BORON REQUIREMENT OF TOMATO (Lycopersicon esculentum mill) IN SOME SELECTED SOILS OF THE NIGERIAN SAVANNA
BORON REQUIREMENT OF TOMATO (Lycopersicon esculentum mill) IN SOME SELECTED SOILS OF THE NIGERIAN SAVANNA
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Date
1997
Authors
OYINLOLA, EUNICE YETUNDE
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Abstract
Boron deficiency is the most wide-spread micronutrient
fertility problems in the Northern Nigerian savanna. Recent report
has indicated response of cotton and some legumes to boron.
Application of boron fertilizer with NPK increases the vegetative
growth and yield and also modifies the fruit of tomatoes. However,
there is dearth of information on the B needs of tomato and soils
supporting the growth of the crop in Northern Nigeria savanna where
about 70% of tomato consumed in Nigeria is produced.
This study established the B requirement of tomato through
systematic laboratory, greenhouse and field experiments. In the
laboratory and greenhouse experiments, the B supplying power of
thirty soils and ability of five extractants (Hotwater, 0.01M
CaCl2, 0. 1N HC1, double acid and morgan solution) to predict the
availability of B to tomato plants were evaluated, and critical
levels in soils and plant established. The field trials which were
conducted at Samaru and Kadawa during the 1992/93 and 1993/94 dry
seasons and 1993 and 1994 rainy (wet) seasons tested the response
of tomato to six levels of B (0, 1, 2, 3, 4 and 5 kg B ha"1 for dry
seasons and 0, 0.5, 1.0, 1.5, 2.0 and 2.5 kg B ha-1 for rainy
seasons) applied in the form of Borax.
Results obtained from the laboratory indicated that, total B
varied from 6-130 mg kg"1, while available B varied from 0.04 - 0.58
mg kg-1. There were correlation among the soil properties, while
the soil B test correlated with some soil properties. Results also
indicated that various combination of soil properties such as pH
•4
and O.C influenced the availability of B in the soils.
Results of the B adsorption and desorption studies revealed
that the values of adsorption maximum (b) (0.030-0.0725 ug g-1) were
low which can render the soil B susceptible to leaching losses.
Also twenty nine out of the thirty soils best fit in Langmuir
equation. The B adsorption of the soils was found to be
irreversible.
Results obtained from the greenhouse indicated response of
some soils to B fertilizer. Although the uptake of B by tomato in
the thirty soils was not correlated with the amount of B extracted
chemically, relative yield correlated with the amounts of B
extracted by hot water.
The critical B level in the soil and plant were established,
the values being 0.13 an 1.06 mg kg-1 B. respectiely.
Results from the field studies indicated that there was
response to B application in the field. Most of the parameters
determined were positively affected by B application. The highest
fruit yield recorded during the dry season was 46 ton ha"1 in
1993/94 which gave an increase of 148% over the control. While the
highest fruit yield recorded for the rainy season was 28 tons ha"1
gave an increase of 165% above the control. Also fruit components
total soluble solids, ascorbic acid, titratable acids, pH and
reducing sugars were modified by recording significant increase
over the controls. However, the highest B rates in both seasons
were toxic to the tomato plants. Boron rates of 2.0 to 3.0 kg ha"1
and 0.5 to 1.5 kg ha"1 appeared to be optimum for tomato plants
under irrigation and rainfed conditions respectively in the savanna
agro-ecology.
Description
Thesis Submitted to the Postgraduate School of Ahmadu Bello
University, Zaria in Partial Fulfillment of the Requirements for
the Award of the Degree of Doctor of Philosophy (Soil Fertility)
IN
THE DEPARTMENT OF SOIL SCIENCE
AHMADU BELLO UNIVERSITY
ZARIA, NIGERIA
1997
Keywords
BORON REQUIREMENT,, TOMATO,, (Lycopersicon esculentum mill),, NIGERIAN SAVANNA