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ThesisItem Open Access Production potential of two fodder grasses under different management practices(Department of Agronomy, College of Agriculture, Vellayani, 1986) Raghavan Pillai, G; KAU; Madhavan Nair, K PThesisItem Open Access Effect of NPK on seed progeny and air layers in cashew ( Anacardium occidentale L. )(Department of agronomy, College of Agriculture Vellayani , Trivandrum, 1985) Harishu Kumar, P; KAU; Sreedharan, CAn experiment was conducted to assess the "Ef f e c t of NPK fertilisers on seed orogeny and air layers in cashew at Cashew Seed Farm, Shanmtigodu under Central Plantation Crops Research Institute , Regional Station, f i t c a l 574 24 3, during 1982-84. fhe treatments consisted of test ing three le v e ls each of d,? and K on seed . rogen/ i.,d ai r layers Ln cashcv/. r ’ne study revc ile 1 t h . t d i f f e r en t grov.'th oar meter 7 i. e . , he L'jl'it, can>py rolLus, surf ice area, le a f area n ; : ; v/erc influenced by increasing le v e ls of I:PR. f ■ r t i I i. s e r s . [' r/ ii chlorophyl l , to I; il v.ug ir , le.it v; .ter f-,■ n* , in-: sp e c i f ic le if w ight v;ere influenced by » b ,n v/11 i I e n i t rci' p n 11 one i n c i i iset i , , ., ii c * * . I', i r 1 y i'ii s r: u I: i- c ’ i I i r r - • * * in f l o w e r i n g , numbt l r, f ft mi. t e, _ .m ,lg ,■ I ; -I -,l puilr-h t'< t-i.l il 'hoots WC IX ; i ? V i . r ‘ I i I -■ 1 nr r r 1.0,1 b y f.f r » i I i d L >n . t’rmt j;un ii r‘ rc rn> r ri o nl; inrl acc' u b i ^ ici-1 c o n t e n t , ] Lc if ion . /c r | , 7 0 1 1 0 ' J W l ! " l p l Mut v Jupic an 1 IglTt wctr drrrc ir.ecl due to d M M, ion w,lH. V ipol ic .Llon ( ivour* rl nut md P i p d i ' - 1 , 4-r d W- i n ( k c - T l u 1 n - Leaf N v;as increased by NPIC. Lear ? was increased by p and K appl icat ion v/hile i t was reduced by N appl icat ion. Leaf K was reduced by H appl icat ion while i t was increased by ? and K appl icat ion. N appl ication resul ted in an Increase in le a f C i, where as P and K reduced i t . M and K reduced le a f Mg while P had no e f f e c t . M increased lui f Zn while P reduced the same. K had no e f f e c t . Cr i t ical levels in Ic if for M and ? are f ixed at 2.09% and 0.14% respectively. hoot CSC was increased by UP.' f e r t i 1 is ition . .1 application reduc’d organic carbon and P ‘./hale- i t i.nere -Scd ^>oil M, h and oH. P appl ication increased o i l d, K and pH. ‘V. ipol icat ion incr*. ia«_ , roi l H, h and oH wher>- as i c r c r\ v c c r: o i l P • rj ind P f spons r, r*. curvul in«. ar while not as i u ■ esnonrs v m Jincir. rhc od.imuni of U and P r , pc-j/trr ,./y ai re no-. c t ivt 1 y . M ixvv.um income W L. 1. ' - * * r t ' l i - r r l In lie 1 IV- r r . rThesisItem Open Access Phosphorus management in a rice based cropping system(Department of Agronomy, College of Agriculture, Vellayani, 1989) Annamma, George; KAU; Sasidhar, V KIn order to standardize an appropriate phosphorus management practice in a rice based cropping system involving rice-rice-cowpea/sesamum, field experiments were carried out in the rice fields of the Instructional Farm, College of Agriculture, Vellayani from June 1984 to September 1986. The experiment was laid out in a randomized block design with three replications. There were eight treatments. The treatments comprised of (1) continuous phosphorus application to all the three crops in the system (2) phosphorus application to the first and second crops of rice (3) phosphorus application to the first crop of rice and third crop of cowpea/sesamum (4) phosphorus application to the first crop of rice only (5) phosphorus application to the second crop of rice and third crop of cowpea/sesamum (6) phosphorus application to the second crop of rice only (7) phosphorus application to the third crop of cowpea/sesamum only (8) control plot with no addition of phosphorus to any of the crops in the system. The salient findings of the experiment are as follows: Phosphorus application had no significant influence on grain and straw yield of first crop of rice. But available nitrogen, available and total phosphorus and available potassium of the soil were increased with phosphorus application. Direct, residual and cumulative effects of phosphorus had no significant influence on grain and straw yield of second crop of rice. Phosphorus uptake could not show any variation due to the different treatments. Available and total phosphorus content of the soil were highest under cumulative phosphorus treatment. All the growth and yield attributes of third