Browse on keywords: fertility nitrogen fertilizer placement
Search results on 05/23/13
2043. Fowler, D.B. and J. Brydon. 1989. No-till winter wheat production on the Canadian prairies: placement of urea and ammonium nitrate fertilizers.. Agron. J. 81:518-524.
A practical snow management system, which utilizes no-till seeding into standing stubble immediately after harvest, has permitted expansion of winter wheat production in western Canada. This study examined grain responses to urea and ammonium nitrate fertilizer banded and broadcast at seeding, or broadcast in the late fall or early spring. A moisture shortage biased the results. Fall banding prior to seeding helped reduce volatilization losses of urea (which were as much as 50%), but presented other problems and did not outperform broadcast ammonium nitrate.
9560. Brage, B.L., W.R. Zich and L.O. Fine. 1960. The germination of small grain and corn as influenced be urea and other nitrogenous fertilizers.. Soil Sci. Soc. Amer. Proceedings, p.294-296..
Field experiments comparing the use of urea to other fertilizers were performed. The fertilizer was placed with the seed in all but two experiments. Urea containing 2.5% biuret reduced stands of small grain by 30% when the equivalent of 20 lb N/ac was applied with the seed. Ammonium nitrate at 80 lb N/ac caused a reduction in stand of 10%. Stands were depressed by 25 and 60% when 40 and 80 lb N/ac, respectively, as reagent urea were used per acre. Urea, containing 10% biuret, applied broadcast at 160 lb N/ac, caused no damage to germination of either corn or barley. Urea was intermediate between ammonium carbonate (most damaging) and ammonium nitrate in a greenhouse germination trial. When fertilizer was mixed with the soil in the laboratory, considerable ammonia was evolved from the soil atmosphere by aeration when either urea, ammonium hydroxide or ammonium carbonate was used. Only traces of ammonia were removed from soils treated with either ammonium nitrate, ammonium sulfate or biuret. Ammonia gas formed from urea, and the contaminant biuret in urea, are therefore both instrumental in causing commercial urea to be toxic to germinating seeds.
9764. Varvel, G.E., J.L. Havlin and T.A. Peterson. 1989. Nitrogen placement for winter wheat in three fallow tillage systems.. Soil Sci. Soc. Am. J. 53:288-292.
Increased soil water storage with increasing amounts of surface residue in winter wheat-fallow cropping systems has not consistently resulted in higher grain yields in the Great Plains. Earlier results had suggested increased amount of surface residue may increase N immobilization and limit N availability, thereby reducing potential for use of the additional stored soil water. This study was conducted to determine if N placement below the zone of organic matter or surface residue accumulation would reduce N immobilization and increase yields.