Farming has been a rollercoaster ride for Tom and Anna Clouston since they took over Tangmere, the family property at Flemington, near Waipukurau, in the middle of the 2007 drought.

Like all farms, they depend on late summer and autumn rains to grow enough grass to get them through till spring.

It is a feed bank farmers draw on through winter to keep their capital stock well fed and healthy so they can deliver the lambs and calves that are their main income source.

But for the Cloustons, and many other farmers throughout New Zealand, over the past few years the rains have been erratic - turning up one year, not the next.

They have a graph that shows Tangmere's pasture growth each year since 2006. The growth curve peaks in autumn in 2006, 2008, 2009 and again this year. But it stays flat in 2007 and 2010.

Hence the rollercoaster ride.

"We were traditionally summer dry with rain in early March, and we could rely on that," Mr Clouston says. "But not any more. Now, it's all over the place - we don't know what's going to happen."

It means they have to farm cautiously, ensuring they have as much grass as possible to cope with unexpected dry spells, and, if the pastures get too low, to have stock that can be sold in a hurry. Without suitable land they don't have the backstop of a cash crop.

To add to their difficulties, much of their soil is clay-based, prone to erosion on the hills and to drying hard in a warm wind.

Some relief comes from a small area of fodder crops, winter kale for cattle and summer rape for lambs. Lucerne is also being tried and, if successful, they could grow up to 50 hectares for extra sheep feed during a long dry period.

In winter and spring they face other hazards. Cold southerlies can be expected at lambing, which they space out over July, August, September and October in their hilly, broken country to avoid heavy losses.

But life at Tangmere is not all doom and gloom. This year, the kind weather has been matched, for the first time in the couple's experience, by high market prices.

And to broaden their smiles, their efforts at coping with these highs and lows have been recognised by the judges of the Silver Fern Farms Hawke's Bay Farmer of the Year competition.

They awarded the title to the Cloustons, saying their risk management, use of technology and reasonable financial performance considering the adverse weather was what separated them from other finalists.

Mr Clouston is not sure that their finances are exemplary but admits they would have been much worse without the use of the computer program Farmax, developed by AgResearch and Hawke's Bay consultants AgFirst Pastoral.

He says he is getting better at using it but mainly relies on the expertise of farm adviser John Cannon, of Challenge Consultancy, Hastings.

"The first year we used it, it made us $60,000. It took the pasture growth figures and stock weights and told us that with the use of nitrogen we could add more cattle. Now I know I can use it with confidence."

Tangmere is a returned servicemen's ballot farm drawn by Mr Clouston's grandfather, Wilf, in 1959. The former Spitfire pilot, who named it after the English air base he commanded in 1949-50, built a woolshed and yards, put on fertiliser, built dams, began planting trees on the most erosion- prone slopes and started fencing the farm into smaller paddocks.

Mr Clouston's father, Richard, took over in 1971 and continued the erosion plantings, installed water systems, did more subdivision and enlarged the farm with neighbouring purchases to its present size of 653ha, of which 590ha is in pasture.

Now aged 69, he still works on the farm for four half days a week.

Mr Clouston did a Bachelor of Commerce (Agriculture) degree at Lincoln, with a double major in valuation and farm management, and went into banking.

But farming was always his goal and after five-and-a-half-years as a rural manager and then new business manager for National Bank he returned to the farm in 2001.

He and Anna, who has a Bachelor of Agriculture degree from Massey and was a 50-50 sharemilker before they met, now have three sons, Sam, 6, Will, 4, and Ben, 2.

They have added to the erosion plantings and continued the subdivision, but since taking over in 2007 their main focus has been on coping with drought.

"Understanding the pasture growth is the key to this farm," Mr Clouston says. "We run 2700 Kelso composite ewes. That is fixed, and the cattle policy is based on what grass is left."

That means that over the past four years the numbers of the dairy beef trading cattle has fluctuated between 330 and 660. "The trouble with that is we need 600 to break even."

In 2007, it rained in January. "We thought, 'That's good, we're set now'," he says. But then it blew. The hot nor'westers dried up the pastures and the grass disappeared.

They reduced cattle numbers, fed out silage, and sent 900 hoggets to graze out of the district till October. The ewes went into lambing in poor condition and low lamb birthweights meant many battled to survive. The lambing percentage fell from 135 per cent to 103 and with it the farm's income. They made a $140,000 loss, although at $22 a stock unit this was considered small for the district.

In autumn 2008, the weather returned to normal. Rain in March and April grew plenty of grass, they lifted cattle numbers to 660 and the lambing percentage rose to 133 per cent. The surplus they made paid off some of the previous year's losses.

In 2009, pastures were looking good at the end of February, but then the hot winds returned and the grass dried off. To make matters worse, winter came a month early and to save the ewes, cattle numbers were kept to a peak of 440.

Luckily, the weather was kind at lambing for all but the hoggets and the lambing percentage rose to 138 per cent. But the reduced cattle numbers outweighed the good lambing figures and they ended up with another loss.

Last autumn it was back to a drought and almost a repeat of 2007. Cattle numbers peaked at 540 and lambing was good at 139 per cent.

Low pastures through winter and spring meant both lambs and cattle were slow to grow - a legacy of this is the 1000 extra lambs still being kept till they reach marketable weights.

This year, perfect weather and high meat and wool prices have lifted them out of the red. "It has rained when we've needed it and the sun has shone when we've needed it," Mr Clouston says. "We've got more grass than we've seen since 2002. Actually, people might say it's a bit too rough, but it is essential we are well set up for winter."

He says the ewes are in reasonable condition and providing they can escape storms at lambing and that prices stay buoyant he is looking forward to a surplus.

He notes, however, that this will put them only slightly ahead financially of where they were before they took over in 2007.

The profits will go into reducing debt. They have a debt-to- equity ratio of 50 per cent. "It's right up there," Mr Clouston admits.

"Fortunately for us, the banks went through a period of handing out money and we were the beneficiaries of that. But that's stopped, there's no more where that came from, and we've got to make the most of it."

Although the last four years of turmoil have taught them a lot, questions still remain.

The cost of buying trading cattle has escalated. "We no longer buy and sell cattle on the same market so as to reduce our exposure to the climatic risk, but has this exposed us more to the market risk?"

And is the intention to plant more lucerne another risk? "It comes at a cost - it means we will have less winter pasture. Are we trying to turn what is really a breeding farm into a finishing farm?"

But questions like these are a welcome challenge.

"I've never once regretted my decision to leave banking and move home to the farm," he says. "Even in 2007, that horror year, when it was wet and miserable and I had four to five hours of feeding out ahead of me every day, I still leapt out of bed and said, 'Yes, I still want to go to work'."

A field day will be held on Tangmere, Ngawaka Rd, Flemington, on May 5.