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AGRO - PRINCIPLES OF AGRONOMY AND AGRICULTURAL. METEOROLOGY. 1. Agriculture – Definition – Importance and scope - Branches of. PRINCIPLES OF AGRONOMY AND AGROMETEROLOGY - Free download as Word Doc .doc), PDF File .pdf), Text File .txt) or read online for free. Francisco J. Villalobos, José Paulo De Melo-Abreu, Luciano Mateos, Elias Fereres. Pages PDF · Wind and Turbulent Transport. Francisco J. Villalobos.

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Principles of Agronomy & Agricultural Meteorology PDF Books free downloadable book Agronomy PDF books useful for agronomy related field. Principles Of Agronomy book. Read 8 reviews from the world's largest community for readers. Principles Of Agronomy. present grammar, which is chieflyintended for beginners,is believed to contain all A Sanskrit Grammar for Beginner.

Course No. Credit Hours 4. Specific Objectives: a Theory By the end of the course, the students will be able to i. A Theory Lecture Outlines 1. Definition of agriculture meaning and scope of agronomy History and development of agriculture in ancient India agriculture in civilization era National and International Agricultural Research Institutes in India Agro-climatic zones of India soils, land use pattern, major sources of irrigation and ground water potential Agro-climatic zones of Andhra Pradesh soils, land use pattern, major sources of irrigation and ground water potential. Tillage and tilth objectives of tillage characteristics of ideal seed bed effect of tillage on soil properties pore space, texture, structure, bulk density and colour of the soil 7. Types of tillage preparatory tillage factors affecting preparatory cultivation, after cultivation, puddling Sowing methods of sowing time and depth of sowing for major agricultural crops cereals, pulses and oilseeds Crop stand establishment factors affecting optimum stand establishment Planting geometry competition types of competition, intra and inter plant competition plant population effect of plant population on growth and yield optimum plant density and planting pattern

ANGRAU- Agronomy notes

Thus the farmers will get better tool at comparatively moderate price. It was designed by H. The head piece is made up of two iron plates. The holes are provided on plates at 7. It works at 30 to Wedges are used to fix the prongs in head piece. It is fixed in front side of the prongs. There are two types of blades viz. The triangular shaped blades are used in fallow land for removing weeds and ploughing soil.

Principles of Agronomy for Sustainable Agriculture

The semi-circular blades are used for interculturing purpose. Prongs are made up of iron. Prongs provided at the end of head piece are equal in length. While Ionger prong is fixed in the middle of the length.

Uses: 1. It is used for preparing seed beds 2. For interculturing crops 3. For removing stubbles and 4. For mixing manures and fertilizers. B Wheel hoe: It is a hoe with one or two wheels. Wheel hoe is used for interculturing purposes in between rows of crops.

There is a wheel attached to the two handles, to which a working tool is attached. Wheel is helpful in guiding the tool and maintaining proper depth. It is useful for kitchen gardens. It consists of: i Wheel ii Axle iii Frame iv working tool. C Hand hoe: It is a hand tool with blade s , tine s and sometimes disc s attached to a frame, used for inter cultivation operation in crops. D Paddy weeder: Paddy weeder is important equipment for interculturing, used in paddy cultivation.

Improved varieties of paddy crops are grown in rows and to keep down the weeds, this implement is used. It is used for uprooting weeds and burying them in puddled soil between crop rows. Answer: Note: practice with different interculturing implements in the field. Maintaining standing water conditions through out crop period is not possible without puddling. What is puddling: Puddling is ploughing the land with standing water so as to create an impervious layer below the soil surface to reduce deep percolation losses of water and to provide soft seedbed for planting rice.

Objectives of puddling: Puddling is done to obtain the following objectives- 1. To achieve the primary aim of destroying the soil structure. The soil aggregates are separated into their individual particles viz; sand, silt and clay. To create an imperious layer below the soil surface. Procedure: Puddling operation consists of ploughing repeatedly in standing water until the soil becomes soft and muddy. Initially, 5to 10 cm of water is applied depending on the water status of the soil to bring it to saturation and above and thereafter first ploughing is carried out.

After 3 to 4 days another 5 cm of water is applied and 2 to 3 days later second ploughing is carried out. By this operation most of the clods are crushed and majority of the weeds are incorporated.

