Browsing by Author "Aiyer, R S"

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Availbale zinc, copper, iron and manganese status of the acid rice soils of Kuttanad, Kerala state
(Kerala Agricultural University, 1975) Aiyer, R S; Rajagopal, C K; Money, N S
Determination of available zinc, copper, iron and exchangeable manganese in the [Cari, Karapadom and Kayal soils of Kuttanad region, Kerala State, revealed that all the three soil types are highly deficient in available copper (90%). Available zinc was deficient in 50% of the Kayal soils studied. High amounts of available iron in the Kari soils suggest the possibility of iron toxicity to rice in these soils. Significant and positive correlations existed between available copper on the one hand and organic carbon (r= + 0.400) and CEC (r= + 0.566! on the other. Available iron was significantly and positively correlated with organic carbon (r= +0689) and CEC (r= -f 0.566) and significantly and negatively correlated with pi! (r= - 0.425) and exchangeable Ca + Mg (r= - 0.408). The results warrant application of copper in all the three types of Kuttanad soils and of zinc in the Kayal soils.
Comparative algological studies in rice fields in Kerala state
(Kerala Agricultural University, Vellanikara, 1964) Aiyer, R S
Comparative micromorphologial and physico- chemical study of the upland and midupland laterite soils of Kerala
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1986) Sankarankutty Nair, R; Aiyer, R S
Comparative morphology and physico-chemical properties of some forest and defrosted soils of Kerala
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1989) Sivadasan, N; Aiyer, R S
In Kerala, continuous denudation of forests along the Western Ghats region has brought about hastening of the process of laterisation which becomes one of the major constraints to agricultural development. Deforestation of different types of forests such as deciduous, semi – evergreen, evergreen and shola may bring about laterisation to different extents. Deforestation and monoculture with different economically important species and plantation crops may delay or hasten the process of laterisation. The present study is, therefore an attempt to understand more about the effect of different monoculture vegetation such as cashew, eucalyptus, tea and acacia on soil properties in comparison with soils of adjoining virgin soils in deciduous, semi- evergreen, evergreen and shola forest ecosystems respectively. The present study reveals that deforestation has harmful effect on soil irrespective of the type of forest vegetation. It causes mechanical eluviation with higher migration of finer particles from surface downwards, increases bulk density of surface soil and lowers the aggregate stability of the soil. Organic carbon is found to be partly leached off and eroded off along with mineral soil. It is also burnt faster due to denudation. The contents of nitrogen and phosphorus increase while that of calcium and manganese decrease as a result of deforestation. Higher amounts of iron and aluminium are noticed in deforested soil than in virgin soils of the natural forests. The heavy mineral fraction constitutes from 2.5 to 27.6 per cent of the fine sand fraction. The dominant heavy minerals are the black opaques viz., ilmenite, red opaques such as hematite, limonite and goethite, sillimanite and zircon. The lighter fraction of the minerals is constituted mainly of quartz (22.6 to 97.5 per cent) with smaller amounts of feldspars and micas. The heavier fractionof the minerals are found to increase in soil due to deforestation brought about by residual accumulation. The influence of different monoculture / plantations on deforested soil varies with the type of vegetation. Increased root activity exhibited by tea and acacia at lower layers have strengthened the structural stability and improved the single value constants such as low bulk density, higher porosity and water holding capacity of the subsurface soil under these two plantations compared to soils under other plantations and virgin forests. The degree of weathering of soil varies with the type of vegetation. Based on the silt/clay ratio the soils studied can be arranged in the following order according to the observable factors on the degree of weathering : eucalyptus > tea > deciduous > semi – evergreen > cashew > shola > evergreen > acacia. Deforestation and monoculture with cashew, tea and acacia enhance the soil pH while monoculture with eucalyptus lowers the pH of the soil. Acacia is found to enrich the nitrogen status of the soil at a faster rate by its ability to fix atmospheric nitrogen. The study also reveals that ferrallitization advances in shola forest even if the level of organic matter in the surface soil is 5.19 per cent while no significant ferrallitization has been observed in acacia plantation having only 4.07 per cent organic matter in the surface soil though, both the soils fall under the same ecosystem. The critical role played by different type of vegetation in the manifestation of laterisation is yet to be studied. The micropedogenesis of kaoloinite from givvsite and silica in solution is clearly noticeable in laterised layers of the profile. Conversion of ferrouse to ferric iron the also observable in the thin section study of the soils. All soils are laterised with developing argillic horizonds and clay skins. The studies on soils of monoculture plantation crops such as cashew, eucalyptus, tea and acacia in comparison to virgin forest soils offers enough evidences from the present work to show that planted forests / plantation crops favour laterisation in general in comparison to virgin forests. Among the various types of monoculture, eucalyptus appears to enhance laterisation to the greatest extent while cashew and acacia favour laterisation to the least.
