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

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.

BORON REQUIREMENT OF TOMATO (Lycopersicon esculentum mill) IN SOME SELECTED SOILS OF THE NIGERIAN SAVANNA

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