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target. Management of water based on the soil and crop environment to obtain better yield by efficient use of IRRIGATION AND WATER MANAGEMENT 345 water without any damage to the environment. Management of water, soil, plants, irrigation structure, irrigation reservoirs, environment, social set up and it’s inter liked r... | Agricultural_studies.pdf | Agri life sciences |
and how much to irrigate?) based on soil types, climatic parameters, crop, varieties, growth stages, season, quality of water, uptake pattern of water by plants, etc., and method of application (How best to irrigate) includes conveyance of water without seepage and percolation losses and water movement in soil, are the... | Agricultural_studies.pdf | Agri life sciences |
irrigation water in crops Avoid excess or insufficient water to the crops. Excess irrigation leads to wastage of large amount of water, leaching of plant nutrients, destruction of beneficial microbes, increase of expenses on drainage, accumulation of salt leading to salinity and alkalinity, water-logging leading to phy... | Agricultural_studies.pdf | Agri life sciences |
so as to maintain the crop without any water stress before it starts to wilt. • Intensity should be low enough to suit the soil absorption capacity. Indian rainfall does not have the above good characteristics to maintain the crop through rainfall alone. The following are the characteristic features of Indian rainfall.... | Agricultural_studies.pdf | Agri life sciences |
better crop planning and to sustain crop production. IRRIGATION AND WATER MANAGEMENT 347 (b) Seasons The seasons of rainfall are discussed in detail in chapter IV. 11.2.2 Sub Surface Water It includes subsurface water contribution, underground water, well water, etc. 11.3 HISTORY AND STATISTICS Irrigation has been prac... | Agricultural_studies.pdf | Agri life sciences |
and Periyar dams are the great irrigation structures built by the British rulers. After independence, Irrigation activities have been accelerated and number of multipurpose river valley projects like Bhakra-nangal in Punjab, Tungabhadra in Andhra Pradesh, Damodar Valley in Madhya Pradesh were established. A. Irrigation... | Agricultural_studies.pdf | Agri life sciences |
Nagarjuna sagar (Krishna) Bihar Gandaka Punjab Western Jamuna, Bhakranangal, Sutlej, Beas Gujarat Kakrapare–Tapti Narmada Madhya Pradesh Gandhi sagar (Chambal, Ranap setab, Sagar) Maharashtra Bhima Jayakwadi (Godavari) Kerala Kalada, Mullai Periyar Karnataka Ghataprabha, Malaprapha and Turga Orissa Hirkund and Mahanadi... | Agricultural_studies.pdf | Agri life sciences |
m.ha. meter soaks or infiltrates into the soil profile. E. Surface run-off Surface run off consists of direct run off from rainfall, melting of snowfall and flow in streams generated from ground water. Total surface run-off has been estimated by Irrigation Commission of India in 1972 as follows: Total surface run off 1... | Agricultural_studies.pdf | Agri life sciences |
Net area irrigated = 31.20 m.ha. Gross area sown = 164.00 m.ha. Gross area irrigated = 80.50 m.ha. G. Land Utilization Pattern in Tamil Nadu Total geographical area = 13.00 m.ha. Area under forest = 2.00 m.ha. Non agricultural area = 1.40 m.ha. Barren and uncultivated = 0.80 m.ha. Pastures = 0.20 m.ha. Tree = 0.20 m.ha... | Agricultural_studies.pdf | Agri life sciences |
made through more than 215 major irrigation projects, 900 medium irrigation projects and many number of minor irrigation projects which consume a yearly outlay of Rs. 25,000–Rs. 35,000 crores in the National budget. After the completion of VI five-year plan we could achieve irrigation potential at the rate of 2.2 m.ha.... | Agricultural_studies.pdf | Agri life sciences |
parts. This requirement is applied either naturally by precipitation or artificially by irrigation. Hence the crop water requirement includes all losses like: • Transpiration loss through leaves (T). • Evaporation loss through soil surface in cropped area (E). • Amount of water used by plants (WP) for its metabolic act... | Agricultural_studies.pdf | Agri life sciences |
WR = ET or Cu + application loss + water for special needs. It can also be stated based on supply source as follows: WR = IR + ER + S Where, IR Irrigation requirement ER Effective rainfall S Contribution from groundwater table. Hence, the idea about crop water requirement is essential for farm planning with respect to ... | Agricultural_studies.pdf | Agri life sciences |