Continuous use of municipal sewage on soil physical and chemical properties
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1987) Karunakaran Nair, G; Aiyer, R S
An investigation was conducted on the physical and chemical properties of the sewage farm soil, Valiyathura in Trivandrum District. The sewage farm soil represents the loose sandy coastal alluvium. The area of the farm extends to 33 hectares under sewage water irrigation. From the farm area/6 blocks were selected representing 20 years and another 6 blocks representing 15 years of sewage irrigation.A comparative study was also made by choosing an adjacent block irrigated with well water. The whole area is cultivated with Napier and guinea grass Profile soil samples from different depths (0-15, 16-30, 31-45,. 46-i/70 cm) were collected for the determination of physical parameters such as bulk density, aggregate stability, stability index, hydraulic conductivity, water holding capacity and capillary and non capillary porosity. The soil chemical properties such as soil reaction electrical conductivity, organic matter content, total ammonical and nitrate nitrogen, total and available major nutrients, secondary nutrients micronutrients, cation exchange capacity and exchangeable cations were also determined from the soil samples collected at different depths. The plant nutrient content due to 15 year and 20 year sewage irrigation were also examined.
Effect of liming and application of mussoorie phosphate on the yield of green gram, var. Co-1, grown in the upland laterites of Kerala state
(Kerala Agricultural University, 1979) Sundaresan Nair, C; Aiyer, R S
Green gram variety Co-1 was grown with different forms and levels of phosphates superimposing a treatment of fully burnt lime at 500 kg/ha. The forms of phosphates compared were Mussoorie phosphate, single superphosphate and a complex fertilizer, factomphos (16:20). The results indicate that the response of green gram variety Co-1 is limited up to 15kg PgCyha and that between the forms, there is no significant difference. The use of Mussoorie phosphate entails a net saving of Rs. 50 per ha at application rates of 15 kg PjOs/ha. After harvest, if the tops are recycled three-fourths of the N applied will be returned to the soil. It has been shown that the pulse crop can give a net profit of Rs, 500 per ha under Kerala conditions.
Effect of nitrogen and phosphorus on the yield and quality of cassava
(Kerala Agricultural University, Vellanikara, 1969) Vijayan, M R; Aiyer, R S
Effect of phorate on rhizobial nodulation in cowpea
(Kerala Agricultural University, 1981) Visalakshi, A; Nair, M R G K; Aiyer, R S
Studies were made on the effect of phorate granules applied along withs seeds at the time of sowing on nodulation in cowpea treated with Rhizobium a compared to nodulation in untreated seeds. In Rhizobium treated plants, phorate caused suppression of nodule development and increase In nodular size, fresh weight and dry weight. In plants untreated with Rhizobium, phorate suppressed nodule formation in the roots and stimulated nodule size and fresh wieght.
