Which of the following methods of applying water may be used on rolling land
Boarder flooding: - The land is divided into a number of strips, separated by low levees called boardes.
If the electrical conductivity of water is in between 250 to 750 micro mhos/cm at 25 °C, then it is classified as
Electrical conductivity between 0 to 250 for low Salinity... 250 to 750 for medium... 750 to 2250 for high and more than 2250 for very high salinity
Sodium absorption ratio SAR is defined as
The value of sodium absorption ratio for high sodium water lies between
Optimum depth of kor watering for rice is
The first watering is known as kor watering and the depth applied is known as kor depth. The kor depth for rice is 190 mm.
Irrigation water having the concentration of Na++, Ca++ and Mg++ as 20, 3 and 1 milli equivalent per litre respectively will be classified as
The relation between duty D in hectares/cumec, depth of water Δ in metres and base period B in days is given by
Duty (D) : - duty is defined as the area of land expressed in hectares that can be irrigatedwith unit discharge, that is, 1 cumec flowing throughout the base period, expressed in days. Delta (Δ) : - Delta is the total depth of water required by a crop during entire period the crop is in the field. Base Period (B) : - when irrigation water is first issued for preparation of the ground for planting the crop to, its last watering before harvesting. Δ = 8.64B/D
The duty is largest
The “outlet discharge factor” is the duty at the head of
The kor depth for rice is 190 mm and kor periods is 14 days. The outlet factor for this will be
Δ = 8.64 B/D => D = 8.64x14x1000/190 = 637 hectares/m³/sec
For supplying water to Rabi crop, kharif crop and sugarcane, the channel is designed for a capacity equal to the greater of water requirement of
As sugercane need whole year supply. while rabi and kharif are seasonal
The ratio of the quantity of water stored in the root zone of the crops to the quantity of water actually delivered in the field is known as
In general, efficiency is the ratio of the water output to input. 1. Water conveyance efficiency: - Ratio of Water delivered to farm or irrigation plot to water supplied from river or reservoir. 2. Water application efficiency: - Ratio of water stored in root zone to water delivered to the farm. 3. Water use efficiency: - Ratio of water used consumptively to water delivered.
The water utilizable by plants is available in soils mainly in the form of
Water present in the soil may classified 1. Hygroscopic water: - When an oven dried sample is kept open in the atmosphere, it absorbs some amount of water from the atmosphere. This is known as hygroscopic water 2. Capillary water: - Excess of hygroscopic water which exists in the pore space of soil by molecular attraction. 3. Gravity water: - Excess of hygroscopic and capillary water which will move out of soil.
The amount of irrigation water required to meet the evapotranspiration needs of the crop during its full growth is called
Evapotranspiration rate is the amount of water that is lost to the atmosphere through the leaves of the plant, as well as the soil surface.
With the increase in the quantity of water supplied, the yield of most crops
The plant growth may be retarded if the soil moisture is either deficient or excessive. 1. If the soil moisture is only slightly more than the wilting coefficient, the plant must extend extra energy to obtain it, and the plant will not grow healthy # Wilting coefficient- That water content at which plants no longer extract sufficient water from the soil for its growth. 2. Similarly, excessive flooding fills the soil pores with water, thus driving out air. Since air is essential to satisfactory plant growth, excessive water supply retard plant growth.
Hydrograph is the graphical representation of
Runoffis that portion of precipitation that is not evaporated. Which ultimately runs to the ocean through surface or sub surface streams. 1. Surface runoff:-Water flows to land and is first to reach streams and rivers, which ultimately discharge the water to the sea. 2. Interflow or sub surface runoff: - A portion of precipitation infiltrates into surface soil and depending upon the geology of the basin runs as sub surface runoff and reaches the streams and rivers. 3. Ground water flow or base flow: - It is that portion of precipitation, which after infiltration, percolates down and join the ground water Reservoir which is ultimately connected to the ocean.
Infiltration rate is always
Infiltration: - Water moving through a soil surface. Infiltration rate: - That rate at which infiltration occurs, measured in mm/hour or a similar unit Infiltration capacity: -Maximum rate at which infiltration will occur.
The depth of water required to bring the soil moisture content of given soil upto it’s field capacity is called
Soil moisture deficiency:- The difference between the amount of water actually in the soil and the amount of water that the soil can hold. The amount of water the soil can hold is generally called field capacity.
Infiltration is the
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