American farmers today are deeper in debt than at any other time in history. In terms of what their earned dollars can buy, their income is the lowest since the 1930s. Wheat prices this week are 20 cents a bushel higher than they were at the end of World War I.

This is one picture of U.S. agriculture today.

Another picture is this:

The value of U.S. farmers' land and other assets has reached a record $730 billion, up $59 billion from 1976. In lowa, farmland gained an average 225 per cent in value from March, 1972, to February, 1977.

American farmers will earn some $20 billion in 1977, the fifth largest amount in history. Banks polled by the Department of Agriculture admit to some concern about debts of farmer clients. Ffive per cent of the agricultural loans they have out now are deemed risky. But there have been few foreclosures.

As those numbers suggest, nation-wide statistics are not much help in understanding the economics and politics behind the farm strike effort being launched today by the American Agricultural Movement.

The reason is that American agriculture is a mosaic of enormous diversity and compexity, one in which weather, soil, farming practices, farm incomes, agricultural costs and even levels of federal support often vary widely from county to county, not to mention form state to state.

The nation's farmers are no monolithic bloc.

Within this diverse group are farmers in Georgia and other parts of the Southeast, where crops were ruined this summer by drought and floods. Drought afflicted farmers from the Maryland and Delaware Eastern shores and wheat growers from the western Great Plains, where grain was damaged and the livestock business has had hard times for several years.Government officials say the movement has been most active in those affected areas.

Elsewhere, though, there are Wisconsin dairymen, Iowa hog farmers and growers in the rich Corn Belt who are doing well. Operators of giant Western cattle fattening yards, who feed beef animals a ton each of corn, are thankful for the low grain prices.

Given this diversity of interests, it is hard to say whether the protesters constitute an isolated minority or the core of a rural movement with enough appeal and power to achieve political and economic objectives.

There are 2.3 million farmers (compared with 2.2 million teachers). As a group they are economically and politically strong - but they have long had trouble organizing for action.)

"I haven't detected an awful lot of panic or reaction in Congress," said an administration aide. Officials in government and on Capitol Hill have been listening attentively but they are not rushing to hand farmers new concessions.

In some sectors, the malaise apparently is a delayed result of farm policies of the previous Republician administration.

Those policies left American farmers very exposed to changes in the world's food economy. Every country protects and supports its agriculture to some degree.

But under former Agriculture Secretary Earl L. Butz, the safety net of government price supports and acreage controls (to prevent stocks from building up) was a miminal one, and farmers were encouraged to grow and sell all the food they could.

Critics called these policies "boom and bust," since the government allowed farm and food prices to fluctuate widely, and let farmers decide what and how much to plant, many months before the crops were sold.

From 1972 to mid-1976, foreign demand for the large surpluses of American wheat, corn and soybeans kept prices up so farmers didn't need to worry about the low safety net.

The unprecedented prices gave crop farmers record returns and contributed to the sharp increase in the value of agricultural land. Farmers went on a prosperity binge, buying new equipment and machinery and taking out large loans with their valuable land as collateral if they needed cash.

But this year, the country's [WORD ILLEGIBLE] up agricultural factory - still operating with very little control under the old Republican era system - ran full tilt into slack demand abroad. As a result, the country produced unsold surpluses reminiscent of the glut era of the 1950s and 1960s.

By this year there was too much grain, no place for it to go, and slumping prices.

Under Butz, farmers were supposed to take the lean years with the good ones.

The new Carter administration's four-year farm law moderates, but does not entirely abandon that policy. The new law sharply increases subsidy payments to grain farmers and increases price supports. The administration is also committed to a system of food reserves that would stabilize international prices.

Administration officials say all this help - which includes $1.2 billion to wheat growers in the next 12 months - is necessary because production costs are rising rapidly. The farmers who are calling for the strike claim that even this is inadequate.

"Their concern is loss of income in volatile markets," says Dawson Ahali of the Department of Agriculture. "Farmers rely more and more on a non-farm sector - chemicals, energy and so on - that doesn't adjust."

One problem is that some of the hardest-working farmers - those who lease the land to others - have not gotten the breaks of mortgage interest tax write-offs enjoyed by their landlords. These family farmers have had a particularly hard time keeping up. Administration officials say they may be the biggest victim of the Butz policies.

So far, though the American Agriculture Movements demands in Congress for "100 per cent of parity" have not won wide support. "Parity" is what a farmer would need to get for a bushel of wheat or other commodity to give him the buying power he had between 1910 and 1914.

This would push wheat prices from their present $2.70 a bushel to just over $5 a bushel. Corn - the basic animal and poultry feed - would also rise, taking meat prices with it. "Within a year, food prices would reach levels 20 to 25 per cent above current levels," the Agriculture Department says.

Chairman Thomas S. Foley (D-Wash.), chairman of the House Agricultrue Committee, said he could not quarrel with the goal.But he added that such high grain and commodity price supports would have to be accompanied by costly and detailed government controls on planted acreage and marketing quotas - something he says he does not foresee.