Prof Adekayode Inaugural 91
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THE FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE DIGITAL SOIL FERTILITY MAPPING: A PARADIGM SHIFT IN SOIL FERTILITY STUDIES INAUGURAL LECTURE SERIES 91 Delivered by PROFESSOR FRANCIS OMOTAYO ADEKAYODE B.Sc. Hons. (Ife); M.Sc. (Ife); PhD (Akure); PGD (ARCSSTE-E, Ife) Professor of Soil Fertility On Tuesday 7th November, 2017 FRANCIS OMOTAYO ADEKAYODE B.Sc. Hons. (Ife); M.Sc. (Ife); PhD (Akure); PGD (ARCSSTE-E, Ife) Professor of Soil Fertility DIGITAL SOIL FERTILITY MAPPING: A PARADIGM SHIFT IN SOIL FERTILITY STUDIES Protocol The Vice-Chancellor, The Deputy Vice-Chancellor (Academic), The Registrar, Other Principal Officers of the University, Deans, Directors, Heads of Departments, Professors and Professional Colleagues, My Lords Spiritual and Temporal, Distinguished Guests and Friends of the University, Ladies and Gentlemen of the Press, Distinguished Ladies and Gentlemen, Great FUTARIANS. 1.INTRODUCTION 1.1 Preamble It is with sincere gratitude to God Almighty that I stand before you all, to deliver the 91st Inaugural Lecture of this great University titled Digital Soil Fertility Mapping: A Paradigm Shift in Soil Fertility Studies. This is the 34th inaugural lecture from the School of Agriculture and Agricultural Technology, The Federal University of Technology, Akure, Nigeria. Mr. Vice-Chancellor Sir, I shall be expressing the obvious to say that my venture into Soil Science is an act of providence; however it is worth mentioning, how this has come to reality. This narrative will be dated back to October 1972 in the residence of Professor R. Duncan an elderly 3 visiting Professor in the Department of Plant Science, University of Ife (now Obafemi Awolowo University) Ile-Ife, Nigeria. I was then in the preliminary class. The University had the tradition of assigning students as advisees to lecturers who would guide them in their academic and social lives. Professor Duncan invited all the Advisees assigned to him to a dinner in his house and after the sumptuous meal, we went into interactive pleasantries. The discussion came up on the benefits of land mechanization in crop production by which means drudgery encountered by farmers could be considerably reduced if not totally eliminated. Professor Duncan watched and listened with rapt attention to the contribution of everybody. All agreed to making mechanized farming replace completely the manual tillage systems except I who expressed a reservation based on the view that continuous mechanization would degrade fast the productivity of the land due to the rapid destruction of soil structure. The discussion turned to a kind of argument. At the end, Professor Duncan intervened and identified me as a promising Soil Scientist. He aligned more to my position that the long-term degradation effects of continuous mechanized farming could outweigh the short-term benefits of larger cultivable farmland. I, there and then, started dreaming to become a celebrated soil scientist. This influenced my choice of soil science in the final year project with the B.Sc. Degree Dissertation titled Efficiency of Phosphorus Application by Banding as Measured in the Nutrient Uptake and Yield of Maize (1976 B.Sc. Thesis) under the supervision of Professor J.A. Adepetu. My master's thesis in 1983 was titled Soil Survey and Mapping in Basement Complex Material and Sedimentary Rocks under the supervision of Professor T.I. 4 and Sedimentary Rocks under the supervision of Professor T.I. Ashaye, while my PhD Thesis in 1998 was titled Tillage Systems and the Effects on Soil Physical and Chemical Properties and the Yield of Maize and Cowpea. It was at this level that I defended in a PhD viva in 1998 before a formal Board of Examiners what I had believed in and earlier expressed in an informal gathering in October 1972. 1.SOIL FERTILITY STUDIES: PAST AND PRESENT 1.1 The fundamental in soil Soil is the most basic material because man came out of it and the physical body of man will return to it; “For out of the ground was thou taken, for dust thou art and unto dust shall thou return” (Genesis 3: 19). 