FACTORS DETERMINING EFFICIENCY OF CYANAMID AND URAMON FOR WEED CONTROL IN TOBACCO PLANTBEDS

Publisher Website
Google Scholar
Abstract
Repeated use of 0.5 lb. or more of Cyanamid per sq. yd. in weed control treatment for tobacco plantbeds on light sandy acid soils resulted in residual pH values of 7.8 to 8. One lb. of Uramon increased the pH sufficiently above the threshhold value of 7.7 to inhibit rapid nitrate-N production but permitted formation and accumulation of 21 ppm. of nitrite N. When Cyanamid was added to Uramon, formation of nitrites was inhibited and ammonia and the pH remained high for at least 74 days. Up to 61% of the calcium-cyanamide N in 1 lb. application of Cyanamid was accounted for as dicyandi-amide N 32 days after treatment, and 28% was still present 87 days after treatment. Hydrogen cyanamide did not persist after 30 days in any instance. Rainfall of 1.6 inches immediately after treatment removed 85% of a 1 lb. application of Uramon and 48% of a 1 lb. application of Cyanamid, accounting for the observed lower efficiency of the former when rain fell immediately after treatment. Cyanamid, upon absorption, was immediately effective in killing certain seeds, but Uramon was ineffective until a significant amt. had been converted to ammonia, a process requiring more than 2 but less than 5 days at avg. fall soil temp.

This publication has 1 reference indexed in Scilit: