There's always trouble in agriculture, and so politicians are always meddling. In one sense they have a mandate to govern, and policies to assure adequate food supplies are a major concern. More importantly, no politician can long survive if they are opposed by farmers. In much of the world farmers are numerous and when riled up are a potent force due to sheer numbers, but even where they are a tiny minority their concerns are influential since food is an emotional issue and they get sympathy and support from city dwellers.

Political tinkering in agriculture is very nearly always destructive. The more they tinker the worse things get and the more tinkering they do.

In the 1970s, India dramatically increased food production, finally allowing this giant country to feed itself. But government efforts to continue that miracle by encouraging farmers to use fertilizers have backfired, forcing the country to expand its reliance on imported food. . .

Behind the worsening picture is the government's agricultural policy. In an effort to boost food production, win farmer votes and encourage the domestic fertilizer industry, the government has increased its subsidy of urea over the years, and now pays about half of the domestic industry's cost of production. . .

Farmers spread the rice-size urea granules by hand or from tractors. They pay so little for it that in some areas they use many times the amount recommended by scientists, throwing off the chemistry of the soil, according to multiple studies by Indian agricultural experts.

Like humans, plants need balanced diets to thrive. Too much urea oversaturates plants with nitrogen without replenishing other nutrients that are vitally important, including phosphorus, potassium, sulfur, magnesium and calcium.

The government has subsidized other fertilizers besides urea. In budget crunches, subsidies on those fertilizers have been reduced or cut, but urea's subsidy has survived. That's because urea manufacturers form a powerful lobby, and farmers are most heavily reliant on this fertilizer, making it a political hot potato to raise the price. . .

In the early years after India gained independence in 1947, the country couldn't even dream of feeding its population. Importing food wasn't possible because India lacked the cash to pay. India relied on food donated by the U.S. government.

In 1967, then-Prime Minister Indira Gandhi imported 18,000 tons of hybrid wheat seeds from Mexico. The effect was miraculous. The wheat harvest that year was so bountiful that grain overflowed storage facilities.

Those seeds required chemical fertilizers to maximize yield. The challenge was to make fertilizers affordable to farmers who lacked the cash to pay for even the basics—food, clothing and shelter.

Back then, giving cash or vouchers to millions of farmers living all over India seemed like an impossible task fraught with the potential for corruption. So the government paid subsidies to fertilizer companies, who agreed to sell for less than the cost of production, at prices set by the government. . .

In 1991, with the cost of the subsidy weighing heavily on India's finances, Manmohan Singh, then finance minister and now prime minister, pushed to eliminate it. Most fertilizer companies lobbied fiercely to retain the program. Many legislators also resisted ending the subsidy, fearing a backlash from farmers.

"The business interests lobbied and the business interests prevailed," says Ashok Gulati, the director in Asia of the International Food Policy Research Institute, a Washington-based think tank, who was involved in the policy discussions at the time. A last-minute compromise eliminated the subsidy on all fertilizers except for urea.

"That's when the imbalanced use of fertilizers began," says Pratap Narayan, ex-director general of the industry group, the Fertilizer Association of India.

With urea selling for a fraction of the price of other fertilizers, farmers began using substantially more of the nitrogen-rich material than more expensive potassium and phosphorus products.

In the state of Haryana, farmers used 32 times more nitrogen than potassium in the fiscal year ended March 2009, much more than the recommended 4-to-1 ratio, according to the Indian Journal of Fertilizers, a trade publication. In Punjab state, they used 24 times more nitrogen than potassium, the figures show.

"This type of ratio is a disaster," Mr. Gulati says. "It is keeping India from reaching the production levels that the hybrid seeds have the power to yield."

It's a tragedy of errors. The political necessity to "do something" results in dumb policies and the continuing necessity of political meddling. Politics is stupid.

The possibility of dramatically increased production with modern agronomic systems coupled with the pressure from a food insecure population resulted in muddled policies. They couldn't just decree that impoverished and illiterate farmers would miraculously become sophisticated growers with deep knowledge, and they couldn't trust their bureaucracy to honestly administer a subsidized agronomic system, so they faked it. By subsidizing fertilizer producers rather than users they destroyed all natural incentive for wise use. They eliminated the crucial price signals needed for decision making, and turned those who once farmed the land into supplicants who now farmed the government.

That was bad enough, but it got very much worse with continued political tinkering. They couldn't afford to continue the subsidy system, but depended for their political lives on the special interests that had been conjured up by the subsidies. So they did the worst thing possible and abandoned the whole idea of an agronomic system, eliminating subsidies for some types of fertilizer but not others. Anyone with a functioning brain could predict the result: increased use of subsidized types of fertilizer, decreased use of other type, a total lack of balance in the system and monotonic degradation of the sector including destruction of the foundation of agriculture - the soil itself.

I often hear nonsensical criticism of agriculture and proposals for wild schemes of increased political control. A favorite tactic is to demonize fertilizer, which is complete nonsense given that nothing grows without it. Like ignorant politicians they backpedal a bit and target their criticism a bit more precisely to demonize "chemical" fertilizers, though all fertilizers are chemicals. Manufactured urea is identical to the stuff in your everyday urine.

Nothing sensible is ever said by such critics though there is abundant need and ample opportunity to do so. The idea of balanced fertility with all required nutrients made available to plants in the proper quantities at the proper times as part of an agronomic system designed to improve the quality of the primary asset - the soil - and so enjoy increasing returns over time is beyond them. It makes a sort of abstract sense but there's no hate in it, no political opportunities, little room for graft or corruption. Worst of all, the result of assiduously applying such a system would be an ever more secure and independent farming sector with ever less need or interest in politicians. The political machine would go redundant. All of the bureaucrats, NGOs and associated industries would be out of work.