eChapters

Crop adaption is closely related to genetics and plant physiology. Knowledge of basic of biological evolution and genetics is essential for an understanding of crop adaptation. Natural selection, the fundamental basis of adaptation has been atmost importance in determining the characteristic of present day crops and its still of great significance in modern plant breeding.

Ecology and ecosystem: Ecology and ecosystem influences adaption and distribution of crops. As such basic knowledge of ecology and ecosystem is necessary to understand adaptation and distribution of crops for maximum economic yields through efficient use of natural and applied inputs.

Ecosystem ecology is the integrated study of living and non living components of ecosystems and their interactions within an ecosystem frame work. This science examines how ecosystems work and relates this to their components such as chemicals, bedrock, soil, plant and animals.

Ecology is the scientific study of relations that living organisms have with respect to each other and their natural environment. Under ecology we study various ecosystems which are part of the biosphere. An ecosystem includes all the organisms and the non living environment that are found in particular place.

Cropping systems are designed to mimic nature and bring diversity into our farming system. The cropping system should provide enough food for the family, fodder for cattle and generate sufficient cash income for domestic and cultivation expenses.

The objective of any cropping system is efficient utilization of all resources viz., land, water and solar radiation, maintaining stability in production and obtaining higher net returns. The efficiency is measured by the quantity of produce obtained per unit resource used in a given time. The objective of traditional agriculture was to increase the production by two means:

a) By increasing area under cultivation.

b) By increasing the productivity per unit area of the crop.

Growth is defined as an irreversible change in the size of a cell, organ or whole organism. Commonly, growth is the increase in the amount of living material (protoplasm) which leads to an increase in cell size and ultimately cell division. Growth occurs only in living cells by metabolic process involved in the synthesis of proteins, nucleic acids, lipids and CHO at the expense of metabolic energy provided by photosynthesis and respiration.

Crop nutrition / plant nutrition refers to the inter relationships of mineral elements in the soil and their role in plant growth and development. This inter relationship involves a complex balance of mineral elements essential and beneficial for optimum plant growth.

Plants require certain element for their growth and development. There are about 60 chemical elements present in the plant and it doesn’t mean that all are essential for normal growth and development.

Arnon and Stout (1939) proposed criterion of essentiality. Which were refined by Arnon (1954) and are popularly known as Arnon’s criteria of essentiality. They are:

Crop density is nothing but number of plants or seedling per unit area. Crop density per unit area depends on the soil, climate and type of crop being planted. For example under extreme conditions, in poor soils and in semiarid regions with no irrigation planting at low density is best. Otherwise crop plants will be thin and weak. In such conditions not only produces low yield but also is the ideal condition for pest and diseases. Crop unit area depends on :

1. Soil fertility: In poor soils, plant density should be lower than in fertile soils.
2. Availability of water: In areas where water is a limiting factor, planting should be done at a lower density.
3. Tillering capacity of the crop: Small grains and other cereals are planted at lower densities due to tillering capacity and elasticity of the crops.

Cultivation involves management of physical environment to produce a favourable habitat for successful crop production. Primitive man used tools to disturb the soil for placing the seeds. The word tillage is derived from the Anglo-Saxon words tilian and teolian means to plough and prepare soil for seed sowing, to cultivate and to raise crops. Jethrotull who is considered as father of tillage suggested that ploughing is necessary so as to make the soil into fine particles.

Tillage is the mechanical manipulation of the soil either with tools and implements for obtaining conditions ideal for seed germination, seedling establishment and growth of crops.

Tillage includes all operations and practices that are used for the purpose of modifying soil physical characters. Tillage is the most difficult and time consuming operation in crop production. About 30 per cent of the total cost of cultivation goes for tillage operations.

