Objectives

The objective of the rice swath harvesting project was to investigate grain quality and grain/straw moisture relationships during swath harvesting.

Specific objectives for 1985 were to evaluate the effectiveness of folding the windrow from the swather so that the grain initially at the top of the windrow is placed in the interior of the windrow, isolating it from the more adverse environments above and below.

Field Procedures

Two operations, swathing followed by combine harvesting, were used. Potential benefits from swathing prior to combine harvesting are 1) earlier harvesting at higher grain moisture content, 2) reduced grain drying costs through natural field drying, and 3) lower straw moisture at harvest. (The earlier harvesting is perceived as leading to improved combine utilization and lower straw moisture to enhance combine efficiency.)

Field trails were conducted at two locations with two different varieties of rice. The variety M-201 ac the Demeter Corporation and M-9 at Heidrick Farms were used to compare cutting heights and folded versus open windrows. Folding was done by hand by turning one half of the windrow onto the top of the other half. This placed the grain, in the center of the windrow with a straw layer below and above the grain.

Head Rice and Grain Yields

The folded swaths had better head rice yields than the open swaths when harvesting occurred more chap one day after swathing. Head rice yields were essentially the same for up to 30 hours after swathing, but the folded swaths retained good head rice yields up to four days after swathing while yields from the open windrows declined.

Temperatures within folded windrows were relatively stable throughout the day while diurnal variations in temperatures at the surface of the windrow ranged between 50 and 95°F.

Grain dried more slowly in the folded windrows. When folding was delayed for one day after swathing, final grain moisture content was reduced without reducing final head rice yields. Heavy dews increased the moisture in folded windrows less than in open windrows because the folded windrows had less surface area.

Grain yield from swathed plots of M-201 were lower than yields from the direct harvesting of standing rice. The additional handling of folded windrows also increased shattering losses. M-201 is more susceptible to shattering than M-9. Grain yield losses from shattering were not observed with M-9, but improved swathers used in the M-9 trials are partly responsible for the differences between the two varieties. Forward travel speed was reduced during harvesting of the lower cut and folded M-201 windrows but not with the higher cut windrows.

Results indicate that swath harvesting sheltering the grain from direct exposure help maintain head yields, extend the harvest season, reduce equipment requirements and reduce drying costs. A successful mechanical system for sheltering the grain in windrows has not yet been designed.