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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 Enhancing the Nitrogen Use Efficiency in Bhindi With Nitrification Inhibitors(Department of Agronomy, College of Agriculture, Vellayani, 1994) Bindu Kurup, S; KAU; Pushpakumary, RAn experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani inorder to find out the effect of nitrification inhibitors in enhancing the nitrogen use efficiency in bhindi. The treatments consisted of four levels of nitrogen viz., 50 kg ha-1, 100 kg ha-1, 200 kg ha-1 and 300 kg ha-1 and three nitrification inhibitors viz., urea, neem cake and mahua cake. Phosphorus and potassium were applied as per package of practices recommendation. The results revealed that nitrogen levels significantly influenced most of the growth and yield contributing characters, yield of bhindi, uptake of nutrients and available nutrient status of soil. Biometric observations like number of leaves, branches, root spread, DMP, LAI, RGR, NAR and CGR increased with increasing levels of nitrogen and the maximum was produced by the highest levels of nitrogen (300 kg ha-1). F1 produced the maximum height and F2 the longest tap root. Time of 50 per cent flowering and number of flowers per plant was maximum with the highest levels of nitrogen (F4). Whereas other yield contributing characters like number of fruits per plant, percentage of fruit set, length and girth of fruit, fruit yield per plant and total yield of bhindi was maximum with F2 (100 kg N ha-1 ). Quality aspects like crude protein and ascorbic acid content of fruits, uptake of nutrients by plant and fruit as also maximum with the highest levels of nitrogen (F4). However, the height of the first bearing node and chlorophyll content of leaves remain unchanged with increasing levels of nitrogen. The optimum level of nitrogen to get maximum fruit yield and net profit was worked out as 142 kg N ha-1 . Nitrification inhibitors caused significant variation in some of the characters like root spread, LAI RGR, NAR, CGR, number of flowers and fruits per plant, percentage of fruit set, length and girth of fruit, crude protein content and ascorbic acid content of fruit, uptake of nutrients by plant and fruit and available nutrient status of soil. In all these cases neem cake blended urea recorded the highest value followed by mahua cake blended urea. From the economic point of view, the maximum net profit of Rs. 11787.74 was obtained for neem cake blended urea and among nitrogen levels, 100 kg N ha-1 recorded the highest net profit of Rs. 16017.50. Thus neem cake blended urea at 100 kg N ha-1 can be suggested as the best economic dose of nitrogen for getting maximum yield and net profit.ThesisItem Open Access Utilization of phosphorus from green manure by rice(Department of Agronomy, College of Horticulture, Vellanikkara, 1994) Pushpa, Joseph; KAU; Mercy, GeorgeAn investigation was undertaken at the College of Horticulture, Vellanikkara, during 1993 – 1994 to study the utilization of phosphorus from green manure by rice. The main objectives of the study were to assess the contribution of phosphorus released from labeled green manure to the phosphorus nutrition of rice and to study the effect of incorporation of green manure on the utilization of applied fertilizer and native soil phosphorus. The effect of incorporated green manure on the dry matter yield of rice was also investigated. The green manure used was Sesbania aculeate. 32p labelled green manure was produced by growing sesbania in sand culture for 50 days. When the plants were 15 days old 32p (carrier free) was applied with water at 30 µCikg-1 sand. The labeled plant material was used for the incubation study and pot culture experiment. The results obtained from the incubation experiment conducted to study the dynamics of P mineralization from green manure revealed that the release pattern of Bray – 1 extractable P was similar both in 0.25 and 0.5 per cent green manure amended soil irrespective of the quantity of green manure added. The available P content of the green manure amended soil was relatively higher at the initial day of incubation, gradually decreased till 25th day and thereafter increased. The contribution of P from green manure and native soil also followed similar trend. As extracts of soil immediately after amending with labeled green manure showed 32p activity, it is possible that Bray – 1 reagent extracted inorganic P from the green manure. The P release from green manure and soil was the least at the 30th day of incubation and then showed an increasing trend for both levels of green manure incorporation. Till 30th day more P was released from 0.5 per cent green manure incorporation, later showed a reverse trend. To study the effect of incorporation of green manure on P utilization by rice, a