• TABLE OF CONTENTS
HIDE
 Copyright
 Introduction
 Salt concentration in the soil...
 Source of soil solution salts
 Distribution and concentration
 Conclusions






Group Title: Research report - Bradenton Agricultural Research & Education Center - GC1976-11
Title: Salt accumulation and tomato production
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067702/00001
 Material Information
Title: Salt accumulation and tomato production
Series Title: AREC Bradenton research report
Physical Description: 3 leaves : ; 28 cm.
Language: English
Creator: Geraldson, C. M ( Carroll Morton ), 1918-
Agricultural Research & Education Center (Bradenton, Fla.)
Publisher: Agricultural Research & Education Center, IFAS, University of Florida
Place of Publication: Bradenton Fla
Publication Date: 1976
 Subjects
Subject: Tomatoes -- Soils -- Florida   ( lcsh )
Tomatoes -- Effect of salt on -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: C.M Geraldson.
General Note: Caption title.
General Note: "October 1, 1976."
Funding: Bradenton AREC research report ;
 Record Information
Bibliographic ID: UF00067702
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 72470215

Table of Contents
    Copyright
        Copyright
    Introduction
        Page 1
    Salt concentration in the soil solution
        Page 1
    Source of soil solution salts
        Page 1
    Distribution and concentration
        Page 2
    Conclusions
        Page 3
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida







AGRICULTURAL RESEARCH & EDUCATION CENTER
S IFAS, University of Florida
S. adnton, Florida
// BRARY
f AREC Bradenton Re'eldi-t Report GC1976-1 October 1, 1976

0 ST4ACCq% ATIO AND TOMATO PRODUCTION

C. M| Geraldson

i FAS. Univ. of Fl R DUCTION

The measure of salt concentration in the soil solution and correlation with crop
response has been a continuing evaluation at the AREC-Bradenton for more than 20
years. Results indicate that optimal levels for maximum production of intensively
grown crops can be established and maintained. This includes proper balance of
nutrients as well as elimination of deficiencies and excesses. Adverse effects on
tomato crop production due to excess salts have been associated with two recent
changes in production procedures:

(1) Changing culture procedures favor the successive cropping of agricultural
lands which in turn favors a continuing accumulation of residual salts in the
total soil. Past studies have indicated how residual salts can be removed and the
problem of excesses be minimized or eliminated.

(2) With the more recent widespread use of mulches, incorporation of varying
quantities of fertilizers in portions of the soil bed has also contributed in
varying degree to accumulation of excess salt in the root zone portion of the soil
bed. Excesses associated with mulching can also be minimized or eliminated by
prescribed fertilizer placement.


Soil solution
fertilizers.
Florida soils


salts primarily come from irrigation waters, soil residues and applied
In this report, the source and degree of accumulation of salts in
and the potential effect on tomato production will be discussed.


SALT CONCENTRATION IN THE SOIL SOLUTION

Salt concentrations are expressed as ppm in the soil solution at a measured or
estimated field moisture level. With irrigated sandy soils the field moisture
levels may range from 10 to 15%. Good growth is normally attained when salt
concentration levels in the soil solution root zone range from 1000 to 5000 ppm.
At 10,000+ ppm the projected yield of tomatoes may be reduced by 50%. Seed
germination and seedling survival may be retarded at levels of 2000+ ppm. Seedling
loss (poor stands) has been a serious problem of many growers.

It is essential that the root develop into that portion of the soil where the most
favorable levels of nutrients (1000-5000 ppm) moisture and air coincide. Roots
expand extensively into zones of higher concentrations (near a fertilizer band) but
are easily damaged if salts move into and concentrate in the soil solution of an
existing root system.

SOURCE OF SOIL SOLUTION SALTS

(1) Irrigation water salt content may range from 100 ppm to over 2000 ppm.
The comparative quality of the available water, if the salA content exceeds 1000 ppm,
should be considered in the choice of a field site.







AGRICULTURAL RESEARCH & EDUCATION CENTER
S IFAS, University of Florida
S. adnton, Florida
// BRARY
f AREC Bradenton Re'eldi-t Report GC1976-1 October 1, 1976

0 ST4ACCq% ATIO AND TOMATO PRODUCTION

C. M| Geraldson

i FAS. Univ. of Fl R DUCTION

The measure of salt concentration in the soil solution and correlation with crop
response has been a continuing evaluation at the AREC-Bradenton for more than 20
years. Results indicate that optimal levels for maximum production of intensively
grown crops can be established and maintained. This includes proper balance of
nutrients as well as elimination of deficiencies and excesses. Adverse effects on
tomato crop production due to excess salts have been associated with two recent
changes in production procedures:

(1) Changing culture procedures favor the successive cropping of agricultural
lands which in turn favors a continuing accumulation of residual salts in the
total soil. Past studies have indicated how residual salts can be removed and the
problem of excesses be minimized or eliminated.

