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Open Access
Recycling of cashew (Anacardium occidentale L.) leaf litter and cashew apple through vermitechnology
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2016) Indu, V K; KAU; Jayasree Sankar, S
The present study entitled “Recycling of cashew (Anacardium occidentale L.) leaf litter and cashew apple through vermitechnology was undertaken in the Department of Soil Science and Agricultural Chemistry and at Cashew Research Station,Madakkathara during 2012-2014.The objectives were to study the efficacy of different enrichners on the manorial value of vermicompost prepared from cashew leaf litter and cashew apple using compost worm Eisenia foetida, to identify the role of introduced microbes in decreasing compost maturity time and to evaluate enriched vermicompost as a manurial source in the potting mixture for raising cashew grafts. The objectives were achieved through two experiments viz., (1) preparation of enriched vermicompost and (2) adjudging suitability of enriched vermicompost as a component in potting mixture for cashew grafts. Ferro cement tanks of 1m3 dimension, 300 Kg capacity and lined with jute bags were used for producing vermicompost. All the tanks were initially added with basic feed mixture (cashew leaf litter, cashew apple, sawdust and cowdung in 3:3:2:6 ratio on weight basis. Along with the basic feed mixture, different substrates were added according to the treatments. The experiment was carried out in a Completely Randomized Design with three replications with five tanks per replication. Nutrient status of substrates and that of matured compost was recorded initially and after compost maturity. In addition, pH was also recorded before and after composting, pH ranged from 4.5 in cashew leaf litter to 7.6 in cow dungand poultry manure respectively. Organic carbon content varied from 23% in poultry manure to 49% in coconut leaf. C:N ratio was found between 402.5 in sawdust to 22.62 in poultry manure. The biochemical constituents viz, cellulose, phenol, tannin and lignin were highest in cashew leaf litter (45.9, 1.62, 0.62 and 13.4 mg/100 g respectively) as compared to cashew apple. The compost obtained from T9(T1+ glyricidia leaf+ coconut leaf+ poultry manure+ Trichoderma viride + Pleurotus sajarcaju@ 500 mg kg-1 each of substrate+ Bacillus sp @ 2 kg m-3of substrate) on maturity (120 days), recorded a pH of 7.4, OC (28.6%), N (2.9%), C:N ratio (11), P (0.90%), K (2.0%), total Ca and Mg (1834 & 1185 mg kg-1 respectively) which was highest among other treatments. Earthworm population increased from the initial 200 numbers to1935 numbers in T9 as against 972 in T2which contained Eudrilus euginiaeas the facilitating worms. Xv Daily observations on temperature, weekly observations on pH, total microbial count (initial and final stages), days for compost maturity and earth worm count at maturitywere theother important observations studied in the first experiment. Different treatments was found to have significant effect on temperature. It increased in all the treatments with the composting process, reached a peak and then decreased coinciding with maturity or cooling phase. Highest peak was attained for T9 with 32.5OC. pH of compost mixture were also influenced by the treatments. pH value increased in all the treatments with progress in composting and shifted towards a neutral condition. Maximum pH was associated with T9 (7.3). Number of days required for compost maturity was minimum in T9(120Days) whereas it was maximum in T1(135Days) and the count of earthwormpopulation was nearly nine fold in T9whereas it was only six fold in T1. The lowest multiplication level was observed with T2 which contained Eudrilus eugineae as the compost worms. Based on manurial value assessed by high content of major nutrients (2.4%,0.90% and 2.06% NPKrespectively), compost from T9 of experiment I was selected as the best and designated as enriched vermicompost. Its suitability as a component in potting mixture of cashew grafts was assessed in another experiment. The study consisted of four treatments in four replication with five poly bags (25 x 15cm and 300 gauge) per replication in a CRD Design. The scion for grafting was collected from variety ‘Dhana’. Performance of the grafted seedlings was evaluated for a period of three months. Observations included chemical analysis with and without applying vermicompost for OC, available N, P, K,Ca, Mg, Fe, Mn, Zn and Cu.In addition pH was also recorded. Among the four treatments studied,T4 (sand, soil and enriched vermicompost in 1:1:3 ratio) recorded highest nutrient status (2.75, 0.34 and 0.72 g kg-1 of NPK respectively).The number of days for seed germination was minimum in T4 (15) as against 20 days recorded for seed germination for T1. Other biometric observations like plant height (40.37cm), number of leaves (35) and collar girth (5.3cm) were observed maximum in plants grown in T4. Phytotoxicity was not seen in any of the treatments during the three months of evaluation. By employing the epigeic earthworms Eisenia foetida, the enormously available but untreated lignocellulotic solid organic resource, cashew leaf litter and cashew apple, could be effectively converted to nutrient rich vermifertilizer by suitably admering with various organic enrichners. The vermifertilizer thus produced could be efficiently used as a component in the potting mixture for raising cashew plants. Crop performance was the best when the vermifertilizer was mixed at three parts on volume basis with one part each of xvi sand and soil. Based on results vermicomposting could be established as a ecofriendly and ecologically sound method for manure from cashew leaf litter and cashew apple
