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ThesisItem Open Access Standradisation of organic and inorganic fertiliser comnbinations for maximising productivity in bitter gourd (Momordica Charantia L.)(Department of Agronomy, College of Agriculture, Vellayani, 1999) Rajasree, G; KAU; Raghavan Pillai, GAn investigation was carried out during 1995-96 and 1996-97 at the Instructional Farm attached to College of Agriculture, Vellayani to study the efficacy of different levels of N applications (200, 250 and 300 kg N ha") in different ratios of organic - chemical N substitutions (l : 1, 1:2 or 2: 1) at different frequencies (F I - full quantity of organic source as basal, F2 - organic source at basal and at 40th and 70th DAS, F3 - organic source as basal + fortnightly equal splits and chemical N source as basal + fortnightly intervals in equal splits in all the frequencies) of application. Two different organic sources ie. farm yard manure and poultry manure were used in two simultaneous experiments viz. Experiment I and 11. The experiments were separately and simultaneously laid out as confounded 33 design in 9 plot blocks with 2 replications, confounding LR2F in RI and LRF2 in R 11. Higher levels ofN nutrition was found to reduce days taken to flower in farm yard manure applied trial while sex ratio was narrowed at 90 DAS in poultry manure applied experiment. Higher jassid population was noticed at 60 DAS when higher levels ofN was supplied predominantly through organic source as farm yard manure. Fungal leaf spot infestation was higher with the application of200 kg N at 90 DAS and was also more with split applications of both farm yard manure and chemical N source at early stages of growth. Full basal application of poultry manure was found to promote the per hectare yield of fruits, fruit yield planr I and number of fruits planr I compared to its split applications. When highest level ofN (300 kg) was supplied through 2: 1 ratio of organic - chemical N substitution using poultry manure as organic source, it effectively increased the fruit yield and number of fruits plant". 2 Shelf life of fruits at room temperature was more when nutrient N was supplied through 2: 1 ratio of organic - chemical N substitution using farm yard manure or poultry manure as an organic source. When N level was increased beyond 200 kg, shelf life of fruits at room temperature slightly decreased even when it was predominantly supplied through organic source of farm yard manure or poultry manure. Similar trend was noticed at refiigeratory condition too. Nitrogen nutrition showed depressing effect on ascorbic acid or vitamin-C content of fruits in Experiment I. Iron content in fruits was more with the application of 200 or 300 kg N level in Experiment ll. When 300 kg N was applied through a major source of poultry manure (2: 1 ratio) it produced higher iron content in fruits. Higher nitrogen levels or nitrogen nutrition through 2: 1 ratio of substitution promoted the soil bacterial population in both Experiment I and II. Full basal application of farm yard manure or poultry manure favourably influenced the soil bacterial population. Nitrogen nutrition showed depressing effect on fungal population of soil in Experiment I while it stimulated the fungal growth in Experiment 11. Soil actinomycetes population was higher with 2: 1 substitution ratio using farm yard manure as organic source ofN. When farm yard manure or poultry manure as organic source was used in equal or higher proportion with chemical N source, it showed moderating effect on the soil acidity. Full basal application of farm yard manure also enhanced the soil pH from the acidic range and the organic carbon content. Application of higher levels ofN increased the net loss ofN, P and K of soil in both the Experiment I and H. Net loss ofN was higher with 1:2 ratio ofN substitution or few or more split applications of organic source (farm yard manure) in Experiment 1. Net loss of nutrients was moderated during the second year of field experimentation. Nitrogen 3 nutrition in 1:2 ratio of substitution enhanced the net loss ofN in Experiment H. Nitrogen nutrition through 2: 1 ratio ofN substitution or basal + 2 split doses of farm yard manure increased the net loss of P in soil. The net loss of K in soil was more when farm yard manure and chemical N sources were applied in 2: 1 or 1: 1 ratio of substitution. Net gain of K was observed in Experiment H, when chemical N source was substituted in higher proportion compared to poultry manure or when full dose of poultry manure was applied as basal dressing. Higher levels ofN application have resulted in negative net energy returns or energy loss in both the experiments. The 1: 1 or 1 :2 ratio ofN substitution caused higher net energy losses in Experiment I while split applications of poultry manure resulted in more energy loss in Experiment H. Total energy output was higher with full basal application of poultry manure in Experiment I. Energy ratios registered a negative value and was higher with low level ofN application in Experiment I and II. Higher gross returns were obtained when full quantity of poultry manure was applied as basal dose in Experiment 11. Application of300 kg N through 2: 1 ratio of organic- chemical N substitution registered higher gross returns in Experiment II. Net returns was higher when 200 kg N ha! was applied. Increasing N level beyond 200 kg was not economic in Experiment I using farm yard manure as organic source. When full quantity of poultry manure was applied completely as basal dose, higher net returns was obtained in Experiment H. Benefit-cost ratio decreased when N level was enhanced beyond 200 kg ha' in Experiment I. Higher benefit - cost ratio was recorded when poultry manure was applied in full dose as basal dressing. Study revealed the favourable influence of organic sources; farm yard manure and poultry manure on fruit quality, shelf life and soil properties. The suitability of poultry manure as organic source for vegetable cultivation was also established by this study.ThesisItem Open Access Development of diagnosis and recommendation integrated system (DRIS) in black pepper (Piper nigrum L.) in relation to yield and quality characteristics(Department of Agronomy, College of Horticulture, Vellanikkara, 