(2) With the more recent widespread use of mulches, incorporation of varying
quantities of fertilizers in portions of the soil bed has also contributed in
varying degree to accumulation of excess salt in the root zone portion of the soil
bed. Excesses associated with mulching can also be minimized or eliminated by
prescribed fertilizer placement.


Soil solution
fertilizers.
Florida soils


salts primarily come from irrigation waters, soil residues and applied
In this report, the source and degree of accumulation of salts in
and the potential effect on tomato production will be discussed.


SALT CONCENTRATION IN THE SOIL SOLUTION

Salt concentrations are expressed as ppm in the soil solution at a measured or
estimated field moisture level. With irrigated sandy soils the field moisture
levels may range from 10 to 15%. Good growth is normally attained when salt
concentration levels in the soil solution root zone range from 1000 to 5000 ppm.
At 10,000+ ppm the projected yield of tomatoes may be reduced by 50%. Seed
germination and seedling survival may be retarded at levels of 2000+ ppm. Seedling
loss (poor stands) has been a serious problem of many growers.

It is essential that the root develop into that portion of the soil where the most
favorable levels of nutrients (1000-5000 ppm) moisture and air coincide. Roots
expand extensively into zones of higher concentrations (near a fertilizer band) but
are easily damaged if salts move into and concentrate in the soil solution of an
existing root system.

SOURCE OF SOIL SOLUTION SALTS

(1) Irrigation water salt content may range from 100 ppm to over 2000 ppm.
The comparative quality of the available water, if the salA content exceeds 1000 ppm,
should be considered in the choice of a field site.







AGRICULTURAL RESEARCH & EDUCATION CENTER
S IFAS, University of Florida
S. adnton, Florida
// BRARY
f AREC Bradenton Re'eldi-t Report GC1976-1 October 1, 1976

0 ST4ACCq% ATIO AND TOMATO PRODUCTION

C. M| Geraldson

i FAS. Univ. of Fl R DUCTION

The measure of salt concentration in the soil solution and correlation with crop
response has been a continuing evaluation at the AREC-Bradenton for more than 20
years. Results indicate that optimal levels for maximum production of intensively
grown crops can be established and maintained. This includes proper balance of
nutrients as well as elimination of deficiencies and excesses. Adverse effects on
tomato crop production due to excess salts have been associated with two recent
changes in production procedures:

(1) Changing culture procedures favor the successive cropping of agricultural
lands which in turn favors a continuing accumulation of residual salts in the
total soil. Past studies have indicated how residual salts can be removed and the
problem of excesses be minimized or eliminated.

(2) With the more recent widespread use of mulches, incorporation of varying
quantities of fertilizers in portions of the soil bed has also contributed in
varying degree to accumulation of excess salt in the root zone portion of the soil
bed. Excesses associated with mulching can also be minimized or eliminated by
prescribed fertilizer placement.


Soil solution
fertilizers.
Florida soils


salts primarily come from irrigation waters, soil residues and applied
In this report, the source and degree of accumulation of salts in
and the potential effect on tomato production will be discussed.


SALT CONCENTRATION IN THE SOIL SOLUTION

Salt concentrations are expressed as ppm in the soil solution at a measured or
estimated field moisture level. With irrigated sandy soils the field moisture
levels may range from 10 to 15%. Good growth is normally attained when salt
concentration levels in the soil solution root zone range from 1000 to 5000 ppm.
At 10,000+ ppm the projected yield of tomatoes may be reduced by 50%. Seed
germination and seedling survival may be retarded at levels of 2000+ ppm. Seedling
loss (poor stands) has been a serious problem of many growers.

It is essential that the root develop into that portion of the soil where the most
favorable levels of nutrients (1000-5000 ppm) moisture and air coincide. Roots
expand extensively into zones of higher concentrations (near a fertilizer band) but
are easily damaged if salts move into and concentrate in the soil solution of an
existing root system.

SOURCE OF SOIL SOLUTION SALTS

(1) Irrigation water salt content may range from 100 ppm to over 2000 ppm.
The comparative quality of the available water, if the salA content exceeds 1000 ppm,
should be considered in the choice of a field site.






