Helen and Charlie Lea's sheep and beef farm is a model to follow for other farmers looking for ways to reduce their nutrient loading.

Buying Ratanui Farm with its mix of easy, rolling and steeper contour, areas of native bush and waterways was an easy decision for Charlie and Helen Lea.

The 225 hectare sheep and beef farm east of Cambridge "had a bit of everything" when they bought the farm in 2004, Charlie says.

"I loved the bush and Helen brought the green out of me a long time ago. I wouldn't like a flat farm, this has got real character."

Gerald Piddock The Leas employ a tailored grazing system on their farm where paddocks are grazed according to stock type.

Over the years they developed the farm by building up the soil's nutrient levels, fencing areas off and getting stuck into a large scale riparian planting programme.

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They have also been innovative by establishing their Cambrilea Weed Spraying business and a native plant nursery that have helped diversify their income streams.

Gerald Piddock The Leas' hereford stud cattle enjoy the shade provided by the numerous trees planted on their farm.

Their efforts were recognised when they were announced as supreme winners for the Waikato Farm Environment Awards and further appreciated when they opened their farm up to the public at a field day.

Their nursery contains about 50,000 plants of 16 different species, two thirds of which are for the Trees for Bees programme.

They used seeds from existing native forests on the property which has a wide range of species including tawa, pukatea, nikau, rimu, and kawakawa.

The Leas use smart water technology to limit their water use in the nursery. An antenna is placed at the farm's high point which sends a message to a shed that monitors and controls water distribution from their bore.

Technology also lets them know if there are any leaks in the piping system that distributes water onto paddocks.

Charlie has set up video cameras at various points around the farm that allow him to view what is happening.

They use a cork valve to control irrigation flow in their nursery. When it rains, the cork expands to push a button that lets their water system know not to irrigate.

He admits to being skeptical at first, but says it works.

"It's a way for us not to waste water in the nursery."

Their property sits on the main road to the Hobbiton farm, made famous by the Lord of the Rings film trilogy and The Hobbit film series, and they get a lot of tourists stopping to take pictures of their livestock.

They planted up a smaller wetland close to the road to convey a positive image to tourists.

"The end result is to have the existing native bush on our farm regenerated into riparian areas. The benefits of that is that these trees are going to last 200-300 years and hopefully these areas will be able to self-regenerate," Helen says.

Charlie uses tailored grazing where areas of the farm are set aside for different livestock. His sheep flock is high in fertility and a facial eczema tolerant coopworth breed.

They have a breeding herd of 130 hereford cow and the past five years the Leas have established an on-farm yearling bull sale each September.

The cows are wintered on swedes planted on the farm's steeper areas. The crop is sown in November and cows go into the paddock in mid-May.

Charlie says the cows get about 16-17 tonnes of dry matter when they arrive and about three hectares of cropping was needed to provide enough winter feed.

The cows are on the crop for three hours a day, providing 60 days of feed across 3ha.

He transitions the cows onto the crop using hay or grass for the first five days and over the 11 years he has cropped, has only had one animal die due to choking.

About four to five metres of crop are left on the fenceline at one of his steeper cropping paddocks as well as a grass and riparian strip to to help buffer any nutrients. Cow hoof prints capture a lot of water and they had little nutrient runoff entering waterways, says Charlie.

The paddocks are then sown into forage rape, giving them a 12t of drymatter crop.

Charlie set stocks his ewe lambs on the crop and by the time it starts to become hard and stalky, they are replaced with cattle. The crop's roots are large enough in late March to help prevent erosion and hold seeds in place when the paddock is re-sown into grass.

The Leas have been able to etch out a profit. Charlie says the farm will gross $1400/ha, up $100/ha due to high beef prices. His fixed costs are about $600/ha providing him about $600-$700/ha.

"Our cattle job grosses us $2000 a hectare, our sheep, $1000 and we get $9.30/kg selling our yearling bulls verses $5/kg for the other products, so that's why we want to make more cattle country not sheep country because it's twice as profitable as long as we are not knocking the environment too much doing that."

When Charlie asked Ballance Agri-Nutrients' Stuart Lumley for a nutrient budget four years ago, he told him he was dreaming because nutrient budgets are usually carried out by dairy farmers.

"We have worked together for four years and have done a series of mitigation strategies and scenarios to make sure that we are not spending too much money on fertiliser and that our environmental footprint is below average," Lumley says.

The farm's latest nutrient budget showed that 2358 kilograms of nitrogen (N) was lost across the farm last year. Of that, 960kg was lost per year on the beef block and 1104kg on the sheep area while the rest was lost from crops, native bush and riparian planting.

Charlie has used 33 tonnes of superten, urea, cobalt granular and selenium on the sheep paddocks and 31.5 tonnes of serpentine super, sustaiN, cobalt granular and selenium on the beef block.

About 18 units of N/ha/year was applied across the farm on the paddocks he used for lambing to help boost his lambing percentage and growth.

Lumley says that equated to 10kg N/ha/year lost to water.

"That is considered very low, it's almost the bottom end of the benchmark and that's due to the fact that Charlie doesn't use much N, his clover is great across the property, due to his high potassium levels and the Ph levels are all above optimum."

For phosphorous, 22kg/ha/year was lost on the beef area and 68kg was lost on the sheep area with 105kg lost in total. The balance of the phosphorous losses came from riparian planting and the crops.

That was considered low as well, he says.

Today, the farm's soil pH levels range from 5.8-6.2 and Olsen P levels range from 20-25 on the sheep block and over 30 on the beef block. It had high potassium levels which helped support the pasture's high clover content which helped to fix nitrogen.

If under the Healthy Rivers plan change rules he had to further reduce his N leaching, he would have to retire the beef stock and run more sheep.

Charlie says he has learned a lot from increasing his knowledge of nutrient budgets.

"I wanted to get the best bang for my buck from those nutrients. I didn't want to mine anything or go backwards."

Helen says they value the ecological area on the farm and the work improved the farm's water quality which was the key outcome for the Healthy Rivers plan change.

"[It] improves water quality by reducing sediment and erosion and the uptake of phosphorous and nitrogen and also minimising E. coli."

The farm has about 25ha of native bush of which half is fenced. More of it will be fenced off in the future, but not at 100 per cent as Charlie liked the stock to be able to access it for shade and shelter.

A further 2.5 kilometres of planting was done, starting three years ago, close to a stream that was attached to the Waitoa River.

"It's great to see at calving the calves taking up shelter and the lambs in this country in summer, so we're already seeing the benefits after a year or two."

The Leas worked with the Waikato Regional Council on their planting and where to retire parts of the farm.

The council's catchment management officer Stephanie Benucci​ says they focused on fencing off and protecting the native bush and gullies on the Leas' farm.

"We are, over four years doing 6.5km of fencing and 15,500 plants. It's a $20,000 project between us, the WRA (Waikato River Authority) and Charlie and Helen."

While it has obvious biodiversity benefits, it also prevents stock from getting stuck in those areas, she says.

Their farm sits at the top of the catchment and they are conscious that the water should leave their farm as clean as possible and that no weed species such as blackberry travel from their farm to neighbouring properties.

Charlie says some of his neighbours down the Karapiro catchment are starting to follow their example.

The dairy farm next door had all of its waterways fenced and his other neighbour was also exploring some mitigation projects and four farmers further down the catchment were also doing projects with the council.

"We're at the top of the catchment, we have done our part."