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

Mt Albert: Ardern Wins

Jacinda Ardern’s victory in the Mt Albert by-election shows Labour is winning and is ready to fight on what matters most to New Zealanders, says Labour Leader Andrew Little.

“I congratulate Jacinda on becoming the new MP for Mt Albert. She’ll represent her constituents with the kind of energy and dedication she’s already shown in her eight years as a list MP...

“With Jacinda now confirmed in Mt Albert Labour will welcome a new list MP who is likely to be Raymond Huo." More>>

 

2040 Target And Lower Standards: “Swimmable” Rivers Five Times More Likely To Make You Sick

Forest & Bird has condemned the government’s new water quality standards, warning New Zealanders that they lock in current levels of water pollution and allow for a 5-fold increase in the chance of getting sick from swimming in a river. More>>

ALSO:

Immigration: Clampdown On Rogue Employers Good First Step

The Human Trafficking Research Coalition is pleased at the new clampdown on rouge employers who exploit migrants announced by Minister Woodhouse this morning, and believes this is a step in the right direction. More>>

ALSO:

Mayor: 750 New Social And Affordable Homes For Wellington (Over A Decade)

The next stage of Wellington’s Housing Upgrade Programme will see at least 750 new units of social and affordable housing built over the next decade, Mayor Justin Lester has announced. More>>

ALSO:


22/2: Christchurch Quake Memorial Unveiled

A city, a region, a nation and an international community impacted by the Canterbury Earthquakes will come together to mark the sixth anniversary of the deadly quake and dedicate Oi Manawa Canterbury Earthquake National Memorial. More>>

ALSO:


November Quakes:

Gordon Campbell: On The Mana-Maori Party Deal

If the self-interest involved wasn’t so blatant, the electorate deal between the Maori Party and Hone Harawira would be kind of poignant. It’s a bit like seeing the remaining members of Guns’n’Roses or the Eagles back on the road touring the nostalgia circuit… playing all the old hits of Maori unity and kaupapa Maori politics. More>>

ALSO:

Private Provision: First Social Bond To Focus On Mental Health

New Zealand’s first social bond will help around 1700 people with mental illness into work, Finance Minister Steven Joyce and Social Investment Minister Amy Adams say. More>>

ALSO:

Immigration: Short Reprieve For Nine Indian Students

A temporary hold on deportations of nine Indian students is a step in the right direction but the Government urgently needs to implement safeguards to stop further injustices to more international students, the Green Party says. More>>

EARLIER:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news