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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 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 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.ThesisItem Open Access Production potential of cassava (Manlhot esculent a Grants) intercropped in coconut gardens(Department of Agronomy, College of Agriculture, Vellayani, 1986) Ramakrishnan Nayar, T V; KAU; Sadanandan, NField experiments were conducted at the coconut Research Station. Balaramapuram during 1983-84 and 1984-85 to study the production potential of cassava varieties Sreevisakham and Malayan-4, intercropped in coconut gardens, as influenced by planting density, growth regulators and different levels of NPK fertilisers. The cassava hybrid Sreevisakham was superior to the popular cultlvar Maiayan-4 in nuirber of nodes plant 1, number of functional leaves plant™1, leaf area index, net assimilation rate, crop growth rates, dry matter production, utilisation index, tuber bulking rate and in fresh tuber yield. For intercropping one hectare of coconut garden in which coconuts are spaced at 7.5 x 7.5 m, cassava plant population of 8000 (spacing 90 x 90 cm) was found to be optimum to produce maximum fresh tuber yield* Cassava plants at higher planting density, were stunted in growth and produced poor quality tubers. The growth regulators cycocel and ethrel though decreased the plant height, could not Influence either the yield attributes or yield and quality of cassava tubers.ThesisItem Open Access Agrotechniques for soil conservation in taungya systems(Department of Agronomy, College of Horticulture, Vellanikkara, 1986) Gopinathan, R; KAU; Sreedharan, CAn experiment on 'Agrotechniques for soil conservation in taungya systems' was conducted at the Instructional Farm, College of Horticulture, Vellanikkara for a period of two years from May 1984 to April 1986. The objectives of the experiment were to asses the run-off, soil and nutrient losses as influenced by the important taungya practices and to evolve economically and ecologically viable agroforestry measures for soil conservation. Eucalyptus , the main tree component , was intercropped with the usually cultivated taungya crops of cassava and rice . The efficiency of cassava planting on ridges, grass farming and grass stripping was also investigated. There were seven treatments replicated thrice in RBD. Daily run-off and soil loss were quantified by installing multi-slot device consisting of 47 slots and brick masonry settling tank specifically designed for the project.ThesisItem Open Access Evaluation of lowcost agronomic techniques for sustained rice production(Department of Agronomy, College of Horticulture, Vellenikkara, 1985) Sreedevi, P; KAU; Sreedharan, CThree field experiments were conducted at the Regional Agricultural Research Station, Pattambi, Kerala to evaluate some of the low cost agronomic techniques for sustained rice production during the period from 1982 to 1985. In the first experiment the performance of IR 42, a rice variety suited to low fertility conditions was assessed under varying levels of nutrition and spacing. Fertilizer, age of seedlings and planting density, for IR 42 were the experimental variables for the second experiment. In the third trial, azolla was evaluated as a low cost biofertilizer for IR 42. The first and third trials were laid out in split plot design while the second trial in factorial RBD. The rice cultivar IR 42 proved its mettle under the low fertility conditions. In fact, it gave an average yield of 2.78 t ha-1 in virippu and 2.32 t ha-1 in mundakan without any fertilizer application. A plant population of 33 hills m-2 (spacing 20 x 15 cm) in conjunction with full dose of fertilizer of 90 : 45 :45 kg NPK ha-1 recorded substantially more grain yield of 4.24 and 3.20 t ha-1 in virippu and mundakan seasons, respectively. Relatively lower grain and straw yields were registered by the treatment 100 hills m-2 (spacing 20 x 5 cm) at all levels of fertilizer application. The net return and benefit cost ratio were more in the former combination. Increasing the seedling number hill-1 from two to four or six was also found to be beneficial for this variety. At lower levels of fertilizer six seedlings hill-1 recorded higher grain yields. However, at higher levels four seedlings hill-1 was found to be superior. During virippu season planting of 35 days old seedlings was found to perform better compared to 30 and 25 days old seedlings whereas in mundakan season, 30 days old seedlings were found preferable in terms of grain yield. Recommended dose of fertilizers (90 : 45 : 45 kg NPK ha-1) with azolla @ 10 t ha-1 and 75 per cent of the same with azolla @ 15 t ha-1 recorded similar grain yields indicating that an extra dose of 5 t of azolla ha-1 could substantially reduce the chemical fertilizer requirement and save as much as 25 per cent of the fertilizer. The benefit cost ratios were almost equal in both the combinations while the return per rupee invested was more in the latter combination. The finding appears to caution against excessive use of azolla expecting better exploitation of all the benefits attributed to it. Nevertheless, data on the residual fertility of the soil after each crop indicate that residual fertility was higher in the plots receiving full dose of fertilizer along with the highest level of azolla, 20 t ha-1.ThesisItem Open Access Production potential of cassava-based cropping systems(Department of Agronomy, College of Horticulture, Vellanikkara, 