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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
Sulphur and boron nutrition and their foliar diagnosis in sesame
(Department of Soil Science and Agricultural Chemistry,College of Agriculture, Vellayani, 2010) Jeena, Mathew; KAU; Sumam, George
A laboratory cum field experiment was conducted to study the effect of S and B on the growth, yield and quality of sesame var. Thilarani and to standardize the foliar diagnosis of these elements in Onattukara sandy loam soil. The study included an incubation study and two field experiments. The treatments comprising the different levels of S and B laid out in 42factorial RBD. The treatments were T1(S0B0), T2(S0B1), T3(S0B2), T4(S0B3), T5(S1B0), T6(S1B1), T7(S1B2), T8(S1B3), T9(S2B0), T10(S2B1), T11(S2B2), T12(S2B3), T13(S3B0), T14(S3B1), T15(S3B2), T16(S3B3). The different levels of S were S0 (0 kg ha-1), S1 (7.5 kg ha-1), S2, (15 kg ha-1) and S3 (30 kg ha-1) and B0 (0 kg ha-1), B1(2.5 kg ha- 1), B2 (5 kg ha-1) and B3 (7.5 kg ha-1). The incubation study was conducted at College of Agriculture, Vellayani to understand the dissolution and release pattern of S and B from their sources gypsum and borax respectively in Onattukara sandy soil. The results revealed that the release of S and B was maximum at the 30th DOI. Increasing levels of S and B has a positive influence on the S content of the soil. T16 (S3B3) recorded the highest value at all the sampling stages for S whereas in the case of B, the treatment combinations which received B at the highest levels in combination with S3 or S2 showed the highest value. The field experiments were laid out at ORARS, Kayamkulam in 42 factorial RBD having two replications using Thilarani as the test crop. It was observed that application of S and B favourably influenced the yield and yield attributes of sesame. T16 was found to be the treatment which gave the highest grain yield and oil yield in both the years and was found to be on par with T14 (S3B1). S3 was the superior S level. As for the different levels of B, B1 can be inferred as the best level. The content of saturated fatty acids such as palmatic and stearic acid showed a decreasing trend with increasing levels of S and B whereas the content of the unsaturated fatty acids showed an increasing trend. The quality attributes of oil such as acid value, iodine value and saponification value was also studied and it was found that there is a decreasing trend with regard to acid and saponification value and an increasing trend for iodine number. The grain protein content also showed an increasing trend with the increase in rate of application of S and B. Regarding the content and uptake of N, P, K, S, B, Fe, Mn, Cu and Zn, a favourable influence for the different levels of S and B was recorded. Results regarding the S and B use efficiency and their apparent recovery showed that with increase in levels of S, an increasing trend was observed for S. In the case of B, increase was noticed up to B1 (2.5 kg ha-1) and there after showed a decreasing trend. This positive influence was also reflected on the available nutrient status of the soil such as organic carbon content, available N, P, K, S, B and DTPA extractable micronutrients. Correlation studies conducted to standardize the part and stage of sampling for the foliar diagnosis of sesame showed petiole at 30 DAS and 20 DAS in the case of S and B respectively. The same stages were found for the soil sampling also for both the nutrients. The critical nutrient level in the part standardised for these two nutrients were standardized using the graphical method proposed by Cate and Nelson (1965). In the case of S, it had been standardized as 0.088 per cent and for B, it had been found to be 28 mg kg-1. The critical nutrient level in soil was also estimated using the scatter diagram technique and was found to be 23 kg ha-1 at 30 DAS for S and 1.4 ppm at 20 DAS for B. Hence the application of S @ 30 kg ha-1 and B @ 2.5 kg ha-1 could faourably enhance growth of sesame with regard to the growth characters, yield and yield attributes and the quality aspects. Moreover, analysis of the plant and soil samples at the critical stages fixed for the respective nutrients will provide the necessary data for the sustainable management of the crop in Onattukara sandy loam soil.