1998) Sreekumaran, V; KAU; Neelakandan Potty, NAn investigative analysis was undertaken during 1993-96 to work out an objective and effective technology for nutritional management of black pepper based on cause and effect relationship. A critical and comparative evaluation of the available methods in this connection, viz. critical level concept, DRIS concept and management based on soil test data, soil analysis was envisaged. Approved standard procedures m estimating soil available and plant contents of nine elements, viz. N P K Ca Mg S Fe Zn and Mn and standard statistical methods were used in the study. A total of 1200 plants aged 14 years maintained at RARS, Ambalavayal were used as the test material in the study. A non-genic variability in yield ranging from 0.16 to 13.8 kg plant-1 was manifested by tile crop which indicated that variability shall be bridged upwards through managerial techniques. The range of available status of the elements in the soil analysis was very high. The lowest range of 0.9 to 4.5 ppm and the highest range of 144 to 1324 ppm were recorded by Zn and Ca, respectively. Soil pH ranged from 4.3 to 6.8. These were at the individual plant level. Foliar content as well as the range of the elements were much less and did not exactly related to soil available contents. Results also indicated that elements showed significant and specific interactions among themselves which varied with the elements. The pattern and magnitude of interactions at soil and plant level were different. Evaluation of soil test data of the study against approved soil test 0 - 9 scale classification showed that rhizosphere environments belonged to medium rich to very rich class and that it could not explain the yield variability and hence could not be a reliable basis of nutritional management in fertile soil. Examination of the foliar content of elements and their comparison with critical levels and ranges fixed by De Waard (1969) and Nybe (1986) respectively, showed that foliar content of all the elements in the study were above the critical levels which suggested that the critical level concept cannot be an adequate guiding principle in nutritional management of black pepper. It may be adequate only in situations where any element becomes specifically critical. Its inadequacy may also be due to the positive and negative interactions of elements in the plant system as well as due to the fact that yield is the resultant of a process involving several elements simultaneously. Negative relationship of P in the early stages and yield level of 6.5 and <1 kg berries at 2.33 and 2.35 per cent level and similar observations confirmed the above contention. DRIS concept was found to be more adaptable to explain the yield variability as it takes into account the content as well as interaction represented by ratios of every element with the others of the high yielding plants and tries to simulate them in low yielding plants. Results of the present study showed that by employing the DRIS concept and nutrient ratios, the content of every element can be identified at any time as absolutely deficient, relatively deficient, relatively sufficient, relatively excess and absolutely excess. This classification enabled to define the nature of recommendation as additive, deletive or ameliorative/corrective. Testing of the classification of the population into discriminative low and high - yielding sub-populations employing mean ± one SD showed that the system may be perfect when the magnitude of yield limiting factors in the entire range of low yield is the same. Possibility of variability in yield limiting factors could be accommodated by sub-dividing the lower yield group into smaller groups as was done in deciles in the study. The results appeared to show that the per plant variability can be accommodated with reasonable accuracy in such a system of micro level yield group identification and application of DRIS norms to them. The unique advantage of the DRIS system to reach the maximum realizable yield through progressive diagnosis based on progressive experimentation shall be substituted by the decile classification proposed in the study to a very good extent. Results of the present study showed that yield and quality factors are largely independent of each other and both can be improved by integrating the respective components even at the higher yield levels obtained in the present study. Analysis of inter-correlation matrix among elements at soil and plant level revealed the possibility of making specific recommendations to achieve progressive yield increases by working out quantity, intensity and rate of release characteristics. of elements in the soil in relation to absorption. Results in the present study showed that scientifically speaking the captions of DRIS indices or index values as " order of requirement" be modified as "order of limiting influences" - the former part of which is relative to metabolic deficiencies and the latter part to the metabolic excess. Imbalance indices have to be viewed as qualitative and not quantitative indices as they are relative, primarily based on the relative deficiencies and excesses which in turn are dependent upon the relative contents and valencies of the ions. The results of the study also revealed that with progressive increase in yield, causing .higher nutrient removal, will make the soil not only more deficient but also increase the frequency of application of nutrients more. The progressive increase in the number of limiting factors with yield improvement caused by higher rate of removal calls for more frequent monitoring and not treating the norm as static for a long period. The results of the experiment have brought to light a graded pattern of nutritional management for black pepper. The primary limiting factors were found to be high native content of Fe and Mn which will have to be ameliorated. Secondly, at the low yield level the yield is limited by a relative deficiency of Zn caused by high P calling for a temporary skipping of P; supplemented with N and K which can take the yield up to 5 kg plant-1. Excess S through the incidental application of prophylactic sprays of Bordeaux mixture and shortage of Ca and Mg appear to be the limiting factors at the higher yield class. Amelioration of acidity