IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 _______________________________________________________________________________________ Volume: 04 Special Issue: 11 | NIT Warangal CSWM-2015 | Oct-2015, Available @ http://www.ijret.org 43 EVALUATION OF FERTILITY INDEX OF WATERSHEDS IN RAYALASEEMA REGION T. Kiran Kumar 1 , N. Kumara Swamy 2 1 Associate Professor of Civil Engg, K.S.R.M. College of Engineering, Kadapa – 516 003, A.P. – India 2 Principal, Vaagdevi Inst.of Technology & Science, Proddatur, Kadapa Dist., A.P. – India Abstract Nature made the soil as a self-renewable natural resource material so far as its fertility is concerned; but, its misuse and overuse, man has disturbed this balance of nature. He has not returned back faithfully what he took from the soil. Basic information on soils has advanced at a tremendous rate, but wisdom in their management, to those who till them, has been slow to come. The result has been rapid decline in soil fertility, fall in yields per acre and insufficient agricultural production in India, particularly so within the last few decades. Fertility in the soil is the result of the presence in it of essential plant nutrients, both major and minor, in adequate amounts and in forms which plants can utilize. In addition, the organic matter in the soil, with its resulting physical and microbiological benefits, is also highly important as it makes the soil a living body. It is necessary to know what the present status of these soil fertility elements is; how they decrease or increase; and what are the ways by which they can be maintained in the forms and at levels which can give high crop production is long-term use. In this paper, an attempt has been made to evaluated the fertility status in watersheds of Kadapa drought prone mandals. Based on fertilize index suggested suitable crops and also required fertilizers for improve the strength of the soil and crop yield. Keywords: self-renewable, fertility, physical and microbiological benefits. --------------------------------------------------------------------***------------------------------------------------------------------ 1. INTRODUCTION The soil is the very foundation of life. It supplies the people with food, fodder, clothing and shelter. All that a man eats – vegetables, grains, milk, eggs, meat or fruits – all that he clothes himself with whether woolens, silkens or cottons and all that he feeds his animals with, come from the fertility released by the soil. The fertility of the soil is, therefore, basic to all human existence. It is in fact the foundation of all life on earth and of civilization in the entire world. Those who dwell in villages as well as those who live in towns – rather the Nation as a whole – have a big stake in their soil and in its fertility. Our soils must be kept in a high level of fertility and made productive or the foundation of life will crumble and our civilization will perish. People living on poor or worn-out soils have poor health and are poverty stricken; those who farm fertile and productive soils are in better health and are more prosperous. Races of men are, therefore, the finished products of the landscape and their development depends on adjustment to the quality of the soils which they inhabit. A distinct race comes up on a distinct soil. The maintenance of the soil which is the chief medium for production of crops is fundamental to the well- being of the human race. A study of the fertility of soil has unquestionably the highest importance to understanding many complex problems concerning agriculture of a country. Soil fertility should not be confused with soil productivity. In almost all treatments on the subject of soil fertility, people prefer to make distinction between the two words. Since soil fertility is defined as the ability of a soil to produce a certain yield of crops, it depends on those factors in the soil that determine its crop production potential. Such factors are the presence of essential plant nutrients in available forms and in a suitable balance; the proper micro- biological status of the soil to provide healthy environment for the release of plant nutrients; and freedom from any toxic or injurious agents, conditions or substances in soil. A soil may be fertile and yet it may not be productive. Thus, a water-logged soil may be highly fertile but may not produce good crops because of the unfavourable physical conditions. Similarly, a fertile soil may have saline, alkali or boron salts, which being toxic to plant growth, restrict its potential power to produce crops. Conversely, a sandy soil poor in fertility may, through the use of fertilizers and water, produce high crop yields. Excess of any injurious substance or toxic principles in the soil may lower, in some areas, the otherwise high crop producing ability of the soil. Besides these factors, there are others which are more or less constant under a set of conditions and can not be influenced by human endeavour. These are the nature and type of the soil and the climate where such soil exists. Amongst the soil factors uncontrollable by man are characters such as topography, soil texture, depth of soil profile, etc. Similarly, the climatic factors such as temperature, light intensity, evaporation, frost, etc., are beyond the influence of human agencies. Precipitation, both the total or its distribution in a