Thursday, October 26, 2017

MULBERRY CULTIVATION (CONT...8) - IRRIGATION

Mulberry leaf production is often limited by the amount of available soil moisture and it can be substantially increased by supplemental irrigation. Since deficiencies of pre­ capitation often occur in the major mulberry growing tracts of the world, it is necessary to provide supplemental irrigation to maintain optimum soil moisture conditions

Irrigation in relation to soil: For efficient use of irrigation water, just enough water is to be applied to bring the moisture content of the soil in the root zone to its field capacity.

Appearance of mulberry crop: Mulberry plants with abundant supply of water are characterized by luxuriant growth, the foliage well developed and the leaves succulent and shiny.

Frequency of irrigation: Frequency of irrigation for the mulberry crop depends upon several factors such as growth phase of plant, soil type and other agro‑climatic conditions.

Quantity of water irrigated: The important considerations for the quantity of water to be irrigated is the root distribution pattern of plant, the climatic conditions and soil type. In order to provide effective irrigation, the following methods of soil moisture measurements are followed.
1.      Gravimetric method of determination of soil moisture;
2.      Using electronic properties of porous blocks;
3.      Use of Tensiometers;
4.      Neutron method of measuring soil moisture.

Interval between irrigation: When the mulberry plant is in the active growth phase, i.e. the sprouting and foliar developmental stages, the crop has to be irrigated frequently and plant growth takes place all the year round.

Quality of water: In addition to the quantity of water, quality of irrigation is also equally important. Normally irrigation water for mulberry should contain less than 1 000 PPM of total soluble salts.

Methods of irrigation: Of the different methods of irrigation adopted, the furrow, flat bed and basin methods are normally practiced.

Furrow method: In the furrow method the field is laid out into a series of ridges and furrows.

Flat bed method: The field is divided into rectangular beds with bunds all around and channels on the sides.

Basin method: The basin method is suitable mostly for tree plantations. In this system irrigation water from the supply source is lead into the basin around the trunk.

Overhead or sprinkler method: This method of irrigation can be practiced in undulating lands where low and high bushes are cultivated. The advantages are (i) most efficient in economizing water use; (ii) there is uniform distribution of water on the foliage; (iii) the percolation loss in porous and sandy soils is avoided; (iv) this is most suited for emergency irrigation; and (v) it can be followed with advantage on sloppy and shallow lands.

Influence on the leaf yield: Yield of mulberry leaves is strongly influenced by both quantity and quality of irrigation water. The increase in leaf yield due to irrigation when compared with rain fed cultivation. Added to this, the leaf production is increased three to four times when balanced fertilizers are applied at regular intervals in addition to irrigation.

Influence on quality of leaf:  The nutritive value of the leaves is determined by chemical estimation and feed values and as judged by the rearing performances, leaves obtained from irrigated mulberry possess more moisture and protein and are more nutritious than those from rain fed crops.

Provision for drainage: Provision of adequate drainage improves soil structure and its productivity. Under waterlogged conditions, the mulberry plants wilt under severe oxygen tension resulting in poor root respiration.

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