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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Ecophysiology and management of Isachne in rice fields of Onattukara(Department of Agronomy, College of Horticulture, Vellanikkara, 1996) Abraham, Varughese; KAU; Tajuddin, EIsachne miliacea Roth is the most dominant weed in the 28,000 ha of low land rice fields of the coastal sandy Onattukara region, situated in Kollam and Alapuzha districts of Kerala. A serious of investigations were undertaken at Rice Research Station, Kayamkulam, during 1991 to 1994 with the objective to identify the major weeds in the rice ecosystem and to bring out the ecophysiology of 1. Miliacea and to find out a suitable weed management strategy for the rice based cropping system of Onattukara. Isachne miliacea was found to be the dominant weed in rice during Kharif and Rabi seasons. The weed seeds germinate in April – May, attains its peak vegetative growth in July and flowers in October. The seeds mature in November and the plants dry off in January with the onset of summer. The weed is propagated by seeds and stem cuttings. Germination of seeds can be prevented by submerging the seeds in the area in water even to a depth of one centimetre. The forcing of the stem cuttings of 1. Miliacea to a depth of five centimetre below the soil surface or maintaining a submergence for more than five centimetre can effectively check the vegetative multiplication of the weed. Seeds attained physiological maturity in November and remained dormant upto March. Seeds of the season that remain on the surface germinate fully in April – May with the pre – monsoon showers while the buried seeds remain dormant. Burying the seeds to more than five centimetre depth and water stagnation in July to November induced secondary dormancy. Viability of the seeds was lost faster at shallow depth of burial. Crop weed competition studies were conducted in Kharif and Rabi for two years with different densities of 1. Miliacea. Weed competition was severe in dry dibbled Kharif compared to wet transplanted Rabi. Even a small density of five 1. Miliacea plants per square metre produced appreciable biomass and reduced the DMP of rice substantially. Integrated weed management study was conducted in Kharif and Rabi for two years in a split – plot design in three randomised blocks. Kharif season treatments formed the main plots for Rabi trial. In Kharif five pre – emergence herbicides were compared with local practice. Local practice of hoeing on 15 DAS and HW twice on 25 and 40 DAS gave maximum grain yield. Application of oxyfluorfen 0.1 kg ha-1 followed by HW on 30 DAS was on par with local practice and ranked second. The performance of other herbicides anilofos 0.40 kg, butachlor 1.25 kg and thiobencarb 1.25 kg per hectare were also satisfactory when followed by one HW on 30 DAS. Pretilachlor 0.50 kg ha-1 was phytotoxic to rice. The tested herbicides effectively controlled 1. miliacea upto harvest of rice compared to local practice. During Rabi the effect of pre-plant spray of glyphosate and hand weedings were compared. Among the treatments a pre – plant spray of glyphosate after harvest of Kharif controlled 1. miliacea best and gave maximum rice yield in Rabi season. Kharif treatments did not show any significant influence on yield of rice during Rabi. From the study it could be concluded that pre – emergence spray of oxyfluorfen 0.1 kg ha-1 followed by one HW on DAS in Kharif and pre – plant application of glyphosate 0.75 kg ha-1 on residual weeds immediately after the harvest of the Kharif crop gave efficient weed control and economic yield of rice in the rice based cropping system involving rice – rice – fallow of Onattukara region.ThesisItem Open Access Effect of cover crops on nutrient dynamics in the rubber plantations(Department of Agronomy, College of Agriculture, Vellayani, 1995) Prathapan, K; KAU; Sreedharan, CThree field experiments were conducted at Bethany Estate, Mukkampala, Kanyakumari District from February 1991 to October 1993 to study the effect of cover crops on the nutrient dynamics in immature, mature rubber plantation and an open area. In Experiment I there were two cover crops viz. Pueraria phaseoloides and Mucuna braceata and five levels of NPK viz. 0:0:0, 0:30:30, 10:30:30, 0:60:60 with one year old RRII-105, replicated thrice and statistically laid in RBD. In Experiment II there was one cover crop Mucuna sp alone with five levels of NPK as above with 8 years old RRII-105 replicated 4 times and statistically laid in RBD. In Expt. III there were 10 