1986) Ashokan, P K; KAU; Sreedharan, CA series of field experiments were conducted during the years 1983-84 and 1984-85 at College of Horticulture, Kerala Agricultural University, Trichur, to evaluate some of the cassava based intercropping systems and to investigate the interspecific interactions. There were three field trials and two micro plot trials. In the first field trial, the treatments were factorial combinations of two planing geometries of cassava viz., paired row and square cluster planting geometries of cassava viz., paired row and square cluster planting and four intercropping practices viz., intercropping with colocasia, elephant foot yam, banana and no intercropping. In the second field trial, there wer 12 treatments derived from the factorial combinations of three geometries of planting (paired row, square cluster and triangular cluster) and four intercropping practices (growing a floor crop of cowpea, groundnut, elephant foot yam and not growing any floor crop) in a cassava + banana intercropping system. In the third field trial, the possibility of growing two crops of groundnut in sequence ( Kharif and cowpea and/or Rabi) and the fertilizer requirements of intercrops were studied. All the three field trials were laid out in randomised Block Design and replicated thrice. In one of the micro-plot trials, 32P absorption by the component species in a cassava + banana + elephant foot yam cassava planted in square cluster was studied. polyculture with In the other micro plot trial 32P absorption by cassava and groundnut under the situations of cassava planted in paired row-ridge, mound and flat bed methods were studied. These two microplot trials were laid out in Completely Randomized Design with three replications. Paired row and square clustered planting of cassava gave similar yields as that of normal method when the plant population was the same. Intercropping cassava in square cluster with elephant foot yam resulted in maximum yield of cassava (20.1 t/ha) and elephant foot yam (10.6 t/ha). Banana and colocasia were also found to be successful as intercrops in cassava planted in paired row or square cluster. Intercropping with elephant foot yam and banana resulted in higher yield of cassava. The intercrops colocasia and elephant foot yam recorded lesser yields than the sole crops whereas in intercrop banana such difference was not observed. The maximum LER of 1.81 was obtained in cassava + banana cropping system. The cassava + elephant foot yam intercropping removed 133, 11, 107, 46, 12 and 18 kg/ha of N, P, K, Ca, Mg and S respectively wheras in the cassava + banana combination the corresponding figures were 227, 14, 236, 70, 16 and 11 kg/ha. From the two year trials, the cassava + banana + elephant foot yam cropping system with cassava planted in square cluster (9070 plants/ha) / triangular cluster (6800 plants/ha) was found to be the most productive and economical cropping system. Elephant foot yam was found to be shade tolerant and the yield reduction in intercropped situation was only marginal. The floor crops of cowpea and groundnut were successful in the first year. The land equivalent ratio in cassava + banana + elephant foot yam intercropping was 1.7 and this cropping system gave a net profit of Rs. 13300 per hectare. The N, P, K, Ca, Mg and S removal in a cassava + banana + elephant foot yam cropping system was found to be 198, 24, 200, 166, 34 and 19 kg/ha respectively. Sequential intercropping in paired row planted cassava was not successful, but growing groundnut and red gram simultaneously in the interspace was found to be successful; groundnut was harvested after four months, red gram after eight months and cassava after nine months. The fertilizer requirements of intercrop cowpea and groundnut were found to be only about 60-90 per cent of the sole crop recommendation and the optimum doses of N, P and K worked out were 6, 18 and 18 kg/ha for cowpea and 4, 30 and 30 kg/ha for groundnut. The main crop of cassava also was benefited by the application of fertilizers to the intercrops. The organic carbon and total nitrogen content of soil were reduced in two or three component intercropping systems by the two year cropping practices. The exchangeable P, K, Ca, Mg and SO 4 increased in situations where legmues alone were intercopped and decreased when banana and a floor crop of cowpea, groundnut or elephant foot yam were intercropped. The micronutrient status of the soil was not remarkably changed by the two season cropping. The intercrop and sole crop systems were not different in their influence on the post crop nutrient status of the soil. The radiophosphorus applied to the root zone of any of the components in the mixed cropping system cassava + banana + elephant foot yam with cassava in square cluster planting was absorbed not only by the treated plants but also by the surrounding species. Banana was the most dominant component in this polyculture. In the cassava + groundnut cropping system, cassava was the most dominant component, accumulating about 90 to 98 per cent of the 32P applied to cassava on mounds/ridges and about 50 percent of that applied to the groundnut root zone in the interspaces. Groundnut root system was small and less active and was able to derive only about 2 to 5 per cent of the 32P applied to cassava mounds. It was also deduced that the root interactions were stronger when all the components of the intercropping systems were a longer duration and it would be mild with legume intercrops of short duration.