Effect of potassium nutrition on the yield and quality of cassava
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1983) Gopalakrishnan Nair, P; Aiyer, R S
Investigations were carried out as the College of Agriculture, Vellayani to find out the optimum dose and time of application of potassium to conserve in relation to yield and quality. For this purpose a seed culture experiment with nutrient solutions at varying duration of it application and a microplot field experiment with different levels of E were conducted during 1977-80. Before conducting the field experiment, two crops of cassavawere taken in the same plot without applying potassium and thus bringing down the available K to a low level.
Environmental planning of two selected river basins of western ghats based on investigations on land use planning and land capabilities
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1987) Binoy Cherian, T; Aiyer, R S
Rapidly changing socio economic structure puts tremendous pressure on human society to find additional resources for its sustenance. Indiscriminate exploitation of the natural resource with scarce concern for the ecological balance has caused disturbances and sometimes total destruction of important portions of the biosphere with immediate or delayed effects being evidenced on a global scale. Land and soil are not resources that are infinite and cannot be exploited for ever. This fragile epidermis of the earths crust is severely affected due to drastic changes in vegetation cover resulting in destruction of soils and losses of nutrients and fertility. The quality and quantity of terrestrial biosphere depends on the soil and land. For studying the extent and state of an environmental impact a well defined natural unit has to be selected. Being a natural physical system where the land and water act as definite determinants of land use, and since it is a well defined natural unit, river basins were chosen as the units for study. The sub water sheds and micro water sheds are the accepted units for ecodevelopment planning. There is a need for detailed studies in natural and agroeco systems in different water sheds in relation to the physical features of the land and soil characteristics. Such studies are required to plan microlevel aspects of eco restoration, and eco development of water sheds especially in Kerala where environmental degradation has reached alarming proportions. The main objectives of the work is as follows: 1. A study of the sub water sheds of Bharathapuzha and Aralampuzha for relief, morphology, drainage, geology, vegetation, climate, soil and land use. 2. A land capability assessment of both the river basins based on details soil studies and traversing of the area. 3. To evolve a set of recommendations for management of the two river basins. The basic approach in the present study is to investigate individual components and bring out their relationship with present land use, that would help to maintain the ecological balance while sustaining human needs. For this two river basins Mangalam-Gayatripuzha and Aralam-Bavalipuzha were selected. The former highly influenced by man and the latter relatively less interfered were chosen for making a comparative study. Environmental components like relief, slope, morphology, drainage, geology, vegetation, climate and soil have been analysed by using standard methodology with respect to individual variables. On the basis of these studies land capability was assessed for each geomorphic unit and the present land use was also studied. Finally a set of recommendations were evolved for the judicious use of each geomorphic unit. With minimum degradation to it. From the study it was found that the Mangalam-Gayatripuzha basin has a mature landscape in comparison with Aralam-Bavalipuzha basin with more diverse geomorphic units. The soil is mainly alluvial in Mangalam-Gayatripuzha basin whereas it is lateritic in Aralam-Bavalipuzha basin. Soil fertility is moderate with no marked variation in both cases. High population density, smaller land holdings and low per capita income have put the land to great stress. Ecologically viable land use based on land capability has become subservient to subsistence land use. Food crops dominate the agricultural scenary in the Mangalam-Gayatripuzha basin whereas cash crops take more area in the Aralam-Bavalipuzha basin. Both the basins are suspectible to erosion and this has been aggravated by large scale deforestation and cultivation of tuber crops on the hill sides. On the basis of these findings it is recommend that deforestation should be completely stopped and afforestation programmes expedited in order to conserve the ecology of both basins. Soil conservation measures should be taken up on a war footing in the Aralam-Bavalipuzha basin with the entire cost borne by the government. Comprehensive programmes must be formulated to bring the catchment of the rivers under good perennial tree and fodder vegetation. Tapioca cultivation requiring greater tillage on slopes should be discouraged or prohibited. A detailed land capability assessment based on natural land use determinates should be worked out for the two basins since large section of the people in the hilly areas are poor with no alternative means of subsistence. Imaginative hill slope agricultural programmes that guarantee subsistence for these people should be evolved.