process by which water in the form of vapour is transferred from the underlying surface to the atmosphere. The essential requirement for evaporation process are: • Source of heat energy to vaporize the irrigated water. • The presence of a concentration gradient of water vapour between the evaporating surface and surrou... | Agricultural_studies.pdf | Agri life sciences |
Hook gauge or a fixed scale attached to a stilling well. The pan is covered with a mesh to prevent animals’ and bird’s disturbances to the water. Evaporation is recorded at a fixed time in the still well by adding water in the evaporimeter to compensate the daily loss of water by evaporation. Evaporimeter is to be clea... | Agricultural_studies.pdf | Agri life sciences |
leaves. The rate of transpiration depends on: • Supply of energy to vapourise the water, and • The water vapour concentration gradient at atmosphere. It is further influenced by the climatic, soil and plant factors. Climatic factors Light intensity, temperature and wind. Soil factors Texture, infiltration rate, water h... | Agricultural_studies.pdf | Agri life sciences |
low value and approaches its maximum. • Maximum Vegetative phase ET or CU rate is maximum if abundant soil moisture is available. • Maturity phase ET or CU rate begins to decrease. • Rooting characters of crop plants. • Environment. If the surrounding lands are barren, ET or CU will be more than the cropped area, which... | Agricultural_studies.pdf | Agri life sciences |
The Kp values for different agro climatic conditions have been already standardized (Refer-Table 18. From FAO Irrigation and Drainage paper 24). For our condition, 0.8 can be taken as Kp value. (a) Selection of crop coefficient for estimating ET The value of ET need to be adjusted for actual crop ET, since under natura... | Agricultural_studies.pdf | Agri life sciences |
use values are required to evaluate and determine the seasonal irrigation water supplies. (c) Peak period consumptive use The highest consumptive use for certain period in the growth season is called the peak period consumptive use. This value is used in the planning and designing of irrigation system. The peak period ... | Agricultural_studies.pdf | Agri life sciences |
climatic factors. Fig. 11.1 Schematic diagram of mechanical weighing lysimeter 1. Retaining tank, 2. Lysimeter tank, 3. Perforated plate, 4. Platform, 5, 8, 9 Balance, 6. Dummy tank, 7. Pipe to remove percolated water, 10. Foundation) Important precautions The soil condition inside the lysimeter must be similar to that... | Agricultural_studies.pdf | Agri life sciences |
of irrigation water, the effective rainfall received during the season and the contribution of moisture from the soil. 1 100 n i Mbi Mei WR IR ER AiDi = − ⎡ ⎤ = + + ⎢ ⎥ ⎣ ⎦ ∑ Where, WR – Water requirement in mm. IR – Total irrigation water applied in mm. ER – Seasonal effective rainfall contribution in mm. Mbi – Moistu... | Agricultural_studies.pdf | Agri life sciences |
season at ith layer of soil. Ai – Apparent specific gravity of the soil at ith layer. Di – Depth of soil at ith layer unit. n – Number of layers in the soil. Disadvantages It does not provide information on intermediate soil moisture condition, short term use, deep percolation losses and peak use rate of the crop. 4. W... | Agricultural_studies.pdf | Agri life sciences |
to the difference between the sum of all gains and sum of all losses and is represented by the hydrological equation. Change in storage = Gain – loss (P + I + GW) – (ET + R + D) Where, P = Precipitation I = Irrigation GW = Ground water contribution ET = Evapotranspiration R = Ruff off loss D = Deep percolation loss P =... | Agricultural_studies.pdf | Agri life sciences |
mm cotton and perennial red gram. Very High ranging from 1000-2250 mm rice, sugarcane, banana and plantation crops. 358 A TEXTBOOK OF AGRONOMY (f) WR range for different crops Crop WR (mm) Rice 1200–1400 Maize 400–550 Sorghum 400–550 Wheat 450–550 Ragi 350–550 Pulses 350–450 Groundnut 350–650 Sunflower 300–500 Cotton 6... | Agricultural_studies.pdf | Agri life sciences |
to field capacity, which in turn meet the ET demand of the crop. It is the difference between the F.C. and the soil moisture content in the root zone before starting irrigation. 1 100 n i Mfci Mbi d AiDi = − =∑ Where, IRRIGATION AND WATER MANAGEMENT 359 d – Net irrigation water to be applied (cm) Mfci – Moisture conten... | Agricultural_studies.pdf | Agri life sciences |
given at about 50 per cent and not over 60 per cent depletion of the available moisture from the effective root zone in which most of the roots are concentrated. In designing irrigation system, the irrigation frequency to be used is the time (days) between two irrigations in the period of highest consumptive use of cro... | Agricultural_studies.pdf | Agri life sciences |