pot culture experiment was done with 32p labeled green manure and amophos. The results revealed that per cent P derived from fertilizer (% Pdff) increased upto 20 days after transplating and thereafter it decreased, whereas the per cent phosphorus derived from green manure (% Pdfg) was very low during the initial stages, and thereafter it increased considerably. So a combind application of green manure and inorganic P fertilizer will meet the P requirement of the crop throughout the growth period. ‘% Pdfg’ increased with increasing rate of application of green manure. Per cent utilization of P from amophos was high during the initial stages of crop growth, later it decreased while the per cent utilization of P from green manure increased considerably after 20 days of transplanting. The per cent utilization decreased with increasing rate of application of green manure. With regard to crop growth characters, significant increase in plant height and tiller number were observed with the application of 0.25 per cent green manure along with amophos. Among the yield attributing characters, number of spikelets per panicle showed significant increase with the application of 0.25 per cent green manure in combination with amophos. Grain and straw yield were also the highest under the same treatment. Both grain and straw yield were significantly low when green manure alone was applied at the higher rate (0.5 per cent).ThesisItem Open Access Plantlet regeneration through somatic embryogenesis in cocoa (Theobroma cacao L.)(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1994) Jiji, Joseph; KAU; Mallika, V KInvestigations on 'Plantlet regeneration through somatic embryogenesis in cocoa' were undertaken in the Department of Agricultural Botany, College of Horticulture, Kerala Agricultural University, Vellanikkara during 1992-94. Studies were made to identify the most suitable medium, the most responsive genotype and most favourable conditions for embryogenesis in cocoa. Conditions for germination of embryoids to plantlet were also standardised. Among the different media tested for embryogenesis namely, MS, WPM and B5, MS medium was found to be the most ideal. Embryoids could be induced only from the tender cotyledon and embryonal axis of immature embryos of 100 days old pods. Other vegetative tissues like leaf, stem, petal, gynoecium, integumant etc. Yielded only non-embryogenic calli in media for somatic embryogenesis. An important finding in the present study was the standardisation of an ideal medium which favoured maximum embryogenesis from embryonic tissues. This medium was MS+ NAA 1.8 + thiamine 1 mg 1-1 + CW 15 per cent + sucrose 4 per cent. This is a modification of medium proposed for cocoa somatic embryogenesis by Adu-Ampomah et al. (1988). As already reported by other workers, the maximum embryogenesis occurred under dark incubation. The ideal incubation temperature was 30±20C. The embryoids originated singly or in clusters from the cotyledon explants. Most of the embryoids lacked a suspensor but some of them did have a suspensor. A typical embryoids had an embryonic axis and two cotyledons. However, aberrant forms were not uncommon with excessive proliferation of cotyledons as well as with disproportionate axes and cotyledons. The study helped to identify some genotype which showed maximum degree of embryogenesis. The Series I hybrid H 6.5 was found to be the ideal source of explant giving high frequency and intensity of embryogenesis as well as with larger sized embryoids having lesser percentage of abnormalities. The selfed progeny (S1) of this out-breeding crop exhibited minimum degree of embryogenesis. This indicates that the degree of embryogenesis may be associated with the vigour of the explant. Germination of embryoid to plantlet was a difficult process. Liquid media with 1/2 MS salts and 5 per cent sucrose was found to favour germination. A pretreatment was required to remove the inhibitors by washing and desiccation. Only embryoids of larger size (>4 mm) germinated properly to plantlet. The recovered plantlets were too small for field establishment. The most significant achievement in the present study was the plantlet regeneration from somatic embryoids and its planting out in the nursery. This was achieved by micrografting the embryoid derived plantlet to a three week old seedling rootstock. The presence of cotyledons was found to be inhibitory and at least a small leaflet in the embryoid derived plantlet was essential for success in micrografting.