microplots, with both cover crops. N, P, K, Ca, Mg content of both Hevea and cover crops were increasing as the crops growth progressed. Fertilizer application to cover crops improved the Hevea leaf nutrient content than the absolute control. Among the levels 10:30:30 was found optimum. Mucuna was found better than Pueraria in increasing the Hevea leaf nutrient content. Girth increment was better with 10:30:30. This was found to be optimum under both experiments. More height increment was observed in this level, as well as in cover cropped treatments when compared to absolute control. Biomass production of cover crops were maximum at 10:60:60 followed by 10:30:30 under both experiments. Biomass production, root weight and length were higher in Mucuna and it was found increasing as the crop growth progressed. Nodule count was higher in Pueraria and the fresh weight of nodule per plant was higher in Mucuna as the size of its nodule was found bigger. Soil Moisture retention capacity was found higher under cover cropped plots at both shallow (0-30cm) and deeper (30-60cm) soil depths at-0.033 and -1.5 Mpa pressures than control. Pore space and aggregation percentage were improved whereas bulk density decreased. Among the levels of NPK 10:30:30 was found optimum in improving the soil physical properties. The percentage of improvement was found greater at shallow depth of soil than deeper. Soil moisture content during summer months were improved in the cover cropped area. The soil moisture in than the top soil (0-30cm) was lesser than the bottom soil (30-60cm) in Pueraria grown plots. This trend was reverse in the case of Mucuna. Growing of cover crops improved the microbial population of bacteria, fungi and phosphate solubilising organisms. The level 10:30:30 was found optimum for the better microbial activity. 10:30:30 was found optimum for better yield and Latex Flow Characteristics. Covercropping has increased the latex yield by 15-20%. 10:30:30 was optimum for better leaf litter production of Hevea. In cover cropped plots the leaf litter production was higher and wintering was delayed by 26-30 days over the control. This has enhanced 10 additional tapping days. Girth is positively correlated with cover crop biomass, nutrient uptake, soil available nutrients, soil moisture contents and Hevea leaf nutrient contents. Strongest correlation for girth was found with Hevea leaf N content, and uptake of N by cover crops, suggesting the importance of foliar diagnosis. Yield was negatively correlated with Mg content of soil.ThesisItem Open Access Effect of nutrition as Influenced by irrigation on growth and yield of oil palm (Elaeis guineensis Jacq)(Department of Agronomy, College of Agriculture, Vellayani, 1994) Thomas, Varghese P; KAU; Sreedharan, CA field experiment was conducted in the oil palm plantations of the Central Plantation Crops Research Institute (CPCRI) Research Centre, Palode, Kerala to study the response of mature oil palm to fertilizer and irrigation applications with respect to growth, yield and uptake of nutrients. There were four levels of fertilizers viz: F0- 0:0:0, F1-600: 300: 600, F2- 1200: 600: 1200 and F3-1800: 900: 1800 g N : p20 : k20 palm-1 year-1. The three levels of irrigation were: I0-no irrigation, I1-45 1 palm-1 day-1 and I2-90 1 palm-1 day-1. The 4x3 factorial experiment was laid out in randomised block design with three replications. The study was also envisaged to establish the importance of leaf nutrient ratios of yield group of palms and its application in identifying nutrient limitations through the Diagnosis and Recommendation Integrated System (DRIS) approach in oil palm. The influence of various climatic parameters on yield of oil palm was studied by relating the monthly yield of oil palm in the field experiment with the monthly weather variables as far behind as 42 months before harvest. Fertilizer application of 1200 g N+600 g P2O5+ 1200 g K2O palm-1 year-1 was found to improve the growth characters such as annual leaf production, number of leaves on the crown, dry matter production of leaf, trunk and bunches, total dry matter production and the crop growth rate. Increase in yield attributes such as number of female inflorescences, sex ratio, average single fruit weight and the number of bunches at F2 level contributed to the significantly high FFB yield at F2 level of fertilizer application. Both palm oil and palm kernel oil production were also maximum at F2 level. For the uptake of nutrients N,P and K by palm parts as well as by the palm as a whole, the F2 level of fertilizer application was