broadly divided into three phases namely: Vegetative phase (a) Crop establishment (first two or three weeks) (b) Crop development (two to six weeks) 360 A TEXTBOOK OF AGRONOMY Reproductive phase (a) Flowering stage (b) Fruiting stage Maturity phase (a) Enlargement (b) Ripening (c) Harvest The entire reproductive and fl... | Agricultural_studies.pdf | Agri life sciences |
rain which reaches the storage reservoir is the effective portion. To a hydro electrical engineer, the rainfall which is useful for running the turbines that generate electricity is effective. To an agriculturist, the portion of total rainfall that directly satisfies crop water needs and also the surface run off which ... | Agricultural_studies.pdf | Agri life sciences |
Management practices Bunding, terracing, contour tillage, ridging, mulching, etc., reduce the run off and increases the effectiveness of rainfall. Crop characteristics Crop with high water consumption creates greater deficits of moisture in the soil. The effective rainfall is directly proportional to the rate of water ... | Agricultural_studies.pdf | Agri life sciences |
the water is applied to the cropped field without much application and other losses, with an objective of applying water effectively to facilitate better environment for crop growth. 11.7.1 Factors Influencing Irrigation Methods Soil type The soil physical properties such as texture, structure, porosity, infiltration r... | Agricultural_studies.pdf | Agri life sciences |
the methods of irrigation to be adopted. Crops to be grown The value of the plant and geometry of the crop to be cultivated are the main criteria to decide the method of irrigation. For example, if the crop is a high value or cash crop or wide spaced crop, sprinkler or drip method of irrigation cab be adopted. Irrigati... | Agricultural_studies.pdf | Agri life sciences |
levees or dykes along both sides of the strips. The end along the strip may or may not be closed, which is based on the length of the strips. If the length of the strip is very long, the end will be closed to have a uniform distribution and to avoid run off loss. Each strip is irrigated independently from upper end (tu... | Agricultural_studies.pdf | Agri life sciences |
0.25 to 0.60 Medium loam soil 10.0–18.0 m 0.20 to 0.40 Clay loam to clay soil 15.0–30.0 m 0.05 to 0.20 (c) ClassificationIt can be further classified as: (1) Graded borders, (2) Level borders. Graded borders have slope ranging from 0.1–0.5% in the longitudinal directions and there is no or very little slope across the ... | Agricultural_studies.pdf | Agri life sciences |
there is no run off. • Leaching of salt is possible by impounding water and giving more opportunity/time for infiltration, stagnation and drainage. • Suitable to lands with smooth, gentle and uniform slope with low to medium infiltration rate. Crops Cereals, millets, pulses, oilseeds. (b) Disadvantages • It needs high ... | Agricultural_studies.pdf | Agri life sciences |
to the basins is small, required depth of the irrigation application is small and field preparation is done by hand or animal drawn implements. Check Basins can be large if the slope of the land is gentle flat, soil is clayey, stream size is large, required depth of the irrigation application is large and field prepara... | Agricultural_studies.pdf | Agri life sciences |
The rings between trees are interlinked with main lead channel by sub channels to get water to the individual rings. As water is allowed in rings only, wastage of water spreading the whole interspaces of trees as in the usual flooding irrigation method is reduced. Weed growth in the interspaces around the rings are dis... | Agricultural_studies.pdf | Agri life sciences |
soil, this method is not suitable because here the water movement is primarily downward and very little in horizontal direction. Besides, the length of ridges or furrows to resist the velocity of flow is very low which in turn may lead to breaching of the structures. This method is adopted for soils having the problem ... | Agricultural_studies.pdf | Agri life sciences |
are adapted to this method. Light soil can be irrigated successfully across slopes up to 5% slope. Up to 8-10% can be irrigated by contour furrow. Contour furrow may be used on all types of soil except in light sandy soil and soil that crack. Corrugation irrigation It consists of running water in small furrows, which d... | Agricultural_studies.pdf | Agri life sciences |
