IN-SITU MOISTURE CONSERVATION TECHNIQUES
Cost
In-Situ Moisture Conservation Techniques
Micro catchments:
1. Functions
Function
- 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
Broad beds and furrows:
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.
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.
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. |
To intercept the runoff flowing down the slope by an embankment.
It helps to control runoff velocity. The embankment may be closed or open, surplus arrangements are provided whenever necessary.
Approximate cost for laying contour bund is Rs. 1500/- per ha.
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.
| 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 |
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 |
| 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 |
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.