-2-


(2) Residual salt in non-cropped or virgin soil measures about 300 to 500 ppm.
Residues as mentioned above can accumulate with successive cropping and can
measure 5000+ ppm with 2 to 3 successive crops (1 crop/calendar year). Catch crops
or cover crops can remove residual nutrient salts but non- nutrient salts such as
sodium chloride tend to persist. Residue salts can also be appreciably reduced by
maintaining ditches during the rainy season so that drainage water can move
through the soil. Here also, a measure of the residual soil salt should be a
factor in the choice of a field site.

(3) The quantity and placement of soluble nutrients, applied in varying degree
to the soil, contributes in varying degree quantities of salt to certain portions
of the soil solution. With mulches, all of the crops nutrient requirement is
applied before planting, thus the quantity and placement become more critical and
will be discussed in detail.

DISTRIBUTION AND CONCENTRATION

Residual soil salts plus those from irrigation water provide a basic concentration
of salt incorporated in the total soil volume. In contrast, fertilizer salts are
concentrated in some portions of the soil usually a portion of the soil bed
with none between the beds. For example, if 100 lbs of soluble fertilizer were
applied over the total acre and incorporated to a depth of 6 inches, 400 ppm would
be added to the soil solution at a 12.5% moisture level. (2,000,000 lbs of soil
per acre 6 inches at 12.5% moisture would equal 250,000 Ibs of moisture; 100 Ibs
of soluble salt per 250,000 lbs = 400 ppm).

The quantity and placement of starter fertilizers varies widely with Florida growers.
It is emphasized at this point that the quantity and placement of starter fertilizers
can be critical. Two units of soluble nitrogen and 4 units of potash in an 800 lb
application of 2-18-4 contribute about 100 lbs of soluble salt. Many growers apply
larger quantities. If the 100 lbs were incorporated in a foot wide band in the
center of a bed where row spacing was 12.5 feet, then 5000 ppm would be added to the
soil solution (400 ppm in the soil solution x 12.5). Similar placement on a 5 foot
row spacing would add 2000 ppm to the soil solution. Furthermore, salts incorporated
in the bed tend to move upward with seepage irrigation and further concentrate
toward the plant hole in the mulch. Thus, increasing concentration in that area puts
the young seedling in a most vulnerable position with regard to potential salt damage.

Minimizing the quantity or eliminating incorporation of the starter fertilizer is
recommended as a procedure to minimize most of the associated problems. A
successful procedure includes surface banding of a major portion of the fertilizer
and surface broadcasting of the starter fertilizer. Thus, the top 2 inches of soil
contain salt concentrations excessive for root growth but functions as a reservoir
of nutrients which move by gradient diffusion as removed by the root. It is
significant that the root can proliferate into a portion of the soil bed (2-8"
depth) where the concentration normally decreases with depth from 5000 to 1000 ppm
and coincides with an optimal moisture-air ratio.

Concentration variations in the root zone portion of the soil bed (2-8 inches)
reflect variations in rates and row spacing when fertilizers are incorporated;
similar variations applied on the bed surface do not appreciably alter the
established nutrient gradient (5000 to 1000 ppm) in the 2-8 inches root zone. When
minimal concentrations in this portion of the bed approach or exceed 5000 ppm,
crop damage and production decreases can be expected. Residual and irrigation water












salts contribute to all levels of the applied gradient which in turn forces a
deeper root system. Whether forced or encouraged by deeper placement of nutrients
or a lower water table, a deeper root system is more vulnerable to a rising water
table with excess rain. In Florida, such a potential vulnerability should most
certainly be avoided to the degree possible.

CONCLUSIONS

Potential salt damage in tomato production should and can be, for the most part,
minimized or eliminated. Soil residuals and irrigation water salts should be
minimal in the crop site under consideration. Analyses for salt content should
be a standard procedure. Accumulations of crop residue salts can be reduced by
catch crops and adequate leaching. Maintaining ditches between crop seasons
facilitates leaching of salts during the rainy season. Salt accumulations
associated with successive cropping is currently a major problem which can be
largely eliminated.

Salt accumulations associated with the incorporation of fertilizer in the soil bed
under plastic mulches can also be largely eliminated by avoided incorporation.
Placement of fertilizers on a flat soil bed surface provides a nutrient gradient
that decreases in concentration from about 5000 to 1000 ppm in the 2-8 inch portion
of the soil bed. This desirable concentration range is designed to coincide with
a favorable noisture-air ratio provided by a constant water table a prescribed
distance below the soil bed surface. The gradient-mulch system is designed to
ninimize stress, including excess salts and has been associated with maximum
production efficiency when used as prescribed.




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