Within 3 to 4 days another 5 cm of water is given and third ploughing is done in both the directions. The third ploughing can be done either with a wetland plough or with a wetland puddler. Thereafter planking or leveling board is run to level the field. To know whether puddling is thorough or not, a handful of mud is taken into the hands and pressed. If it flows freely through the fingers and if there are no hard lumps, puddling is considered to be thorough.

During puddling individual soil particles viz; sand, silt and clay are separated. The soil layer with high soil moisture below the plough sole is compacted due to the weight of the plough.

The soil particles separated during the puddling settle later. The sand are first to settle at the bottom over which silt particles settle and finally clay particles fill the pores in between thus making an imperious layer over the compacted soil. Implements used: Puddling can be done with several types of implements depending on the nature of the soil.

Most of the farmers use wetland plough or worn out dryland plough or mouldboard plough. Tractor drawn puddler can be used for puddling by attaching cage wheel to prevent sinking. It is an implement used for churning the soil in standing water.

Puddler is used for preparation of paddy fields with standing water after initial ploughing. It breaks up the clods ad churns the soil. A common puddler used in this country has three pudding units, each having four paddles mounted on an axle. The axle with the pudding units is freely mounted on two bearings, fitted on a frame made of metal or wood.

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The weight of the puddler including its beam is within range of 30 to 40 kg only. Advantages: 1. The most important advantage of puddling is reduced percolation losses of water. Maintenance of standing water in the puddled field leads to less weed infestation in the paddy crop. Green manure, crop residues and other organic matter is thoroughly mixed with soil during puddling. Provides congenial soil condition for easy transplanting. Disadvantages: 1. Puddling leads to compaction of sub-surface soil thus making a hard pan which hinders the aeration and root development of subsequent crop in the rotation.

Puddling destroys the soil structure. Puddling leads to more weed infestation in the next crop of the cropping sequence. There is wastage of fuel, labour and time.

Maintenance of standing water in the puddled field multiplies the water requirement of the crop. Question: Why puddling is considered as necessary evil for lowland paddy cultivation? Answer: Note: practice the procedure of puddling in the soil.

Out of these methods, sowing in lines by seed drill is the most common and popular method of sowing in Gujarat. The crops are sown in lines parallel to one another, therefore weeding and interculturing can be easily done between two lines of the crop. Regulation of seed rate and adjustment of depth of sowing is also possible by this method. Seed drill Seed drill is a machine for placing the seeds in a continuous flow in furrows at uniform rate and at controlled depth with or without the arrangement of covering them with soil.

Function of Seed drill: Seed drill performs the following functions. Classification of seed drill: A Indigenous Seed Drill : 1 Surat Faidko 2 Charotar tarfan 3 Amadavad chavad 4 Dantal of Saurashtra 5 Bharuch seed drill or Vankhedu 6 Panchmahal seed drill or Panchotiyo 7 Bhal seed drill B Improved seed drill: 1 Seed-Cum-Fertilizer drill 2 Cultivator with seeding attachment 3 Planter 1 Seed cum fertilizer drill: Seed drills, fitted with fertilizer dropping attachment, distribute the fertilizer uniformly on the ground.

It is called seed cum fertilizer drill. Such a drill has a large seed box which is divided length wise into two compartments, one for seeds and another for fertilizers. Seed drill may be classified as: i Bullock drawn ii Tractor drawn. Depending upon the method of metering the seeds, bullock drawn seed drill can be further divided into two groups viz; those in which seeds are dropped a by hand, b or mechanically. There are a number of bullock drawn implements which are used for sowing seeds in which seeds are dropped by hand.

In different parts of the country it is made in different sizes and shapes. Components of tractor drawn seed drill : A seed drill with mechanical seed metering device mainly consists of : i Frame ii Seed box iii Seed metering mechanism iv Furrow openers v Covering device vi Transport wheels. The frame is strong enough to withstand all types of loads in working condition.

A small agitator is sometimes provided to prevent clogging of seeds. Covering the seeds are usually done by pattas, chains, drags, packers, rollers or press wheels, designed in various sizes and shapes. Some seed drills have got pneumatic wheels also. The wheels have suitable attachments to transmit power to operate seed dropping mechanism.