by supplying Ca + Mg carbonate, substitution of S containing fungicides and application of N and K shall constitute the recommendation, beyond which P may have to be applied.ThesisItem Open Access Developement of diagnosis and recommentation integrated system(Department of Agronomy, College of Horticulture, Vellanikkara, 1998) Sreekumaran, V; KAU; Neelakandan, Potty NAn investigative analysis was undertaken during 1993-96 to work out an objective and effective technology for nutritional management of black pepper based on cause and effect relationship. A critical and comparative evaluation of the available methods in this connection, viz. critical level concept, DRIS concept and management based on soil test data, soil analysis was envisaged. Approved standard procedures m estimating soil available and plant contents of nine elements, viz. N P K Ca Mg S Fe Zn and Mn and standard statistical methods were used in the study. A total of 1200 plants aged 14 years maintained at RARS, Ambalavayal were used as the test material in the study. A non-genic variability in yield ranging from 0.16 to 13.8 kg plant-1 was manifested by tile crop which indicated that variability shall be bridged upwards through managerial techniques. The range of available status of the elements in the soil analysis was very high. The lowest range of 0.9 to 4.5 ppm and the highest range of 144 to 1324 ppm were recorded by Zn and Ca, respectively. Soil pH ranged from 4.3 to 6.8. These were at the individual plant level. Foliar content as well as the range of the elements were much less and did not exactly related to soil available contents. Results also indicated that elements showed significant and specific interactions among themselves which varied with the elements. The pattern and magnitude of interactions at soil and plant level were different. Evaluation of soil test data of the study against approved soil test 0 - 9 scale classification showed that rhizosphere environments belonged to medium rich to very rich class and that it could not explain the yield variability and hence could not be a reliable basis of nutritional management in fertile soil. Examination of the foliar content of elements and their comparison with critical levels and ranges fixed by De Waard (1969) and Nybe (1986) respectively, showed that foliar content of all the elements in the study were above the critical levels which suggested that the critical level concept cannot be an adequate guiding principle in nutritional management of black pepper. It may be adequate only in situations where any element becomes specifically critical. Its inadequacy may also be due to the positive and negative interactions of elements in the plant system as well as due to the fact that yield is the resultant of a process involving several elements simultaneously. Negative relationship of P in the early stages and yield level of 6.5 and <1 kg berries at 2.33 and 2.35 per cent level and similar observations confirmed the above contention. DRIS concept was found to be more adaptable to explain the yield variability as it takes into account the content as well as interaction represented by ratios of every element with the others of the high yielding plants and tries to simulate them in low yielding plants. Results of the present study showed that by employing the DRIS concept and nutrient ratios, the content of every element can be identified at any time as absolutely deficient, relatively deficient, relatively sufficient, relatively excess and absolutely excess. This classification enabled to define the nature of recommendation as additive, deletive or ameliorative/corrective. Testing of the classification of the population into discriminative low and high - yielding sub-populations employing mean ± one SD showed that the system may be perfect when the magnitude of yield limiting factors in the entire range of low yield is the same. Possibility of variability in yield limiting factors could be accommodated by sub-dividing the lower yield group into smaller groups as was done in deciles in the study. The results appeared to show that the per plant variability can be accommodated with reasonable accuracy in such a system of micro level yield group identification and application of DRIS norms to them. The unique advantage of the DRIS system to reach the maximum realizable yield through progressive diagnosis based on progressive experimentation shall be substituted by the decile classification proposed in the study to a very good extent. Results of the present study showed that yield and quality factors are largely independent of each other and both can be improved by integrating the respective components even at the higher yield levels obtained in the present study. Analysis of inter-correlation matrix among elements at soil and plant level revealed the possibility of making specific recommendations to achieve progressive yield increases by working out quantity, intensity and rate of release characteristics. of elements in the soil in relation to absorption. Results in the present study showed that scientifically speaking the captions of DRIS indices or index values as " order of requirement" be modified as "order of limiting influences" - the former part of which is relative to metabolic deficiencies and the latter part to the metabolic excess. Imbalance indices have to be viewed as qualitative and not quantitative indices as they are relative, primarily based on the relative deficiencies and excesses which in turn are dependent upon the relative contents and valencies of the ions. The results of the study also revealed that with progressive increase in yield, causing .higher nutrient removal, will make the soil not only more deficient but also increase the frequency of application of nutrients more. The progressive increase in the number of limiting factors with yield improvement caused by higher rate of removal calls for more frequent monitoring and not treating the norm as static for a long period. The results of the experiment have brought to light a graded pattern of nutritional management for black pepper. The primary limiting factors were found to be high native content of Fe and Mn which will have to be ameliorated. Secondly, at the low yield level the yield is limited by a relative deficiency of