Effect of ATC,N-Serve 24 E and thiourea nitrification inhibitors on yield and N uptake of barley fertilized with fall-applied N1

Solution urea and aqua NH₃ were injected in bands 9 cm deep and spaced 45 cm apart with and without nitrification inhibitors during October in 10 field experiments in north-central Alberta. ATC (4-amino-1,2,4-triazole hydrochloride), N-Serve 24 E (2-chloro-6-trichloromethyl-pyridine) and thiourea were used in two experiments, ATC only in another six experiments, and N-Serve 24 E only in another two experiments. Yield and apparent recovery of applied N in barley grain were determined. In the two experiments where fall treated plots were soil sampled in the following spring, 44% of the fall-applied N was recovered in the soil when inhibitors were not used. But where the inhibitors were added to the fall-applied N as NH₄−N in May was 4% and 31% without and with addition of inhibitors, respectively. Likewise, in experiments where three inhibitors were used, the treatments with inhibitors increased the yield and N recovery in grain by more than 50% compared to fall application without inhibitors. In the other experiments, fall-applied ATC or N-Serve 24 E did not always increase yield or N recovery in grain. Considering all experiments with ATC, the average recovery of applied N in barley grain was 28, 40 and 57% for fall banding, fall banding with ATC and spring application, respectively. In view of this and previous work in north-central Alberta, inhibitors injected in bands in the fall slowed nitrification and improved yield, but nests or large granules of urea were more effective. Scientific paper No 553, Lacomba Research Station, Research Branch, Agriculture Canada.     

Effect of rates of nitrogen and relative efficiency of sulphur-coated urea and nitrapyrin-treated urea in dry matter production and nitrogen uptake by rice

Summary A field experiment conducted for two rainy seasons (1974 and 1975) on a sandy clay loam soil at the Indian Agricultural Research Institute, New Delhi showed that at 100kg N/ha the apparent recovery of urea nitrogen by the rice crop was only 28%, which was raised to 41.7% by treating urea with Nitrapyrin and to 47.4% by coating urea withneem (Azadirachta indica Juss) cake. The recovery with sulphur-coated urea was 37.7%. Dry matter production nitrogen concentration in plant and uptake by rice were increased as the rate of nitrogen was increased from 0 to 150kg N/ha. Advantage of treating urea with Nitrapyrin or coating withneem cake was seen more in grain than straw yield.