It may be called a part of the seed drill for opening boot from where they fall into the furrow. Components of animal drawn seed drill : i Head piece: It is made up of wood and all other parts are fixed on it. Seeds are poured into it. Seed and fertilizer can be sown at a time. Seeds of different size can be sown. The required quantity of seed and fertilizer can be sown. The fertilizer can be sown below the seeds.

Inter row spacing can be adjusted according to our requirement. It is made up of iron, hence its durability is more. It may be three rows cultivator. Three tyned cultivators with seeding attachment is used for sowing seeds in three rows at a time. The rate of seed dropping is controlled by hand. The main parts of the cultivator are the frame, three tynes fitted with reversible shovels, handle with seeding attachment and the beam.

This implement is drawn by a pair of average bullocks. Figure: Animal drawn seed-drill Figure: Cultivator with seeding arrangement Function of planter: i To open the furrow ii To meter the seed iii To deposit the seed in the furrow iv To cover the seeds and compact the soil over it. Components: A planter consists of following parts : i Hopper ii Feed metering device iii Knock out arrangement iv Cut-off mechanism v Furrow opener and vi Other accessories.

A planter has seed hopper for each row. Hopper is usually made of mild steel or any other suitable material. The different types of planters are: 1. Potato planters 2. Sugarcane planter Semi-automatic 3. Manual rice transplanter 4. Japanese rice transplanter 5. Fertilizer distributor Tractor mounted Question: what are the distinct advantages of the seed-cum-ferti drill?

Answer: Exercise: 7 Study of Different Methods of Sowing Date: Sowing is an operation of putting the seeds in the soil at particular distance and depth for raising the crop after proper preparation of the field. Seeds are sown either directly in the field seed bed or in nursery where seedlings are raised and transplanted later in the field. Methods of sowing : 1. Broadcasting : This is oldest method of sowing.

This method is suitable for close growing crops which do not require a specific geometric area. Crop plants which do not require special type of cultural practices e.

This method is followed in the crops having short life period. Seeds are spread or scattered by hands over the field and covered with the help of wooden rake or light plank. Drilling : Drilling is a practice of dropping the seeds in furrows by a mechanical device in parallel rows.

Distribution of seeds is regulated by releasing seeds in to the bowl by the hand. For covering the seeds light planking is done by plank. Dibbling : Putting the seed or few seeds in a hole or pit or pocket, made at predetermined spacing and depth with a dibbler or very often by hand.

This method is suitable for wide spaced crops requiring a specific geometric area for their canopy development or cultural practices. First all lines are marked vertically and horizontally with the help of a marker at a particular distance.

At each cross seeds are dibbled with the help of a dibbler manually. Then seeds are covered with soil. Cotton, Castor, Indianbean, Pigeonpea etc. Planting : Placing of plant parts vegetative propagates in soil is called planting. The vegetative propagates are planted directly in the field.

They should be healthy, vigorous, at proper stage of growth and with sufficient number of readily sprouting buds. Transplanting: Transplanting is the removal of an actively growing plant from one place and planting it in another place for further growth and development.

In this method seeds are not directly sown in the field but seeds are sown first in nursery with proper care. After proper growth generally four weeks , seedlings are uprooted and transplanted in well prepared main field.

This method is useful for raising the crops which have small sized seeds and require more care in the initial stage. Saplings — Subabool, Sag, Eucalypts etc. Answer: Question: Write the suitability of dibbling method of sowing. Answer: Question: What do you mean by planting and transplanting methods? Answer: Note: Actual operation of different sowing methods should be done in field.

Compost is prepared from vegetable and animal refuse collected on the farm or in town or villages. As such, composts differ in nature and composition based on organic material used for its preparation. A Compost Composting is largely a biological process in which micro organisms of both types namely aerobic and anaerobic decompose the organic material and lower the carbon: nitrogen ratio of the refuse. The final product of composting is well rotten manure known as compost.

Methods of preparing compost : 1. Compost from farm litter rural compost : The main components of rural compost are weeds, crop stubbles, bhusa or straw, crop residues such as cotton stalks, groundnut husks, leaves, sugarcane trash, animal urine soaked earth and litter from cattle shed, waste etc.