zone of crop to replenish soil moisture immediately. (ii) Furrow length Optimum length furrow is usually the longest furrow that can be efficiently and safely irrigated. Long furrows are an advantage in inter cultivation. Proper furrow length depends largely on hydraulic conductivity of soil. It should be shorter in po... | Agricultural_studies.pdf | Agri life sciences |
Surge irrigation is a method of surface irrigation through furrows or border strips wherein water is applied intermittently in a series of relatively short on and off time periods during the irrigation (Humphrey, 1989). Water is let into a long furrows or border strips in an intermittent flow instead of conventional co... | Agricultural_studies.pdf | Agri life sciences |
the second surge length. Thus in surge flow, the advancing water along the furrow is faster resulting in uniform wetting from the head to the tail end of furrow. Under the conventional continuous flow, wetting is more in head end than at tail end. When more water is allowed to increase the wetting depth in the tail end... | Agricultural_studies.pdf | Agri life sciences |
Tail end water loss may increase if not managed properly • Lengthy furrows of more than 100 m are required • Ensuring proper gradient to such lengthy furrows is difficult • With progress in surge cycles and number of irrigations, the bulk density is increased due to soil consolidation • More suited to shallow rooted cr... | Agricultural_studies.pdf | Agri life sciences |
methods where water is applied through network of pipelines by means of pressure devices. 1. Sprinkler irrigation system/point source method In this method the irrigation water is sprayed to the air and allowed to fall on-the ground surface more or less resembling rainfall. The sprinkling of water or spray of water is ... | Agricultural_studies.pdf | Agri life sciences |
crust soil, it facilitates early germination and establishment by means of light and frequent irrigation. • Wastage of land for basin, ridges and furrows and irrigation channels are reduced. Sprinkler head Riser pipe End plug Second lateral position First lateral position Tee coupling Debris screen Pressure gauge Gate ... | Agricultural_studies.pdf | Agri life sciences |
spring. The water ejected through the nozzle strike the metal ring which changes its direction by the help of the spring attached to this which in turn causes the spray of water in all directions. The whole sprinkler Fig. 11.9 Twin nozzle rotating type sprinkler head Spring terminal Wear washer Oscillating arm spring O... | Agricultural_studies.pdf | Agri life sciences |
by pressure–nozzle size relation, sprinkler spacing and wind condition. Sprinkler selection and spacing The choice depends on diameter of coverage required, pressure available and discharge of sprinkler. The data given in tables 1 and 2 may serve as guidance in selecting the pressure and spacing desired. Table 11.6. Ma... | Agricultural_studies.pdf | Agri life sciences |
Normal Permanent Small over Low Inter High of under free under free over head head system pressure mediate pressure sprinkler sprinkler sprinkler system system pressure system system system system Pressure 0.7-1.0 1.0-2.5 3.5-4.5 2.5-4 1.5-2.5 2.5-5 5-10 range (kg/cm2) Sprinkler 0.06-0.25 0.06-0.25 0.2-0.6 0.6-2.0 0.3-... | Agricultural_studies.pdf | Agri life sciences |
following equation R = 1.35 dh R = Radius of wetted area (m) d = Diameter of nozzle h = pressure head at nozzle (m) Design of sprinkler systems A sprinkler system is designed in order to achieve high efficiency in its performance and economy. The informations needed for designing sprinkler system are: • map of area • w... | Agricultural_studies.pdf | Agri life sciences |
large area can be irrigated by using few skilled operators. They are more expensive initially because of extra pipes, sprinklers and fittings required but, savings can be made because of reduced labour. It is suitable for automation irrigation system and areas where labour is difficult to obtain. Fertilizer application... | Agricultural_studies.pdf | Agri life sciences |
Sub main If the area is larger, the sub mains are used to take water from main pipes to field which is normally having an inner diameter of 37 mm. Laterals These pipelines are normally having lesser diameter than mains and sub mains usually of 12 mm made of black poly alkathene pipes which deliver water from main or su... | Agricultural_studies.pdf | Agri life sciences |
hence plants do not suffer for want of water. • There is no seepage or percolation or evaporation losses. • Weed growth is restricted due to limited area of wetting zone. • Fertilizers (fertigation), chemical like pesticides (chemigation) and herbicide (herbigation) can be applied through irrigation. Hence, saving of i... | Agricultural_studies.pdf | Agri life sciences |
