Application Of liquid fertilizers
It includes:
1. Starter solutions: Solutions of fertilizers, generally consisting of N-P2O5 – K2O in the ratio of 1:2:1 and 1:1:2 are applied to young vegetable plants at the time of transplanting. It helps in the rapid establishment of seedlings and quick early growth. Advantages:
i) The nutrients reach the plant roots immediately and
ii) The solution is sufficiently diluted so that it does not inhibit growth.
Disadvantages:
i) Extra labour is necessary and
ii) Fixation of phosphate is greater.
2. Foliar application: It refers to the spraying of leaves of growing plants with suitable fertilizers solutions. These solutions may be prepared in a low concentration to supply any one plant nutrients. It is preferable to soil application when:
i) The soil conditions or a competitive crop makes nutrients from soil dressing unavailable, like late application of N to crops raised under Rainfed condition,
ii) An accurately time response to fertilizers is required. E.g.: change in the reason,
iii) Routine applications are made of insecticidal or pesticidal sprays to which nutrients the crop prevents application of fertilizer to the soil but permits its application to the leaves from a high clearance sprayer or from a helicopter.
Difficulties (disadvantages) associated with this method are:
i) Leaf burn on scorching may occur, if strong solutions used.
ii) Small quantities of nutrients can be applied in one single spray due to low concentrations.
iii) Several applications are needed for moderate to high fertilizer doses, and
iv) Costly method than soil application.
3. Direct application to the soil: With the help of special equipment, anhydrous ammonia (a liquid under high pressure up to 200 PSI or more) and N solutions are directly applied to the soil. It allows direct utilization of the cheapest N source. Plant injury or wastage of ammonia is very little if the material is applied 10cm below the seed. Otherwise, the N from ammonia will be lost. If requires moisture content at field capacity and good soil tilth.
4. Application through irrigation water: Straight and mixed fertilizers containing N, P & K easily soluble in water, are allowed to dissolve in the irrigation stream. The nutrients are thus carried in solutions. This saves the application cost and allows the utilization of relatively in expensive soluble fertilizers, like N-ous fertilizers.