Wintering impacts on water not so cool

By Bala Tikkisetty

As winter approaches, it is a good time for farmers to prepare for the potential impacts of stock wintering on soil health and water quality.

As farmers will know, winter can be a very vulnerable time of year for farming operations generally.

Animal condition can drop from the effects of wind, cold and wet conditions. Soil stress levels can be elevated as wet pastures become pugged from grazing and stock wintering practices can impact surface and ground water quality.

So I’d like to discuss some ways of protecting soil and water quality in winter.

By way of background, I’d note that many studies have shown that water quality guidelines and standards have been exceeded as a result of intensive agricultural activities.

Dairy farming has rapidly expanded in Waikato and like any expanded land use practices there are a number of potential environmental impacts that are to be considered when planning for a conversion or managing an existing property.

Also, higher livestock densities during the winter can cause a localised accumulation of livestock waste that can be easily transported to surface water. High runoff is due to the compaction of the soil from cattle’s hooves and grazing practices. Water contamination from grazing operations includes increased sediment and bacterial counts in runoff.

On the soil quality front, wet pasture, heavy grazing and the resulting compaction can reduce pasture growth and impact negatively on farm productivity.

But dairy, beef and deer farmers can take a proactive stance to safeguard the environment.
Feed pads and stand-off pads are options for protecting soil physical structure over wet periods. Feed pads area dedicated concrete platforms where supplementary feeds are brought to the stock. In this option, higher feed efficiency is achieved as the wastage is reduced to about five per cent as against about 20 per cent and more when silage is fed in paddocks.

Stand-off pads are dedicated loafing areas for stock. These pads are constructed using a softer free-draining surface and utilise materials like wood chips. As stock can be withheld from pasture for longer periods of time, the area required per cow has to be bigger, say about eight square metres. Capture of effluent is an important aspect of stand-off pads. It requires that the humped and hollowed base is sealed underneath either with compact clay or artificial liner or concrete.

Of late, herd home technology is gaining popularity and can be a good option for stock wintering. It is a combination of a feeding platform, stand-off facility and animal shelter. Sheltered feeding for stock takes place over slatted concrete floors. As the animals stand on the reinforced slatted floors, their effluent drops through the slats and into a concrete lined bunker below.

Sacrifice paddocks can be used as a last resort, when other options are not available, to stand animals off when it is very wet or as an area to feed animals hay and silage.

The important things to remember with sacrifice paddocks are:

• Don’t just spread feed in the same area all the time -work it around the paddock to ensure complete coverage.
• Every now and then drag a set of light harrows around to help break up the excreta. This ensures good exposure to sunlight that will kill any pathogens / parasites that could otherwise build up in the paddock.
• Avoid paddocks closer to waterways, property boundaries and significant ecological features.
• Remember that with this option you are sacrificing future production on one paddock to protect others. There is a cost to this lost production.

The disadvantages of sacrifice paddocks include the risk of soil structural damage and possible animal health problems such as lameness and mastitis. If soil potassium levels become too high (potassium is excreted in urine) it can predispose the calving cow to metabolic problems.

So obtaining good information about the characteristics of the soils on individual farms is important as understanding the soils helps identify the risks associated with them. Farmers can then decide whether feed pads or stand off pads are necessary to protect our soil.

When building feed and stand off pads allow for solid and liquid waste disposal. Design the pad in such a way that the contaminants run into effluent disposal systems. Locate the feed pad or stand-off pad well away from any waterway.

Do not feed out supplementary feeds in areas where run-off water may reach any water body. If possible avoid feeding out in these paddocks altogether.

Shelter will be helpful on the stand-off areas in reducing the maintenance requirements, thus saving feed and allowing a shorter grazing time to reduce soil or paddock damage.
 

• Bala Tikkisetty is a sustainable agriculture coordinator at Environment Waikato. For further information contact him on 0800 800 401 or email bala.tikkisetty@ew.govt.nz..