Rice harvests, fighting, and diplomacy are all in season for troubled Kampuchea

The month of October seems to draw together all the strands of the Kampuchean problem. Inside the country, the rains are coming to an end. The pro-Vietnamese government in Phnom Penh is taking stock of the new rice harvest. And the antigovernment guerrillas of the Coalition Government of Democratic Kampuchea (CGDK) are assessing the results of their activities over the rainy season, when guerrillas in Indochina traditionally are believed to have an advantage over conventional armies.

And at the United Nations, the annual debate over the Kampuchean (Cambodian) seat begins.

The guerrilla activities at this time of the year worry the pro-Vietnamese government of Heng Samrin. But the regime now is probably more concerned by the state of the harvest. Despite its natural richness, Kampuchean agriculture is almost totally dependent on the weather for its irrigation. This year's rains have been late and uneven.

The rains did not fall until mid-July in western Cambodia, late July in the east. Travelers in the western province of Battambang, the country's principal rice producer, say that peasants there still have surplus rice from last year stored under the raised floors of their homes. They are looking forward to another good crop this year.

In some eastern provinces the rains have probably come too late to do any good. Peasants in Prey Veng Province are already talking of leaving their land and heading for Phnom Penh in search of work.

Low water levels this year will probably cause another problem, -agricultur- alists say: Rats will have been able to breed unhindered by the flooded fields.

If the Phnom Penh regime does run into difficulties with the harvest this year, it will not get much help from the UN.

Although an effort of the Association of Southeast Asian Nations (ASEAN) to stop UN aid to the interior has been defeated, the UN program is badly short of money. Its administrators say that it needs about $16 million this year for its agricultural and education programs. So far it has raised less that $4 million from UN members. Coalition supporters at the UN are known to feel that the emergency inside Kampuchea is over, and that any further aid to Phnom Penh is simply economic aid for a state that UN members do not recognize.

The UN Kampuchea program may not be helping its own image. While its program budget is probably the lowest since the beginning of the Kampuchean emergency, its team on the ground is probably the biggest ever: 16 people.

The UN program for Khmers living in camps along the Thai-Kampuchean border, on the other hand, has plenty of money. The program currently feeds about 228, 000 Khmers, and has a budget for 1983 of $31 million.

ASEAN and its allies, of course, support this program quite actively. The Khmers they are helping are either supporters of the coalition, or at least live in camps controlled by the three factions of the anti-Vietnamese coalition. The food distributed - about 1,900 calories a day - is vital for the well-being both of the coalition civilian base and its fighters.

On the diplomatic front, the present incumbents of Kampuchea's UN seat, the CGDK - a loose coalition of the Khmer Rouge and two noncommunist groups, Son Sann's Khmer People's National Liberation Front and the supporters of Prince Norodom Sihanouk - do not not seem in any danger in the debate of the current General Assembly session. Their main backers - ASEAN,the United States, and China - feel that they will hold the seat with about the same majority as last year, 90 votes to 29.

But the CGDK would like to score military successes inside Kampuchea that equal its annual diplomatic victories, and the months preceding the UN debate normally see an upsurge in fighting.

This year was no exception.

Starting toward the end of July, Khmer Rouge bridge destruction activities picked up speed. In one night they attacked four bridges around the western city of Battambang, and destroyed at least one of them. Travelers say they have now adopted the tactic of planting mines around the destroyed structures to discourage any locals from offering to help rebuild them.

In August, nine Soviet cotton specialists were ambushed and killed in an upland district of Kompong Cham Province, southeast of Phnom Penh.

The Soviets now do some of their traveling by helicopter, although other foreigners still use the road. The Khmer Rouge were held responsible for the Kompong Cham attack, as well as for two attacks on the Phnom Penh-Battambang train at the beginning and the end of last month. Khmer Rouge train ambushes are generally bloody affairs. The ambushers mine the track, and when the ramshackle train, with passengers crammed inside and often overflowing onto the the roof, is blasted to a halt, they into the crowds of survivors.

On both occasions this year the ambushes were in Kompong Chhang Province. Casualties, mostly civilians, are said to have been high. Vietnamese troops, especially in large concentrations, have not been known to use the train, which has proved vulnerable to ambush.

Attacks like this are nothing new. The two main CGDK factions - the Khmer Rouge and the Son Sann group - had, however, promised something different and impressive this season.

(Khmer Rouge radio claimed last week that they had killed 219 Vietnamese troops in the second attack Sept. 29. The radio did not mention an attack earlier in the month.)

This spring, at the beginning of the rainy season, a Khmer Rouge field commander told a visiting journalist that the Khmer Rouge planned to cut off the temples of Angkor Wat - the cultural symbol of Kampuchea - from the nearby town of Siem Reap. Attacks on Siem Reap had already started, the commander said.

This does not seem to have materialized. Siem Reap has not been reported to be under attack, and foreigners from Phnom Penh recently visited Angkor.

Son Sann's guerrillas planned an extensive military campaign that would culminate in the creation of permanent bases around the Tonle Sap. This, too, was apparently unsuccessful. Some of Son Sann's commanders reportedly felt that the plans were too ambitious for the number of troops at their disposal. And their plans to train more guerrillas with the help of Malaysia quickly ran into trouble.

A new guerrilla training school staffed by about 16 Malaysian-trained instructors opened in May. But inadequate food and poor living conditions - plus the fact that the Chinese had provided only CKC rifles, a weapon considerably inferior to the AKs they had promised - quickly led to mass desertions.

About half the 1,000 trainees are thought to have deserted. The school's commander, who had also been trained in Malaysia, slipped back to his home in the United States, reportedly saying that he was going to visit his wife. He did not return for several months.

Some deserters were recaptured, and reportedly had their heads shaved and were ''exiled'' from areas under Son Sann's control as a punishment. Rumors that some of the deserters were shot have not been confirmed.