MAJOR NUTRIENTS

1.NITROGEN:

ROLE

• In plant growth ,fruit number ,size and yield.
• To increase the total soluble solids.
• Reducing sugar contents of fruits.

DEFICIENCY SYMPTOMS

• Typical chlorotic on older leaves,
• Later spread on younger leaves.
• The leaf cuticular thickness is less and epidermal palisade parenchymatous .
• Cells are loosely arrenged ,while spongy parenchymatous cells are compactly arrenged.

2.PHOSPHOROUS

ROLE

• In improving the fruits size.

DEFICIENCY SYMPTOMS

• Purplish fiecks on lamina towards the tip are formed.
• The manifestation of purplish rusty pigmentation all over fully matured leaves.
• The leaf thickness will be more than normal.
• In shoot section the eoidermal cortex ,vascular and pith region cells will be compacted.

3.POTASSIUM

DEFICIENCY SYMPTOMS

• In recently matured leaves irregular chloretic areasfirst appear along the margin,later turns to blakish grey.
• In shoot cuticular thickness is reduced,epidermasl and cortex cells are thinner and enlarged.

FERTILIZER APPLICATION

Annual fertilizer requirements( Fertilizer dosage gms/plant/year)

MICRO NUTRIENTS

1.ZINC:

DEFICIENCY SYMPTOMS

• The deficiency of zinc is marked by small and erect leaves.
• Shorter internodes and defoliation of terminal and poor fruiting in field conditions.

REMEDIES

• The deficiency can be corrected by spray of zinc sulphate(0.2 to 0.5%) during active growth period.

2.IRON

DEFICIENCY SYMPTOMS

• In calcareous soils iron chlorosis is common with general yellowing of leaves
• Premature leaf shedding and dieback may occur.

REMEDIES

• Corrected by spray of ferrous sulphate(0.2 to 0.4%) during active growth period.

3.BORON

DEFECIENCY SYMPTOMS

• The crop is sensitive to boron deficiency.
• The leaves become chlorotic and dieback of branch starts.

REMEDIES

• It is recomennded to spray borax (0.05%) thrice from june at monthly intervals

TIME OF APPLICATION

• Manures and fertilizers should be applied in two split doses ,first applied in the beginning of the monsoon in dry rainfall areas .
• Split application is fallowed in the trees that are bearing heavy crops.
• After application fertilizers are covered with top soil and irrigated.
• Application of FYM is done pre or post monsoon besides, N, P and K are applied twice in a year.
• The first half in beginning of monsoon and the remaining  half doses the end of monsoon.
• The doses vary due to soil types,climatic conditions,varieties,age of plantation and  mgt practices.

METHOD OF APPLICATIONS

• In a well established sapota plantation maximum feeder  roots are equally distributed under the canopy of the tree with in a depth of zero to thirty cms and width at radial distance up to 90 cms.

• Shallow circular trenches of 15 to 20 cms depth at a radial distance of 60 to 90 cmsare taken and manures and fertilizers are applied.

• Manures and fertilizers may be applied in sep-oct.
• Application is done in ashallow circular basin 15 to 20 cms deep ,60 to90 cms away from the trunk.
• Application of fertilizers is followed by the irrigation.
• The following doses of  manures(kg per tree) and fertilizers (gms per tree)have been found beneficial for obtaining  higher yield of sapota.