found to be the optimum. It was observed that 79% of the total uptake of N, 77% of P and 82% of K are removed annually through leaves and bunches from the system. A K-Mg antagonism was also detected in nutrient uptake. The yield of palm was found positively correlated with leaf production, leaf area, net assimilation rate, number of bunches produced, vegetative dry matter, P and K in soil and the total uptake of N, P and K by the palm. Both net income and benefit cost ratio were also found favorable at F2 level of fertilizer application. Irrigation at I2 level has resulted in increased leaf production, leaflets per leaf, leaf area, leaf dry matter, mesocarp dry matter and the bunch dry matter. Physiological parameters like relative water content, leaf water potential, stomatal resistance, leaf temperature and net photosynthesis were all favourable at I2 level of irrigation. Female flower production, sex ratio, single fruit weight and number of bunches produced were also more in I2 treatment. This has resulted in increasing FFB production at I2 level. Palm oil production was also more at I2 level. Total uptake of N, P, K and Ca were also found to be maximum at I2 level of irrigation. The net profit and benefit cost ratio were also maximum at I2 level. Leaf nutrient ratios of palms in different yield groups: were used to evolve parameters and norms for Diagnosis and Recommendation Integrated System (DRIS) in oil palm. The range of nutrient ratios within the zones of balance, moderate imbalance and imbalance were determined which were also illustrated through DRIS charts for three nutrient combinations. The DRIS approach was used to evaluate the nutrient balancing of the different treatments of the field. The order of relative importance of the five nutrients was determined using nutrient imbalance index (NII) values as indicated below: K> P> N> Mg> Ca The F2 level of fertilizer application in the experiment was found to be the most balanced among the tested fertilizer levels. The possibility of magnesium becoming a potential limiting nutrient at higher levels of fertilizer application has been brought out from the study. The superiority of balanced nutrition in increasing total dry matter production and bunch yield became evident from the study. The studies on climatic relationship with yield revealed that the pattern of variation in monthly yield remained the same inspite of irrigation throughout the summer months. The relationship of monthly yield of oil palm with monthly climatic parameters was evaluated up to a period 42 months before harvest. When eight climatic parameters were considered together, the influence of these weather parameters at seven specific lag periods viz. 1-4, 9-10, 13-16, 20-23, 25-28, 32-33 and 37-40 were found important for oil palm. Of these the lag 25-28 was found to be the most important as the relationship of climatic parameters with yield at this period was more. Relative humidity, maximum temperature and rainfall were identified as the most important variables influencing palm yield. Using results obtained from regression studies yield prediction models were constituted. It is concluded that yield prediction using the three or more variables is possible for oil palm 26-28 months in advance of harvest. The salient findings from the study is that a fertilizer dose of 1200g N+ 600 g P2O5+ 1200 g K2O palm-1 year-1 and irrigation level of 90 l palm-1 day-1 applied through drip system during the summer months are required to obtain maximum FFB yield from mature oil palm. The order of importance of nutrients for oil palm is determined as K> P> N> Mg> Ca. With the above level of fertilizer application the palms were found to have a more balanced nutrition. However continued application of fertilizers might possibly lead to magnesium deficiency unless corrective measures are adopted. Relative humidity, maximum temperature and rainfall are found to be the most important climatic parameters influencing oil palm yields. The influence of climatic parameters at seven lag periods 1-4, 9-10, 13-16, 20-23, 25-28, 32-33 and 37-40 were found to be more pronounced on palm yield. From these studies it became possible to predict oil palm yields 26-28 months in advance using models based on these weather parameters.ThesisItem Open Access Agronomic evaluation of biofarming techniques for forage production in coconut gardens(Department of Agronomy, College of Agriculture, Vellayani, 1996) Sansamma, George; KAU; Raghavan Pillai, GTwo field experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala State to study