Zn caused by high P calling for a temporary skipping of P; supplemented with N and K which can take the yield up to 5 kg plant-1. Excess S through the incidental application of prophylactic sprays of Bordeaux mixture and shortage of Ca and Mg appear to be the limiting factors at the higher yield class. Amelioration of acidity by supplying Ca + Mg carbonate, substitution of S containing fungicides and application of N and K shall constitute the recommendation, beyond which P may have to be applied.ThesisItem Open Access Nutritional balance analysis for productivity improvement of rice in iron rich lateritic alluvium(Department of Agronomy, College of Horticulture, Vellenikkara, 1999) Bridgit, T K; KAU; Potty, N NInvestigation entitled “Nutritional balance analysis for productivity improvement of rice in iron rich lateritic alluvium” consisting of seven experiments was conducted during 1995-1997 in the farm attached to the Agricultural Research Station, Mannuthy. Objective of the study was to identify the factors that limit the productivity of rice in the lateritic alluvium, estimate the nature and extent of their influences, formulate and test the methodology to overcome them and to evolve high – tech management programme to get 6 t or more yield of grain per hectare. The study included evaluation of the influences of all the cultural and nutritional inputs on the content and balances of N,P,K,Ca,Mg,S,Fe,Mn,Zn, Cu and SiO2 in the root, culm and leaf at MT and PI and boot leaf in addition to uptake in grain and straw. Results revealed the following Field evaluation of the crop performance in 36 locations of Thrissur and Palakkad districts of Kerala spread in km2 and three soil types revealed that yield ranged from 2800 to 9000 kg ha-1. Low productivity was not due to real deficiency of any of the 11 elements in the foliage. Foliar concentrations of individual elements were more than what has required to produce yield levels above 7000kg ha-1 in some locations expect for silica. Low realized yields were found to be due to the excess plant contents of non-applied elements especially Fe, Mn,Zn and Cu as well as their interactions in plants. As such, soil test or tissue test values of elements were found inadequate, a “content balance combined approach” was found to be better tool in nutritional management. Iron content of the root of the order of 50,000 ppm under submerged conditions was found to inhibit morphological and physiological development leading to low yield. Physiologically, lower development of chlorophyll ‘a’ and its poor stability as well as a higher sap PH lead to low dry matter accumulation. Morphologically the effect was expressed through very few long roots at MT,low root weight, root damage and failure of further initiation of roots, protracted production of fewer tillers as well as their decline and low dry matter accumulation in the shoots between MT and flowering periods. Yield variation due to the early suppression alone was of the order of 1800 kg ha-1. Harmful effects of Fe in the plant was less subsequently as Fe decreased progressively with growth of the plant. Manganese and Zn and to some extent Cu found to take over from Fe in the post panicle initiation phase. Leaf concentrations of these elements at PI and flowering stages rise far higher the critical levels. Manganese was found to reduce photosynthetic efficiency at this stage and Zn was identified with affecting translocation to the grain from vegetative parts in the maturity phase, thereby affecting translocation to the grain from vegetative parts in the maturity phase, thereby affecting grain – straw ratio. Lower productivity of second crop (September – October compared to first crop (April – May seeded rice) was found to be due to the higher foliar concentrations of Mn and Zn in the PI stage onwards. Cultivation under continuous submergence aggravated these inhibiting influences. Thus low yield of rice in laterite soils was found to be due to a multi – element multiphase effect. Nutritionally these effects could be recognised through narrow N/Fe, N/Mn, K/Fe, K/Zn ratios. Application of Ca @ 150 kg lime ha-1 could reduce the Fe content of the plant and S at 100 kg ha-1 could reduce Mn and Zn content in the plant at PI. Substituting urea with Ammonium sulphate for top dressing appeared to be better to contain Mn and Zn at PI stage. Application of SiO2 at 250 kg ha-1 and increasing the levels of K from the present level of 45 kg to 120 kg ha-1 and resorting to dry seeding in April-May crop and wet seeding in October-crop and irrigation once in three days after disappearance of ponded water were found to be effective means of containing the low yield malady and raise the yield beyond 6 t ha-1. This production programme has the advantage that it does not involve much additional input, offers the scope of reducing P application by 50 per cent and scientifically sustainable as it keeps nutrient removal within the levels of application of N, P and K. This programme also offers a way to progressional yield improvement above 6 t ha-1 as the levels of Fe, Mn and Zn in the leaves are still far higher than suggested critical levels.ThesisItem Open Access Biological and control of the weed Mikania micrantha HBK in Kerala(Department of Agronomy, College of Horticulture, Vellenikkara, 1999) Mini Abraham; KAU; Abraham, C TMikania micrantha is a recently introduced weed spreading fast in agricultural and non-agricultural areas of Kerala. It is commonly known as mile-a-minute weed in English and as American vally, Padvayara etc. in Malayalam. A study on "Biology and control of the weed Mikania micrantha HBK in Kerala" was undertaken at the College of Horticulture, KAU, Vellanikkara during 1995-1999 to study the distribution, biology, competition to crops and alternate uses of Mikania and also to develop recommendations for controlling the weed. Infestation of Mikania was found to be widespread in Ernakulam and Kottayam districts and in most parts of Trichur, Idukki, Alappuzha and Pathanamthitta districts. The weed has not yet spread to the southern districts, with no infestation in Thiruvananthapuram and only isolated incidence in Kollam district. In the northern districts of Malappuram, Palakkad, Kozhikode, Wynad, Kannoor and Kasaragod, only isolated infestation was noticed. Mikania is a fast growing herbaceous perennial climber belonging to the family Asteraceae. The weed seeds germinated in April-May, flowered in October and took 9 to 12 days for seed maturity. Inflorescence is an umbel of heads. Average seed output per plant was 45812 with an average production of 357 inflorescence, each having 32 flowers (four seeds per head). Fresh seeds gave 80 per cent germination and the viability decreased to zero after seven months of storage. 