Evaluation and suitability rating of ten major soil series of the command area of Kallada Irrigation project
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Tavanur, 1992) Premachandran, P N; Aiyer, R S
The present study was undertaken covering the ten identified important soil series of the command area of Kallada Irrigation Project, with the objective of evaluating the soils based on their morphological and physico chemical characteristics. The soil series selected are Mannar, Adoor, Sooranad, Palamel, Mylom, Erath, Bharanikavu Kallada, Pooyappally and Kunnamkara. Profile pits were dug in the typical areas identified and the morphological features observed were recorded as per soil Survey Manual (1970). The salient features of the area in respect of location, physiography, drainage, vegetation and land use were also recorded. The physical and chemical properties of the soil samples collected were determined by standard analytical procedures. These soil series have been evaluated on the basis of land evaluation and rating of productivity parameters The productivity parameters considered in the present study include soil texture, depth, soil reaction, drainage, cation exchange capacity, base saturation, electrical conductivity, coarse fragments, slope and nutrient status. For each parameter, a range of scale is prepared, and numerical values assigned based on principles of land evaluation. Productivity of the soil has been calculated by multiplying the ratings of the individual parameters and expressed as percentage. The ten soil series selected for study have been classified as per the comprehensive soil classification system – Soil Taxonomy. Five soil series namely Kallada, Mannar, Erath, Pooyappally and Kunnamkara are grouped under Entisol. four series namely Bharanikavu, Palamel, Mylom and Sooranad under Inceptisol and Adoor series under Ultisol. The land capability classification of these soils shows that the Kallada soil series comes under class IIe, Sooranad, Mylom, Erath, Pooyappally and Kunnamkara series under class IIw, Palamel, Bharanikavu, major part of Adoor and a portion of Kallada under class IIIe and Mannar serious under class IIIsc. A portion of Adoor series is grouped under class IVe. The irrigability classification of these soils revealed that the Mannar series comes under class 2s, Kallada under class 2t, Sooranad, Mylom, Erath, Pooyappally and Kunnamkara under class 2d, Adoor, Palamel, Bharanikavu and a portion of Kallada series under class 3t. A portion of Adoor series in grouped under the irrigability class 4t. The productivity rating of these soil series gives the following results. The Kunnamkara soil series with a rating of 38.7 percent rank first for paddy. The study shows that the Earth soil series is the least productive for paddy. Coconut, tapioca and banana. The Palamel series having a rating of 31.4 percent, with good rating class is the most suitable for coconut. The kallada soil series ranks top both for tapioca and banana with rating of 27.6 and 38.8 percent respectively.
Evaluation of the role of elements Ca, Mg, S and B in the nutrition of groundnut with reference to monovalent (K) to divalent (Ca + Mg) catonic ratios
(Department of Soil Science and Agricultural Chemistry,College of Agriculture, Vellayani, 1984) Suresh Kumar, P; Aiyer, R S
Extractable aluminium in the rice soils of Kerala
(Kerala Agricultural University, 1979) Karthika Kutty Amma, M; Alice Abraham; Aiyer, R S
Twenty surface soils representing four major rice soil types of Keraia viz., the Kari, Karapadom, Kayal and low level laterites were extracted with different extractants viz.. one normal potasium chloride at different soil solution ratios, one normal ammonium acetate adjusted to different pH values and water and the alluminium estimated. Based on the results, one normal potasium chloride with a soil solution ratio of 1 :10and water were adjudged to be good for predicting toxic levels of Al in this soils. The result obtained further indicate that most of the Al extracted is of the exchangeable type in the case of Kayal and low level laterite soils, while it is not so in the case of Kari and Karapadom soils. The results of the present investigation thus project the need for a very systematic evaluation of the extractable Al content of the highly acid rice soils of Kerala in relation to the existence of Al toxicity to the rice crop.
