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Edit Comment Close Premium member Presentation Transcript In-situ moisture conservation principle and practices: In -situ moisture conservation principle and practices Present by SWC C22 Watershed Management 2+1 1 V.MANIKANDAN; Bte-08-027 B.Tech( Agricultural Engineering ) College Of Agricultural Engineering, Tamil Nadu Agricultural University, Kumulur, Tiruchirapalli-621712Slide 2: SWC C22 Watershed Management 2+1 2Slide 3: Dryland Agriculture :- SWC C22 Watershed Management 2+1 3 Problems of Crop Production in Dryland Dry farming Technologies IN-SITU Moisture Conservation Techniques Drought ManagementIn-situ conservation: In-situ conservation The contour cultivation is the simplest method of in-situ conservation where each furrow will act as miniature reservoir to hold rain water. SWC C22 Watershed Management 2+1 4IN-SITU MOISTURE CONSERVATION TECHNIQUES: IN-SITU MOISTURE CONSERVATION TECHNIQUES Micro catchments. Broad beds and furrows. Contour bund SWC C22 Watershed Management 2+1 5Other methods : Other methods Contour wash stops, Stubble mulching, Broad bed and furrow system, Basin listing , tied ridging, Contour bunding, Contour trenching, Staggered trenching, Conservation ditching SWC C22 Watershed Management 2+1 6Micro catchments: Micro catchments -It is useful for insitu moisture conservation and erosion control for tree crops. -Micro catchments used for sloping lands. SWC C22 Watershed Management 2+1 7Micro catchments: Micro catchments SWC C22 Watershed Management 2+1 8Micro catchments: Micro catchments SWC C22 Watershed Management 2+1 9Micro catchments: Micro catchments SWC C22 Watershed Management 2+1 10Micro catchments Functions: Micro catchments Functions To conserve insitu moisture and reduce soil loss. Circular basin of one meter diameter for level lands depending upon infiltration and rainfall. ‘ V’ ditches of size 5m x 5m with trees planted centre and height according to the rainfall and slope of slopy lands. Saucer basins / semi circular bunds with 2m diameter to a height of 15-20cm across the slope. SWC C22 Watershed Management 2+1 11General information: General information Technique Storage capacity per unit (m3) Annual run-off contribution to soil moisture Additional water stored per ha (m3) Estimated surface Run-off control (%) Triangular catchments (V-Bunds) 13 5200 80 Crescent bunds 10.2 4080 73 Technique Cost/ha (Rs.) Triangular catchments (V-Bunds) 6000-7000 Crescent bunds 2500-3000 Cost :- SWC C22 Watershed Management 2+1 12Salient features: Salient features Slope ranges from 2 –8% Soil type – Light to moderate texture Insitu moisture conservation with staggered planting Suitable for dry land Horticulture & Agroforestry Bund height – 30 to 45 cm . SWC C22 Watershed Management 2+1 13Broad beds and Furrows: Broad beds and Furrows The broad bed and furrow system combines an element of erosion control with surface drainage . Normal bed width adopted is 150 cm with 30 cm wide furrows at the end of the beds . The broad beds and furrows have been found to be suitable for managing the deep black soils in India where surface drainage during the monsoon period is a problem. In INDIA where surface drainage during the monsoon period is a problem. SWC C22 Watershed Management 2+1 14Cont..: Cont.. The beds function as mini bunds at a grade and they help in reducing the velocity of surface runoff and increase the infiltration opportunity time. The excess water is removed through the furrows. SWC C22 Watershed Management 2+1 15Bed and furrow system: Bed and furrow system SWC C22 Watershed Management 2+1 16Bed and furrow system: Bed and furrow system SWC C22 Watershed Management 2+1 17 Bed FurrowBroad beds and Furrows: Broad beds and Furrows Function : To control erosion and to conserve soil moisture in the soil during rainy days General information : The broad bed and furrow system is laid within the field boundaries. The land levels taken and it is laid using either animal drawn or tractor drawn ridgers. Cost : Approximate cost for laying beds and furrows is Rs. 1000/- per ha. Salient features : Conserves soil moisture in dryland Controls sol erosion. Acts as a drainage channel during heavy rainy days. SWC C22 Watershed Management 2+1 18Contour bund: Contour bund Contour bunding is the construction of small bund across the slope of the land on a contour so that the long slope is cut into a series of small ones and each contour bund acts as a barrier to the flow of water, thus making the water to walk rather than run, at the same time impounding water against it for increasing soil moisture. Contour bunds divide the length of the slope, reduce the volume of runoff water, and thus preventing or minimizing the soil erosion SWC C22 Watershed Management 2+1 19Cont..: Cont.. Contour bunds are constructed in relatively