the potential of biofarming techniques for forage production in coconut gardens. The study was carried out for a period of two years from September 1993 to August 1995. The influence of the different nutrient management techniques on uptake of nutrients, quality of produce and physico-chemical properties of soil was also investigated. In experiment no.1. the influence of two nitrogen fixing organisms., viz. Azospirillum and Azotobacter and the role of Vesicular Arbuscular Mycorrhiza (VAM) in improving the growth and production of guinea grass and congosignal was studied under inoculation alone and also in combination with chemical fertilizers. The nitrogen fixers were tested under varying levels of fertilizer nitrogen and for VAM the level of phosphorus varied between treatments. The prospects for vermicompost use for guinea grass production was examined under experiment no. 2. It was also envisaged to compare the impact of integrated use of manures and fertilizers with the continuous use of chemical fertilizers alone. Results of experiment no.1 revealed that Azospirillum inoculation alone and in combination with fertilizers had significant positive influence on guinea grass production. Azotobacter inoculation showed only limited effects on growth and yield of the forage grass during the first year but the effect was significant during the second year. The results indicated that 25 per cent of the recommended nitrogen could be saved through the use of either of the biofertilizers. VAM inoculation when combined with full dose of recommended fertilizer nitrogen and potassium, showed significant superiority over the POP treatment at 0, 25 and 50 per cent phosphorus doses while the 75 percent P dose gave comparable yields. The quality parameters of the forage recorded values on par or superior to that of the recommended fertilizer treatment. The use of biofertilizers improved the net income and benefit : cost ratio from guinea grass cultivation. The inoculation treatments were found to have a favourable influence on the physical and chemical properties of the soil. Integrated use of the nitrogen fixing organisms with chemical fertilizers was found effective for Congosignal cultivation. Pooled analysis studies indicated that when inoculated with either Azospirillum or Azotobacter, 50 per cent of the recommended fertilizer nitrogen was adequate for yields. VAM inoculation alone elicited significant yield increase over the absolute control. Combind doses of VAM with chemical fertilizers at all levels of applied phosphorus responded more or less similar to the recommended fertilizer treatment. This indicated the possibility of completely substituting the need for fertilizer phosphorus in VAM inoculated congosignal. The VAM effect in promoting growth and yield of the forage was found to decline in the presence of applied phosphorus. The data on economics also favoured the use of biofertilizers. Experiment no. 2 revealed that guinea grass responded well to integrated use of manures and fertilizers. As per pooled analysis vermicompost @ 5 t ha-1 or Farm yard manure @ 10 t ha-1 when combind with 75 per cent of the recommended NPK were comparable with the 100 per cent NPK treatment. Application of the organic manures improved the quality of the produce. The physic-chemical properties of the soil was also favourably influenced by the integrated use of manures and fertilizers. The economic analysis of the data emphasised the need for reducing the reliance on purchased inputs. Coconut yield was found favourably influenced by intercropping of the fodder grasses.ThesisItem Open Access Status and availability of sulphur in the major paddy soils of Kerala and the response of rice to sulphatic fertilizers(Department of Agronomy, College of Horticulture, Vellenikkara, 1995) Purushothaman Nair, N; KAU; Thajuddin, EA series of investigations were undertaken entitled “ Status and availability of sulphor in the major paddy soils of Kerala and the response of rice to sulphatic fertilizers” at College, of Hortculture, Kerala Agricultural University, Vellanikkara from 1990 to 1994 with the objectives: (i) to assess the sulphor status of major paddy soils of Kerala (viz. alluvial and brown hydromorphic) (ii) to identify and appropriate soil test procedure for estimation of available sulphor in these soils (iii) to determine the critical levels of sulphor in the soils and plant (iv) to study the response of rice to two popular sulphatic fertilizers of Kerala (viz. ammonium sulphate and ammonium phosphate sulphate) and (v) to assess the sulphur use