Horizontal and vertical movement of potassium in the Neyyattinkara-Vellayani soil association from a long term fertilizer experiment under coconut
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1989) Premakumar, S; Aiyer, R S
The present study aims at finding out the movement pattern of applied potassium in the long term fertilizer trial under coconut. The other targets are to find out the suitable site for soil sampling from coconut garden for nutritional studies. The investigation is done by taking surface and surface samples from four sites away from bole of the coconut palm at 90 cm interval. Of this the second site coincides with the site of fertilizer application (180 cm away from bole). In addition to this, for finding out the extent of leaching, three profiles were dug at the site of fertilization in the K0, K1 and K2 treatments with highest dose of N and P combination. Soil samples are collected at 15 cm interval from the profiles upto 105 cm. Leaf samples from 14th frond also collected simultaneously. These samples are collected from a permanent fertilizer trial under coconut which is on going in the coconut Research station, Balaramapuram. This is a 33 NPK, factorial confounded experiment with two replications. Exchangeable, water soluble and non – exchangeable potassium is determined in all the soil samples collected. In addition to this soil separates, CEC, organic matter, pH, Calcium content and Magnisium content also found out. The water soluble, exchangeable and non – exchangeable K values are compared among different sites of sampling and depths in order to broughtout the effect of application of potassic fertilizer for the last 24 years in the soil. The values of different forms of K is correlated with soil characteristics to fine out the impact of various characters in the mobility of potassium. A multiple linear regression analysis is carried out with the leaf nutrient concentration as a dependant variable and the available K at sampling points as independent variable. A clear conical movement pattern is obtained in case of water soluble and exchangeable K. The non – exchangeable K did not show an increase in concentration as a result of addition of potassium fertilizer. The water soluble and exchangeable K were distributed within the root zone of the palm. The leaching of K is upto 75 cm from the surface. It cannot be considered as lost because coconut has sufficient root distribution in this zone. Higher doses of application of K did not move to greater depths than that of medium dose. The mobility of applied K is affected by soil properties like coarse sand fraction, clay fraction, CEC and organic matter. Increase in sand fraction increased the movement K to subsurface layers. But clay fraction has a negative correlation. The index leaf k level has a positive correlation with the available K at various sampling points. The leaf K content is influenced most by the available K level at the subsurface layer of second sampling site (180 cm from bole). Thus, the soil sample for nutrient analysis should be derived from the 30 – 60 cm layer of 180 cm away from the base of the palm.
Influence of applied nutrients and stage of harvest on the yield and physicochemical properties of essential oil of palmarosa (Cymbopogon martini Stapf var. motia)
(Department of Soil Science and Agricultural Chemistry , College of Agriculture, Vellayani, Trivandrum, 1985) Chinnamma, N P; Aiyer, R S
Influence of soluble aluminium on the yield and growth characters of the rice plant
(Kerala Agricultural University, 1979) Alice Abraham; Koshy, M M; Aiyer, R S
The effect of 0, 10, 20, 30, 40 and 50 ppm aluminium on the yield and growth characters of the rice plant grown in solution culture was studied, Toxicity symptoms of aluminium were not manifested on the tops while root growth was progressively decreased in 20, 30, 40 and 50 ppm aluminium containing pots. Decrease in root growth was associated with a tendency for root branching and the formation of mere vascular traces in the root cortex. The reduced root growth did not suppress the yield.
Morphological and Physico-chemical properties of the kayal soils of Kuttanad, Kerala State
(Division of Agricultural Chemistry, College of Agriculture, Vellayani, 1975) Gangadhara Menon, P K; Aiyer, R S
A study made on the morphological and physico-chemical characteristics of the kayal profiles of the Kuttanad region of Kerala revealed the following salient features. (1) These soils are classified under the order- ENTISOL, Sub order- Aquent and great group- Hydraquent according to the seventh Approximation. (2) Texturally they are classified mostly as silty loan or sandyclay loan, fine sand being the dominating fraction in all the profiles and layers. Only the surface soil of the Chithira kayal profile is clayey in texture with a maximum of 36.5 per cent clay. (3) The physical characteristics of the two profiles from the Rani kayal vary widely. While the profile 1 shows a decrease in clay content with increase in depth, the second profile shows a reverse trend for clay as well as fine sand. Fine sand is maximum in the middle layer of profile 1.
