08/08/1991

Broiler Litter for Fertilizer Highlights AU Cotton Field Day

BELLE MINA, Ala.—Cotton and poultry are the mainstays of north Alabama agriculture. As about 100 cotton farmers attending a Cotton Field Day at the Tennessee Valley here saw and heard, the two enterprises can work well together.

Poultrymen have an ongoing problem of disposal of litter from broiler houses. Cotton farmers in the state have an ongoing problem of finding ways to reduce the cost of nitrogen that is vital to cotton production, without subsequent yield reductions. In Alabama Agricultural Experiment Station research at the Substation, broiler litter from nearby poultry operations is being used to fertilize cotton. Auburn researcher Charles Mitchell noted that plots fertilized with two tons of litter per acre produced 2,460 pounds of seed cotton per acre, which was virtually the same as yields from plots receiving 120 pounds of nitrogen per acre from commercial fertilizer.

In the same test, 120 pounds of nitrogen from commercial fertilizer produced the highest yield among several commercial fertilizer rates tested. And, two tons per acre of litter produced the highest yields. Thus, the comparison of two tons of broiler litter and 120 pounds of nitrogen per acre.

In the second year of the test, plots that received 120 pounds of nitrogen both years were compared to plots with two tons of broiler litter both years and two tons of broiler litter the first year, but no nitrogen fertilizer in 1991--the second year of the test. "We will know more when we get the yield data from this year's crop, but on July 2, cotton with the commercial fertilizer was 15 inches tall. Cotton with two tons of litter in 1990 and none this year was also 15 inches tall. Cotton with two tons of litter both years was 17 inches tall. "We have been surprised by the growth of cotton on the residual nitrogen from last year's litter and by the lack of difference between the two litter treatments," Mitchell said.

An informal survey of cotton growers who use broiler litter reflected a wide variation of price. One grower paid only $4.50 per ton, but is charged $1.20 per mile to have it delivered to his farm. Others paid flat rates of $15-$20 per ton. Mitchell noted that in most cases in north Alabama the optimum rate of two tons per acre of broiler litter cost about the same as 120 pounds of nitrogen from commercial fertilizer.

Stoneville 453 was the top yielding cotton variety over the past three years in variety testing at the Substation, according to Auburn researcher Wiley Johnson. It was the only variety to average over 900 pounds of lint per acre for the past three years. Other popular varieties, such as DPL 20, DPL 51 and DES 119, averaged about 850 pounds per acre. The Tennessee Valley cotton variety test is one of nine conducted throughout the state by the Alabama Agricultural Experiment Station, according to Johnson.

Charles Burmester, an extension cotton specialist and researcher at the Substation, noted that early crop rotation tests showed little yield advantage over continuous cotton. However, last year cotton grown in rotation with corn or with soybeans and winter wheat both showed about a 100 pound per acre increase in seed cotton yield. In the same test, no-till cotton planted directly into cotton stubble produced about 200 pounds per acre less than the conventionally planted crop. However, no till cotton planted into wheat stubble had comparable yields to conventional cotton.

Chet Norris, assistant superintendent of the Substation, showed the visitors results of weed control in cotton with a new herbicide, Command. Though not yet labeled for use in cotton, Command did an excellent job of controlling velvetleaf. "This material is weak on pigweed and morning glory, but it has consistently done a good job on velvetleaf, which is consistently one our major weed problems in this area," Norris said.

During the meeting, Auburn researcher Mike Patterson showed preliminary results of a minimum herbicide input test and entomologists Barry Freeman and Mike Gaylor gave an update on insect problems in the Tennessee Valley.

In his opening remarks, W.B. Webster, superintendent of the Substation, noted that the 760-acre research facility received only 3.8 inches of rain in June and July, compared to 18.5 inches in April and May. Despite the extreme weather conditions, Webster said Tennessee Valley cotton farmers remain optimistic of producing a good crop. This is evidenced by such a large turnout for a field day and by the interest shown by growers in the research work underway at the Substation, he concluded.

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By:
Roy Roberson