2.2 The ancient non-laboratory researched soil fertility studies Soil fertility and the management had been linked to human existence from the history of man and indeed human civilization is deeply rooted in the use of soils. The basics of soil fertility was at creation when God put man in the garden of Eden to maintain it, as it was written “And the Lord God took the man and put him into the garden to dress it and to keep it” (Genesis 2: 15). By this, the aesthetic value with luxuriant beautifully looking vegetation was obtained as a result of fertile soil, rich in nutrients. When man fell out of God's favour through his disobedience by eating the forbidden fruit, God cursed the ground for his sake, as it was written “Cursed is the ground for thy sake; in sorrow shalt thou eat of it all the days of thy life” (Genesis 3: 17). The productivity of the soil had been reduced to the minimum as a result of the curse. This would 5 management and He directed man to till the ground for six years and the seventh year to allow it to rest and rejuvenate. It was written, “Six years thou shalt sow thy field, and six years thou shalt prune thy vineyard and gather in the fruit thereof; but in the seventh year shalt be a Sabbath of rest unto the land, a Sabbath for the Lord: thou shalt neither sow thy field nor prune thy vineyard” (Leviticus 25: 3 – 4). This was precisely soil conservation practise. The display of soil fertility understanding was demonstrated when Moses sent spies to survey the promised land the Israelites were advancing to, for occupation. The spies came back with report as written “We came unto the land whither thou sentest us and surely it floweth with milk and honey and this is the fruit of it” (Numbers 13: 27). This report depicted high soil fertility status inferred from vegetation studies. Several other instances could be found in the Holy Bible of non-laboratory researched soil fertility studies based on native intelligence. 2.3 The ancient laboratory researched soil fertility studies The observations of improved soil fertility as a result of addition of manure were reported by the ancient people of the likes of Homer in 800 B.C., Archilocus in 700 B.C. and Theophrastus in 300 B.C. Theophrastus specifically reported his observation of improved soil fertility status when farmers ploughed in the residues from previous bean crop while Virgil in 19 B.C. advocated the application of legumes to improve soil fertility (Tisdale et al., 2003). The early investigations on plant nutrition conducted by Johann Baptista Van Helmont (1577 – 1644), John Woodward (1665 – 1728), Nicolas Thiodore de Saussure (1767 – 1845) and Justus von Liebeg (1803 – 1873) were chronicled in Bareja (2011). 6 2.4 The modern soil fertility studies The study of modern soil science was reported in Feller et al. (2012) to have its origin in the mid-17th century. It had indeed been generally accepted that the impetus of present-day soil science began with V.V. Dokuchaiev in U.S.S.R. in 1900 and Hilgard in U.S.A. in 1907 (Bridges, 1975). Soil classification, a branch of soil science intricately linked to soil fertility mapping was first studied by Dokuchaiev who, recognizing soil as an independent natural body that could be studied by field and laboratory methods based the classification of soils on observable features on the soil itself. Dokuchaiev and his research collaborators reported that many soil types had a definite geographical location associated with definite climatic regions and vegetation (Bridges, 1975). Further soil research studies were carried out by other investigators that included Robinson (1949) who used the criteria of drainage, degree of leaching and types of humus in soil studies. The classification system of Kubiena (1958) consisted of 5 main soil groups and many sub-groups, arranged according to specific horizon classes, as well as the type of humus present while Northcote (1965) used texture to map Australian soils. The ancient approach earlier reported was rather subjective and greatly influenced by the level of perception of the investigator which was not based on any mathematical modelling. The American Soil Survey staff (1960) used the surface and sub-soil diagnostic horizons to map and classify soils from which the productivity could be inferred. Physical, chemical and biological properties were employed in mapping the soils to determine the productivity. 7 determine the productivity. The specific characteristics chosen to appraise the soils productivity were depth (P), texture and structure (T), base saturation (N), salinity (S), organic matter (O), nature of clay (A), mineral reserves (M), drainage and soil moisture (H). A function (p) of the different characteristics could be expressed as p = f (P, T, N, S, O, A, M, D, H) and when each function had an index, the productivity of the soil could be calculated by the expression p = P x T x N x S x S x O x A x M x D x H. The values obtained for each soil when plotted against frequency would produce the preliminary five classes of very high productivity (65 to 100), high productivity (35 to 64), medium productivity (20 to 34), low productivity (8 to 19) and very low productivity (0 to 7) when the ideal soil for production had a rating of 100 (FAO, 1985). The instance of several other mathematical demonstrations as carried out by Mitschelich was reported in Harmsen (2000) whereby an equation that related plant growth to the supply of plant nutrients was developed.