Open Access
Site specific nutrient management for chilli (Capsicum annum.L) in kalliyoor panchayath of kerala
(Department of Soil Science and Agricultural Chemistry,College of Agriculture,Vellayani, 2011) Priya, U K; KAU; Sudharmai Devi C R
Site Specific Nutrient management is a technology in precision fanning that offers chance for farmers to achieve the targeted yield taking into consideration the potential yield of the crop by application of apt amount of fertilizers. The technology is farmers' friendly, eco-friendly and also consumer friendly. In Indian scenario wherein farmers are suffering from yield losses up to 40% due to micronutrient deficiency of soils mainly zinc and boron deficiencies are the yield limiting factors of production. Kerala the soils are low in basic ions that are posing serious threat to crop production. The Judicious application of chemical fertilizers along with micronutrients is necessary for sustainable crop production. The present study "Site Specific Nutrient Management in" Chilli (Capsicum annuum.L.) in Kalliyoor Panchayath Of .Kerala" was carried out to satisfy the objectives viz. study the spatial variability of area, to find outtheindigenous nutrient supply via omission trials, fix a target yield based on the potential yield of the crop and formulate a site specific nutrient recommendation to obtain the targeted yield. In order to understand the spatial variability survey was conducted at 25 sites of Kalliyoor panchayath. The results of survey showed that the soils showed wide variation in terms of soil physical and chemical properties. Soil phosphorus status , was high in all cases other nutrient concentration ranged from low to high. The spatial variability necessitated carrying out the omission trials at four different sites that were ranked according to the nutrient status into high, medium first level, medium second level and low fertility soils. From the omission trials the recovery fraction and, indigenous nutrient supply were calculated. Utilising all these parameters in QUEFT model SSNJ\:1.--tre tments were fixed. /' / / - :l.33- The high yield target was fixed at 16 t ha that was 50% of the potential yield. The nutrient recommendation generated for HYT was 104.8: 13.6: 201 kg N, P205 and K20 ha-I. Medium yield target was fixed at 168:51: 230 kg N, P205 and K20 ha- I. Taking into account micronutrient and secondary nutrient deficiencies in the soil. In high yield target soil application of micro nutrients and secondary nutrients along with application of 1 % foliar spray of boron was recommended. Micronutrients for soil application were boron @ 5 kg ha-I in form of borax, zinc @ 20 kg ha-I in form of zinc sulphate. Secondary nutrients applied were calcium @ 30 kg ha-I in form of CaS04, magnesium @ 7.5 kg ha-I in form of MgS04. The requirement of sulphur was met from soil applied zinc sulphate, calcium sulphate and magnesium sulphate. In medium yield target only soil application of micro and secondary nutrients along with the application of QUEFT generated recommendations for the crop; POP + micronutrient recommendations were evaluated. Simultaneously an absolute control was also carried out. Soil analysis was carried out for all the physical and chemical properties of the soil initially before the crop was raised, and after each harvest. So that change in soil properties as a result of application of treatments could be evaluated, since the application of fertilizer coincided with each harvest. The results derived from the experiment proved the superiority of SSNM over other treatments with respect to the yield major nutrient and micronutrient uptake. , Where high yield target registered a cumulative yield of 17. 32 tons, medium yield target registered a cumulative yield of 11.75 tons this was _much superior to POP+SNMN that registered an yield of 9.83 tons, or the package of practice recommendation that registered an yield of only 8.3 tons . Farmers practice registered inferior yield data of only 5.2 tons. The study revealed that the site specific nutrient management is an efficient technology to increase the yield of crops and hence provide additional income to the farmers; this technique also provides a -134 - scope of increasing the yield without over application of fertilizers that would result in deterioration of the soil physical and chemical properties in long run.