artificial rain. It offers a number of benefits to the farmer. It reduces water consumption by 50 per cent as compared to flood irrigation in achieving the same yield. As a result of the reduced water consumption with the raingun irrigation system, large savings accrue. Irrigation time comes down (60 percent time is sa... | Agricultural_studies.pdf | Agri life sciences |
it can also be applied with excellent results to a number of other crops such as groundnut, tapioca, onion, potato, maize and forage crops etc. Permanent system In permanent system of installation raingun riser stands are permanently fitted to solid set pipeline network. Riser can also be supported by cement concrete b... | Agricultural_studies.pdf | Agri life sciences |
• Lift irrigation 11.8.1 Gravity Irrigation Here water is supplied to the land by gravitational flow. There are two types namely (i) Perennial, (ii) Inundation. (i) Perennial In this system, water is assured throughout the crop period from the reservoir. This may be either direct or indirect irrigation. In direct irrig... | Agricultural_studies.pdf | Agri life sciences |
(b) Non-system tanks The Non-system tanks depend upon rainfall in their catchment area and do not have any link to river system to get water. 378 A TEXTBOOK OF AGRONOMY 11.8.3 Lift Irrigation In this system, water is lifted from a reservoir or river or canal or well by using mechanical or electrical power to irrigate t... | Agricultural_studies.pdf | Agri life sciences |
B. Velocity area method This method is used to determine the discharge rate in a pipe or open channel by multiplying the crosssectional area of flow at right angles to the direction of flow by the average velocity of water. Rate of flow/Discharge rate = Area (a) × velocity (v) (in m3/sec) a = Area of cross-section of a... | Agricultural_studies.pdf | Agri life sciences |
of channel (m) Velocity 0.85 m sec Average time taken by float (sec) = × = The average velocity is calculated by multiplying a co-efficient factor (0.85) as above. The flow rate of the water is worked out using the formula Q = a × v Rate of flow (Q) = average velocity × cross sectional area of the channel. (b) Using cu... | Agricultural_studies.pdf | Agri life sciences |
are: (1) Weirs/notches, (2) flumes, (3) orifices, and (4) pipes and siphon tubes. These devices are used to measure the rate of flow commonly read, on a scale and computing the discharge of flow from standard formula or table. Water measuring devices (i) Weirs (ii) Flumes (iii) Orifices (iv) Pipes and Siphon tubes 1. T... | Agricultural_studies.pdf | Agri life sciences |
weir should not be less than 5 mm and not more than two thirds of the crest width. • Measurement should be made using a scale located at a distance of about four times the head. Limitations • Not accurate unless measurements are properly maintained • Require considerable loss of head • Not easily combined with turn out... | Agricultural_studies.pdf | Agri life sciences |
rectangular weirs may be computed from the Francis formula Contracted rectangular weir Q = 0.0184 (L-0.1H)3/2 (one end contraction) Contracted rectangular weir Q = 0.0184 (L-0.2H)3/2 (two end contraction) Contracted rectangular weir Q = 0.0184 LH3/2 (no end contraction) Where, Q = Discharge (lit/sec) L = length of cres... | Agricultural_studies.pdf | Agri life sciences |
flowing water does not affect operation or accuracy. It gives reasonably accurate measurement even when partially submerged. The flumes of 7.5, 15, 23 and 30 cm sizes are generally used in field measurements. 10 cm 30 cm 42 cm Straight edges Bevelled edge 12 Gauge M.S. sheet 45 to 60 cm 50 to 80 cm 6 mm dia. holes spac... | Agricultural_studies.pdf | Agri life sciences |
will operate under submergence than rectangular shaped ones without correction being necessary to determine the exact relationship. • Extreme approach conditions and sediments deposited in the approach does not affect the head discharge relationships. • The trapezoidal shape fits the common canal section more closely t... | Agricultural_studies.pdf | Agri life sciences |
pipe can be used to estimate the discharge. Such a procedure is rapid, inexpensive and convenient. Measurement is made for the x and y coordinates, where x is measured parallel to the pipe and y is measured vertically. Horizontal measurement of the jet (x) is measured from the end of the pipe to the centre of the jet i... | Agricultural_studies.pdf | Agri life sciences |
less than 0.37 dp., where dp is the inside diameter of the pipe, then flow is sub critical. When the jet height exceeds 1.4 dp, water discharges from the pipe with supercritical flow in jet flow. The discharge from a vertical pipe can be estimated using the equation given by Lawrence and Brawnworth in metric system as ... | Agricultural_studies.pdf | Agri life sciences |