crop of cowpea and sesamum were increased by the direct and cumulative effects of phosphorus. Grain yield of cowpea was significantly increased by the direct application of phosphorus. Eventhough not significant the highest sesamum yield was accorded by the direct and cumulative application of phosphorus. Phosphorus uptake in all the growth stages of the crop was highest in direct phosphorus plots. Available and total phosphorus content of the soil was highest in continuous phosphorus applied plots. There was no significant influence on grain and straw yield of first crop of rice after cowpea and sesamum in the direct, residual and cumulative effects of phosphorus. Residual phosphorus was sufficient to maintain the available nitrogen status of the soil. Available phosphorus of the soil was increased by the direct, cumulative and continuous application of phosphorus and total phosphorus by continuous application of phosphorus. Balance sheet of available phosphorus revealed that the soil phosphorus level almost maintained, where phosphorus was applied only to the third crop of cowpea or sesamum. The highest net return and benefit-cost ratio for the rice-rice-cowpea and rice-rice-sesamum system was obtained when phosphorus was applied only to the third crop in the rice fallow and the residual effect being utilized by the succeeding rice crops.ThesisItem Open Access Seed production in stylosanthes gracilis under varying levels of population density, nutrition, moisturiser regimes and cuttings(Department of Agronomy, College of Agriculture, Vellayani, 1989) Balachandran Nair, G K; KAU; Sreedharan, CAn investigation was carried out during the period from July 1980 to March 1982 in the Instructional Farm, College of Agriculture, Vellayani to study the agronomic techniques required for maximum seed production in Brazilian lucerne (Stylosanthes gracilis). The following three separate field experiments were conducted and data collected and analysed. The first experiment entitled ‘influence of cultivars and plant population on seed production’ was laid out as a22 Factorial Experiment in R. B. D and replicated five times with the objective to find out the best cultivar of Stylosanthes gracilis for seed production along with the seed rate. The treatments consisted of combinations of two cultivars of Stylosanthes gracilis viz. Schofield and Cook, and two seed rates viz. 2.5 and 5 kg/ha. The second experiment entitled ‘nutritional requirements of Stylosanthes for seed production’ was laid out as a32 Factorial Experiment in R. B. D and replicated thrice with the treatment combinations of three levels of phosphorus viz.80, 120 and 160 kg P2 O5/ha and three levels of lime viz. no lime, 375 and 750 kg lime/ha. The objective was to assess the phosphorus and lime requirement of the crop for maximum seed yield. The third experiment entitled ‘Effect of moisture regimes and cuttings on seed production’ was conducted as a 32 Factorial Experiment in R.B. D and replicated thrice with treatment combinations of three irrigation schedules (IW/CPE ratios) viz. 0.50, 0.75 and 1.00 and three cutting schedules viz. no cutting, one cutting and two cutting. The objective was to investigate the efficiency of irrigation schedules and cuttings on seed yield. The results from the investigation revealed that the variety cook produced significantly higher seed yield of about 64 kg/ha as against 35 kg/ha obtained from the variety schofield. The seed rate of 5 kg/ha gave the higher seed yield of about 56 kg/ha as against the seed yield of about 43 kg/ha under the seed rate of 2.5 kg/ha. The seed yield attributing characters like setting percentage of seeds and number of seeds per plant were maximum for the variety cook. All the growth characters contributed to about 66 per cent of the variation in seed yield. The highest net return per hectare was obtained when the variety schofield was grown under a seed rate of 2.5 kg/ha. Application of phosphorus at 120 kg and lime at 375 kg per hectare gave maximum seed yield of about 80 kg/ha. It was also found that higher levels of phosphorus like 120 or 160 kg/ha helped to increase the setting percentage of seeds. The biometric characters such as spread of plants, number of branches and LAI were significantly influenced by the application of 120 kg phosphorus and 375 kg lime per hectare. The nutrients uptake was also enhanced by the application of phosphorus and lime at the above levels. The growth characters influenced the seed yield by 53 per cent. The economic optimum doses of phosphorus and lime for maximum seed