Open Access
Nitrogen and sulphur interaction on their release pattern and use efficiency in ferralitic soils.
(Department of Soil Science and Agricultural Chemistry,College of Agriculture, Vellayani, 2011) Mariya Dainy, M S; KAU; Usha, P B
An experiment was carried out at College of Agriculture, Vellayani to investigate the interactive effect of nitrogen and sulphur on their release pattern and use efficiency in ferralitic soils with bhindi as the test crop. The experiment consisted of an incubation study and a field experiment. The incubation study was carried out to understand the release pattern of N and S from their sources viz. urea and gypsum in the soil at different sampling stages (30 and 100 days of incubation) using ferralitic soil kept at field capacity. The treatments consisted of M1N1S1, MINIS2 , M1N1S3 , M1N2S1 , M1N2S2 ,M1N2S3 ,M1N3S1 , M1N3S2 , M1N3S3 , M2N1S1 , M2N1S2 , M2N1S3 , M2N2S1 , M2N2S2 , M2N2S3 , M2N3S1 , M2N3S2 and M2N3S3 and M0N0S0 . Levels of N include N1 (50 kg ha-1), N2 (80 kg ha-1) and N3 (110 kg ha-1). M1 include P2O5 @ 8 kg ha-1+ K2O @ 25kg ha-1 (current POP) and M2 include P2O5 @ 35 kgha-1 + K2O @ 70 kg ha-1(modified POP). Different levels of S are S1 (10 kg ha-1), S2 (15 kg ha-1) and S3 (20 kg ha-1). Soil samples were collected and analyzed for pH, available N and available S content. There was increase in pH value to the neutral range at fifty per cent flowering stage (30 Days of Incubation) and all the treatments showed a decreasing trend in the pH value at 100 Days of Incubation. Available N and available S content increased to some extent at fifty per cent flowering and decreased at the final harvest stage. Application of N up to 110 kg ha-1 significantly increased the available N status of soil and S application up to 20 kg ha-1 increased the soil S status during incubation. The field experiment was laid out in 2×3×3+1 factorial RBD having three replications using bhindi variety Varsha Uphar as the test crop. The treatments were similar to that of the incubation study. S application @15 kg ha-1 significantly reduced the internodal length. N and S interaction N @ 80 kg ha-1 and S @ 15 kg ha-1 showed significant influence on fruit length. The maximum number of fruits and highest yield was obtained when the nutrients were applied @ 80 kg N ha-1 + 8 kg P2O5 ha-1 + 25 kg K2O ha-1 + 15 kg S ha-1. Considering the N and S interaction effects, combined application of N @ 80 kg ha-1 and S @ 20 kg ha-1 increased the number of fruits and yield. Application of N up to 80 kg ha-1 increased the crop yield and above this level, there was reduction in yield. The increase in number of fruits per plant by the application of N and S may be due to the highest uptake and efficient utilization of nutrients. N @ 110 kg ha-1 and S @ 20 kg ha-1 recorded the highest dry matter content. S application @ 15 kg ha-1 showed significant influence on N Use Efficiency (NUE) in bhindi. Application of 80 kg N ha-1 + 8 kg P2O5 ha-1 + 25 kg K2O ha-1 + 15 kg S ha-1 resulted in highest NUE. By the application of urea and gypsum, there was slight increase in the soil pH. After N and S application, there was increase in organic carbon content of the soil. At fifty per cent flowering all the nutrients showed an increase in availability and there was a decrease at the final harvest stage because of crop uptake and various losses. N application @ 110 kg ha-1 significantly increased the available N status in the soil. S application up to 20 kg ha-1 significantly increased the available P K and S content in soil. As the levels S increased, there was increase in the exchangeable calcium in soil. Higher levels of application of N recorded higher N content in both plant and fruit. Application of P and K at M2 (35 kg P2O5 ha-1 + 70 kg K2O ha-1) level significantly increased the content of P, K and Ca in plant and fruit. Increased S application increased the Ca content in plant since gypsum was used as the source of S. S application up to 20 kg ha-1 had significant influence on the fruit Ca and Mg concentration. The interactive effect of N and S was not significant in the case of S content in plant. But, N2S3 (N @ 80 kg ha-1 and S @ 20 kg ha-1) recorded the superior value. N application had got positive influence on the content of P, K, Ca, Mg and S in plant and fruit. By progressive increase in S application up to 20 kg ha-1and N application up to 80 kg ha-1, there was significant reduction in N: S ratio. N and S fertilization had significant