method Tracer methods of water measurement are independent of stream cross-section and are suitable for field measurements without installing fixed structures. In these methods, a tracer substance in concentrated form is introduced into the flowing water and allowed to mix thoroughly. The concentration of the tracer is... | Agricultural_studies.pdf | Agri life sciences |
how much of water to apply? Both criteria influence the quantity and quality of the crop. It indicates how much of irrigation water to be used and how often, it has to be given. Excess irrigation is harmful because: • it wastes water below root zone • it results in loss of fertilizers nutrients • it causes water stagna... | Agricultural_studies.pdf | Agri life sciences |
is 6 mm per day, it means every day we have to give 6 mm of water to the crop. Practically it is not possible since it is time consuming and laborious. Hence, it is necessary to schedule the water supply by means of some time intervals and quantity. For example the water requirement of 6 mm/day can be scheduled as 24 m... | Agricultural_studies.pdf | Agri life sciences |
through deep percolation. Irrigation methods Basin method allows more infiltration through more wetting surface which in turn needs more water and long interval in irrigation frequency. Furrow method allows less infiltration due to less wetting surface which needs less water and short interval in irrigation frequency. ... | Agricultural_studies.pdf | Agri life sciences |
different time intervals fixed arbitrarily are tried without considering the soil and weather characters. The irrigation treatment which gives the maximum yield with minimum depth and extended interval is chosen as the best irrigation schedule. Earlier workers have adopted this practice to work out the duty of water fo... | Agricultural_studies.pdf | Agri life sciences |
crops can be indexed as: IRRIGATION AND WATER MANAGEMENT 389 Low Low to Medium Medium to high High cassava alfalfa beans banana millets cotton citrus cabbage red gram maize soybean fresh green vegetables groundnut wheat rice, sugarcane sunflower tomato (d) Plant observation method Normally in field condition, farmers u... | Agricultural_studies.pdf | Agri life sciences |
main field. Normally the field soil is mixed with sand in 1:2 ratio and refilled in the micro plots made in the field. The seed of the same crop and variety is grown in micro plot with all similar cultural practice as that of the main crop. The crops in micro plot show early stress symptoms than that of main field. Bas... | Agricultural_studies.pdf | Agri life sciences |
harvesting except for vegetables like Lettuce, Cabbage etc., which need water up to harvesting. Under scarce condition, in an irrigation project or in a farm, if mono cropping is followed with staggered sowing or planting, it is better to schedule irrigation to crop which has reached mid season stage since it is the mo... | Agricultural_studies.pdf | Agri life sciences |
– Flowering, fruit setting and enlargement Mango – Flowering Coffee – Flowering and fruit development At critical stages, favourable water level should be ensured through timely irrigations. IRRIGATION AND WATER MANAGEMENT 391 (b) Meteorological approach/Climatological approach The basic principles employed with this a... | Agricultural_studies.pdf | Agri life sciences |
will give the cumulative pan evaporation value at which irrigation is to be made i.e., IW/R = CPE. For example, the irrigation depth (IW) needed is 50 mm and the ratio (R) to be tried is 0.5, therefore, the Cumulative Pan evaporation value needed to irrigate the field is, IW/R = 50/0.5 = 100 mm If the 100 mm of CPE is ... | Agricultural_studies.pdf | Agri life sciences |
and less frequency (b) Climate: Climate is classified based on reference ET as follows: Reference ET 4-5 mm/day – Low 6-7 mm/day – Medium 8-9 mm/day – High Table 11.8. Reference ET (mm/day) for different Climatic Zones Climatic zone Mean daily temp. 15 oC 15–25oC > 25oC Low Medium High Desert/arid 4–6 7–8 9–10 Semi ari... | Agricultural_studies.pdf | Agri life sciences |
4 40 11 8 6 55 14 10 7 70 Wheat 8 6 4 40 11 8 6 55 14 10 7 70 Tomato 6 4 3 30 8 6 4 40 10 7 5 50 1* – Low temperature of 15°C, 2* – Medium temperature of 15 – 25°C, 3* – High temperature of > 25°C IRRIGATION AND WATER MANAGEMENT 393 Adjustment in this method for Non peak periods In early growth stages The irrigation co... | Agricultural_studies.pdf | Agri life sciences |