efficiency of 35S labelled ammonium sulphate and ammonium phosphate sulphate. The studies were conducted in four parts. In Part 1 of the studies, 105 samples each from alluvial and brown hydromorphic soils were collected from 10 rice growing districts of Kerala based on area under rice crop, estimated soluble SO4-S, adsorbed SO4-S, total sulphur content and organic + non sulphate sulphur contents. The soils were classified in to categories of low, medium and high based on the available SO4-S extracted by CaCl2. From this part of the study it was found out that 56 per cent of alluvial soils and 83 per cent of brown hydromorphic soils were deficient in sulphor. Sulphur deficient locations and sulphur sufficient locations were delineated. Sulphur status map for rice soils of Kerala was prepared. In Part II, representative soils belonging to three status categories (low, medium and high) were collected from 30 locations each of alluvial and brown hydromorphic types and conducted a pot culture with two treatments (S0 and S40 kg S ha-1) with two replications. These soils were analysed with 12 methods of sulphur estimation using different extractants. The relative yield of grain, straw and total biomass and relative uptake of nutrient S were estimated. Correlations between relative yields and sulphur extracted by different methods were studied. From this the suitability of the methods were evaluated. It was found that all the 12 methods studied could extract available SO4 – S satisfactorily. Scatter diagrams were drawn with relative yields of grain, straw, biomass and uptake of S against the sulphur extracted by different extractants. The critical levels were worked out following the Cate and Nelson procedure. The best suitable extractants for the estimation of sulphur in alluvial soil and brown hydromorphic soil were found out by assessing the responsiveness of rice in soils classified as deficient by each extractant. It was observed that in alluvial soil the critical levels varied between 5 to 22 ppm for different extractants. Monocalcium phosphate was to be the best extractant for alluvial soils. In brown hydromorphic soil the critical levels varied between 6 ppm to 20 ppm. Monocalcium phosphate + acetic acid was found to be the best extractant for brown hydromorphic soils. Relationship between plant content of S and relative yield of grain studied by Cate and Nelson procedure showed that in alluvial soil 0.075 per cent S and in brown hydromorphic soil 0.08 per cent S in plant at harvest were critical concentrations below which response to applied sulphur can be expected. In Part III of the studies, two locations having sulphur deficiency, one each falling under alluvial and brown hydromorphic soil, were selected for field experiments (CSRC, Karamana – alluvial and RARS, Pattambi –brown hydromorphic). Field experiments were conducted in these two locations for two seasons (Kharif and Rabi 1992-93) with nine treatments (control – S0, 4 levels of ammonium sulphate – S10, S20, S30, and S40 and 4 levels of ammonium phosphate sulphate - S10, S20, S30, and S40 kg S ha-1 in 2x4+1 factorial RBD with 3 replications). The results revealed that sulphur levels significantly increased yield of grain and straw and growth attributes like productive tillers. Sink capacity and dry matter production were increased by sulphur application. Among the two sources ammonium phosphate sulphate was found to be superior to the other. Agronomic efficiency, physiological efficiency and apparent recovery efficiency showed that the efficiencies were maximum at low level of sulphur (10 kg S ha-1). Sulphur levels increased, S, N and K uptake. The ratios of nutrients removed per ton showed that the ratios of these nutrients to sulphur narrowed down with sulphur application over control. The gross income, net income and B: C ratio were higher for sulphur application and the highest values were for 30 kg S ha-1. The physical optimum levels ranged between 25.34 to 31.47 and the economic optimum levels ranged between 23.06 and 28.73 for the sources in two locations at the two seasons. The economic optimum levels of AS and APS were 27 and 25 kg S ha-1 respectively. There was no residual effect in general, except that at brown hydromorphic soil sulphur @ 40 kg ha-1 could contribute to meet the requirement of sulphur for the succeeding crop in producing more grain yield. In Part IV of the studies, a pot culture experiment with 35 S labelled AS and APS was conducted at Radiotracer lab. The radioassay and chemical analysis were conducted. The soil and levels of S were same as that of field experiment. The specific activity of grain and straw increased with higher levels of 35 S application. The sulphur use efficiency in alluvial soil was highest at sulphur rate of 20 kg S ha-1. In brown hydromorphic soil sulphur use efficiency was highest at 30 kg S ha-1. Sulphur taken up from fertilizer significantly increased with sulphur levels in both the soils. A-values were on par for different levels in both the soils. Brown Bydromorphic soil showed higher A-value, sulphur use efficiency and total sulphur taken up from fertilizer.ThesisItem Open Access Applicability of diagnosis and recommendation integrated system (Dris) in coconut palm (Cocos nucifera L.)