influence on leaf chlorophyll content and application of 80 kg N ha-1, 35 kg P2O5 ha-1, 70 kg K2O ha-1 and 15 kg S ha-1 showed the superior value for chlorophyll content. An increasing trend was noticed with higher levels of N up to 80 kg ha-1 and S up to 20 kg ha-1. N and S application significantly enhanced the uptake of nutrients. Uptake of phosphorus, potassium, calcium, magnesium and S were highest when N, P, K and S were applied @ 80 kg N ha-1+ 35 kg P2O5 ha-1+ 70 kg K2O ha-1+ 20 kg S ha-1. N application @ 80 kg ha-1 significantly influenced the B: C ratio. Among the treatments M1N2S2 (80 kg N ha-1 + 8 kg P2O5 ha-1 + 25 kg K2O ha-1 + 15 kg S ha-1) which gave the highest yield showed the highest B: C ratio. Maximum B: C ratio was obtained when N and S were applied @ 80 kg ha-1 and 15 kg ha-1 respectively. As the levels of S increased, B: C ratio also increased. Fertilization of N, P, K and S @ 80 kg ha-1, 35 kg ha-1, 70 kg ha-1 and 15 kg ha-1 respectively recorded the minimum Percentage Disease Incidence (yellow vein mosaic). Among the treatments, yield, number of fruits per plant, N Use Efficiency and B: C ratio were highest for M1N2S2 (80 kg N ha-1 + 8 kg P2O5 ha-1 + 25 kg K2O ha-1 + 15 kg S ha-1) and it can be considered as the best treatment combination. Application of N significantly increased the yield and the yield was highest at N2 level (80 kg N ha-1). There was reduction in yield if we apply N @ 110 kg ha-1. By the application of S along with N increased the NUE and we can reduce the dose of N to 80 kg ha-1 instead of 110 kg N ha-1 for bhindi.
Open Access
Physico-chemical properties of rain water harvested under different situations in lateritic
(Department of soil science and agricultural chemistry, College of horticulture,Vellanikara, 2014) Ibrahim Hassen, Abdu; KAU; Betty Bastin
Rain water harvesting is universally accepted as an important measure of water conservation throughout the world. The quality of irrigation water has become a more serious problem than quantity in different parts of the world. The characterization of quality of water is crucial for assessing the suitability for i rrigation. Hence a study was taken up on “Physico-chemical properties of rain water harvested under different situations in lateritic soil’’ in the main campus of Kerala Agricultural University, Vellanikkara during September, 2012 to August 2013. The objective of the study was to compare the physico-chemical properties of rain water from different water sources in lateritic soil. Water was collected from five sources viz, rainfall (RF), rain water harvesting pond (RWH) , Kotteppadom pond (KP), well water (W) and surface runoff (SR). The experiment for surface runoff study was laid out in an area with a gentle slope between 5 – 10 per cent . Four rain pits were dug in this area with dimensions of 0.5 m x 0.5 m x 0.5 m and lined by polyethene sheet. Water samples were taken from these water sources for one year at monthly intervals and they were analyzed for various physicochemical parameters such as colour, turbidity, pH, EC, TDS, COD, BOD, SAR, RSC, NO 3 - , Cl - and Fe. The amount and distribution of rainfall received as well as the inflow to the rain water harvesting pond were also studied. Soil samples were collected from around rain-pits before and after rains and analyzed for the content of nutrients. The total quantity of rainfall during the study period was 2872.0 mm. The maximum amount of rainfall was observed in June and the minimum in January, 2013. The amount of rain water harvested in pond during the study period was 625.48 m which comes to 63 per cent of its storage capacity. The quality of water from different sources was compared based on the results of physico-chemical analysis. It was found that pH was highest (6.69) for water from Kotteppadom pond during summer and lowest (5.54) for water from rainfall during post monsoon season. The EC and TDS values were maximum for well water during pre- monsoon season and there was significant difference among the different sources. There was no significant difference among the sources of water as regards the content of Cl and NO 3 - over the different seasons. The values for BOD and COD varied significantly over the different sources as also the seasons. Significant difference was observed for SAR and RSC values among the different sources and seasons. Loss of nutrients from soil via surface runoff from a sloppy area was studied. Soil samples were analyzed for various physico-chemical