Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 


Watch out for soils in winter

Watch out for soils in winter

by Bala Tikkisetty
June 10, 2014

The winter months are when farm soils can come under particular pressure from things like pugging and compaction.

So farmers are advised pay particular attention at this time of year to ensuring, as much as possible, their soils remain healthy, as this is essential to any profitable farming operation and its long-term sustainability.

If the soil is physically healthy and fertile, crop and pasture production will be high.

The physical structure of soil controls the movement of air and water through the soil, and the ability of roots to penetrate into the soil. It also provides habitat for a number of beneficial organisms, including earthworms. Soil with good structure has a significant number of pores that provide aerobic conditions, good drainage and high water-holding capacity.

Plants require about 10 elements in large quantities (macronutrients), and about eight in small quantities (micronutrients). Of the major elements, carbon, hydrogen and oxygen are obtained from oxygen and carbon dioxide in the air. Others include nitrogen, phosphorus, potassium, sulphur, calcium and magnesium. Minor elements include iron, manganese, copper, zinc, molybdenum, boron, chlorine, silicon and cobalt. In natural ecosystems when plants and animals die many of these nutrients are cycled back into the soil. However, in farming ecosystems, plant or animal biomass is removed with harvesting. To supply essential elements for plant growth farmers add nutrients to the soil in a number of ways such as using fertiliser and animal effluent application to land.

So, during the winter months, it’s important to safeguard this investment in soil health and fertility and the time and money involved.

Compaction and pugging of wet soils in winter can particularly damage the soil structure.

Pugging is caused by animals’ hooves sinking into the soil surface (sometimes as deep as 15 centimetres) when they tread in very wet soils. This leaves a ‘puddle’ effect and can lead to compacted layer of soil.

Such compaction occurs when the soil is compressed or squeezed. In addition to being caused by animal treading, vehicles or farm machinery also contribute to this problem.

Compaction on dairy and drystock sites is a particular concern as it reduces the number and size of pores available for water and gas movement in soil. It reduces aeration, nutrient uptake, root growth and distribution, and potentially decreases infiltration and increases runoff. The most sensitive indicator of compaction is macroporosity. Previous research reveals that macroporosity below 10 per cent will inhibit pasture growth.

Soil scientists have found that compacted soil can reduce the amount of dry matter in pasture by 200 kilogrammes per hectare per month. (Aerating the compacted soil at the correct depth and time can increase the amount of dry matter by about 30 per cent within six months .)

Other problems caused by pugging and compaction include more frequent and persistent surface ponding, as well as increased sediment, nutrient and effluent losses to waterways through surface run-off. It also takes longer for pugged or compacted pasture to recover after grazing and weed invasion often occurs in the bare sites pugging and compaction create.

Problems like these can be minimised by:
• reducing stock density, especially on sensitive paddocks like those that are wet
• not feeding out on sensitive paddocks
• constantly monitoring pugging and compaction during at-risk periods and moving stock off before damage occurs
• grazing the back of the paddock first.

Another important issue for soil health management and water quality is how animals are wintered.

Losses appear to be exacerbated by high density urine patches deposited at times of the year when plant growth rates are low and drainage is high (the types of conditions typical in winter). Consequently, on a per hectare basis, nitrogen leaching losses from grazed winter forage crops are high relative to losses measured under pasture.

*************

Bala Tikkisetty is a sustainable agriculture coordinator at Waikato Regional Council.

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

 

PARLIAMENT TODAY:

Salvation Army On Homelessness: Hard Times In West Auckland

The report details an uncomfortable story of people whose only option is to live an unhealthy, dangerous and damaging street life... The social housing needed by these people is not currently available in sufficient quantity. More social housing is required in the West. More>>

ALSO:

Message For PM: NZ Supports Te Reo Māori – You Should Too

As Māori Language Week celebrations and commemoration of 40 years draws to an end, the Māori Language Commission, Te Taura Whiri i te Reo Māori, is once again hugely encouraged by the widespread support for Māori language from throughout the country ... More>>

ALSO:

Arming Police: Frontline Police To Routinely Carry Tasers

"In making the decision, the Police executive has considered almost five years worth of 'use of force' data… It consistently shows that the Taser is one of the least injury-causing tactical options available when compared with other options, with a subject injury rate of just over one per cent for all deployments." More>>

ALSO:

Gordon Campbell: On D-Day For Dairy At The TPP

While New Zealand may feel flattered at being called “the Saudi Arabia of milk” it would be more accurate to regard us as the suicide bombers of free trade. More>>

ALSO:

Leaked Letter: Severe Restrictions on State Owned Enterprises

Even an SOE that exists to fulfil a public function neglected by the market or which is a natural monopoly would nevertheless be forced to act "on the basis of commercial considerations" and would be prohibited from discriminating in favour of local businesses in purchases and sales. Foreign companies would be given standing to sue SOEs in domestic courts for perceived departures from the strictures of the TPP... More>>

ALSO:

"Gutted" Safety Bill: Time To Listen To Workplace Victims’ Families

Labour has listened to the families of whose loved ones have been killed at work and calls on other political parties to back its proposals to make workplaces safer and prevent unnecessary deaths on the job. More>>

ALSO:

Regulators: Govt To ‘Crowd-Source’ Regulatory Advice

A wide-ranging set of reforms is to be implemented to shake up the way New Zealand government agencies develop, write and implement regulations. More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
More RSS  RSS News AlertsNews Alerts
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news