Morphological and physio chemical properties of Karapadom soils of the Kuttanad region of Kerala State
(Division of Agricultural Chemistry, College of Agriculture, Vellayani, 1975) Santhakumari, G; Aiyer, R S
A study was mads on ths morphological and physico-chemical properties of 3 profiles of the Karapadom soils of the Kuttanad region. The study revealed many salient features of Karapadom soils The main conclusions drawn from the results obtained are summarised as follows 1. The soils can be texturally classified as clay, loamy sand, silt and silty loam* Maximum percentage of clay was recorded by the top layer of Vettikaripadom, lowest layer of Mathurpadom and sub-surface layer of Mathurvadakke padom profiles. 2. In Mathurpadom and Mathurvadakke padom absolute specific gravity Increased with increase in depth and there is no general trend in the value of apparent density. 3. Mathurpadom and Mathurvadakke padom profiles are strongly acidic when compared to Vettikaripadom which is situated on the western most boundary of Kuttanad near Punnapra. 4. Electrical conductivity increased as depth of the profile increased in Mathurpadom and Mathurvadakke padom profiles. 5. In the three profiles, the organic carbon varies from 0.79 to 4.09 per cent and nitrogen varies from 0.11 to 0.3 per cent. She carbon nitrogen ratio of the profiles varies from 6.58 to 18.33
Nature of acidity in upland and rice fallows in relation to response of pulse crop to liming
(Department of Soil Science and Agricultural Chemistry,College of Agriculture, Vellayani, 1983) Sudharmai Devi, C R; Aiyer, R S
Soils over vast areas of uplands and rice lands in Kerala are acidic in nature. High concentrations of Al and Mn often limit the productivity of pulses when grown in these areas. The present investigation was aimed at detecting the toxic factors causing acidity and locating suitable varieties of cowpea and blackgram suited to these soil situations. It was further programmed to find out the optimum levels of lime that would be required to arrive at a low input management programme for pulses. For this purpose a large number of soil samples were analysed. Several pulse varieties were screened in respect of their tolerance and a pot culture study was conducted to assess their productivity, the results of which are summarised and appropriate conclusions drawn. The collected soils were acidic in nature, the factors causing toxicity being high concentration of Al and Mn. The soils require large amount of lime as amendment. Cation exchange capacity of these soils is very low and to some extent contributed by Al and Mn. Screening experiments were conducted to select varieties which are tolerant to Al and Mn toxicity. As a result S-488, a cowpea variety and Velloor, a blackgram variety were selected as tolerant ones. Comparative assessment of the yielding ability of the selected varieties, with the recommended varieties New Era (cowpea) and T9 (Blackgram) revealed that they could yield as much as or even better than the recommended varieties. The recommended varieties require high doses of lime for a substantial yield whereas the selected varieties could give economic yield with practically no liming. The observations on number of pods, grain yield, haulm yield and number of nodules revealed that the two selected varieties could excel the others in these aspects Uptake studies indicated that the increased yield in the case of the selected varieties is mainly due to the enhanced uptake and fixation of N and uptake of P and K. From the results of the study, it was concluded that the cowpea variety S-488 and the blackgram variety Velloor can be cultivated successfully under acid soil conditions. They possess the ability to give economic yields with little or no liming. These results have to be tested in farmers 'fields to evolve a low input management strategy for pulse cultivation in garden lands as a vegetable in kharif season and in the rice fallows in summer season.
Occurrence of blue green algae in the acid soils of Kerala
(Kerala Agricultural University, Vellanikara, 1966) Anandavalli Amma, P; Aiyer, R S; Subramoney, N