parameters such as pH, EC, OC, 3 available N, P, K, Ca, Mg, Fe, BD, PD and WHC. The different parameters were estimated both before and after receipt of rainfall. The mean values of these parameters and percent changes along with t-value were found out. During summer, after the rains, there were significant changes for the parameters like pH, OC, as well as available nutrients like K, Ca, Mg, Fe, and the percentages of decrease were 1.67, 0.67, 37.94, 25.46, 5.62 and 8.85 respectively. The water holding capacity was also decreased by 4.80 per cent. During monsoon, available nutrients like N, P, K, and WHC decreased to the extent of 23.68, 26.24, 49.32 and 7.29 per cent respectively. In general, it was found that the rainfall and rain water harvested in the water harvesting pond were superior to well water, KP pond water and surface run off water. Salinity was low for water from all the sources. Surface run off in an area with moderate slope (5-10 %) resulted in loss of nutrients like K, P, Mg and Ca. -
Open Access
Long term effect of field management on soil quality in ultisol
(Department of soil science and agricultural chemistry, College of Horticulture,Vellanikkara, 2013) Nithya, A M; KAU; Betty Bastin
Soil quality is directly related to agricultural sustainability. Assessment of soil quality is essential for determining the sustainability of land management systems. It is generally accepted that intensive agricultural production leads to a decline in soil quality. For this reason, it is highly essential to monitor soil quality to avoid soil degradation and in doing so, preserve the production capabilities of the land and protect environment. The response of soils to management and input depends on soil quality. It is therefore important to identify the soil characteristics responsible for changes in soil quality, which may eventually be considered as soil quality indicators for assessing agricultural sustainability. The present investigation has been undertaken to study the “Long term effect of field management on soil quality in Ultisol”. It was conducted in the main campus of Kerala Agricultural University, Vellanikkara during December, 2012 to June, 2013. The objective of the study was to evaluate the soil quality under different long term field management conditions in an Ultisol (Vellanikkara series) based on physical, chemical and biological indicators. Here, an attempt has been made to evaluate the physical, chemical and biological properties of soil using available soil quality indicators. Five different fields were selected namely, natural forest, rubber plantation, cocoa garden, STCR experimental field and tapioca fields. Soil samples were collected from three depths namely 0-15 cm, 15-30 cm and 30-60 cm. The different sampling sites within each field were selected based on slope percentage. The samples were characterized for soil texture, aggregate size distribution, soil temperature, water holding capacity, single value constants, pH, EC CEC, AEC, SiO2/R2O3, organic carbon , lime requirement, available macronutrients, secondary nutrients, micronutrients, counts of bacteria, fungi and actinomycetes and enzyme activity. The sampling areas were also surveyed and documented for the presence of earthworms and termites. The physical characteristics like water holding capacity, soil aggregate stability and soil temperature showed a decreasing trend with depth in the different fields. Forest ecosystem showed the most conducive physical characteristics followed by cocoa and rubber. The contents of available nutrients, secondary nutrients and micronutrients were found to be the highest in surface samples. The forest ecosystem showed relatively high values for organic carbon, and available nutrients like nitrogen, sulphur, boron, iron, manganese, zinc and copper. Microbial activity was found to be the highest in surface soils in almost all fields. The highest counts of bacteria and actinomycetes were reported in forest ecosystem and lowest in tapioca field. Fungal activity was found to be the highest in cocoa field followed by forest ecosystem. Enzyme activity was also found to be the highest in surface soils in the different fields. Soil quality was evaluated using available soil quality indicators. Based on scoring with the soil quality parameters, the highest scoring was observed for natural forest followed by cocoa field. Correlations between various soil quality parameters of different fields were also worked out. .
