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ThesisItem Open Access Comparative micromorphologial and physico- chemical study of the upland and midupland laterite soils of Kerala(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1986) Sankarankutty Nair, R; KAU; Aiyer, R SThesisItem Open Access Nutrient dynamics if the rice based cropping systems(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1989) Sundaresam, Nair C.; Subromonia, Aiyer, RThesisItem Open Access Exchangeable aluminium as an index of liming for the acidic upland soils of Kerala(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1987) Meena, K; KAU; Alice, AbrahamAluminium toxicity is the major factor limiting crop production in the acidic soils and the usual practice of alleviating aluminium toxicity is liming* / The present investigation was carried out to find out the distribution of water s dluhle and exchangeable aluminium in the acidic upland soils of Kerala and to test the suitability of exchangeable aluminium as an index for liming them* It was further programmed to find out the growth, yield and nutrient uptake pattern of two acid sensitive crops namely cowpea and fodder maize in soils under different levels of exchangeable aluminium brought out by the use of different levels of lime* Chemical analysis of eighty soil samples representing the five major upland soil types of Kerala viz* laterlte, alluvial, red loam, sandy and forest a oil have indicated the highest amount of exchangeable aluminium and percentage aluminium saturation in the laterite soils* The soil with 3 high level of exchangeable aluminium and percentage aluminium saturation was selected for conducting a pot culture experiment to test the suitability of using exchangeable aluminium as an index of liming* The exchangeable aluminium content of this soil was maintained at different levels by applying different levels of lime and the performance of these crops in this soil was compared by making biometric observations and by chemically analysing plant and soil samples* From the results of the study it was seen that higher levels of exchangeable aluminium adversely affected the growth, yield and nutrient uptake In cowpea and fodder maize* Maintenance of exchangeable aluminium at 1*26 me/100 g with a corresponding percentage aluminium saturation valua of around 30, by the use of 500 kg lime/ha appeared to be the optimum for maximising the yield of cowpea* But in fodder maize this level of lime was found to be insufficient and complete elimination of aluminium toxicity appeared to be essential for maximising production* Since the critical levels of exchangeable aiuainiua appears to be different for different crop3, it is desirable that lias levels to reduce exchangeable aluminium to such a critical level alono be applied. The results of the present study thus point to the advantage in adopting the exchangeable aluminium level of soil as a better index of liming for various crops grown in the upland acidic soils of Kerala.ThesisItem Open Access Management of acidity by combined application of lime and gypsum in a low activity clay soil of Kerala(Department of soil Science and Agricultural Chemistry, College of agriculture, Vellanikkara, 1992) Jessy, Jacob K; Venugopal, V KThesisItem Open Access Effect of submergence on the soil testing parameters of paddy soils(Department of soil Science and Agricultural Chemistry, College of Agriculture, Vellayani., 1986) Usha, Mathew; Alice, AbrahamThesisItem Open Access Factors governing response of rice to liming in Kerala soils(Department of soil science and Agricultural chemistry, College of Agriculture Vallayani , Trivandrum, 1986) Mary Kutty, K C; KAU; Subramania Aiyer, RA study has been conducted on the factors governing response of rice to liming in Kerala soils with a view to evolve suitable coliorative measures. A five pronged approach to the studies made are highlighted to enable a clear understanding of achievements as against the objectives and approaches made. A laboratory study with one hundred soil samples to assess the nature of acidity of four major rlce growing tracts of Kerala State viz.,Kuttanad, pokali, kole and latoritic alluvium has been carried out. The kuttanad soil lncludes karl, karapadon and kayal lands. Path coefficient anaysis of important fifteen acidity contributing factors against seven parameters for measurement of soil acidity and the inter-relation ships of 22 soil characters show that aluminium saturation of effective CEC is the best parameter for measurement of soil acidity. karapadon and hoyol land3. Path coefficient analysis of Important flftaon acidity contributing factors against seven parameters for racasurcsnont of soil acidity and tho intor-rclationahlpo of 22 soil characters show that aluminium saturation of effective CEG Is tho boot parameter for measurement of soil acidity. '*’*** fifteen factors ldontlflod as proton sources .ooount tor 95.9 por oont of th. mo.ourom.nt. vaulting th. 00. hundnd «il “ "P1” « • 9rOUp*S * pPln0lp*1 . —a erne seven clusters ire formed. This goipaMnt H ^ appliaatlan of prinoip.1 