The effects of injecting nitrapyrin (‘N‐serve’), carbon disulphide or trithiocarbonates, with aqueous ammonia, on yield and %N of grass

Abstract

Nitrapyrin and carbon disulphide (CSz), or sodium or ammonium trithiocarbonate (which evolve CSZ in soil), were injected with aqueous ammonia (NH3) into grassland in three successive seasons at Rothamsted and at Woburn, using a new site each season. Injection was done either in November ('autumn'), or in the following February or March ('spring'). When applied in autumn, the inhibitors increased yield and %N of grass after the mild, wet winter of 1974-75, but had little or no effect in the two subsequent seasons. These effects are consistent with rates of nitrification of the injected NH3, estimated by KCl extraction of soil taken from injection slits, and with winter rainfall. When inhibitors were applied in spring, yields were consistently improved at Rothamsted but depressed at Woburn. All effects were small. Nitrapyrin or CS2, injected with aqueous NH3 into grassland in autumn, reduces nitrogen losses that occur in winter. However, judging from grass yields, in these experiments (in south-east England) losses were only a small fraction of the dose of N applied.Injecting these inhibitors with NH3 in spring can delay nitrification and increase the persistence of the injected N, but this will not necessarily increase yield.

Assessing the need of maincrop potatoes for late nitrogen by using isobutylidene di-urea, by injecting trification inhibitors with aqueous N fertilizers and by dividing dressings of ‘Nitro-Chalk’

“…At Woburn, although aqueous urea was sometimes less good than 'Nitro-Chalk' its performance was seldom improved and often worsened by injecting an inhibitor with it. Ashworth et al (1980) found that the same nitrification inhibitors decreased yields of grass when injected in spring, but not in autumn, on the sandy soil at Woburn. They made tentative suggestions that inhibitors then increased the uptake of NH 4 -N to the detriment of grass growth on a soil supplying less NCyN than the Rothamsted soil did.…”

“…Potatoes (cv. Pentland Crown) were grown at Rothamsted in 1976, 1977and 1978and at Woburn in 1979and 1980, followed by winter wheat (cvs Atou in 1976-7 and 1977-8 and Flanders in 1978-9, 1979-80 and 1980.…”

Inhibition and Stimulation of Nitrification by Potassium Ethyl Xanthate

“…A range of such inhibitors is available for application along with ammonium-based fertilizers, the most commonly used being nitrapyrin (Goring, 1962). Inhibition of nitrification by xanthates was first reported by Lees (1952) and their potential commercial use has been investigated recently by Ashworth et al (1977Ashworth et al ( , 1979Ashworth et al ( , 1980. These compounds release carbon disulphide which is a potent inhibitor of nitrification (Powlson & Jenkinson, 1971) and the most suitable compound for field application is potassium ethyl xanthate (PEX), which provides a slow release of carbon disulphide in the soil over several weeks.…”

A comparison of nitrogen fertilizers for spring and summer grass production

“…A high injection rate of aqueous ammonia with a nitrification inhibitor, as used in these experiments, might be expected to produce delayed spring growth whether injected in winter or spring (Ashworth et al.. 1980). This delay was apparent only in 1985 when March was particularly cold.…”