Open Access
Silicon availability of tropical soils with respect to rice nutrition
(Department of Soil Science and Agricultrural Chemistry, College of Horticulture,Vellanikkara, 2016) Arya Lekshmi, v; KAU; Jayasree Sankar, s
Silicon (Si) is the second most abundant element in soil. The amount of silicon in soil depends on parent material, soil type, pedogenic process and landscape. In soil solution, Si is present as monosilicic acid which is the only form that the plant can absorb from soil. The productivity of rice is comparatively low in soils of Kerala. As a ̳Si – accumulator‘, rice can benefit from Si nutrition. The application of Si can enhance growth and yield of rice. With this background, studies were conducted to categorize major rice growing soils of Kerala according to plant available silicon and to evaluate the efficacy of different sources of silicon including rice straw in wetland rice. The release of silicon from different soils added with various silicon sources under different water regimes was also monitored. Soil samples were collected from five different locations representing major rice growing regions of Kerala viz., Kuttanad, Kole land, Pokkali, sandy and lateritic to categorize them according to plant available silicon. The available Si ranged from 7.70 mg kg -1 (sandy soil) to 34.91 mg kg -1 (Kole land soil) in the order Kole land > Pokkali > lateritic > Kuttanad > sandy soil. All the soils under study were categorized as low in available Si. The available Si had positive correlation with organic carbon, available N, Ca, Mg, Fe, Mn, Zn, exchangeable K, Ca, Mg and CEC and negative correlation with available boron, AEC and silica-sesquioxide ratio. These soils were subjected to fractionation of silicon. The major fractions of Si were mobile, adsorbed, organic, occluded, amorphous and residual Si. The percentage distribution of fractions of Si in these soils were in the order; residual Si > amorphous Si > occluded Si > organic Si > mobile Si > adsorbed Si. Quantity – intensity relationship of five major rice growing soils at two temperatures viz. 25 0 C and 40 0 C were studied. The highest buffer power was indicated by Kuttanad soil followed by Pokkali and sandy soils at 25 0 C. It clearly indicated that these soils have a higher power to retain Si on solid phase and replenish its concentration in soil solution as and when it is depleted through plant uptake or leaching. The equilibrium Si concentration and the amount of Si adsorbed by each soil were used to test the fitness of data to the adsorption isotherms viz., Langmuir, Freundlich and Temkin. The data obtained from the adsorption experiments fitted into Freundlich and Temkin equations, but not to Langmuir equation at 25 0 C. At 40 0 C no adsorption equations were obtained for any soil.An incubation study was conducted to know the extent of release of Si on addition of different sources of silicon such as rice husk ash, biodecomposed rice husk, calcium silicate and sodium silicate in five rice growing soils under submerged water regime (SWR) and field capacity water regime (FCWR). Addition of Si significantly increased the release of available Si in all soils except Kole land soil after a month. Kole land soil showed higher release of available Si after two months. The highest release of available Si was at SWR in case of Kole land and Kuttanad soil, where as Pokkali, sandy and lateritic soils showed more release of available Si at FCWR. Irrespective of soils, treatment with sodium silicate showed higher release of available Si. Total Si showed a decreasing trend over the period of incubation for three months in all the soils. A field experiment was conducted at Agronomic Research Station, Chalakudy to evaluate the efficacy of different sources of silicon including rice straw in wetland rice. Rice husk ash, biodecomposed rice husk, calcium silicate and sodium silicate were used as source of Si along with fertilizers as per package of practice recommendation (NPK alone). The maximum number of panicles per hill, number of spikelets per panicle, thousand grain weights and minimum number of unfilled grains per panicle were recorded in treatment with calcium silicate application. The maximum grain yield of 6.90 t ha -1 was recorded in treatment T 5 (T 2 + Calcium silicate) and significantly superior (fig.54) over all other treatments. This increase in yield may be due to the effect of application of Si on soil fertility, nutrient uptake, and plant growth. The direct effect of Si fertilization on increased number panicle per hill, number of spikelets per panicle, and thousand grain weight and decreased number of unfilled grains per panicle might be the reason for increased grain and straw yield in treatment with calcium silicate. The treatment with POP + sodium silicate showed the highest uptake of Si by grain and straw of rice. The sources of Si had no residual effect on grain and straw yield of succeeding rice crop. In general, sandy soil low in available Si had a high response to applied Si in achieving higher grain yield.
