nutritional scours.

Calf meals containing coccidiostats are important, and once intake in individual calves declines below 1 kg per calf per day, they become ineffective at managing the protozoan parasite. Affected calves often have a tail coated with dark faeces which contain digested blood and mucous. When symptoms become serious, veterinary advice including a faecal sample diagnosis is required with specific treatment initiated. These symptoms in young calves are often mistaken for worms.

Internal worms don’t become a significant issue in calves until grass is the greatest part of their diet for at least a month. Infective larvae are ingested which causes depressed feed intake and subsequent poor liveweight gain. The need for drenching generally occurs when calves are approximately 100 kg.

The take home message is that calves that are kept in sheds and fed primarily milk, pellets and hay do not need drenching for worms when released from the shed as they haven’t eaten any infective larvae in the shed.

When considering what types of drench to use on calves, the following points are important:

  • Ensure all equipment is clean and delivering the correct dose of drench using a measuring cylinder. Missing this basic step unfortunately contributes to worms developing drench resistance.
  • Abamectin is toxic in calves less than 100 kg.
  • The safest drench option for the first drench is a BZ/levamisole oral combination, for example VETMED Combomax Oral.
  • Don’t drench while the calves are feeding and don’t mix drench with milk as this can result in toxicity, death or ineffective drenching.
  • Once over 100 kgs, drench calves at 28 day intervals through the summer and autumn using a triple combination oral product, for example VETMED Triplemax Oral.
  • Best practice recommendation is to do a 10 day post-drench check once during the summer to determine if the drench being used is working effectively.
  • Due to the size of animals in the autumn, changing to either an injectable or pour-on product may be considered. Whatever product used must contain levamisole to control Cooperia worms.

Drenching is only part of the parasite control program. Where possible the following points are equally important to consider:

  • Avoid running high stocking rates of calves on the same paddocks year after year, as this can result in high infective larvae burdens.
  • Nutrition of the calf is paramount to ensure effective immune function. This includes optimal weaning transition feeding, trace element supplementation and preventative vaccinations.
  • Incorporate grazing of adult cattle or other species, for example, sheep to reduce pasture contamination.
  • Stick to a regular 28 day drench programme where possible, with effective triple combination oral drenches, for example VETMED Triplemax Oral, to prevent contamination of pasture. 

To put an effective parasite programme in place, talk to your local PGG Wrightson Technical Field Representative.

 Sponsored by VETMED/agritrade

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Growing top tomatoes

Juicy red tomatoes plucked straight from your vege patch are hard to beat. Store bought tomatoes never taste quite as good as those fully ripened and grown with love in the sun at home. 

Once the cold weather has passed and the soils have warmed up its time to plant tomatoes. Depending on what region you live in, tomato planting can start from September, and seedlings may be available as early as August in garden centres. However, it can be safer to wait for more settled weather, Labour weekend is known as the traditional tomato planting time in the north, and show week for the south of the country. 

When it comes to choosing your tomato seedlings, choose a variety that is suited to your cooking preferences. If you fancy delving into sauces, relishes and soups, choose varieties that have intense flavour and are heavy croppers. For those who enjoy eating tomatoes in salads and sandwiches go for the fleshy ones, which have less juice, or go for small and sweet cherry tomatoes if you simply like to eat yours plucked straight from the vine.

It is best practice not to plant your tomatoes in the same spot as last season, or in the same spot as potatoes were planted as diseases can remain in the soil and affect your new crop. Like building a house a good foundation is the key to success in your garden. The better the soil, the better your plants will grow. If you are starting with an existing garden bed dig in organic matter to your soil such as Tui Compost and Tui Blood & Bone. Both will increase microbial activity, encourage earthworms, and replenish your soil with nutrients used during previous growing seasons. The addition of Tui Blood & Bone to your garden also provides a natural source of nitrogen for healthy plant growth, and phosphorus for strong root development. You can then add a layer of Tui Tomato Mix, which is specially formulated with extra potassium to encourage a plentiful harvest of big juicy fruit. If you are planting in pots and containers use Tui Tomato Mix. 

If you are sowing tomatoes from seed, you will need to plan ahead to make sure they are grown enough to plant outside when you intend to. The best times to plant are early in the morning or late in the day, so your plants are not exposed to the hot sun straight away. When you plant your tomatoes, use stakes in the soil for each tomato plant before planting to provide support and avoid damaging the roots later.

Your plants use nutrients from the soil as they grow, so replenishing the nutrients used by your tomatoes ensures they will grow to their full potential. For tomatoes planted in garden beds feed with Tui Tomato Food every four weeks during key growth periods of spring and summer. Tui Tomato Food is a blend of nitrogen, phosphorus and a generous amount of potassium formulated to promote the growth and fruiting potential of all types of tomatoes. For tomatoes in pots and containers use an all-purpose controlled release fertiliser. 

For more information about the Tui range, pop into your local PGG Wrightson store.

As your tomatoes grow, follow these key tips to make the most from your crop:

  • Remove the laterals to encourage bigger and better fruit. Laterals are the shoots that grow out from the side of the stem. 

  • Keep the birds from beating you to your crop, cover plants with netting to protect them. 

  • Keep your tomatoes watered. Healthy, fertilised tomatoes will have a better chance of keeping insect pests and diseases at bay.


Supplied by Tui

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