Discussions regarding soil temperatures under mulch
(3/5/02 - 3/18/02)

______________________________________________________________

postings: 11
countries: Benin, Ecuador, Honduras, United States, South Africa, New Zealand, Virgin Islands
organizations/institutions/companies: HortResearch, Cornell University, Rand Water, CIEPCA, Minifarms, University of the Virgin Islands

From: Gail Andrews
To: MULCH-L@cornell.edu
Subject: Soil temperatures
Date: Tue, 5 Mar 2002

Can any one tell me what are the benefits of reducing temperature variation in the soil when using mulch? It is regularly noted, but I am vague as to the actual benefits this has for plants in warm conditions.

Thank you to every one who responded on my question about soil moisture.

Gail Andrews
Rand Water
South Africa

______________________________________________________

Date: Tue, 05 Mar 2002
To: MULCH-L@cornell.edu
From: M McGuire
Subject: Soil temperatures

In tropical areas, I believe the benefits would accrue mostly in the drier periods when the plant is susceptible to drought and heat stress. A moderated soil temperature is just one less stress for the plant, one less constraint to growth. In some cases, such as poorly drained soils or where there is a risk of frost, mulch can aggravate existing threats.

M McGuire
University of the Virgin Islands

______________________________________________________

From: NTAMBWE KANUNU
To: MULCH-L@cornell.edu
Subject: FW: mulch and temperatures response, crop plant response to mulch, different types of mulch and method of application
Date: Wed, 6 Mar 2002

Can any one supply me with the above information as pertaining to mulch as well as the benefit of each type of mulch application in area such the DRC, Congo where there is lot of rainfalls and tell me what are the benefits of reducing temperature variation in the soil when using mulch and how it can be done?

Truly yours

Timothee Kanunu
(Congo?)

______________________________________________________

From: Robert Carsky
To: MULCH-L@cornell.edu
Subject: RE: FW: Soil temperatures
Date: Wed, 6 Mar 2002

Armand Van Wambeke discusses in his book (Soils of the Tropics: Properties and Appraisal, McGraw-Hill, Inc., New York, 1992, ISBN 0-07-067946-0) some effects of soil temperature on plant growth. They include 1) seed germination - several crops have maxima beyond which germination is reduced - 2) root growth - same as germination, and 3) activity of soil microbes such as Rhizobium, Azotobacter,and Nitrobacter. This is on page 18.

Robert Carsky
CIEPCA, Benin

______________________________________________________

Date: Wed, 06 Mar 2002
From: Thomas Gaiser
To: MULCH-L@cornell.edu
Subject: Re: soil temperature

Dear mulchers,
We have some indications, that in well drained Acrisols (Paleustalfs) in subhumid West Africa, the nitrifiers activity is reduced, whereas the decomposition process of organic matter still continues, producing more ammonium than nitrate in the soil. This can provoque antagonisms between K and ammonium, leading to K deficiency symptoms of high demanding crops (like maize) in soils with low K availability.

For more details, please refer to:
Gaiser, T., Stahr, K. and Kang, B.T. (1998): Mulching effect on soil nitrification and K uptake of maize in a tropical Acrisol. Proceedings of the 16th World Congress of Soil Science. Montpellier, France. CD-ROM. I can also provide the manuscript to you.

Best regards,
Thomas Gaiser

______________________________________________________

From: Roland Bunch
To: mulch-l@cornell.edu
Date: Wed, 6 Mar 2002
Subject: Soil temperatures

Dear mulchers,

Actually, there are many, many effects of temperature on soils, including faster mineralization of organic matter (ie greater om loss), the reduction of populations of earthworms, changes in the composition of soil flora and fauna, and changes in many of the chemical reactions that occur in the soils. Many of these are mentioned and/or explained in Ana Primavesi's "Manejo Ecologico del Suelo".

Roland Bunch
Organization: COSECHA, Valle de Angeles, Honduras

______________________________________________________

Date: Wed, 06 Mar 2002
To: mulch-L@cornell.edu
From: Harold van Es
Subject: soil temperature

Hello Gail,
A quick response to your question. The moderating effect of mulch on soil temperatures in warm climates primarily relates to the performance of plants and soil-borne fauna. Plants, even tropical species, have an optimum soil temperature for growth, typically between 25 and 40 degrees C. Many of us working in the temperate climates are aware of the growth limitation of cold soil. Bare soil in hot climates intercepts a lot of solar radiation and can get very hot (especially when also dry), thereby pushing the temps beyond the the optimum range. If you want to read up on this some more, Rattan Lal did several studies on this in the seventies/eighties while he worked at IITA.

In terms of the soil critters, the temperature and moisture extremes under bare ground may create an inhospitable environment. Mobile organisms such as worms may move down into the soil (although the subsoil is clearly a less desirable environment), while "immobile" organisms may simple die off or reduce population. Mulches moderate the extremes and make the soil more hospitable, and may also provide a continued source of energy. I am not certain of any studies that have separated the effects of tempearture, moisture and mulch in controlled studies, but this is generally accepted knowledge.

I hope this helps.

Regards from New Zealand,
Harold M. van Es, Professor
Crop and Soil Sciences, Cornell University
Currently on sabbatic leave at HortResearch, New Zealand

______________________________________________________

From: Gail Andrews
To: MULCH-L@cornell.edu
Subject: RE: soil temperature
Date: Thu, 7 Mar 2002

Thank you.
If I understand you all well, the benefits of cooler more moderate temperatures in the soil under mulch are rather indirect , microbial activity (soil-borne fauna), mineralization and the plant experiences less stress. Is this aspect not counteracted by the fact that mulching causes the air in the plant canopy to become warmer and dryer. The stomata either transpire more or they close down. This closing down could be a water saving aspect for later?

Gail Andrews
Rand Water, Horticulturist, South Africa

______________________________________________________

Date: Thu, 14 Mar 2002
From: Stephen G. Sherwood
Subject soil temperatures/primevasi book
To: MULCH-L@cornell.edu

Estimados,
How might I purchase the Ana Primavesi book in Spanish? I am located in Ecuador.

Steve

______________________________________________________

Date: Tue, 18 Mar 2002
To: MULCH-L@cornell.edu
From: Richard Fowler
Subject: Soil temperatures

Forgive the late response (been away).
Has Ana Primavesi's "Manejo Ecologico del Suelo" been translated into English.

Any other texts we should be looking at.
Richard Fowler

______________________________________________________

From: Ken Hargesheimer
Date: Mon, 18 Mar 2002
Subject: Re: Soil temperatures
To: MULCH-L@cornell.edu

It has not. I have read it in Spanish but with difficulty as it is rather technical.

Ken Hargesheimer

______________________________________________________

To: MULCH-L@cornell.edu
Date: Mon, 18 Mar 2002
Subject: Re: Soil temperatures

Estimado Richard,
No, Ana's book is presently only in Spanish and Portuguese. ILEIA/Netherlands is looking into getting it translated into English, but that effort is still in the early stages, as far as I know.

I wrote a short, 15-page paper giving some of the basic ideas of Ana's book, in English, in case anyone doesn't know by now.

Sincerely, Roland Bunch
Organization: COSECHA, Valle de Angeles, Honduras