l» a probably th. ur district could however bo grouped together In a cluster with a range of aluminium saturation of effective CBC 70# 1 to 75,0 per cent. The fourth and fifth clusters °f soils studied except the kari soil and having tioir aluminium saturation of effective CCC in tho range of 40.1 to 70.0 por cent. Tho kayal soils of Kuttanad, poWcali and lstsritlc alluvium find a placo in tho sixth cluster with an aluminium saturation of effective CCC in tho range of 30.1 to 40.0 ~jCr cent. The seventh cluster nalnly of lateritic alluvium and a few loss acidic pokkali soils has aluminium saturation of effective CtC below 30.0 per cent. A pot cult ire experiment has been conductod in a highly acid soil hnri s o il o f Kuttanad having tho pH values 3.5 with 39 rico variotioo In or.lor to ocroon out a variety tolorant to acidity. Tho varlotlon hovo boon acroonod £or toloranco to acidltyunlng th. method of D2-0tatloticn. nolocting tho impor- , „h,.a throo cluotoro ora formed. Thoy hova tant character, ano . . flB toiorwit. tedium tolorant boon oharactori«od a and l.aat tolaa th. tolarant varlotl.. Jyothi variety acidity. ****** ^ .jvoc.cy of a p M of ia ranWd t *• • r method, of managmant ..... oowblnlng v.ri.ty 1 including lining and v»»vn>«ing for obtaining better productivity m hl3hly ^ soils of k« . u . liming la a hydro-an\eliorativo process, a pot culeKperlnon,. has been carried out to otudy the effect of 3 -eto^iaia coupled with washing with different levels of water and periods between washing in two highly acid soils. The fact that washing the ooil two or throe tinvas at an interval of 2 days maintaining 10 can water from tlio ooil surface after the application oa lino lu noro efficient often yielding better rerulta with a lower Lining done will certainly make the use of l-inin'1 materials in the management of acid soiis An economic promoaition. This further orroloins the preference for low rates L i •- *- of llmln already acca. tod try farm ra in Kuttanad in spite of oonorve 1 Lae"", of rosoon.sG to li.nin , in resGoj-cn st itions, where tho s o ils ire r.uc.i lesn acid than those confronted in cultivator’s f i e ld a. *, o t cult iroa»no?l.jant hao ixi'.n conducted to otudy tho ff o ' graded lovolo of lining (on dry and wot noli baoio) isingj tiio non'. tr- ,*l-rant vori ty in lour major ncld rlao noil ypon suc„h a-nn Lat-rltic alluvium, Uolo, i»kl;ali and tori soils (,.o f i r s t crop and tho subsequent thrco crons roo:>octivoly. Ml the ros >onso functions fittod hava l>oan in quadratic rxxlol .jcoopt those Involving lo t o r lt ic alluvium. in tolo soil. ti.o residual a££oct o£ limine, io much in , , in tho nocond succeeding avidence only m ^ crop.aCtor which a drastic decrease In ,y#i4enlldd has boon obtained. In th« case of __ r•siflual offoot, however, has been pronounce poWcali no . ^ crop8. In kari soil, th. maximum yl.ld In the second ^ ^ fcha ,uphoat rats of liming nor as could not be obta^ ^ for r.^du.1 effsct.. Th. r.al- • o o n s s ' j u e n o . , r a p i d l y b y t h . .M o n d o r o p dual »PP“ In the case of laterltic alluvium9 application of lime maximum ever* the yield decreases significantly and rapidly. Response functions for the first and second crops could not be worked out. This indicates that tho maximum yiold might have been attained at a lovol of liming bo low 1/4 La doso. However* for the third and fourth crops, at tho rate of liming tried, a quadratic residual response function could bo fitted. Tho results on residual effect of lime hnvo alco shown that higher rates of lirr.e application introduces problems of roacidification at a faster rate. Tho depressive effects of line at higher rate are again a pointer to the need to ac opt low lining rates ;?ut ’./ith frequent applicationsThesisItem Open 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 SPalmarosa, 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.ThesisItem Open Access Availability indices for stressed nutrients for coconut (Cocos nucifera L) in an ultisol(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2003) Priya, P; KAU; Sureshkumar, PThe present study was conducted with an objective to analyse the soil-plant system, the levels and interactions of nutrient ions in soil, soil solution and plant thereby / finding out the contributing factors to yield. The importance of the term relative intensity lies in the fact that the contribution of mineral elements to growth and yield of plants depend much on the relative amount of one element with respect to the others rather than the absolute content of individual elements. To study the ionic interactions and to unravel the role of Net Ionic Equilibrium based on Ratio Law on soil plant system, a sample of fifty phenotypically identical palms varying in yield from 14.4 to 84.4 nuts palm" year"! grown under an Ultisol were selected. Index leaf samples were collected during pre and post monsoon seasons from 25 palms each from high yielding and low yielding groups. Soil samples were also collected from the basins of these palms during the same seasons at 30 cm (surface) arid 60 cm (subsurface) depths. Soil solutions at saturation point were extracted from the surface samples by centrifugation technique. These leaf, soil and solution samples were analysed / . for different nutrient ions, and the NIE ratios in these three phases were worked out with respect to K and Na. The soil samples were acidic in nature and the variation in rhizosphere pH must have definitely influenced the solubility as well as absorption of different nutrient ions. In the case of available nutrients, the micro nutrients showed significant direct relation with yield both for high and low yielding populations. This might be due to their restricted availability due to aerobic oxidised condition where Fe and Mn might have been precipitated and got into unavailable forms. The BaCh exchangeable ions and the CEC derived from summing up of these exchangeable ions influenced yield directly. Exchangeable K had got a significant dominance in deciding the NIE ratio in soil, solution and in index leaves. Exchangeable K controlled the soil solution concentration of K which in turn controlled the NIE ratio in solution and the ratios in plant. Exchangeable K directly controlled the plant K content and plant K was positively and significantly correlated with the NIE ratios in plant and these ratios were positively and significantly correlated with yield. The negative significant correlation of exchangeable K with plant Mn and Zn revealed the antagonistic effect of exchangeable K in restricting the absorption of Mn and Zn by plants. Among the ionic concentrations in soil solution, Fe was positively and significantly correlated with yield in both the seasons. Soil solution concentrations of Ca and Mg were antagonistically and significantly related with plant Mn content. Potassium content and the NIE ratio in index leaves were found to have a significant direct relation with yield in the pre-monsoon season. Potassium, Ca and Mg were the dominant cations in plant deciding the total cation concentration in index leaves. The NIE ratios between the exchangeable ions, the ions in soil solution and the ions in index leaf samples were mutually, .positively and significantly correlated among themselves. This lead to the conclusion that there exists a constancy in the relative proportion of nutrient ions in the entire soil-plant system which followed Ratio Law. The study lead to the conclusion that the soil test values of the individual ions alone or the plant content of individual ions alone can't give a clear picture of optimum nutrient requirements for the plant. The relative concentration of K in soil through the ~ concentration in soil solution was found to govern the relative concentration in plant which in turn influenced the yield.ThesisItem Open Access Effect of Vermicompost on the yield and quality of tomato (lycopersicon esculentum Mill.)(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1996) Pushpa, S; KAU; Prabhakumari, PAn investigation was carried out at the Instructional Farm, attached to the College of Agriculture, Vellayani to evaluate the Effect of vermicompost on the yield and quality of tomato. The experiment was laid out in Randomised Block Design with ten treatments and three replications. Biometric observations viz. height of the plant, number of leaves and number of floweres were greately influenced by the application of vermicompost compared to farm yard manure. Yield attributes like mean fruit weight and girth of fruits were also found to be significantly influenced by the vermicompost application. Vermicompost application has got a significant influence on the yield of tomato. Plants receiving 25t vermicompost along with full dose of inorganic fertilizers produced maximum yield followed by the plants receiving 25 t farm yard manure along with full dose of inorganic fertilizers. Germination count and viability was maximum when vermicompost was used as the organic source. Maximum germination count and viability was observed when 100t ha-1 vermicompost was used. Vermicompost application has also got a significant influence on fruit qualities. Protein, and carbohydrate content were more in vermicompost treated plants compared to farm yard manure application. Chemical properties of the soil was significantly influenced by the application of vermicompost. pH, organic carbon, available N, P2O5, K2O, Ca and Mg was maximum when 25t vermicompost along with full dose of inorganic ferilizers was used. However availability of micronutrients Mn, Cu, Zn was more in 100t vermicompost applied plots. Application of vermicompost increased the uptake of nutrients by plants. Maximum uptake of all nutrients viz. N, P, K, Ca, Mg, Mn, Cu and Zn was found in plants treated with 25t vermicompost along with full dose of inorganic fertilizers. Correlation studies showed that nutrient uptake was significantly and positively correlated with availability of nutrients. Yield and nutrient uptake of plants were significantly and positively correlated with availability of nutrients and so vermicompost can be effectively used for increasing the fruit yield and quality of fruits in tomato.