Open Access
Enzyme Characterization of the acid sulphate soils of Kuttanad
(Department of Soil Science and Agricultural Chemistry, college of Agriculture, Vellayani, 2016) Arya Nath V; KAU; Aparna, B
Regarding the enzyme status of the acid sulphate soils, the activity of urease was the highest in Thakazhi (L4-75.78 ppm of urea hydrolyzed g-1 soil h-1) in the surface layer. Acid and alkaline phosphatase activities were found to be the highest in Purakkad (L3-57.58 μg pnp released g-1 soil h-1) and Thakazhi series (L4-46.41 μg pnp released g-1 soil h-1) respectively in the surface layers. The highest activity of dehydrogenase was noticed in Thuravur series (L6-115.74 μg of TPF released g-1 soil 24 h-1) in the surface and Kallara series in the subsurface layers (L2-55.39 μg of TPF released g-1 soil 24 h-1). Karappadam and Kayal recorded the values of 145.73 and 114.80 μg of TPF released g-1 soil 24 h-1 for dehydrogenase activity respectively at surface layers. With regard to the microbial population, Thottappalli (L5) recorded the highest total bacterial count and fungal population in both surface and subsurface layers. Thiobacillus spp. recorded the highest population of 9.08 log cfu g-1 of soil at Kallara series (L2) while P solubilizers recorded the highest count at Ambalapuzha series (L1). Thuravur series recorded the highest actinomycetes population in subsurface soils. Micahelis – Menten constant, Km and the maximum velocity Vmax for different enzymes were determined and it was observed that for dehydrogenase Vmax value was found to be the highest in 6th week and for phosphatase only after 12th week of incubation. Thematic maps were prepared based on themes like microflora and enzyme status using GIS (ARC VIEW). Hence the study conclude that, with respect to biological fertility status of the study area, Purakkad recorded the highest enzyme activity number (23.69) at 0-15 cm, while Kallara series recorded the highest enzyme activity number in the subsurface layer and are observed to be biologically sustainable.
Open Access
Substrate impact on biogas production and manurial value of slurry
(Department of Soli Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2015) Anooja, C Lonappan; KAU; Beena, V I
The growing population of the world increases energy demand and waste generation. Due to lack of proper recycling technology, large quantities of biodegradable wastes are being produced. Biogas production is a good technology for mitigating both the problems. The slurry produced after biomethanation is a good manure which provides balanced nutrition for crops and improves soil quality. There are large varieties of biodegradable wastes which can be used as feed stock for biogas production. The quality and quantity of biogas and slurry generated are based on the nature and composition of feed stock. In order to find out an efficient substrate from the available substrates in Kerala and to determine manurial value of different types of slurry, the present study was undertaken at College of Horticulture, Vellanikkara during 2012 – 2014. To elucidate the impact of different substrates on biogas production, an experiment was laid out with three replications and six treatments viz., cow dung alone and co digestion of cow dung with poultry manure, goat manure, biodegradable house hold waste, elephant dung, and pulse residue in 1:1 ratio with equal quantity of water. The biogas generated from different treatments were analysed for CH 4 and CO 2 . The highest CH 4 production was recorded for the treatment combination of pulse residue with cow dung which was on par with cow dung and elephant dung combination, while the highest CO 2 was recorded in the biogas produced from poultry manure and cow dung combination. The hydraulic retention time recorded was lowest for elephant dung and cow dung combination. The highest organic carbon content was recorded in the slurry generated from cow dung alone, which was on par with the combination of goat manure with cowdung. The highest ammoniacal nitrogen content was recorded for biodegradable house hold waste - cow dung combination followed by pulse residue - cow dung combination. The highest total nitrogen content was observed for cow dung - poultry manure combination and cow dung - goat manure combination.157 A pot culture experiment was conducted to find out the manurial value of the slurry obtained from the treatments for biogas production with three replications and six treatments. This experiment was done by irrigating the pots with the slurry obtained from the treatments along with absolute control, as per Package of Practices and Recommendations of KAU (both were irrigated with fresh water) and with fresh undigested cow dung slurry with cowpea (var. Bhagyalakshmy) as test crop. The highest number of pods per plant and the highest yield were obtained from the plants which were irrigated with biogas slurry produced from pulse residue and cow dung combination. After harvest, the highest organic carbon content was noted in soil which was irrigated with biogas slurry produced from elephant dung and cow dung combination. The highest available nitrogen and available phosphorus content was recorded for soil irrigated with slurry produced from cow dung alone and cow dung - pulse residue combination. Available potassium content in soil was highest for in the soil which was irrigated with slurry produced from poultry manure and cowdung combination which was on par with slurry produced from elephant dung- cow dung combination. The plants irrigated with the slurry produced from cow dung-pulse residue combination and cow dung-elephant dung combination had recorded highest uptake of total nitrogen. Plants raised from the seeds obtained from these treatments showed greater shoot length, seedling length and vigour index. However elaborate studies are necessary to monitor the hormones present in different types of slurry generated from different substrates.