2 The weed can propagate by seeds and stem . cutti ngs. Seeds kept for germination on the soil surface (0 cm depth) gave maximum germination, whereas even the slight burying of the seeds prevented germination. From the stem cuttings, maximum establishment was for the cuttings from the basal portion of stem when planted at zero depth of planting followed by middle and apex portio . Sprouting per cent decreased with depth of planting with no sprouts arising when planted at 5 cm below the surface. No sprouts were produced from internode at any depth of planting. Leaves did not sprout, but the leaf petioles with axillary bud produced sprouts. Competition from Mikania suppressed the growth of pineapple, banana, rubber, coconut, cocoa and teak plants. It also delayed the flowering and reduced the fruit weight of pineapple and banana. Among the. physical methods of control, digging at monthly interval was found to be the best followed by digging at bimonthly interval, sickle weeding at monthly interval and sickle weeding at bimonthly interval. Pre emergence herbicides, diuron 0.5 kg ha") and oxyflourfen (0.20 kg ha:') resulted in prevention of germination and establishment of Mikania followed by atrazine, butachlor, metolachlor, alachlor, pretilachlor and fluochloralin. All forms of 2, 4-D resulted in complete drying of Mikania. Even the lowest dose (0.25 kg ha') tested gave 92-99 per cent control of Mikania. Other herbicides in the order of effectiveness were glyphosate, glufosinate ammonium and paraquat. 3 Eighteen insect pests were found infesting Mikania. The major pests were aphid, tea mosquito bug, thrips and the lepidopteran pest, Spilosoma obliqua. However, since all these insect pests are polyphagous in nature, their utility for biological control is limited. Pathogens infecting the weed were identified as Colletotrichum gloeosporioides, Alternaria alternata, Curvularia lunata Var. aria and Corynespora cassicola. The toxic metabolites (both endotoxin and exotoxin) isolated from Colletotrichum sp. and Alternaria sp. produced necrotic symptoms on Mikania. Size of the leaf spot increased with time leading to complete drying of the leaf by four days. Biornass yield of single Mikania plant was 2.25 kg fresh weight (18.25 % dry weight). Under natural field condition biornass yield from one square metre area was 2.012 kg fresh weight. Average increase in the length of vine per day was 6.29 cm. The mean content of different nutrients in Mikania was 2.35 per cent N, 0.39 per cent P, 3.58 per cent K, 0.82 per cent Ca, 0.42 per cent Mg, 0.013 per cent Mn, 0.167 per cent Fe, 0.0045 per cent Cu and 0.022 per cent Zn. Rate of decomposition of Mikania was faster during the initial period and decreased towards the end of the study, reaching almost 100 per cent decomposition by one year. <, Fodder value was studied by estimating the chemical composition and fibre fraction of Mikania. It contained an average of 14.63~ cent crude protein, 2.36 per cent fat. ~:3.2 per cent crude fibre, 48.75 per cent nitrogen free extract, 8.92 per cent ash, 0.87 per cent calcium and 0.42 per cent phosphorus. The fibre fractions 4 contained 42.42 per cent neutral detergent fibre, 33.22 per cent acid detergent fibre, 0.096 per cent cellulose, 9.2 per cent hemicellulose and 10.84 per cent lignin. The analysis for anti-nutritional factor hydrocyanic acid showed negative result. Allelopathic effect of Mikania when used as mulch or incorporation as well as the effect of the Mikania extract were studied using the test crops, rice, cowpea and rubber. Mikania had an inhibitory effect on growth of rubber, but the growth of rice was enhanced by its application. Treatment with Mikania extract did not have any influence on germination and radicle length of rice seeds where as in cowpea seeds the allelopathic effect was very much pronounced.ThesisItem Open Access Studies on some competing factors in the intercropping systems of rubber (Hevea brasiliensis Muell. Arg)(Department of Agronomy, College of Horticulture, Vellenikkara, 1999) Mathew Joseph; KAU; Vikraman Nair, RField experiments were conducted at the Kerala Agricultural University during 1994-97 to study the extent of involvement of root level competition and competition for light in the early years of growth of rubber. Rooting pattern of rubber was studied employing 32p soil injection technique. Activity was applied at varying lateral distances of 50, 100, 150, 200 and 250 cm from the plant and varying depths of 10, 25, 50, 75 and 100 cm. This experiment was laid out in randomised block design and was replicated thrice. In another experiment, rubber was intercropped with banana cv. Poovan under two systems of planting. The extent of root competition was evaluated using 32p soil injection technique. Both rubber as well as banana were treated with the radio label 32p. It was applied in four circles of varying radii of 25,50, 100 and 150 cm around the plant. Along each circle, nine equidistant holes were made and required activity was applied in alternate holes at depths of 25, 50 and, 75 cm. This experiment was laid out in CRD. In a third field experiment, the intensity of light infiltration through rubber canopies of varying ages was studied. For this, fields with one to seven-year-old rubber were selected and in each age group the extent of filtered light was measured. These were related with the biological parameters of rubber plant viz., girth, height and canopy diameter. The most important findings of the investigation are abstracted below. Uptake of soil applied 32p by one-year-old rubber is maximum when the radio chemical was applied in a lateral distance of 50 cm and depth of 25 cm. The interaction between lateral distance and depth of application of 32p was significant. The extent of root activity in one-year-old rubber was