Fertilization for the basic rubber plantations:
4.1. Inorganic fertilizers:
– Dose and type of fertilizer: the dosage and types of fertilizers according to the land grade and the prescribed tree age. If possible use NPK or mixed fertilizer instead of single fertilizer.
– If possible, apply fertilizer according to nutritional diagnosis.
– Fertilizer: Inorganic fertilizer is divided into 2 – 3 times in the year.
+ Year of new planting: the first application after planting a new month, the second application of the first time at least one month.
+ Second year onwards: Apply twice at the beginning of rainy season and before the end of rainy season at least 1 month.
– Time of fertilizing: Apply fertilizer when the soil is moist enough, do not fertilize at times of heavy rain and rainy season.
– How to apply: from the first year to the fourth year of the hoop or the hole around the root of the rubber in the shape of the foliage to fertilize, then fill the soil. From the end of the fourth year on, fertilize the 1.0 m wide band between two rows of rubber. The gardens have green and humus crushed holes and on sloping land> 10o, fertilizer must be applied to the hole. Before spreading the soil out of the hole, spread it in the hole and fill it with the plant residue in place.
Foliar fertilizers are used in the first two years of rubber plantation. Only foliar fertilizers in the list are allowed for use in rubber trees.
– Time of spraying: The first spraying after planting a month, after spraying 15 days apart. Only spray foliar fertilizer on days without rain and average outdoor temperature> 150C, spray from 7-10am.
– How to spray: adjust and maintain the spray always create spray mist, spray the top and bottom of the leaf at the recommended dose.
4.3. Apply organic fertilizer:
– Types of organic fertilizer that can be used on the basic rubber plantations include traditional organic fertilizers, organic compost and organic mineral fertilizers. These fertilizers must meet the standards of nutritional quality, hygiene and toxins as defined by. For micro-organic fertilizers, only use fertilizers in combination with inorganic fertilizers.
– It is recommended to add organic fertilizer for orchard to improve soil fertility, increase inorganic fertilizer efficiency when humus content is <2.5% or carbon content C% <1.45%. When organic content is high or for basic plantations using green squash, no compost is added.
– Organic fertilizers can not completely replace inorganic fertilizers. Therefore, when adding organic fertilizer, it is necessary to apply the equivalent amount of inorganic fertilizer as specified in.
– In the period from the closed orchard to the business stage, when adding organic fertilizer, apply to the humus pit or if there is no humus hole, buried carefully into the soil at the place of inorganic fertilizers.
– Do not allow the use of manure, uneconomic manure and industrial wastes, untreated processing plants in accordance with State regulations on rubber plantations.
– Do not apply fertilizers when the soil is inundated or partially flooded.
5. Trimming, creating canopy for basic construction rubber:
5.1. Planting shoots, horizontal shoots:
– After planting, shoots must be cut and propagated in a timely manner so that the buds are well-developed.
– Pruning, creating canopy: in the early years of basic construction, pruning, creating canopy at a height of 2.5 m – 3 m.
– In the first year only pruned shoots when the top layer is stable.
– From the second year, pruning should be done. On the top two leaves of the tree always leave 2 – 3 buds / floor development. Maintaining controlled pruning till the tree forms canopy.
5.2. Create canopy for basic construction rubber:
– Conditions for creating a canopy for basic construction: Unplaned orchards at an altitude of 3.0 m or higher in the third year, then cut tops to create canopy.
– Method of creating canopy:
For late branched branched shoots, cut tops at 3 m or more, cut positions are at the top leaf layer and leave 3 leaves at the cut top. Only proceed when the top leaf layer has stabilized.
+ Number of buds left on the tops to create new canopy of at least 3 buds; The distance between the shoots is at least 15 cm and is uniformly distributed so that the foliage is well balanced, limiting branch fractures, wind breakage.
6. Intercropping in rubber plantations:
– Set up legume cover in the first year. On the intercropping area of short-term trees, set up the vegetation cover immediately after stopping intercropping.
Legumes can be used as mats for the basic rubber plantations such as Kudzu (Pueraria phaseoloides), P. triloba, Mucuna India (Mucuna bracteata, M. cochinchinensis).
– For Kudzu and Cassava, 3 rows of mats were planted between 2 rows of rubber at a distance of 1.0 mx 1.0 m (density 4,000 – 5,000 holes per hectare intercropped). Harvesting seeds according to specific conditions.
– For Mucuna India, plant one row between two rows of rubber trees at a distance of 5 – 6 m (250 – 300 cavities / ha).
– Weeding, fertilizing the mulch helps to grow quickly in the first year, especially need to apply lime when planting mulch. Where weeds grow strongly, weeding 1 to 2 stages 30 to 45 days apart.