Orchard Management (1+1)

EXERCISE 14

EXERCISE 14: LAYOUT OF IRRIGATION SYSTEMS IN FRUIT ORCHARDS-SURFACE IRRIGATION

Aim: The aim of irrigating a fruit should be to wet the entire root zone without substantial losses of water through seepage beyond root zone.

Irrigation is one of the most important aspects of orchard management. It is required to maintain sufficient moisture in soil for obtaining yield of good quality fruits. There are several methods of irrigations each having certain advantages and disadvantages. As fruit plants must be irrigated at frequent intervals throughout of their life span, the type of method planned for a particular orchard should be laid out immediately after planting

Procedures:
Check basin:

1. Prepare basins immediately after planting.
2. Make trenches between the rows of plants.
3. Join these trenches with tree basins (Fig. 14.1).
4. Make sure that irrigation water should not directly touch the trunk as there is a risk of disease infection. The basins should be made slopping downwards from the tree trunk. However, heaping of soil around the trunk should also be avoided as it keeps the wet soil in contact with scion portion leading to soil borne diseases like gummosis (citrus), and collar rot (apple).

Fig. 14.1 Check basin system of irrigation

Furrow method:
1. Prepare irrigation channel of 20 cm depth and 60 cm width in between the tree rows, however channel should be quite nearer to the tree rows.
2. In this system, the water moves slowly in furrows in the area between the rows. The trees are fed through the lateral movement of water.


Basin system.

In this system, basins around the trunk are linked directly with one another through strait channel (Fig. 14.2). This system is suitable for young fruit trees.

Fig. 14.2. Check basin system of irrigation

Modified basin system.

1. Prepare main channel in between the tree lines
2. Link each basin independently through small sub channels (Fig. 14.3).

Calculation of water requirement of fruit plant:

Water requirement of fruit plant can be calculating by employing evapo-transpiration technique. Under irrigation method, water is being replaced in the soil to compensate the loss. For this purpose, evapo-transpiration is calculated. The evapo-transpirational loss of water is treated as total water requirement of the plant. The requirement of water for a particular fruit crop is calculated by using the formula given below:

Water requirement (litres/day) = Pan evaporation (mm/day) x row to row spacing (m) X plant to plant spacing (m) x crop factor x Pan factor x percentage of wetted area.

Where;
Crop factor = 0.6
Pan factor = 0.7
Wetted area = 0.2-0.3

Suppose, if pan evaporation is 5 mm, row to row and plant to plant spacing is 6 meter, the water requirement would be then = 5x 6 x6 x 0.6 x 0.7 x 0.2 = 15.12 litres per day.

Observations to be recorded:

Record water evapo-transpiration loss in the orchard by pan evaporation and accordingly work out water requirements of different fruit crops under traditional methods of irrigation.