Open Access
Effect of continuous application of rice husk ash (RHA) on inceptisols of palakkad eastern plains
(Department of Soil Science and Agricultural Chemistry,College of Horticulture, Vellanikkara, 2016) Rincy, Rose T John; KAU; Jayasree, Sankar S
The study entitled “Effect of continuous application of rice husk ash (RHA) on Inceptisols of Palakkad Eastern plains” was conducted during 2014 - 16 in the Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara with the objective of finding out the physical and chemical changes of soil resultant to continuous application of RHA and its relationship with performance of coconut palms. Vadavannur region under Inceptisol soil order of Palakkad Eastern plains stands out as a location where RHA (the product obtained on partial oxidation of rice husk, from rice mill, at a temperature around 250 to 400oC) is continuously being applied in the field for three decades along with inorganic nutrients to the coconut palms at the rate of four to five baskets/palm on volume basis. In this study, RHA samples were collected from the rice mills and analyzed for its composition in terms of carbon, macro and micro nutrients and the beneficial element silicon. Further, representative surface soil samples were collected during August -December 2015 from four RHA amended and non- amended locations of the Palakkad Eastern plains (Vadavannur, Muthalamada, Thathamangalam and Mullakkalkolambu) and its physico- chemical properties were determined. The index leaves (14th leaf) of coconut palms were also collected from RHA amended and non-amended locations and biometric characters (length of index leaf, total number of leaflets per index leaf, average length and width of leaflets, number of bunches per palm and average yield) were recorded. Samples of soil and plant were analyzed for different nutrients viz. C, N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, Na and Si. Analysis of RHA revealed that its pH was alkaline (7.5-8.3). Cation exchange capacity of the material ranged from 7.5 to 9.5 cmol(+) kg-1. Chemical constituents included Si (35%), C (7%), N (0.18- 0.27%), P (0.39-0.57%), K (0.35-0.58%), Ca (0.08- 0.1%), Mg (0.09-0.2%) and micronutrients in trace amounts. On comparison of the physical properties of soil in amended and non-amended locations, the aggregate stability, infiltration rate, water holding capacity and porosity were found to be positively influenced by RHA application. The content of total N, total and available P and K and available Si of soils showed significant increase in amended regions. Exchangeable cations and effective cation exchange capacity were also more in the RHA amended regions. The content of total carbon and particulate organic carbon especially that associated with micro-aggregates was high in the amended area as compared to the nonamended area. A significant difference in the biometric observations of index leaves (length of index leaves and total number of leaflets per index leaf) of palms in amended location as against non-amended locations was another noticeable feature. The palms under integrated nutrient management along with RHA yielded more. The average yield per palm was observed as 86 nuts/year. The content of major nutrients, Ca and Si in the index leaves was also recorded high in the RHA amended palms. The farmers of Vadavannur region resorted to RHA application only with an objective to address the issue of environmental nuisance and menace, without attributing any scientific rationale on its value as a soil amendment. The results of the present study indicate the benefit of application of RHA in improving the physical and chemical properties of soil. The alkaline pH of RHA establishes its suitability as an alternative liming material for acid soils to improve the soil fertility and productivity. It is suggested that further studies conducted under designed experimental stipulations for validation of RHA would decipher more precise information on its suitability as a balanced material for soil amendment.

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