low rainfall areas, having an annual rainfall of less than 600 mm, particularly in areas having light textured soils . For rolling and flatter lands having slopes from 2 to 6% contour bunding is practiced, in red soils. SWC C22 Watershed Management 2+1 20Slide 21: SWC C22 Watershed Management 2+1 21 Contour bundSlide 22: SWC C22 Watershed Management 2+1 22 Contour bundSlide 23: Contour bund Source: http://terra-agro.com/Company/bhj/images/wasteland1.jpg SWC C22 Watershed Management 2+1 23Contour bund: Contour bund Function : To intercept the runoff flowing down the slope by an embankment. General information : It helps to control runoff velocity. The embankment may be closed or open, surplus arrangements are provided whenever necessary. Cost : Approximate cost for laying contour bund is Rs. 1500/- per ha. Salient features : It can be adopted in light and medium textured soils. It can be laid upto 6% slopes. It helps to retain moisture in the field. SWC C22 Watershed Management 2+1 24Design parameters for contour bunds: Design parameters for contour bunds RAMSER’S FORMULA: V.I. = [(S/a) + b] x 0.3 where, V.I . = Vertical interval, m S = Slope of the field, %, a & b = Constants a = 3 for medium and heavy rainfall zones = 2 for low rain fall zones b = 2 Horizontal interval (H.I.) = 100 x V.I./ S SWC C22 Watershed Management 2+1 25Slide 26: Length of contour bund / ha = = 100 x 30 % total length is added for Lateral and side bunds Total volume of earth work = 1.3 x 100 x x A Total area lost/ha due to bunding = 1.3 x 100 x x W Where , A = Area of cross section of the bund, m 2 W = Bottom width of the bund, m SWC C22 Watershed Management 2+1 26Slide 27: Depth of water impounding on the u/s of bund Where , RF = Maximum rain fall in mm The height of the bund = 1.2 h including 20% free board . = h = √ (V.I.)(RF)/500 } SWC C22 Watershed Management 2+1 27Specification for bund cross section : Specification for bund cross section Depth of soil (m) Base width (m) Top width (m) Height (m) Side slope (m) Area cross section (sq.m) Shallow soils (7.5 – 22.5 cm) 2.67 0.38 0.75 1.5 : 1 1.14 Medium soil (22.5 – 45 cm) 3.12 0.60 0.85 1.5 : 1 1.56 Medium deep soils 4.25 0.60 0.90 2 : 1 2.18 SWC C22 Watershed Management 2+1 28In-Situ Moisture Conservation Techniques : In-Situ Moisture Conservation Techniques Soil Type Rainfall In-Situ Moisture Conservation Techniques Red soil Low Dead furrow at 3-6 m interval Medium Sowing on flat bed and riding later with eventual cultivation High Graded border strips Black soil Low Contour cultivation Medium Dead furrows at 3-6 m interval High Graded open furrow (0.2 to 0.3 m3) at 10 m interval across the slope SWC C22 Watershed Management 2+1 29OTHER METHODS : OTHER METHODS SWC C22 Watershed Management 2+1 30CONTOUR CULTIVATION : CONTOUR CULTIVATION This is nothing but the practice of ploughing, planting and cultivating across the slope mostly along the contour line. This practice of cultivation prevents the excess rain water from flowing freely and rapidly down the slope and eroding the soil particles badly. Every furrow acts as a miniature reservoir to hold the excess run off and supply back to the crops. This method of contour cultivation will be effective on lands with mild slope only (i.e. less than 2%). For lands with greater slopes, this has to be supplemented with other engineering measures. SWC C22 Watershed Management 2+1 31CONTOUR WASH STOPS: CONTOUR WASH STOPS This practice consists of providing thick rows of closely established tall growing or hedge plants along contour lines at regular intervals according to the nature of slope, rain fall and other conditions. varying from 15 m to 45 m horizontal or 1.2. m to 1.5 m vertical intervals Properly established wash stops at suitable intervals will not only afford effective resistance to flowing run off and retard the velocity of flow, but also screen off the silt washed down . SWC C22 Watershed Management 2+1 32STUBBLE MULCHING: STUBBLE MULCHING Stubble mulching is a crop and soil management practice that utilizes the residues of the preceding crop by leaving a large percentage of this vegetative residue on or near surface of the ground. SWC C22 Watershed Management 2+1 33Slide 34: SWC C22 Watershed Management 2+1 34Slide 35: SWC C22 Watershed Management 2+1 35Slide 36: SWC C22 Watershed Management 2+1 36 Stubble mulching to reduce soil erosion.Stubble mulching benefits: Stubble mulching benefits The mulch breaks the fall of the rain drops, thus dissipating their energy and reducing or eliminating their dispersing action on the structure of the soi1. i.e.: It prevents direct impact of rain drop on soil. The obstacles presented by leaves, stems and roots within the mulch impede the surface flow thus controlling sheet erosion. The mulch promotes infiltration through maintenance of an open soil