Thumbnail Image

Theses

Browse

19851
Reset filters
Subject: Soil Science and Agriculture Chemistry × Author: Chinnamma, N P × Author: KAU × End date: 1989 × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    Influence of applied nutrients and stage of harvest on the yield and physicochemical properties of essential oil of palmarosa (Cymbopogon martini Stapf var. motia)
    (Department of Soil Science and Agricultural Chemistry , College of Agriculture, Vellayani, Trivandrum, 1985) Chinnamma, N P; KAU; Aiyer, R S
    Palmarosa, an essential oil crop introduced in Kerala, from Maharashtra, nearly two decades ago, is spreading steadily la the pialas and midland regions of North Kerala. Several agro-techniques have yet to he standardised for the commercial cultivation of this crop in the State. The present studies were undertaken at the Aromatic pnfl Medicinal Plante Research Station, Odakkaly during 1980-'8 4 to obtain information on the nutrition of palmarosa, optimum harvest intervals to ensure maximum herbage and oil yields and the factors influencing the quality of oil. The treatments in the major field experiment (1980-'82) consisted of three levels of N, and KgO, each at 25, 50 And 75 kg/ha along with six intervals of harvest at 40, 45, 50, 55, 60 and 65 days. The total number of treatment combinations wore 162 in a 3^ x 6 confounded asymmetrical factorial design. Tho main experiment was continued for another two yoaro limiting tho observations, to the yield of herbage and oil. This was then followed by an observation trial with intervals of harvest longer than tho maximum of 65 doye tried in the main experiment. In the main experiment the herbage yield vns significantly increased by application of P2°5 ^2°* Nitrogen did not have any eignifioant offeot on herbage yield poaeibly due to tha medium level etatua of soil N in the ABSTRACT ^erimental plots. The oil yield was Bignifioantly enhanced by P205 application at 50 kg/ha. Different levels and K showed no significant influence on the yield of oil. Harvest intervals showed significant influence on herbage yield, oil yield and oil content and the maximum value was recorded by the 65 day interval. A path analysis of the herbage yield with related cnaracters has shown that the height of the plant is the most important yield attribute influencing directly the yield of herbage. Path analysis of oil yield showed that oil yield is mainly dependent upon herbage yield. The direct effects on oil yield by yield attributes are found to be in the decreasing order of number of tillers with inflorescence, height of the plants and length of inflorescenoe. Maximum indirect affect via herbage yield is expressed by the height of the plant and length of inflorescence. All these directly and indirectly contributing factors arc soon to be markedly influenced by tho applioation of phosphorus and intervals of harvoat* Herbage yield and oil yield for various harvest lntorvalo obtained In the flrot two years wore fit tod In a Cobb-Dcughlua reoponoo function and tha expooted values «leulat«d were found to be very olooe to tho actual observed values• In thethird and fourth year of the experiment, the ghest herbage and oil yields were recorded by 60 day interval followed by the interval of 65 days, A quadratic Sanction for the data pooled over for four years was fitted to see if the data show a diminishing return with an increase in harvest interval and it was found that the optimum herbage yield and oil yield were obtained when the harvest was done at 62 and 63 days interval respectively. The final observational trial also indicated that the herbage and oil yields were maximum for a harvest interval of 65 days beyond which it decreases. Increase in the levels of both N and P tended to increase the content of geraniol and to decrease the content of geranyl acetate which are the price determining quality attributes of the essential oil. But the maximum interval of harvest viz., 65 days tried in the main experiment was not sufficient for moot of the physico-chemical properties of oil ouoh os specific gravity, refractive index, geraniol content, geranyl acotato content etc. to reach the minimum limit prescribed by 131. The observational trial showed that the oil obtained at intervale of 95 days and above satisfied the 131 specification with respect to all the phyalco-ohemioal properties of the oil. However, at thle herveat Interval the yield Itself wae considerably depressed compared to the yield at 65 day Interval. Th, eoonomloe worked out for different Intervale of harveab baaed on the ourrant market prloe of the oil paeein« as above the I SI limits as fe. 240/- per kg (oil from harvest intervals at and above 95 days) and those below them at Fs.220/- per kg (oil from harvest intervals of 55, 65, 75 and 85 days) it has been found that a wider cost benefit ratio and net return per rupee investment are obtainable for harvest intervals ranging from 65 to 85 days. However, 65 day interval has the advantage of early returns from the investment. Application of 50 kg PgO^/ha in view of its significant effect on herbage yield, oil yield and oil quality increase the net profit per rupee invested for the harvest interval of 65 days. The average removal o f II, P, K, Ca and Mg from the s o i l by palmarosa per h ecta re per year lias a lso been worked o u t . The optimum f e r t i l i s e r le v e l fo r palmarosa i s 25 kg II, 50 kg P?05 and 25 kg K20 per h ectare over an a p p lic a tio n o f spent g ra ss at 5 tonnes per h ectare per y e a r . The optimum h arvest in to r v a l i s 65 days. TIiIb would give maximum horbago y io ld , o i l y io ld ond ea rly return from in v e stm e n ts.