confined to a lateral distance of 50 cm and a vertical distance of 25 cm was over 90 per cent. 2 In two-year-old rubber, uptake of soil applied 32p was significant with respect to lateral distance and the highest activity was noticed at 50 cm followed by 100 cm distance. The effect of depth of application was also significant and 50 cm depth recorded maximum recovery of the radio label. The interaction effect was also significant. Regarding the root activity pattern of two-year-old rubber, about 80 per cent activity was confined to a zone of 100 cm lateral distance and 50 cm depth. During the third year, maximum recovery of soil applied 32p was obtained from a lateral distance of 50 cm followed by 100 and 150 cm. Uptake of activity was found to be independent of the depth of application. More than 90 per cent of root activity was concentrated to a lateral distance of 150 cm from the plant. Uptake of 32p by both rubber and banana was higher when these crops were grown alone during the first year of planting. Among the intercropped situations,there was more of sharing of applied activity during first year in the case of the double row system of intercropping banana. Root activity of rubber was reduced to approximately one third by intercropping with a single row of banana and this was further reduced in the double row system. Uptake of 32p by two-year-old rubber was higher when intercropped with single row banana than double row. 3 In the second year also, percentage root activity was more for sole rubber and banana as compared to their mixed stand. The root activity of rubber was reduced to approximately 24 and 16 per cent in rubber mixed with single and double row banana, respectively. In the third year also, sole crops of rubber and banana registered higher uptake rate of radioactivity compared to the intercropped situations. Radio uptake by three-year-old rubber plants under intercropped situation was higher in the single row system of planting banana. Root activity was reduced to 27 and 17 per cent under single row and double row systems of intercropping banana, respecti vel y. Absorption of 32p by banana when intercropped with three-year-old rubber was higher in the single row system than in the double row system of banana. The percentage values were 27 and 8 per cent, respectively. Uptake of activity by banana was maintained at much higher levels during the three years of intercropping under single row system (60 to 27 per cent). But in the double row system the activity was drastically reduced with age. The degree of root competition between rubber and banana was minimum when rubber was intercropped with single row of banana during the initial three years of planting rubber. The growth of rubber tree is closely associated with the steady increase in all the growth parameters during the immature phase. ."', 4 Progressive development of rubber canopy proportionately reduced the light infiltration from 97 per cent at the close of first year to a meagre 7 per cent at the end of the seventh year. All the growth parameters observed were significantly related among themselves and had a negative correlation with the percentage of light infiltration. Reasonably accurate prediction on available infiItered light is possible using the equation y = ab", if only anyone parameter of growth observed is known. It is concluded that the active roots of rubber are concentrated in radial distances of 50, 100 and 150 cm from the plant during the first, second and third years of growth respectively. Majority of roots are found below soil surface to a range of 20-30 cm during the initial three years. Based on these, it can be tentatively recommended that fertilisers for rubber may preferably be placed in basins of proportionate radius and at a depth of 20-30 cm during the first, second and third years respectively. Banana can be grown in the inter row spaces of rubber as a rainfed crop during the initial three years. Insufficiency of filtered light through the rubber canopy will limit the scope for intercropping beyond the third year of growth of rubber.ThesisItem Open Access Sustainable technology for higher productivity in mulberry sericulture(Department of Agronomy, College of Horticulture, Vellenikkara, 1999) Anilkumar, A S; KAU; John, P SCultivation of mulberry is a pre-requirement for silk industry. Being a perennial crop it will be well adapted to the West Coast. Formulation of sustainable production technology is a necessity for its popularisation. Three experiments under the project 'Sustainable technology for higher productivity in mulberry sericulture' were carried out at the College of Horticulture, Vellanikkara during 1994-96 to develop appropriate agro-techniques for mulberry cultivation under tropical condition. The first experiment consisted of combinations of three levels NPK, viz, 150:60:60,225:90:90 and 300: 120: 120 kg ha:' year", four green manuring methods, viz, in situ cultivation and incorporation of cowpea, in situ cultivation and composting of cowpea, green leaf manuring and no green manuring and five biofertilizer treatments viz, Azospirillum, Vesicular Arbuscular Mycorrhizae (VAM), Phosphorus Solubilising Bacteria (PSB), combined application of Azospirillum, VAM and PSB and no biofertilizer. Response of two varieties of mulberry, viz, K-2 and S-54 to four irrigation levels ie, no irrigation, irrigation at CPE 15 mm, irrigation at CPE 30 mm and irrigation at CPE 45 mm and four soil moisture conservation techniques, ie, incorporation of coir pith, mulching with coconut husk, incorporation of silkworm litter and control were studied in the second experiment. In the third experiment, effect of combinations of three different planting geometry, ie, normal row planting, paired row planting and high density planting, three levels of shade, ie, no shade, 25 % shade and 50 % shade and five intercropping systems with green manure crops, viz, cowpea, mimosa, desmodium, calapagonium and no green manure crop were included. All the three experiments were laid out in split plot design. ii Experiment I. Cost effectiveness in mulberry nutrition under irrigated condition Integrated nutrient management involving the application of NPK @ 225:90:90 kg ha" year", in situ cultivation and incorporation or composting of cowpea and combined