days or 42 mm for every 6 days. The 49 mm for every 7 days is the appropriate interval for local situation. Hence, this method of intervals for irrigation can be adopted. B. Simple calculation method It is based on the estimated depth of irrigation application and calculated irrigation need of the crop over growing sea... | Agricultural_studies.pdf | Agri life sciences |
complex components like supply system, soil, climatic condition; crop, cultural practices, crop responses and plant nutrient level are considered to work out the model. (d) Empirical methods Many empirical methods have been developed to estimate Evapotranspiration values of the crop. Among this, modified Penman, Blaney... | Agricultural_studies.pdf | Agri life sciences |
mean daily temperature in oC over the month considered P = mean daily percentage of total annual daytime hours IRRIGATION AND WATER MANAGEMENT 395 obtained from Table 1 for a given month and latitude (Refer: “Crop Water Requirement, FAO Irrigation and Drainage Paper No. 24”) c = adjustment factor which depends on minim... | Agricultural_studies.pdf | Agri life sciences |
With this value, the special water demand like pre plant irrigation, leaching requirement and economically unavoidable irrigation, application losses are to be added for scheduling irrigation. System as a whole approach Rotational water supply Rotational water supply is one of the techniques in irrigation water distrib... | Agricultural_studies.pdf | Agri life sciences |
to facilitate development of new roots. The same water level is required for tiller production during the vegetative phase. At the beginning of the maximum tillering stage, the entire water in the field can be drained and left as such for one or two days which is termed as mid season drainage. This mid season drainage ... | Agricultural_studies.pdf | Agri life sciences |
peg penetration and pod development stages. After the sowing irrigation, the second irrigation can be scheduled 25 days after sowing i.e., 4 or 6 days after first hand hoeing and thereafter irrigation interval of 15 days is maintained up to peak flowering. During the critical stages the interval may be 7–10 days depend... | Agricultural_studies.pdf | Agri life sciences |
grand growth period. Response for water is less in this stage and this will be still less in the ripening stage. During the ripening phase as harvest time approaches, soil moisture content should be allowed to decrease gradually so that growth of cane is checked and sucrose content is increased. 5. Maize Total water re... | Agricultural_studies.pdf | Agri life sciences |
thereby boll setting may be decreased. Irrigation is continued until the first boll of the last flush opens, and then irrigation is stopped. 7. Sorghum Total water requirement is 350–500 mm. The critical periods of water requirement are booting, flowering and dough stages. The crop will be irrigated immediately after s... | Agricultural_studies.pdf | Agri life sciences |
the filed (WR) Y FWUE and expressed as kg/mm/ha WR = (iii) Physiological water use efficiency (PWUE) The physiological WUE is calculated in terms of the amount of CO2 fixed per unit of water transpired Rate of photosynthesis PWUE . Rate of transpiration = (iv) Irrigation efficiencies of irrigation projects Many irrigat... | Agricultural_studies.pdf | Agri life sciences |
root zone moisture content up to field capacity is considered as efficient irrigation. If on the other hand, the amount of water applied grossly exceeds that actually needed for replenishment; the irrigator application efficiency is very low. To illustrate, consider a field, which needs 9 cm depth of water to bring the... | Agricultural_studies.pdf | Agri life sciences |
of the observed conveyance efficiencies are: Continuous supply with no substantial change in flow – 90% Rotational supply with no substantial change in rotation – 80%areas of 70–300 ha Rotational Supply in projects more than 7,000 ha and less than 10,000 ha without effective management and communication – 65%–70% netwo... | Agricultural_studies.pdf | Agri life sciences |
Integration of all water resources like surface, ground water, wastewater, snow, dew etc., is most important to achieve maximum food production per unit quantity of water used to meet the demand from 1 billion population present. In this juncture, water resources itself become a constraint due to abnormality in distrib... | Agricultural_studies.pdf | Agri life sciences |
them to realize that water is an economic input and conservation of water is their prime responsibility. Improvement in conveyance structure A large quantity is lost through conveyance from source to field. It is estimated that about 30-40% of water is lost in conveyance systems. Reducing or totally preventing such los... | Agricultural_studies.pdf | Agri life sciences |