yield were found to be 149 kg and 593 kg per hectare respectively. The highest gross and net returns were obtained from plots treated with phosphorus and lime at 120 kg and 375 kg per hectare respectively. Irrigating the crop at IW/CPE ratio 1.00 gave the maximum seed yield of 89 kg/ha. When the crop was left without cut it produced the highest seed yield of 92 kg/ha. The maximum setting percentage of seeds and leaf production were observed when the crop was irrigated at ratio 1.00 and without cut. The no cutting treatment gave maximum number of seeds per plant. The biometric charaters like height, spread, number of branches and length of branches were all found maximum in treatments where no cutting was given. Maximum water use efficiency for seed production was recorded by the lowest irrigation ratio of 0.50 and also when the crop was left without cut. About 46 per cent of the variation in seed yield was explained by the growth characters. Maximum net return per hectare was obtained when the crop was irrigated at IW/CPE ratio 1.00 and without cut.ThesisItem Open Access Influence of levels of nitrogen, methods of application and plant population on the performance of the high yielding rice variety sabari(Department of Agronomy, College of Agriculture, Vellayani, 1989) Mohamed Kunju, U; KAU; Sadanandan, NAn investigation was undertaken to study the effect of different levels and methods of nitrogen application and different plant populations on the growth, yield and quality of the rice variety sabari in the southern Region of Kerala. The treatments consisted of four levels of nitrogen (40,80,120 and 160 kg/ha), two methods of application of nitrogen (application of the entire dose through soil and 75 per cent through soild plus 25 per cent through foliage) and three levels of spacing viz.10x10cm (100 hills/m2) 10x15 cm (67 hills /m2) and 10x 20 cm (50 hills m2). The experiment was laid out in split-plot design, replicated thrice and conducted for two years at the Instructional Farm, College of Agriculture, Vellayani. Growth characters like plant height, number of tillers per hill, leaf area index and dry matter production at different stages of growth increased with incremental doses of nitrogen. Closer planting resulted in smaller plants and higher number of tillers per unit area. The leaf area index was high in closer planting. Total dry matter production at harvest was more in 10x15 cm spacing. Foliar application of nitrogen (25 per cent) increased the total dry matter production at harvest. Increasing levels of nitrogen delayed flowering. Number of panicles per unit area, length of panicle, weight of panicle, number of spikelets per unit area filled grains per panicle and number of grains per unit area were increased due to incremental levels of nitrogen. Application of the second top dose of nitrogen through foliage produced more number of panicles. It also increased the weight of panicle, number of filled grains per panicle and number of filled grins per unit area. Test weight of grain was more at higher levels of nitrogen. Foliar application also increased the test weight of grain. Maximum yield of grain was recorded at 120 kg/N/ha which was on par with 160 kg N/ha. The average yields of grain at the 40,80,120 and 160 kg N levels were 3149, 3818, 4106 and 4027 kg/ha respectively. Foliar application of the second top dose of nitrogen was superior to soil application in increasing grain yield. Higher grain yield was obtained at 10x15 cm spacing. Quadratic response curve was found to be a suitable fit for nitrogen dose. The overall economic optimum level of nitrogen was 120 kg/ha. It was low (109 kg/ha) at closer spacing and high (124 kg N/ha) at wider spacing. Straw yield was increased with increasing levels of nitrogen application. Foliar application also increased the straw yield. Foliar application of nitrogen resulted in higher grain straw ratio while higher levels of nitrogen decreased the ratio. Increasing doses and foliar method of nitrogen application increased the nitrogen content of plants at flowering and of straw and grain at harvest. Protein content of grain was high at higher levels of nitrogen. It was also increased due to foliar application. The uptakes of nitrogen, phosphorus and potassium were more at higher levels of nitrogen and foliar application. This was not influenced by different spacings. Increasing levels of nitrogen application resulted in only a marginal increase in the residual available nitrogen status of the soil. Residual available phosphorus and potassium in the soil were not