These materials are converted in to compost manure on the farm. The available refuse on the farm are collected and stored till the sufficient quantity is available for compost making. A trench of suitable size i. The accumulated refuge is well mixed and a layer of 30 cm thickness is spread all along the length of the trench. This layer is well moistened by sprinkling slurry of cow dung and water or earth and water.

Again a second layer of 30 cm thickness is then spread followed by sprinkling slurry. This process is followed till the heap rises to a height of 45 to 60 cm. The top is covered with a thin layer of earth.

After three months decomposition, the mass is taken out of the trench and formed into a conical heap above the ground and covered with earth. After one or two months, the manure is ready for application. Such compost generally contains 0. Compost from sugarcane trash: There are two methods for preparing sugarcane trash compost. The materials required for composting are cane trash, cane leaves, cattle dung and urine.

First sugarcane trash is put in a layer of about 30 cm thickness. Over this, a second layer of cattle dung and urine of 15 cm thickness is spread. The entire material is spread in alternate layers, till the height of the material is 75 to 90 cm above the ground level. One or two watering should be done during summer.

Under such conditions, decomposition is anaerobic and high temperature dose not develop. Loss of ammonium is negligible because in high concentration of carbon dioxide, ammonium carbonate is formed which relatively a stable product.

The compost is ready within four to six months. The advantage of this method is that no further attention and turning of the materials is required. The ground is leveled. The compost heap should be 1.

The material is heaped in layer as stated in peat method. Four to five layers of trash are put one over the other till the heap is 75 to cm high. The heap is plastered with mud. After about one to two months is given the first turning. Turning should be done with wooden rake from one end of heap. Thus, mixing out side material with that from inside. Generally, two or three turnings are required for a compost decomposition of the cane trash. After 4. This method is suitable for use in rainy as well as in winter season.

The disadvantage of this method is that it requires more labour for turning. Compost from town refuses Town compost The main components of town compost are night soil, street sweepings, dust bin refuse and wood ashes. This compost contains on an average 1. Compared to FYM, town compost prepared from refuse and night soil is richer in nutrient value. B Farmyard manure: The main components of farmyard manure are excreta of animal dung and urine of farm animals , litter bedding material and miscellaneous farm and household wastes.

The decomposed manure prepared from these materials is called farmyard manure or farm manure or barnyard manure. Trench method of preparing FYM In this method a trench of 6. All available dry litter and refuse from the farm and the house should be heaped near the cattle shed. To view it, click here. Ravi Gopal rated it it was amazing Jan 31, NavNeet Kaur rated it really liked it Feb 27, Gauri Dagade rated it really liked it Oct 01, Akhil Kandakatla rated it really liked it Feb 14, Arafat rated it it was amazing Jan 30, Mukund Kumar rated it it was amazing Aug 18, Pandi Priya rated it did not like it Oct 17, Montu Patar rated it liked it Mar 20, Amit Singh rated it liked it Feb 22, Sreevalli rated it it was amazing Dec 19, Nitin rated it liked it Mar 19, Dec 19, Ranadip added it.

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The crop to be grown: Crops like sorghum can be grown with rough tilth. For very small seeded, Crops like tobacco, chilles etc fine tilth is required. Deep tillage is required for crops like tuber crops and sugarcane.

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Types of soil: Clay soil can be ploughed only with in a narrow range of soil moisture and the power or draught required is high. Light textured soils can be ploughed under a wide range of soil moisture and require less drought.

Deep tillage is not permitted in shallow soils in low rainfall areas as it leads to rapid drying and loss of stored soil moisture. Deep cultivation is possible in high rainfall areas. Type of farming: Intensive cropping requires intensive tillage. Tillage operations done between the crop rows with the following objectives: To destroy the weeds To form soil mulch To prevent cracking of soil To prevent crust formation.

Intercultivation starts from very early stage of crop i. Short duration crops require two-three intercultivations while long duration crop requires intercultivations. After cultivation: It includes intercultivation and various other special operations carried out in a standing crop. They include. Thinning and Gap filling. Rogueing in crops for seed purpose.

Earthing up in crops like sugarcane, banana, and groundnut. Propping in banana 5.

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Desuckering in banana 6. Wrapping and propping in sugarcane 7.