application of Azospirillum, VAM and PSB was found to increase the total fresh leaf yield of mulberry. In the silkworm rearing trial, leaves from mulberry garden receiving NPK @ 300: 120: 120 kg ha" year", in situ cultivation and incorporation or composting of cowpea and combined application of Azospirillum, V AM and PSB registered higher leaf consumption due to better leaf quality and consequently improved cocoon weight, shell weight and filament length. Though the level of fertilizers didn't influence the per cent infection of V AM, the spore load in soil was increased with increase in fertilizer levels. Moderate level of NPK viz, 225:90:90 kg ha' year" recorded maximum colonisation of Azospirillum. PSB population increased with increasing levels of fertilizers. In situ cultivation and composting of cowpea and combined application of Azospirillum, V AM and PSB showed maximum colonisation of Azospirillum and PSB. The economic analysis of the system revealed the significance of NPK application @ 225:90:90 kg ha" year", in situ cultivation and composting of cowpea and combined application of Azospirillum, V AM and PSB in terms of gross income, net income, benefit: cost ratio (BCR) and sustainable yield index (SYI). Experiment 11 Utilization of agricultural byproducts for economising water use and improvement in leaf quality and productivity of mulberry The combination of the variety S-54, irrigation at CPE 30 mm and mulching with coconut husk resulted in significantly higher total fresh leaf production. Leaf quality parameters such as leaf moisture and leaf protein contents were higher in the variety S- 54, however, the moisture retention during 24 hour storage was more with the variety III K-2. Irrigation and mulching with coconut husk resulted in increased leaf protein content. Seasonal and daily consumptive use, and crop coefficient were higher in S-54, and increased with irrigation at CPE 15 mm and mulching with coconut husk. The variety S-54 irrigated at CPE 30 mm resulted in maximum crop water use efficiency. However, field water use efficiency was highest with respect to S-54 with irrigation at CPE 45 mm and mulching with coconut husk. The silkworm rearing trial revealed the superiority of the variety S-54 with respect to leaf consumption, larval weight, cocoon weight, shell weight, filament length and filament weight. The economic analysis of the system proved the significance of the variety S-54, irrigation at CPE 30 or 45 mm and mulching with coconut husk in relation to gross income, net income, BCR and SYI. Experiment Ill. Shade tolerance and in situ development of green manure sources in mulberry Paired row planting, cultivation under open conditions and intercropping with green manure cowpea resulted in maximum fresh leaf production at all harvests. Paired row planting and cultivation under open conditions resulted in the production of quality leaves with respect to leaf moisture and protein content which in turn improved the larval and cocoon characters and post cocoon parameters. Intercropping with green manure Mimosa improved the available nitrogen content of soil after the experiment. Intercropping with green manures, viz, cowpea, Mimosa, Desmodium or Calapagonium were beneficial in increasing the available potassium content of soil. The economic analysis of the system revealed the superior performance of paired row planting, cultivation under open conditions and intercropping with cowpea and subsequent green manuring in relation to gross income, net income and BCR. The combination paired row planting, cultivation under open conditions and intercropping with green manure Mimosa resulted in the highest SYI.ThesisItem Open Access Nutrient- growth regulator interaction in snakegourd (Trichosathes anguina L.) under drip irrigation system(Department of Agronomy, College of Agriculture, Vellayani, 1998) Elizabeth K, Syriak; KAU; Raghavan Pillai, GTwo field experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, to study the effect of varying levels of nitrogen (n), ethephon (g) and drip irrigation frequency (i) on the productivity of snakegourd. The influence of the treatments on the size, quality and shelf life of the produce and also on the physico-chemical properties of soil was investigated. The trials were conducted during the summer seasons (December to April) of 1994-'95 and 1995-'96. The experiments were laid out in 4 2x2 + 2 asymmetrical confounded factorial design with two replications and each replication included two blocks. Combinations of four levels each of N (35, 70, 105 and 140 kg ha'), ethephon (0, 50, 100 and 200 ppm) and two frequencies of drip irrigation (5 mm CPE and 10 mm CPE) constituted the treatments along with two controls (nogoiI and llogoi2) in each block. The highest order interaction NOI was confounded in both the replications. Results of the field experiments revealed that during both the years of experimentation, nitrogen, ethephon and irrigation frequency exerted significant positive influence on the fruit yield of snakegourd. During both the years, the higher levels of nitrogen (105 and 140 kg N ha') were found to be significantly superior to the lower levels (70 and 35 kg N ha'). Pooled analysis of the yield data also revealed a similar trend. Growth characters like internodal length, number of leaves plant" and dry matter production showed significant enhancement due to N application. The positive significant effect of N was manifested in the yield attributes viz., number of fruits plant" and average fruit weight. Significant increase in the WUE of the crop due to N application was also observed. The content and uptake of major nutrients also increased substantially due to applied N. Nitrogen improved the quality of fruits, significantly, in terms of crude protein, total sugars, reducing sugars and ascorbic acid content. However, the shelf life was adversely affected by it. The highest net profit and B:C ratio were recorded by 105 kg N ha' (Rs. 74,636/- and 2.37, respectively) compared to the other levels of N. Considerable improvement in the physico-chemical properties of soil due to applied N was also noticed. The results of the field experiments also indicated significant yield . increase in snakegourd due to ethephon application. The higher levels of ethephon ie., 100 and 