6050 disappearance Water saving 47% – 30% – This finding is helpful not only for micro level alone but also to change the water release pattern at macro level too and a turn system can be adopted in canal operation system. Further investigation reveals that 2 days dry spell in light textured soil and 2–3 days dry spell... | Agricultural_studies.pdf | Agri life sciences |
water one day after the disappearance of ponded water can be adopted not only to save water but also to increase the yield to some extent. • Plastering field bunds and plugging of all crevices, rat and crab holes to avoid water loss through seepage. • Proper levelling of the field. • Water should be stopped 10–15 days ... | Agricultural_studies.pdf | Agri life sciences |
phase. • Trash mulching to a thickness of 10 cm uniformly 3 days after planting to tide over drought by moisture conservation and to reduce weed incidence. • Application of 2 to 3 per cent kaolin spray to mitigate the water loss through transpiration. • Alternate furrow irrigation: Irrigate alternate furrows in rotatio... | Agricultural_studies.pdf | Agri life sciences |
possible. 4. Other management techniques • Summer ploughing has to be done in large scale which is not only a water conservation method but also checks weed growth, facilitate easy puddling etc. • Strengthening of field bunds to minimize the water loss through leakages and to impound rainwater to increase the infiltrat... | Agricultural_studies.pdf | Agri life sciences |
main causes which lead to development of salty soils (Salinity or alkalinity). (i) Arid climate About 25% of earth surface is arid in which salt accumulation is a common problem. In India, about 25 m.ha are salt affected with different degrees of degradation. (ii) High subsoil water table When the water table is within... | Agricultural_studies.pdf | Agri life sciences |
Alkali/sodic > 15 < 4 > 8.5 404 A TEXTBOOK OF AGRONOMY Reclamation of saline soil Leaching or flushing with good quality of water provided, there should be good drainage system should be there to flush water. Reclamation of alkali soil By converting exchangeable sodium into soluble salts by adding the following amendme... | Agricultural_studies.pdf | Agri life sciences |
of amendments viz., gypsum and press mud is found to suppress the sodium and chromium content in plant and soil. • Growing resistant crops like ragi, cotton, barley and rice can be advocated. • Growing green manure crops like sunnhemp, daincha and kolinji can be advocated. • Growing resistant varieties like COC 771 in ... | Agricultural_studies.pdf | Agri life sciences |
wastes like crop residue, farm waste, coir pith, filter cake etc., at the rate of 20 tones per hectare once in every year can be applied. Poorly drained clay soils can be improved by providing tile drains and trenches intermittently. To make the soil more IRRIGATION AND WATER MANAGEMENT 405 permeable and to overcome po... | Agricultural_studies.pdf | Agri life sciences |
in the irrigation water is high, the salts will accumulate in the crop root zone and affect the crop growth and yield. Excess salt condition reduces uptake of water due to high concentration of soil solution. Permeability Some specific salts reduce the rate of infiltration into the soil profile. Toxicity When certain c... | Agricultural_studies.pdf | Agri life sciences |
Variable > 10 > 4 406 A TEXTBOOK OF AGRONOMY Majority of natural ground waters have pH between 7.2 and 8.5 and are either in equilibrium or even super saturated in respect of calcite and dolomite. Water with pH less than 7.2 seems to be unsaturated in respect of calcite. Water samples with pH > 8.4 invariably have SAR ... | Agricultural_studies.pdf | Agri life sciences |
pH, CO3, HCO3, Cl, SO4, Ca, Mg, Na and B). • Total concentration of soluble salts or salinity (EC). • Concentration of sodium ions, in proportion to calcium and magnesium or sodicity (SAR). • Trace element boron may be toxic to plant growth, if present in limits beyond permissible. • The effect of salt on crop growth i... | Agricultural_studies.pdf | Agri life sciences |
to ensure effective irrigation management for salt control are the water requirement of crop and quality of irrigation water. Correct irrigation should restore any soil water deficit to control salt levels. C. Use of poor quality water Besides the salinity and alkalinity hazard of water, some industrial effluents and s... | Agricultural_studies.pdf | Agri life sciences |
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