Nipping in castor 8. Topping, Trimming and in tobacco basal leaves are removed. Defoliation in cotton Hand pollination in sunflower. Fertilizer application and in irrigation also comes under after cultivation.

Maintaining standing water throughout the crop period is not possible without puddling. Puddling is ploughing the land with standing water so as to create an impervous layer below the surface to reduce deep percolation losses of water to provide soft seedbed for planting rice. Puddling operation consists of ploughing repeatedly in standing water until the soil becomes soft and muddy.

Initially, 5cm to 10 cm of water is applied depending on the water status of the soil to bring it to saturation and above and the first ploughing is carried out. After 3 to 4 days, another 5 cm of water is applied and later after 2 to 3 days second ploughing is carried out. By this operation, most of the clods are crushed and majority of the weeds are incorporated. Within 3 to 4 days, another 5 cm of water is given and third ploughing is done in both the directions.

The third ploughing can be done either with a wetland plough or with a wetland puddler. Planking or levelling board is run to level the field. To know whether puddling is thorough or not, a handful of mud is taken into the hand and pressed. If it flows freely through fingers and if there are no hard lumps, puddling is considered to be thorough. Unlike in other tillage. The individual soil particles viz. The soil layer with high moisture below the plough sole is compacted due to the weight of the plough.

The soil particles separated during puddling settle later. The sand particles reach the bottom, over which silt particles settle and finally clay particles fill the pores thus making impervious layer over the compacted soil.

Puddling is done with several implements depending on the availability of equipment and nature of the land. Soils with bulk density less than 1. The feet of the animals sink very deep during puddling. Under such a situation, puddling is done with spades by manual labour.

Most of the farmers use wetland plough or worn out dryland plough or mouldboard plough. Wetland puddler consists of a series of blades attached to a beam at an angle. When it is worked, the soil is churned and puddling operation is completed quickly compared to the country plough. Generally green manure is applied to rice field which is incorporated by green manure trampler. Tractor drawn implements can be used for puddling by attaching cage wheels to prevent sinking.

Good tilth 2. Optimum soil moisture at sowing depth 3. Manures and fertilizers. Seed material: Seeds grains used for sowing 2. Veg propagules stem cutlings, rooted slips, tubers, rhizomes, etc Stem cuttings sugarcane, rose Rooted slips forage crops. Fodder crops Tubers potato Rhizomes turmeric. Characteristics of seed or seed material: Free from rogues offtypes Free from other crop seeds Free from weed seeds. Free from inert material 2. Fully matured and well developed. Free from storage pests and seed borne diseases Ex.

Red rot in sugarcane Tikka leaf spot in groundnut 4. Free from dormancy dormancy problems are seen in groundnut, rice, sunflower 5. Viable soybean looses viability quickly 6. Time of sowing: Sowing very early in the season may not be advantageous. Delayed sowing invariably reduces yields a. In rainfed groundnut, sowing beyond July reduced the yields of all varieties at Tirupathi.

Advancing sowing of Rabi sorghum. Sowing the crop at optimum time is beneficial. Increases yields due to suitable environment at all the growth stages of the crop. Optimum time of sowing for Kharif crop June or July 2. Optimum time for Rabi crop - last week of October to first week of November 3.

Summer crop - First fortnight of January. Depth of Sowing: Uneven depth of sowing results in uneven crop stand. Plants will be of different sizes and ages and finally harvesting is a problem as there is uniformity in maturity.

The thumb rule is to sow seeds to a depth approximately times their diameter. Very small seeds like tobacco are placed at a depth of one cm. Bold seeded crops like castor, groundnut, cotton, and maize etc. Seed rate: Quality of seed purity, germination percent, viability, free from dormancy, free from seed borne diseases, etc 2. Seed treatment: Fungicidal treatment mainly to avoid seed borne and also soil borne diseases Thiram, Captan, Mancozeb, Carbendazim, etc.

Pesticide treatment Malathian for control of scale insects in sugarcane, Quinolphos for stem borer of rice. Hot water treatment sugarcane sets are dipped in 52 C for 30 minutes to control red rot and smut diseases in sugarcane. Special treatments dung treatment or acid treatment ml conc. Scarification Rubbing against hard surface to soften the hard seed coat e.