Soil is defined as a thin layer of earth’s crust which serves as a natural basic medium for the plant growth. Soil is a dynamic natural body composed of minerals, organic materials and living forms on which plants grow. Soil are formed by the weathering of rocks and minerals in presence of soil forming factors like climate, organisms, relief or topography, parent material and time (cl,o,r,p,t).The weathering of rocks and minerals are associated with physical and chemical phenomenon. The principal agents of physical weathering are temperature, water, wind, plant and animals. Chemical weathering is affected through the process of hydrolysis, hydration, carbonation, oxidation and reduction.

Each soil is characterized by a given sequence of horizons. Combining of this sequence is known as soil profile. Soil profile is a vertical section of the soil through its horizons. The layers or horizons in the soil profile vary in thickness and have different characteristics like colour, texture, structure etc. The horizons are designated by O, A, E, B, C and R.

Horizon: The layers seen in the vertical section of the soil profile are called horizons.

Seed is the living link between plant and progeny and biologically seed is ripe fertilized ovule and a unit of reproduction of flowering plant. Agronomically, a seed material or propagule is the living organ of crop in rudimentary form used for propogation.

Propagation Asexual Sexual Seed Stem cutting Ex: Sugarcane Grafting Rooted slips Ex: Grasses Tubers Ex: Potato Budding Corms Rhizomes Layering

Plants perpetuate / multiply either sexually or asexually. Sexual methods are through seeds and asexually through vegetative parts. Most of the crop plants produce viable seeds which are used for sowing. Those used for multiplication are called seeds and those which used for human consumption are called grains.

Seed consisting of intact embryo, stored food and seed coat which is viable and has got a capacity to germinate. Embryo has two parts:

Crops: Is a cultivated plant that is grown on large scale commercially, especially cereal, pulses, fruits or vegetables.

Classification of crops : Several crop plants are alike with respect to ontogeny (Development), morphology, anatomy, physiology and requirement of environment. Classification is done to generalize similar crop plants as a class for attaining better understanding of them. Field crops are classified in several ways.

Agriculture plays a key role in the overall economic and social well being of the country. Though the share of Agriculture in both GDP and employment has declined overtime, Agriculture still forms the backbone and occupies a pride of place :

1. Agriculture contributes 24 per cent to the Gross Domestic Product. GDP was declined from 39 per cent in 1983 to 25 per cent during 1999-2000 and now it 17.32 per cent.
2. Provides livelihood support for more than half of the population in the country. The sector provides employment to 56.7 per cent of the India’s work force.
3. Agriculture has been the source of raw material for industries. Majority of the industries depending on agriculture for their raw materials. Ex: Textile (Cotton, Jute), Sugar (Sugarcane, Sugar beet), Small & medium scale industries like soaps, dyes, medicines, vitamins, preservation of fruits and vegetables, dhal milling, rice husking, Jaggery making, oil crushing, handlooms etc.
4. It provides large part of market for industrial goods viz., seeds, fertilizers, pesticides, implements, machines like pump sets, trucks, tractors, power tillers, sprayers etc.
5. Support roadways, railways, airways and shipways for transport of inputs & produce.

Higher plants demand certain basic things for their growth. As many as 52 factors (basic things) influencing crop growth have been identified :

• 100 per cent of the land has sufficient CO₂ in the atmosphere and sunlight
• 83 per cent have favourable temperature
• 64 per cent have favourable topography
• 46 per cent have reliable rainfall
• 40 per cent have satisfactory fertile land

It is supposed that man was evolved on earth about 15 lakh years ago. This man started to move by standing erect on his feet and called Homo erectus L. Later the modern man was evolved called Homo sapiens L. (Sapiens means learning habit) due to his continuous learning habit. It is difficult to trace the exact period of beginning of agriculture. Archeological evidences indicated that, Agriculture started about 50,000 years ago.

Hunting was the primary source of food in olden days and was prevailed for long time. They obtained his food through domestication of some animals like dogs, horse, cow, buffalo etc. They live in the periphery of the forest and migrate from one place to another in search of food. It was not comfortable and they started enjoying by settling at one place near the river and started agricultural system.