appreciably influenced by any of the treatments. Net income and benefit cost ratio were highest at 120 kg N/ha. Foliar application also increased the net income. Among the different spacings 10x15 cm spacing recorded the maximum net income. A combination of 120 kg N/ha of which 25 per cent applied through foliage at the panicle initiation stage with 10x15 cm spacing was found to be the most ideal for maximum benefit from the rice variety sabari under the agroecological situations of the southern Region of Kerala.ThesisItem Open Access Effect of continuous N P K Fertilization on the growth and yield behaviour of coconut with special reference to potash nutrition and its interrelation with other mineral nutrients(Department of Agronomy, College of Agriculture, Vellayani, 1985) Pushpangadan, K; KAU; Sadanandan, NAt the Coconut Research Station , Balaramapuram in Trivandrum District of Kerala State an experiment was laid out in 1964 to assess the growth characters, yield attributes and yield of coconut variety West Coast Tall. The study was further enlarged to include the critical levels of leaf nutrient concentration as related to yield and the soil fertility statusdue to continued NPK fertilization . The treatments consisted of three levels of N, P and K (N-0, 340, and 680 g;P-0, 225 and 450 g and K-0, 450 and 900 g per palm per year). The experiment was laid out in a 3 raise to 3 partially confounded factorial design with two replications. Application of N enhanced the growth characters viz., production of female flowers, percentage fruit set, yield of nuts, weight of nuts, mean thickness and weight of meat, weight of copra and oil percentage. However the effect of N was found to be quadratic at the highest level applied. Application of P although improved the female flower prodcuction, its effect was negative towards copra weight and oil percentage . For the remaining characters studied, the initial level of 225 g per tree per year was found to be adequate.ThesisItem Open Access Agronomic investigations on 'TARO' (Colocasia esculenta L.) variety - Thamarakannan(Department of Agronomy, College of Agriculture, Vellayani, 1986) Mohan Kumar, C R; KAU; Sadanandan, NIn order to standardize the cultural and fertilizer requirement of two (Colocasia esculata) two separate field experiments were conducted during 1983-84 and 1984-85 at the College of Agriculture, Vellayani. The first experiment (Experiment A) with treatments consisting of two sources of planting material (side and mother corn) four spacing (60 x 30, 45 x 45, 60x 45, 60x60 cm) and five sources of mulching (Green leaf, Coconut coir/husk waste, Water hyacinth, black polythene and no mulch) was conducted in asplit plot design. The second experiment (Experiemnt B) was a 3 x 2 partially confounded factorial design with three levels each of nitrogen (40,80,120 kg ha-1), P2O5 (25, 50,75 kg ha-1), K2O (50, 100,150 kg ha-1) and two times of application (two split application of N and K and three split application of N and K) with two replicationThesisItem Open Access Potash nutrition of tapioca (Manihot esculenta Crantz.)(Department of Agronomy, College of Agriculture, Vellayani, 1982) Muraleedharan Nair, V; KAU; Sadanandan, NAn investigation was undertaken at the College of Agriculture, Vellayani and Rice Research Station, Kayamkulam for two years during 1977-79 to study the performance of tapioca (Var. Sree Sahya) under two different agroclimatic conditions. The treatments consisted of three levels of nitrogen (50, 125 and 200 kg N/ha) and three levels of potassium (50,125 and 200 kg K2O/ha) at three times of application. The experiment was laid out in a 3 partially confounded factorial design with two replications.ThesisItem Open Access Ecophysiology of azolla and its management for rice production(Department of Agronomy, College of Agriculture, Vellayani, 1985) Alexander, D; KAU; Sadanandan, NIn order to explore the agronomic potential of azolla for rice production, an investigation entitled 'Ecophysiology of azolla and its management for rice production ' was carried out at the Regional Agricultural Research Station, Pattambi, during the years 1980 to 1984 with the following objectives: (1) To study the influence of environmental conditions on the growth and establishment of azolla. (2) To assess the nutritional requirement of azolla. (3) To find out the time of application and optimum quantity of azolla inoculum required for growing it as an intercrop with rice. (4) To identify the geometry of planting rice favouring the multiplication of azolla in the field.