Breaking dormancy GA. Mixing seed with other materials to increase the bulk in case of small seeded crops, mixing with sand or soil in case of crops like Sesamum, Lucerne, mustard, ragi, etc.

Removal of broken kernels, ill filled seed eg: Rhizobium treatment in case of legumes specific Rhizobium cultures are available depending upon the crop. These are helpful in fixing atmospheric N.

Seed bed preparation Coarse tilth for groundnut, redgram, etc bold seeds Fine tilth for ragi, mustard, etc small seeds 4. Time of sowing important to meet the climatic requirements of each crop.

This is very important in rainfed crops. In case of late sowing maturity may coincide with drought , pest and disease incidence may be more and may affect.

Depth of sowing related to seed size, soil moisture availability. Deep sowing may result in poor crop stand low germination. Too shallow sowing may also result in failure of germination. Optimum soil moisture 7. Optimum soil temperature and aeration 8. Spacing depends on crop and variety 9. Proper covering of the seed in broadcast sowing bird damage is more if seeds are not properly covered.

Formation of soil crust in case of lateritic soils soil crust formation may hinder germination. Shallow and frequent harrowings are practiced to break the crust. Compaction of seed bed firm compaction is required between seed and soil for good germination and also to minimize soil moisture loss. But hard compaction may prevent seedling emergence.

This may happen in heavy soils. Bird damage in some crops crops dig the soil and carry away sprouted seeds of maize. Competition is the struggle between individuals with in a population for available resources, when the level of resources is below the combined need of the members of the population. How does competition occur in plants? Crop plants are not grown in isolation but in closely spaced populations.

In the early phase of growth, individual plants are small and widely spaced and do not interfere with each other. At some point, as the plants grow, they start to interfere with their neighbours and competition begins.

Two plants, no matter how close, do not compete with each other so long as the growth resources are in excess of the needs of both. When the immediate supply of a single necessary factor falls below the combined demand of the two plants, competition begins. Competition for nutrients: Nutrient uptake increases with increase in plant population.

Higher population under low fertility conditions leads to development of nutrient deficiency symptoms because of competition. Competition for light: Competition for light may occur whenever one plant casts a shadow on another or within a plant when one leaf shades another leaf. In early plant growth stages, there will be little mutual shading and even at relatively low light intensities the plant will be able to photosynthesize with full efficiency.

As the plants grow, mutual shading increases and light becomes a limiting factor. Competition for water: The success of any plant in community for water depends on the rate and competitiveness with which it can make use of the soil water supply.

Intra-specific and inter-specific competition: In populations of similar genotypes, in the absence of weeds, the competition is intra-specific with in species , where different species of crops are grown, in mixtures and where weeds present, the competition is inter-specific between species. Plant population and growth High plant density brings out certain modifications in the growth of plants.

Sometimes it may happen that moderate increase in plant population may not increase but decrease plant height due to competition for water and nutrients but not for light. Leaf orientation is also altered due to population pressure. The leaves are erect narrow and are arranged at longer vertical intervals under high plant densities. This is a desirable architecture. Plant population and yield Decrease in yield of individual plant at high plant density is due to the reduction in the number of ears or panicles.

Under very high population levels plant become barren, hence optimum plant population is necessary to obtain maximum yield.

Optimum plant population Optimum plant population for any crop varies considerably due to environment under which it is grown.

It is not possible to recommend a generalized plant population since the crop is grown in different seasons with different management practices. Different planting patterns are followed to suit different weed control practices and cropping systems. Plant geometry refers to the shape of plant while crop geometry refers to the shape of space available for individual plants.

Crop geometry is altered by changing inter and intra-row spacing. Square planting It is reasonable to expect that square arrangement of plants will be more efficient in the utilization of light, water and nutrients available to the individuals than in a rectangular arrangement. In wheat, decreasing inter-row spacing below the standard cm i. In crops like Tobacco, intercultivation in both directions is possible in square planting and helps in effective control of weeds.

However, square planting is not advantageous in all crops. Groundnut sown with a spacing of 30x10cm 3. Pod yield is reduced either by increasing rectangularity or approaching towards square planting. Rectangular planting Sowing the crop with seed drill is the standard practice. Wider inter-row spacing and closer intra-row spacing is very common for most of the crops, thus attaining rectangularity.