Agronomy is a branch of applied science deals with the principles and practices of field crops production and management of soil for higher productivity. The term Agronomy is derived from Greek word agros meaning field and nomos meaning to manage.

Norman (1980) defined Agronomy as the science of manipulating the crop environmental complex with dual aims of improving Agricultural productivity and gaining a degree of understanding of the process involved.

In recent times, Agronomy has assumed newer dimensions and can be defined as ‘A branch of Agricultural science that deals with the methods which provide favourable environment to the crops for higher productivity’.

Agriculture

The term agriculture is derived from Latin word ager or agri meaning soil and cultura meaning cultivation. Agriculture is a broad term encompassing all aspects of crop production, livestock farming, fisheries, forestry etc. Agriculture is a branch of applied science and is the art of farming including the of cultivating the soil for producing crops and raising livestock. There are three main spheres of agriculture-geoponic meaning cultivation in soil, hydroponic meaning cultivation in water and aeroponic meaning cultivation in air.

Agriculture is a productive unit where the gifts of nature like land, light, water and temperature are integrated into a single primary unit that is crop plant which is indispensable for human beings. The secondary productive units of agriculture are animals including livestock, birds and insects which feed on the primary units and provide concentrated products such as meat, milk, wool, eggs, honey, silk and lac.

An experiment is a systematic process or activity which leads to collection of information on certain objects to give an answer to the objectives of the researcher.

The experiment in which certain absolute values like average, correlation coefficient, median, mode, etc are worked out to describe the population is known as absolute experiment.

The experiment in which the effects of different objects under consideration are compared is known as comparative experiment.

The variable whose change we wish to study is called as Response variable. For example- yield, mortality rate of insects etc.

The variable whose effect on the response variable we wish to study is termed as Factor. For example - variety, fertilizer, insecticide etc.

Here factor is the independent variable and response variable is the dependent variable.

The various levels of a factor whose effect on the response variable we wish to study are known as Treatment.

Chi-square test is a non-parametric test as the null hypothesis does not contain any assumption regarding the population parameter. Chi-square is also written as c₂. In this chapter two uses of chi-square test will be dealt with. They are the following :

Samples having size, n - 30 are known as large sample. For large values of n (i.e., for n - 30), almost all the distributions are very closely approximated by normal distribution. Thus in this case we apply the normal test, which is based upon the area property of the normal probability curve. Large Sample Test is also known as Z-test or SND (Standard Normal Deviate) test.

A sample is said to be small sample if the sample size(n) is less than 30. Various small sample tests are: (i) t-test (ii) F-test

t-test performs the following tests for small sample(s).

1. To test the equality between a single sample mean and the assumed population mean.
2. To test the equality of two independent sample means.
3. To test the equality of two paired sample means.
4. To test the equality between sample correlation coefficient and the assumed population correlation coefficient

The aggregate of data forming a subject of investigation is known as population. Example, All the crop plants grown in a plot; all the fruit plants in an orchard, etc. The population may be:

1. Finite: No. of observations are definite. e.g., number of farms in a village, no. of house in a locality, no. of trees in an orchard are all finite population.
2. Infinite: Number of observation are indefinite e.g., (a) Number of insects in a region, number of grasses in a field etc. are all infinite population.

The Population may be:

1. hypothetical or theoretical

   Hypothetical population consists of unit that has no physical existence. This population exists only in imagination. For example, Result of tossing coin, throwing die,

2. Existent or real population consists of units that are physically present. This population actually exists. For example, Number of employees in a factory, Number of farms in a village.

Concept of correlation was given by Karl Pearson in 1890.

The study of strength and nature of relationship between two variables is called correlation. Two variables are said to be correlated, if the change in one variable affects the other variable. Correlation is also known as covariation.

Bivariate Distribution: Distribution involving two variables is known as bivariate distribution. For example, Height and weight of persons, yield and production of a crop in.

On basis of type of association between variables, correlation is of two types: