Discussion on reducing nitrogen availability in soils
(7/13/01)

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postings: 4
countries: Benin, Canada, Costa Rica
organizations/institutions/companies: CIEPCA, AAFC

From: Kithisiri B Dassanayake
To: MULCH-L@cornell.edu
Subject: Reducing N availability in soils
Date: Fri, 13 Jul 2001

Hi everybody!

I am looking a help, wonder whether abybody could give me an idea on the following issue?

We are working soils rich in organic nitrogen (high available mineral N as ammonium and nitrate) to be precise, excess N. (Organic matter content 10% with high rainfall in winter) what I want is to reduce N availabiltiy.

We are planing (a) to use nitrification inhibitors (b) destroy the legumes in the mixed sward) and increase grass (rye) density. Your ideas please? any suggestions on reducing N avaiability in soils etc.....

Thank you,

Kithisiri B Dassanayake

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Date: Fri, 13 Jul 2001
To: MULCH-L@cornell.edu
From: Donald Kass
Subject: Re: Reducing N availability in soil

We once reduced N levels by planting sorghum. You could then either harvest the sorghum with the grain--or before it produced grain--and feed it to animals.

Donald Kass
CATIE, Costa Rica

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Date: Fri, 13 Jul 2001
From: Albert Chabi Eteka
Subject: RE: reducing N availability in soil
To: MULCH-L@cornell.edu

Hi Kithisiri,

Things are sometimes complex to understand. In West Africa, we look for natural sources of N. This is the reason why we use legume cover crops like Mucuna spp. in short fallows to increase the level of N and the organic matter content, while you are looking for the inverse. Most of our soils have a low organic matter content (less than 1 %). I cc this e-mail to our francophone list members (EVECS-L), they may be for help.

God bless you.

[Chers membres de EVECS-L, veuillez répondre au message de Kithisiri en Anglais s'il vous plaît. Mais si vous le faites en Français, je ferai un effort pour le traduire en Anglais surtout si le message est court. Merci.]

Albert Chabi Eteka
CIEPCA Coordinator
Centre d'Information et d'Echanges sur les Plantes de Couverture en Afrique
Center for Cover Crops Information and Seed Exchange in Africa
Republique du Benin

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Date: Fri, 13 Jul 2001
From: John Potter
To: MULCH-L@cornell.edu
Subject: reducing N availability in soil

Hi, Kithisiri,

I'm not so sure about using the nitrification inhibitors, but your other plans make sense to me. Certainly, with excessive N, growing a cellulosic crop like rye or any other grain/grass should use up N and help balance your C:N ratio. In Canada, this is the kind of situation where we would plant a heavy N-requiring crop such as corn (maize), sorghum/sudangrass, etc. Particularly, crops that return high amounts of high-carbon content organic matter to the soil are desirable.

Cheers,

John W. Potter, Nematologist
AAFC
Canada