This rectangular arrangement is adopted mainly to facilitate intercultivation. Sometimes only inter-row spacing is maintained and intra-row spacing is not followed strictly and seeds are sown closely as solid rows. Miscellaneous planting arrangements Crops are sown with seed drills in two directions to accommodate more number of plants and mainly to reduce weed population.

Crops like rice, finger millet are transplanted at the rate of seedlings per hill. Transplanting is done either in rows or randomly. Every alternate row is skipped, and the population is adjusted by decreasing intra-row spacing, it is known as paired row planting. It is generally practised to introduce an intercrop. Soil productivity refers to the capacity of a soil to produce crops. A productive soil must be fertile, but a fertile soil may not be productive. Soil productivity is influenced by 1.

Soil fertility 2. Physical condition of soil depth, structure, texture 3. Activity of soil micro organisms 4. Soil moisture 5. Inhibitory factors like acidity, alkalinity, salinity, water logging, etc. Nutrients are lost from the soil in the following ways 1.

Removal by weeds 3. Leaching losses more in sandy soils 4. Loss through erosion 5. Loss in gaseous form N by denitrification and Volatilization So it is necessary to add nutrients to the periodically.

N P K It is considered as an index of available nutrients to plants 1. Soil productivity It is a broader term used to indicate yields of crops. It is the interaction of all the factors that determine the magnitude of yields.

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It is one of the factors for crop 2. The other factors are water supply, slope of the land, depth of water table etc. It can be laboratory analysed in the 3. It can be assessed in the field under particular climatic conditions. It is the resultant of various factors influencing soil management to produce crops. Soil fertility can be maintained by: Organic manures bulky and concentrated 2. Inorganic fertilizers 3.

Bio-fertilizers rhizobium, azolla, azatobactor, BGA. Soil amendments lime, gypsum, paddy husk, groundnut shells etc. Weedicides or fungicides copper fungicides add Cu, Triazines add N. Green manures or green leaf manuring 7. Crop residues stubbles, etc. Soil organic matter: Any material of plant or animal origin found in the soil is known as Organic matter. It is very difficult to identify the parent material from which it is derived. Uses of Organic Matter: Helps in aggregation of soil particles and improves the structure, permeability and water holding capacity and aeration.

It serves as a reservoir of plant nutrients. Organic acids and CO2 produced during decomposition help to dissolve minerals like P, K and make them more available. It helps in maintaining soil pH 5. It is the source of energy for micro organisms, earthworms and other living things.

Helps to maintain soil temperature 8. Alkalinity is reduced. The rate of decomposition of organic matter is dependent on the activity of soil micro organisms, which in turn is dependent on1. Soil moisture content 2. Soil temperature 3. Soil aeration 4. N ratio of the original material added.

A weed is a plant growing where it is not wanted. Weed is an unwanted plant. A plant with ve value. A plant interferes with intended use of land. A plant growing with desired plant. Losses due to weeds: Weeds compete with crop plants for resource like light, moisture, nutrients.

Weeds cause reduction in crop yields. Weeds increase cost of cultivation. Weeds are alternate hosts for crop pests and diseases. No Crop 1. Echinochloa sp. Parthenium Crotalaria Amaranthus, Datura. Weeds reduce the quality of produce. Cuscuta as an admixture with Lucerne spoils seed quality. Wild onion and wild garlic as weeds in fodder crops impart off-flavour to milk.

Xanthium impairs wool quality of sheep. Weeds cause human health problems. Allergy by Parthenium hysterophorus Mosquitoes causing malaria, Yellow fever encephalitis and filariasis breed on Pistia and Salvenia. Hay fever and asthma caused by Franseria sp. Rhododendron sp. Sorghum halepense poisonous to cattle. Problems of water contamination. Render drinking water unfit. Reduce flow of water in irrigation channels. Eichornia typha.

Reduction in land value due to Cyperus rotundus and Cynedon dactylon Allelopathy: Harmful affects of plant due to release of phytochemicals on other plants root exudates. Avenafatua affects germination of weed. Seed exudates. Benefits from weeds: Constant source of new genes Saccharum spontaneum is a wild cane used in breeding. Fodder value As leafy vegetables, Amaranths and Celosia.