(Department of Agronomy, College of Horticulture, Vellanikkara, 1994) Mathewkutty, T I; KAU; Tajuddin, EA study on the applicability of diagnosis and recommendation integrated system (DRIS) in coconut palm (Cocos nucifera L.) was conducted at the department of Agronomy, college of Horticulture, Vellanikkara during 1991-’94. The study was conducted using coconut population of var. West Coast Tall being maintained at three research stations of Kerala Agricultural University namely, Regional Agricultural Research Station, Pilicode; Agricultural Research Station, Mannuthy and Coconut Research Station, Balaramapurm. Eight hundred palms varying in their yield from 5.8 to 162.7 nuts per palm per year were selected for developing DRIS norms. Leaf samples were collected from the 14th frond and were analysed for macro and micronutrients namely N, P, K, Ca, Mg, S, CI, Fe, Zn and Mn employing titrimetric, spectrophotometric, flame photometric or atomic absorption spectrophotometric method depending on the element. DRIS norms were developed using the data generated from the chemical analysis of leaf samples using the methodology of Beaufils (1973). The palm population was divided into low-and high-yielding subpopulations. The means and variances of nutrient concentration as well as their ratios (totalling 90 including inverse ratios) were worked out for the two subpopulations. The variance ratios were then computed for each nutrient and each nutrient ratio to examine their statistical significance and those discriminating significantly between the two subpopulations were considered for DRIS norms. When both the ratio and its inverse form were significant, the one which had a higher variance ratio was selected. Mean values of the selected individual nutrients and nutrient ratios of the high yielding sub population formed the DRIS norms. Five nutrients and 33 nutrient ratios were selected on the basis of higher variance ratios as DRIS norms. Thirty one DRIS charts involving selected three-nutrient combinations can be constructed from the selected nutrient ratios. A qualitative assessment of nutritional imbalance involving three nutrients is possible by utilising these DRIS charts. DRIS technique also provides another approach that can accommodate any number of nutrient ratios in which nutrient indices are worked out using DRIS norms and the observed nutrient ratios for the plant under test. The DRIS index for a nutrient indicates its relative abundance among the nutrients considered in its computation. Lower the value of the index for a nutrient, greater is its requirement. The accuracy of diagnosis of nutritional imbalance by DRIS approach was tested for ten selected nutrients in palm receiving varying levels of NPK under a factorial experiment. From this it was observed that DRIS index for a nutrient varied not only with the applied level of that nutrient but also with the applied level of other nutrients and an improvement in yield with increase in DRIS index value was obtained for the application of K. The overall nutritional balance of a palm is given by the nutrient imbalance index (NII) which is the sum of the nutrient indices irrespective of the sign. A strong negative relationship was observed between this NII and yield. DRIS norms developed on the basis of different yield cut-off values showed that they were affected by the criterion used for dividing the population into low-and high-yielding groups. Similarly DRIS norms developed for different soil type as well as for different climatic situations under the same soil type had also shown variations indicating their influence on DRIS. A comparison of DRIS approach with critical level approach indicated that DRIS could supplement information on balance or imbalance of nutrients in coconut palm and it could be used beneficially in nutrient management programmes in conjunction with critical level approach.