Time and frequency of fertilizer application
The efficiency of fertilizer usage depends on the time, frequency and method of application. Unless the fertilizers are applied at the right time in the right way the chances of losses are more. Fertilizers should be applied when there is sufficient moisture in the soil. However, heavy rainfall period should be avoided to minimize runoff and leaching losses. In the year of planting, fertilizer application is done 2-3 months after planting i.e. during September- October. In NE regions, if planting is done during April- May with polybag plants, the first round of application may be done two to three weeks after planting followed by the usual round in September-October. From second year onwards, the fertilizers should be applied in two equal splits during April- May (pre-monsoon) and September- October (post-monsoon) when there is enough moisture in the soil.
Method of application
The method of application depends on the stage of growth of the plants. Young plants have only very limited root system in the initial few years. During the first year, fertilizers should be evenly distributed over a circular band of 30 cm all around the base of young plant, leaving about 7 cm from the base and slightly forked into the top 5 to 8 cm of soil. The plant bases should then be immediately mulched. The second application (9 months after planting) should be done in a circular band of 45 cm width leaving 15 cm around the plant base. The applications in subsequent years till the canopy of the rubber plants closes should be made in circular bands of steadily increasing width. Once the canopy closes, 5 to 6 years after planting, fertilizers should be applied in square or rectangular patches in between four trees and gently forked in. Where legume cover is present or where it has died out leaving a thick mulch, broadcasting in the inter-row areas can be resorted to. Deep pocket placement of fertilizers and application too close to the base of the trees should be avoided.
NPK fertilizers |
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