structure. Improves organic matter content of the soil in long run practice . SWC C22 Watershed Management 2+1 37Random tie ridging : Random tie ridging Tied ridging consists of covering the land surface with closely spaced ridges in two directions at right angles so that a series of small rectangular basins are formed. Tied ridging is found to be successful on permeable soils rather than on shallow soils. It is also advisable to back up the system with other measures like terraces or ground bunds. SWC C22 Watershed Management 2+1 38Slide 39: SWC C22 Watershed Management 2+1 39 Random tie ridgingGRADED BUNDING: GRADED BUNDING Medium sized bunds built with 0.1 to 0.5% along contour Suitable for low permeable soils Suitable for land slope of 2 - 8% Aimed at removing excess rain water to safe drains Suitable for > 600 mm annual rain fall area SWC C22 Watershed Management 2+1 40Slide 41: The spacing between two graded bunds is based on the formula V.I. = [(S/a) + b] x 0.3 where, V.I. = Vertical interval, m S = Slope of the field, %, a & b = Constants a = 3 to 4 b = 2 For graded bonds, the horizontal interval, length per hectare and cost estimation is similar as that of contour bunding. SWC C22 Watershed Management 2+1 41CONSERVATION DITCHING: CONSERVATION DITCHING It is an alternate technique for graded bunding in black soil areas by the ICAR Research Institute, Bellary. Instead of constructing graded bunds to dispose off the excess rain water safely, the rain water is harvested and stored in wider ditches dugout in place of graded bunds SWC C22 Watershed Management 2+1 42Slide 43: The rain water is harvested and stored in wider ditches dugout in place of graded bunds. The water thus harvested is proposed to be utilised for providing one or two supplemental irrigation to the crop raised between the ditches at critical stages ensuring a better harvest. The bed width of the ditch was 61 cm and the depth was also 61 cm. The ditch was provided with an upstream side slope of 5:1 and a down stream slope of 1.5:1. SWC C22 Watershed Management 2+1 43 Cont..CONTOUR TRENCH: CONTOUR TRENCH Contour trenching consists of trenches excavated along a uniform level across the slope of the land in the top portion of catchments . The main idea is to create more favorable moisture conditions and thus accelerate the growth of planted trees. SWC C22 Watershed Management 2+1 44Slide 45: Trenches are not more than 15 m long and are generally staggered. In the cross section they rarely exceed 0.3 m x 0.3 m, the object being merely to fix sufficient moisture in the soil to enable the berms to be re-vegetated. Side slopes of the trenches are 1: 1 or 0.5: 1, according to the nature of soil. SWC C22 Watershed Management 2+1 45GRADED TRENCHING: GRADED TRENCHING The trenches are limited in length to about 450 m, starting from the end farthest from the outlet, trenches run level for 90 to 120 m, than on a gradient increasing from 1 in 500 to 1 in 300 at the outlet. The bunds or equalizers in the trenches are left closer at about 3 to 4.5 m apart. SWC C22 Watershed Management 2+1 46Slide 47: SWC C22 Watershed Management 2+1 47 Slope (%) V.I (m) Gentle slopes 5-10 13.5-19.5 Medium slopes 10-25 6-13.5 Steep slopes >25 1.25 m The trenches are located as below according to slopes:Slide 48: SWC C22 Watershed Management 2+1 48 In Tamilnadu contour and staggered trenches are adopted in high rainfall hilly areas of lands with slopes steeper than 3%, or any slope with badly eroded soil. Instead of contour trenching, graded contour trenches (modified American types) have been suggested. The trenches are limited in length to about 450 m, starting from the end farthest from the outlet, trenches run level for 90 to 120 m, than on a gradient increasing from 1 in 500 to 1 in 300 at the outlet. The bunds or equalisers in the trenches are left closer at about 3 to 4.5 m apart.Situations for various bunding options: Situations for various bunding options Bunding options Soil type Rainfall (mm) Slope (%) Contour bund Light soil <600 >1.5 Graded bund All soils >600 1.5 Bench terraces Deep soil >1000 6.0 Graded boarder strip Deep alfisol and related red soil >800 >1.5 SWC C22 Watershed Management 2+1 49IMPROVING SOIL MOISTURE STORAGE: IMPROVING SOIL MOISTURE STORAGE Addition of silt, clay, organic matter etc., Increases field capacity and also raises wilting point to marginal increase in available moisture holding capacity. SWC C22 Watershed Management 2+1 50Reference:-: Reference:- http:// agritech.tnau.ac.in/agriculture/agri_majorareas_watershed_watershedmgt.html http :// dolr.nic.in/dpap.htm http:// agricoop.nic.in/guide.htm http://dolr.nic.in/iwdp1.htm http://agri.ap.nic.in/rvp.html SWC C22 Watershed Management 2+1 51Slide 52: SWC C22 Watershed Management 2+1 52 Thank you You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.