Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 525507
Title Over de afbraak van Ca-cyaanamide in den grond
Author(s) Temme, J.
Source University. Promotor(en): J. Smit. - Wageningen : Veenman - 100
Publication type Dissertation, internally prepared
Publication year 1946
Keyword(s) bodem - calcium - nitrificatie - organische verbindingen - bodemchemie - derivaten - cyanen - soil - nitrification - organic compounds - soil chemistry - derivatives - cyanogens
Categories Soil Chemistry
Abstract The weed killer calcium cyanamide was also a slowly acting N fertilizer. It released N as urea, which was subsequently converted to ammonium carbonate and nitrate. The first phase was mainly physico-chemical involving hydrolysis to calcium hydroxide and cyanamide, which was then hydrolysed to urea. It was promoted by free H +in the soil and exceeded any possible microbiological action, as application initially caused a decrease in the soil microflora.
The second phase was microbiological; first urea was released. The herbicidal effect was due to the formation of dicyanodiamide and its decomposition products, which were toxic also to most micro-organisms. It formed at high pH (8-10) if the topdressing became moist. Nitrification was depressed in concentrations higher than 10% of total N. But the initial effect perhaps limited the proliferation of pathogens.

Apart from killing weeds, it might injure both crop and microflora, if not incorporated into the soil.

A method was developed of estimating the rate of ammonification and nitrification of calcium cyanamide for different soil samples and, thus, the amount of fertilizer needed for optimum effect.
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