200 ppm, were found to be significantly superior to the lower levels in this regard. Growth and yield attributes as well as quality of fruits were favourably influenced by ethephon. Through its indirect positive effect on fruit yield, the higher levels of ethephon improved the WUE of the crop significantly over its lower levels. The economic analysis also revealed the positive effect of ethephon on the net profit and B:C ratio and the highest values were registered by 200 ppm ethephon (Rs. 71,194/- and 2.31, respectively). With respect to irrigation frequency, il (irrigation at 5 mm CPE) registered significantly higher fruit yield compared to i2 (irrigation at 10 mm CPE): Growth characters and also the quality of fruits exhibited a similar trend. More frequent irrigation treatment (i.) exerted its positive significant effect on yield attributes viz., number of fruits plant:' and mean weight and girth of fruits. The physical optima for N at il were worked out to be 100 and 115 kg ha" during the first and second year, respectively. Economic analysis also revealed the favourable effect of frequent drip irrigation, with il registering substantially higher net profit and B:C ratio (Rs. 70,038/- and 2.28, respectively) compared to i2 (Rs. 61,615/- and 2.14, respecti vel y) .. A perusal of the data on fruit yield and economics of the treatment combinations elicited the favourable effect of n3g4il which registered the highest fruit yield, net profit and RC ratio (31.06 t ha", Rs. 1,04,271/- and 3.04, respectively) and hence this combination could be adjudged as the best one for snakegourd cultivation.ThesisItem Open Access Integrated nutrient management for rice based cropping systems of Onattukara tract(Department of Agronomy, College of Agriculture, Vellayani, 1998) Shalini Pillai, P; KAU; Muraleedharan Nair, VAn investigation was carried out at the Rice Research Station, Kayamkulam to identify the most suitable rice based cropping system for the Onattukkara tract and to evolve a suitable ecologically and economically viable integrated nutrient management practice for the system. The experiment was laid out in a 4x6 factorial strip plot design and was carried for two consecutive years extending from April, 1994 to May 1996. The treatments consisted of four cropping systems (rice-rice-sesamum, rice-rice-groundnut, rice-rice-cowpea and rice-rice-bhindi) and six nutrient management levels (N1 farmers' practice, N2 - Package of practices recommendations, N3 three-fourth recommended N as chemical + one-fourth as FYM, N4 - three-fourth recommended N as chemical + one-fourth as FYM + Azospirillum, N5 - three-fourth recommended N as chemical + one-eighth as FYM + one-eighth as vermicompost and N6 - three fourth recommended N as chemical + one - eighth as FYM + one - eighth as vermicompost + Azospirillum). During the third crop season the treatments N2 to N6 was package of practices recommendations (for the respective crops) while N1 was farmers' practice itself. Among the different nutrient management levels tested, the treatment wherein one-fourth recommended N was substituted with FYM and vermicompost along with Azospirillum recorded the maximum grain yield for first crop rice and second crop rice (irrespective of cropping system). The same treatment also supported a better straw yield by maintaining a favourable grain:straw ratio. In ricc-rice-'sesamum, the production efficiency was highp.st when one-fourth recommended nitrogen was supplied through farmyard manure and vermicompost along with Azospirillum. The BCR was maximum when the same treatment was applied without Azospirillum. In rice-rice-groundnut, rice- rice cowpea and rice-rice-bhindi, the same trend followed. Rice-rice-bhindi cropping system recorded the maximum production efficiency followed by rice-rice-groundnut during both the years, and rice-rice-sesamum recorded the minimum value. The overall mean returns was maximum with the cropping system,rice- rice-groundnut. It was followed closely by the rice-rice-bhindi cropping system. While rice-rice-cowpea recorded the meaning of economic returns during the first year, rice- rice sesamum recorded the same during the second year. Studies on the physico-chemical properties of the soil showed that the cropping system, rice-rice-sesamum resulted in a slight increase in bulk density, water holding capacity and water stable aggregates. The organic carbon, total nitrogen and available phosphorus content of the soil increased, while the soil pH, available nitrogen and available potassium contents decreased. The cropping system, rice-rice- groundnut resulted in an increase in bulk density, water holding capacity, water stable aggregates, organic carbon, soil pH, total nitrogen and available phosphorus and a decrease in the available nitrogen and available potassium contents. While there was an increase in the water holding capacity, water stable aggregates, organic carbon, total nitrogen, available nitrogen and available phosphorus there was a slight decrease in bulk density and soil pH in the cropping system, rice-rice- cowpea. The rice-rice-bhindi cropping system resulted in a decrease in the bulk density and soil pH and available potassium and an increase in the water holding capacity, water stable aggregates, organic carbon, total nitrogen, available nitrogen and available phosphorus. The balance sheet of nitrogen showed•a positive balance in the cropping systems rice-rice-groundnut and rice- rice-cowpea and a negative balance in the other two systems. All the cropping systems tested resulted in a negative balance for available phosphorus and a positive balance for available potassium. The cropping system, rice-rice-groundnut was observed to be the most efficient one. followed by rice-rice-bhindi based on the productive efficiency, benefit cost ratio and soil sustainability. The marginal benefit cost ratio for the different nutrient management practices showed that the treatment comprising three fourth recommended dose of N as chemical + one-eighth as FYM + one-eighth as vermicompost (for first and second crop rice) and package of practices 1ecommendations for groundnut (third crop) was the most economic. However, for the rice-rice-bhindi cropping system, the package of practices recommendations was observed to be more economical.