Castor

Oil Development In Castor

Introduction

  • Castor is an important commercial crop valued for the oil contained in its seeds.
  • It is, therefore, not only interesting but also necessary to trace the development of oil in the castor bean and to determine and understand the factors influencing it.
  • Earlier formed beans contain more oil than the later ones, and that seeds borne on the main fruiting spike are richer in oil content than those on the secondary or tertiary branches important points to be noted is that the oil content goes on increasing even after the dry stage is reached, ie., even after the fruits on the spike have dried.
  • This increase in oil content continues for over 30 days after the dry stage.
  • Thus the correct time of harvest would not be immediately the dry stage.
  • Thus the correct time of harvest would not be immediately after the fruits are dry by at least 20 to 30 days after the fruits are dry.
  • To achieve this, it is essential to have fruits of a non-dehiscent nature.
  • The rate of increase in oil content varies from year to year, indicating thereby that seasons have considerable effect on the rate of deposition of oil.
  • In the first 30 days after fruit discernibility, only a very small quantity of oil is deposited.
  • In the next 10 to 20 days, a very rapid increases takes place and nearly two-fifths of the oil is deposited.
  • In another 10 days, i.e., from 50th to 60th day after fruit discernibility, the rate is nearly doubled.
  • Roughly, between 50th and 60th days after fruit discernibility, nearly 80 per cent of the total oil is deposited.
  • After 60 days, the rate rapidly falls down.
  • The period during which maximum oil is deposited varies from season to season.

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Factors Affecting Oil Content Of Seed

Effect of soil fertility on the oil content of castor

  • Castor is raised on all types of soils. In the Telangana region, it is grown on very poor sandy soils, whereas in northern India it is raised on rich alluvial soils.
  • It is, therefore, interesting to know if the soil fertility has any effect on oil content.
  • The oil content of the seed is not effected by fertility of soil.

Oil content of seed from spikes of different orders

  • Castor produces a number of branches and each branch terminates in a spike.
  • The most important orders are the main spike , the primary spike and the secondary spike.

Spike orders
-Percentage of oil
NPH 1
H.C.6
Primary spikes
52.80
51.36
Secondary spikes
52.83
50.66
Tertiary spikes
52.33
50.90
Quarternary spikes
51.50
-

  • There are no significant differences in oil percentage of different orders of spike in above varieties in experiment.

Effect of age and different methods of storage on oil content of castor

  • At Rajendranagar Farm, experiments were conducted by storing the seed of castor strains H.C.1, and H.C.2 in open trays, in gunny bags, in sealed kerosene tins and in glass jars.
  • The first two methods are usually followed in warehouses and cultivators houses whereas the last two are followed in laboratories.
  • Even though the figures are some what erratic in certain cases, yet can be safely concluded that oil contentdoes not go down with the age of seed nor does it go down if stored in open or closed containers.
  • But the chemical composition of the oil was not studied and hence it is not certain if that is affected by age or mode of storage.
  • In Tamil Nadu, castor-seed was stored in gunny bags.
  • Even after three years, there was no deterioration either in free fatty acids or total oil content.

Effect of degree of maturity of seed on oil content

  • The local castor varieties are usually shedding varieties.
  • Hence, if the spike is allowed to stand till all the fruits are dry, there is a danger of some of them dehiscing and shedding the seed.
  • So the cultivators usually harvest the spikes before all the fruits are dry.
  • From the data presented under the heading Determination of oil in seed from capsule discernibility to capsule maturity it is clear that in fruits harvested before they are dry, full development of oil is not realised.
  • It was found that with one-fourth fruits on spike dry, the oil percentage of the spike is 45.11 0.311; with half the number of fruits dry, it is 45.13 and177; 1.489; with three-fourth dry, it is 47.56 and177; 0.368 and with all fruits dry, it si 48.39and177; 0.595.
  • It is, therefore, advisable to harvest when all fruits are dry, though for this it is necessary to grow non-shattering varieties.
  • The chemical composition of oil with different degrees of maturity is worth studying.
  • Since castor-oil is largely used in industries, it is of the utmost importance to harvest the crop at the proper time.
  • The oil content in relation to the method of harvest was studied at the Agricultural Research Station, Tindivanam (Tamil Nadu).
  • No difference was found in the oil content of produce harvested as and when the capsules became dry and that harvested when one or two capsules in a spike showed signs of drying and immediately dried in the sun.
  • Both these treatments were superior to harvesting when a few capsules show signs of drying and heaping and weighing down the produce.
  • The free fatty acid content was also the highest in the treatment.
  • The results show that it is not necessary to delay harvest till all the capsules in a spike are dry.
  • The harvest can be taken up when one or two capsules show signs of drying but the produce must be immediately sun dried thoroughly.

Effect of manuring of the soil on oil content

  • To determine the economics of manuring castor with farmyard manure, groundnut-cake and castor-cake, experiments were conducted at Rajendranager Farm.
  • Incidentally, the oil content of seed under different treatments was determined, but there was no statistical significance between differences.
  • Hence, it was concluded that manuring of the field has no effect on oil content.

Effect of temperature, sunshine and region on oil content

  • Takao found that in Thailand where the rainy season is from April to middle of October, seeds ripening from recemes which bloomed during rainy season deteriorate more in quality than those which bloomed in the dry season.
  • This was due to (I) insufficient fertilisation owing to heavy rains, (ii) increase in the moisture content of seeds, (iii) decrease of oil content by higher relative humidity, (iv) increase of crude protein content.
  • In tropical regions there is no problem of air temperature throughout the year, but higher relative humidity and lack of sunshine have a great influence on seed characters and on the quality of oil.
  • Similar results were obtained at Tokyo which is in temperate zone.
  • But the results obtained at Kuwaiti which is in arid zone were entirely different.
  • The kuwaiti seed raised in kuwaiti or Shanghai seed obtained.

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Telangana

Castor

Castor Management