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 Time of application of pre-emergence herbicides on phytotoxicity and weed control in semi-dry rice(Department of Agronomy, College of Horticulture, Vellenikkara, 1994) Susan Lee Thomas; KAU; Sreedevi, PA field experiment entitled 'Time of application of pre-emergence herbicides on phytotoxicity and weed control in semi-dry rice' was conducted during first crop season (Virippu) of 1933 i.e., from May to September at Agricultural Research Station, Mannuthy under the Kerala Agricultural University, Vellanikkara, Thrissur. The objective of the trail was to find out the best time of application of pre-emergence herbicided on phytotoxicity and weed control in semi-dry rice. The experiment was laid out in split plot design with three replications. Treatments included in the trail were pre-emergence application of herbicides such as pendimethalin, thiobencarb, butachlor and oxyfluorfen at 0, 3, 6 and 9 days after sowing with handweeded and unweeded plots as the controls. The dominant weeds found in the experiment field were Digitaria sanguinalis and Cynodon dactylon among grasses, Cyperus rotundus and Cyperus iria among sedges and Cleome viscosa and Ageratum conyzoides among broadleaved weeds. The population of grasses was reduced by the application of oxyfluorfen at 6 DAS and pendimethalin upto 6 DAS. Hanweeding was significantly superior than the herbicides in lowering the number of sedges and broadleaved weeds. At 30 DAS the highest weed control efficiency was recorded by oxyfluorfen. Though phytotoxic symptoms were developed in rice seedling where oxyfluorfen was applied at 6 and 9 DAS, it later recovered by about two weeks. Pendimethalin and oxyfluorfen treated plots gave the highest number of tiller/m2. Chlorophyll content of leaves and dry matter production of rice were more in pendimethalin treated plots. Yield attributing characters and yield were higher in plots treated with pendimethalin at 3 DAS. Total returns and return per rupee invested were higher in the case of pendimethalin at 3 DAS and oxyfluorfen at 9 DAS.ThesisItem Open Access Effect of incorporation of cropes residues on productivity of succeding rice crop(Department of Agronomy, College of Horticulture, Vellenikkara, 1994) Beena Jacob; KAU; Mercy GeorgeAn experiment was conducted at the Agricultural Research Station, Mannuthy during the summer and kharif seasons of 1993 to evaluate the effect of cowpea and groundnut residue incorporation on the productivity of succeeding rice crop in comparison to a green manure Sesbania rostrata and a pre-rice fallow under four levels of N (0, 35, 70, and 105 kg/ha). The experiment was laid out in a split plot design with four replications. Biomas yield on dry weight basis was higher for groundnut and sesbania (7.0 t/ha) while N accretion was higher from cowpea (133kg N/ha). Extractable ammonium in the soil was the highest in sesbania incorporated treatments and minimum in plots preceded by fallow. Sesbania underwent faster mineralization compared to residues and mineral-N accumulation reached a peak 15 days after incorporation. Cowpea residue and sesbania incorporation resulted in higher plant height and tiller production. The dry matter production of rice by incorporation of sesbania was on par with cowpea residue when 70 kg N/ha was applied for rice. Sesbania incorporated treatments recorded the highest leaf area index whereas chlorophyll content at boot leaf stage was maximum in cowpea residue treated plots. Number of spikelets per panicle and total number of spikelets per panicle were higher in sesbania incorporated treatments which was on par with that of cowpea residue treated plots. Grain yield was higher after sesbania (3.24 t/ha) and cowpea residue (3.23 t/ha) incorporation and sesbania along with 70 kg N/ha produced the highest grain yield of 3.74 t/ha. N, P and K contents of grain were maximum when rice was grown after cowpea residue incorporation. Total uptakes of N, P and K at harvest were also the highest after cowpea residue incorporation which was statistically similar to that of sesbania incorporation. Even though NPK uptake increased by application of 105 kg N/ha, they were on par with 70 kg N/ha. Groundnut-rice system and sesbania-rice system were comparable in retaining a higher level of soil fertility. Net income was higher from groundnut-rice system whereas return per rupee invested was higher for cowpea-rice system.