|Straw - 71
BURNING METHODS STILL IMPROVING
Pending further progress, spreading straw with the standard harvester attachment seems recommended as reducing particulate product in burning, and also reducing stem rot.
Burning was studied in 3 front-fire and 3 back-fire burns. Raking 2 straw rows together speeds drying and improves combustion by making a hotter fire. Smoke particles per ton of fuel were less with back-firing. It appears that back-firing or raking involves much less man-hours and lower costs than incorporation or mobile incinerations.
MOBILE INCINERATORS NOT SO HOT SO FAR
The Oregon State model, originally designed for grass seed straw, needs modification for tests with rice. So far, speeds were too slow (3/4 to 1'/a mph). A California unit uses the return-stack principle (similar to approved orchard heaters), but it still needs modification. Both units had after-fires that tied up substantial fire-fighting equipment and crews. In any case, costs make this method impractical at present.
TWO STRAW PROJECTS ARE NOW ON THE SHELF
The projects are: 1) collecting and burning straw in stacks; and 2) precipitation of smoke particles. Cost studies indicate stacking for burning would cost about the same as baling and roadsiding. Add the cost of burning, air-supply equipment, and a burning site--and shelving seems inevitable at least for now. The proponent of the precipitation equipment hasn't yet made it available for tests.
BURN AND NO-BURN DAYS
Better information for deciding "burn" and "no-burn" days has been developed by UC experts. Because results indicated that such decisions can be made more applicable to field burns in the Sacramento Valley, the Air Resources Board has begun using these new criteria. Wind monitoring continues at several weather stations in the Valley.
STRAW FEEDING IS POSSIBLE--AND IMPRACTICAL?
Digestibility of straw to animals was increased by treatment--about 30% by alkali treatment and about 35% by ammonia treatment. Lambs found it palatable, and studies are being conducted with beef cattle.
Straw can be cubed for cattle feeding by adding supplemental feed ingredients such ground barley, beet pulp, almond hulls, or some commercial product with good nutrition and bonding.
So it's possible. Practicality would seem to rest on costs of gathering straw and unknown future developments in alternative methods of disposal.
þ INTERIM RECOMMENDATIONS FOR STRAW MANAGEMENT
Pending final recommendations, get straw into maximum contact with soil for faster decomposition. A cold, wet winter can be largely overcome by a few weeks of spring temperatures favoring decomposition unless soil is dry. Added nitrogen doesn't speed decomposition much. Chopping was no better than uniform spreading in effects on grain yields of the following year.
REDUCING STRAW TONNAGE
Studies continue on developing a plant with less straw without reducing yields per acre. About 135 short-stature long-grains will be tested in small plots in '72.
þ PROPER CHOPPING IMPROVED INCORPORATION
Straw from the combine windrow was cut and spread by a modified shear-bar type of field forage chopper. Chopped straw pieces were mostly shorter than 3 inches and did not interfere with disking or plowing. Estimated chopping costs: about $2.25 per acre. One chopper can keep up with 4 or 5 combines. Chopping can be done immediately after harvest or any time later.