As Green manures Tephrosia Have medicinal value Leucas aspera for snakebite Phyllanthus niruri for jaundice Calotropis for gastric troubles Argemona mexicana for skin disorders Imperata cylindrical for thatching Cynodon for soil conservation.

Critical period of crop weed competition: It is the period of crop growth during which weeds cause great loss to the crop and this is the period during which the crop has to be maintained in a weed free environment.

Weed competition is severe in early stages of crop growth.

Principles of crop weed competition: Time of emergence of crop and weed. Type of weed species involved Weed number Weed weight. Pathogens like bacteria, fungi, virus are sprayed on weeds for their control. De vine. Many aquatic weeds are controlled by carp fish Grass carp, silver carp, common carp. Competitive plants Parthenium it controlled by Cassia sericea.

Dinozeb was the first chemical introduced in in India. Weedicides are effective and provide weed control from the very first day, safe to crops, cultural and mechanical methods can be avoided and perennial weeds can be controlled.

Herbicides Two types: Inorganic Ex: Organics Ex: Based on time of application herbicides are grouped as below: Pre-plant incorporation PPI 2. Pre-emergence 3. Wettable powder WP 2. Soluble powder SP 3. Emulsificable concentrate EC 4.

Sol concentrates SC 5. Granules GR 6. Based on methods: Foliage application 2. Blanket application 3. Direct spray 4. Protected spray 5. Spot treatment. Soil Application: Surface application Sub surface layering Broadcast and band placement Fumigation. Active ingredients ai Part of the formation i.

Of pdf principles agronomy

Herbicides carriers Water for spraying sand for broadcasting Herbicides are available with different trade names. Why herbicides are not popular in India.

Lot of human resource, available for work 2. Large area is rainfed where effectiveness is uncertain 3. Lack of awareness 4. Intercropping situations limited availability of selective herbicides for both the crops 5.

Small holdings with family labour. Irrigation is the artificial application of water to the soil to supplement the rainfall and groundwater contribution to assist the crop production. To supply the moisture essential for plant growth. For better utilization of production factors.

To provide crop insurance against short spells of drought. To soften tillage pans 6. Intensive cropping is made possible 7. Timely seedbed preparation and timely sowing. To create favorable microclimate for crop growth. Higher yields as well as stability in production. Method of irrigation Depending on soil type, slope, source of irrigation water, nature of crop methods differ. Surface methods of irrigation a. Sub- surface methods 3.

Sprinkler irrigation. Quantity of irrigation water depends on rooting depth and water holding capacity of soil. Irrigation water can be quantified through weirs, flumes, orifices, water meters etc. Removal of excess water from the surface or below the surface of the soil so as to create favourable conditions for plant growth. Causes of Water Logging 1. Intensive rains 2. Floods 3.

Soil slope 4. Bunds 5. Defective irrigation 6. Seepage from unlined canals. Effects of ill drained conditions 1. Lack of aeration of soil. Restricted root growth and lodging problems 3.

Difficulty in tillage. Increase in salinity in top layers of soil. All crops including rice require well drained conditions. Crops like maize mustard are very sensitive to water logging or ill drainage even for a short period. Mid season drainage is important in rice. Drainage can be surface drainage or Sub surface drainage.

Benefits of drainage 1. Helps in soil aeration 2. Facilitates timely tillage operations. Better and healthy root growth. Favours growth of soil microorganism better mineralization 5.

Warming up for optimum soil temperature maintenance. Promotes leaching and reduce water logging. Improves anchorage and reduce lodging. Improves soil structure and decreases soil erosion. Improves sanitary and health conditions and makes rural life happy.

It indicates the yearly sequence and spatial arrangement of crops and fallow in an area. Cropping System: It is an order in which the crops are cultivated on a piece of land over a fixed period of time.

Disadvantage in Monocropping Improper use of moisture and nutrients from the soil Control of crop associated pests and weeds become a problem. Crop rotation: It is a process of growing different crops in succession on a piece of land in a specific period of time with an object to get maximum profit from least investment without impairing soil fertility. Principles of crop rotation: The crops with tap roots should be followed by those which have a fibrous root system 2.

Leguminous crops should be grown after non leguminous crops. More exhaustive crops should be followed by less exhaustive crops. Selection of crops should be demand based.