There is a wide difference in the financial performance of the top 25% of farmers and the bottom 25%.

Top performers manage to make profits in all but the hardest of times, while many of those at the other end of the scale cling on by virtue of generous farm subsidies and inflated land values.

In the latest official figures (2012-2013), the Farm Business Income (FBI) of the lower quartile lost £14,000. the overall average profit was £30,000, and those in the upper quartile made £88,000 (nearly three times the average FBI).

FBI is the headline-level measure of farm income, or profit, and represents the return of the whole farm business, that is, the total income available to all unpaid labour and their capital invested in the business.

Pig and poultry producers aren't subsidised, but most of the rest of Scottish agriculture is to some extent or other. The FBI of the average arable and dairy farmer is greater than the subsidies they receive, but most beef and sheep farmers are heavily dependent on support from the taxpayer. For instance, the FBI for the average dairy farmer in 2012-13 was £82,087 including his subsidy receipts of £42.139, while the FBI of an average beef producer in a Less Favoured Area (LFA) in the same period was £42,179 and included subsidy income of £56,721. Similarly, while the average FBI of an LFA sheep producer was £28.156, subsidies totalled £37.716.

Top farmers pay attention to detail, invariably sell their produce for premium prices, and despite controlling costs are not averse to investing in their businesses to become even more efficient.

The best arable farmers achieve heavy yields not just because they have good land, but because they keep a very close eye on their crops for pests and diseases. As a result of their attention to detail, their crops are invariably top quality that sell for premium prices. Better still, top farmers carefully watch market trends and tend to sell when prices are close to their peak.

It's the same for top beef producers. Making money by breeding beef cattle from beef cows, or sucklers as we call them, is notoriously difficult in the absence of subsidies. Only a handful manage to achieve that, and once again it's all down to attention to detail.

Top suckled calf producers breed more calves per hundred cows, that grow faster to heavier weights at the time of sale. Because they have more potential for growth than others in the market, and have built up a reputation for doing well, they sell for premium prices. Once again, tight control over labour, machinery and feed costs help to nudge the bottom line into the black, so that subsidies become a financial bonus rather than a lifeline.

Sheep producers operate in a low income, Cinderella industry, that's a notoriously sure way of turning a pound into tuppence. Despite that, canny breeders produce more lambs per hundred ewes, that weigh more at weaning. More importantly, their breeding ewe lambs and draft ewes sell for substantial premiums.

As a freelance agricultural journalist I regularly write features on Scotland's leading farmers and never cease to be amazed out how "clued-up" and "switched-on" they are.

What is becoming apparent to me is the wide range of prices that dairy producers are receiving for their milk. For instance, someone selling their milk on a Tesco Muller contract is currently being paid 32.01p per litre (ppl), while at the other end of the scale those selling into First Milk's liquid pool are paid 22.7ppl. That price differential is worth an extra £93,000 per year for a herd producing 1million litres. While there is a wide range of cost-of-production figures for different farming systems, that vary between 26ppl and 32ppl, those selling to First Milk's at 22.7ppl are bound to be losing money.

Of course that difference is greatly magnified when you remember that while the average Scottish herd is about 165 cows, numbers range from as few as 70 or 80 to a couple of thousand. Compounding the issue is the fact that larger herds tend to get better prices for their milk because it is usually more economical to collect larger volumes.

Latest figures from the Scottish Dairy Cattle Association revealed that the number of dairy herds in Scotland has continued to fall to its lowest level ever of just 993, and that trend looks set to continue as the more efficient producers get bigger at the expense of the less-efficient.