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.ThesisItem Open Access Economising nitrogen in brinjal using nitrfication inhibitors(Department of Agronomy, College of Agriculture, Vellayani, 1994) Durga, T; KAU; Kuruvila, VarugheseAn experiment was conducted in the instructional Farm attached to the College of Agriculture, Vellayani during kharif 1993 to find out the possibilities of economizing the use of nitrogen for brinjal utilizing nitrification inhibitors. The different treatments tried involved the combinations of three levels of nitrogen viz, 75 kg, N ha-1 (n3), 56.25 kg. N ha-1 (n2) and 37.50 kg. N ha-1(n1) and four sources of nitrification inhibitors viz., ordinary prilled urea (s1), neem cake mixed urea (s2), neem cake coated urea (s3) and coal tar coated urea (s4). The experiment was conducted as a factorial randomized block design with three replications. The results of the study revealed that levels of nitrogen exerted a profound influence on all the growth characters, yield attributes and uptake of nitrogen by the crop. With increasing levels of nitrogen from 37.50 to 75 kg. ha-1 the height of the plant, number of branches per plant, number of leaves per plant, LAI, RGR, DMP, number of flowers and fruits per plant, fruit characters viz., length, girth, volume and weight of fruits, yield and nitrogen uptake, markedly increased. Sources of nitrification inhibitors also showed a significant influence on most of the growth characters and yield attributes. Among the sources tried, neem cake mixed urea (s2) showed its superiority with respect to number of branches and leaves per plant, DMP, number of flowers and fruits per plant, percentage of fruit set and yield. The different sources of nitrification inhibitors did not show any variation in the uptake of nutrients by the crop and also on the available nitrogen status of the soil at different intervals. The economic analysis through partial budgeting indicated that a return of 1.73 per rupee invested was obtained by using 75 kg. N ha-1, and 1.57 and 1.01 by using 56.25 and 37.50 kg. N ha-1 respectively. Among the sources of nitrification inhibitors tried, neem cake mixed urea gave a maximum return per rupee of 1.60 followed by coal tar coated urea (1.42), neem cake coated urea (1.41) and ordinary prilled urea (1.32).ThesisItem Open Access Herbage production of leguminous crops in summer rice fallows(Department of Agronomy, College of Agriculture, Vellayani, 1994) Rajasree, G; KAU; Raghavan Pillai, GAn Investigation was carried out at Cropping Systems Research Centre, Karamana, Thiruvananthapuram to study the fodder production potential of four legumes (cowpea variety CO -5, cowpea variety C-152, cowpea variety Karnataka local and Sesbania rostrata) under three levels of lime (0,125 and 250 kg per hectare) and three levels of phosphorus (0, 30 and 60 kg P2 O5 per hectare) in summer rice fallow. To study the residual effect, a bulk crop of paddy was raised in the first crop season retaining the same layout. The trial was laid out as a split – plot experiment in RBD with three replications. Application for lime increased the growth attributes like plant height, number of leaves, LAI and number of branches, in all fodder legumes. Various growth parameters were increased due to the application of phosphorus. Combined application of lime and phosphorus improved the growth parameters through the indirect effect of increased availability of nutrients. Combined application of higher levels of lime and phosphorus decreased the nodulation in Sesbania rostrata. Combined application of 125 kg lime and 60 kg P2 O5 improved the crude protein content. Application of 250 kg lime increased the plant phosphorus content which however decreased with increasing levels of application of phosphorus. Combined application of 125 kg lime and 60 kg P2 O5 resulted in more plant potassium content. Increase in lime levels from O to 125 kg increased calcium content of legumes. Combined application of 125 kg lime and 30 kg P2 O5 produced more magnesium cont3ent in plant than 250 kg lime and 60 kg P2O5 treatment combination. Available nitrogen content in soil after the experiment increased with the combined application of 250 kg lime and 30 kg P2O5. Combined application of moderate levels of lime and phosphorus resulted in more available phosphorus and potassium contents. Available calcium content of soil increased with increasing level of lime, but magnesium content of soil was found to decrease with the application of 250 kg lime. Sesbania rostrata and cowpea variety CO – 5 produced taller plants, while Sesbania rostrata followed by cowpea variety C – 152 recorded more number of leaves and LAI. Sesbania rostrata also recorded maximum number of branches, but was poor in nodulation where the combined application of 250 kg lime and 60 kg P2O5 declined the stem nodulation. Green fodder yield was maximum in cowpea variety C-152, while dry fodder production was maximum in Sesbania rostrata. Sesbania rostrata recorded highest crude protein, phosphorus, calcium and magnesium contents where as CO-5 had maximum plant potassium content. Available soil potassium content was lowest under cowpea variety CO-5. Uptake of nutrients were maximum in Sesbania rostrata and minimum in Karnataka local. The trial also indicated the suitability of Sesbania rostrata as a fodder crop on account of its higher dry matter production and nutrient content. Cowpea variety C-152 was found to be more economic as a fodder crop under summer rice fallow conditions.