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
Characterization and evaluation of on-farm liquid organic manures on soil health and crop nutrition
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2017) Sreya, U Parvathi; KAU; Ushakumari, K
The experiment entitled “Characterization and evaluation of on-farm liquid organic manures on soil health and crop nutrition” was undertaken at College of Agriculture, Vellayani during 2014-2017.The study was envisaged to characterize the on-farm liquid organic manures viz., cow urine, panchagavya, fish amino acid, vermiwash and jeevamrutha, to monitor the nutrient release pattern under laboratory conditions and to evaluate the efficacy of soil and foliar applications of these liquid manures on soil health and crop nutrition using bhindi as test crop. The study consisted of three parts. The first part comprised the preparation and characterization of above said on-farm liquid organic manures. These manures were prepared as per standard procedures and characterization study was conducted to determine the physical, chemical, biological and biochemical properties. Physical properties viz., colour and odour of different on-farm liquid organic manures were recorded. Among the liquid organic manures studied, fish amino acid and panchagavya showed acidic pH and other three liquid organic manures viz., cow urine, jeevamrutha and vermiwash recorded neutral pH. Regarding EC, jeevamrutha recorded the lowest value (1.53 dSm-1).The highest OC content (39.96%) was recorded by fish amino acid followed by panchagavya. Among the major nutrients, the highest N content (0.45%) was found in panchgavya followed by fish amino acid. The highest P content was recorded by FAA (0.41%). Maximum K content (0.17%) was recorded in cow urine followed by panchagavya, vermiwash and jeevamrutha. S content of all the liquid organic manures were higher compared to Ca and Mg content. The highest contents of Ca, Mg and S were recorded by fish amino acid. The Fe content (39.92mg L-1) was highest in jeevamrutha and the lowest in fish amino acid. Cow urine was found to be rich in Mn (0.400 mg L-1) and Cu (21.21 mg L-1).The maximum zinc content (2.00 mg L-1), IAA (6.00μg ml-1) and GA (35.00μg ml-1) were found in fish amino acid. Panchagavya was rich in cytokinin (2.82 mg L-1) whereas, ascorbic acid content (37.50 mg 100g-1) was the highest in vermiwash. Fish amino acid was registered the highest enzyme activities, except for dehydrogenase activity which was found to be maximum in cow urine (371.27 μg of TPF g -1soil 24 h-1) followed by fish amino acid (336.98 μg of TPF g -1soil 24 h-1). The maximum population of bacteria was observed in vermiwash and fungal population was presented in all liquid organic manures except cow urine. The highest azotobacter population was observed in fish amino acid. K solubilizers were found to be the highest in vermiwash whereas E.coli, P solubilizers, azospirillum and Pseudomonas sp. were not detected in any of the above liquid organic manures. The second part of the experiment was laboratory incubation study to monitor the nutrient release pattern from soil treated with the on-farm liquid organic manures for a period of two months. The study consisted of 6 treatments which included soil alone and soil treated with 10 per cent dilution of all the liquid organic manures separately and all the treatments were maintained at 60 per cent moisture level. In general increased pH and EC values were observed in all the treatments received diluted liquid organic manures compared to control. Regarding the release of major, secondary and micronutrients, there was significant difference in available nutrient contents between treatments during the periods of incubation. Regarding the release of N and P during incubation study, soil along with FAA 10 per cent recorded the highest release pattern whereas soil along with cow urine 10 per cent recorded the highest K release throughout the incubation period. There was increased release of Ca in the treatments received liquid organic manures. The highest Mg release throughout the incubation period was registered by the treatment received cow urine 10 per cent. Available iron content was higher in T5 (soil 5 kg + jeevamrutha 10 %) compared to other treatments. A significant difference was found among treatments with respect to available Zn content. Initially (0th day of incubation), all the treatments were recorded higher values compared to values recorded on 7th ,15th ,30th , 45th and 60th days of incubation. There was increasing trends in the Cu content of soil from 0th day of incubation to 60th day of incubation except in the case of T3 (soil 5 kg + FAA 10 %). Treatment T1 (soil without treatments) recorded the lowest values for all nutrients throughout the incubation period. The third part of the experiment was to evaluate the efficacy of soil and foliar applications of on-farm liquid organic manures in a pot culture experiment using bhindi as test crop. The treatments included were 75 per cent N as enriched vermicompost along with diluted liquid organic manures separately as soil and foliar applications. Plant height, LAI, dry matter production, number of flowers, number of fruits per plant and total fruit yield were found to be the highest in T5 (75 % N as EVC + panchagavya 3 % foliar application). Chlorophyll a, b and total chlorophyll content were the highest in T10 (75 % N as EVC + jeevamrutha 10 % soil application). T1 (KAU PoP) recorded the highest average fruit weight. T4 (75 % N as EVC + FAA 5 % soil application). registered the highest crude protein content while crude fibre content was lowest in T7 (75 % N as EVC + cow urine 10 % foliar spray). Ascorbic acid content was the highest in T5 (75 % N as EVC + panchagavya 3 % foliar spray) and was on par with T7, T2,T9 and T11. The results of the post harvest analysis of soil revealed that pH, EC, organic carbon and labile carbon contents varied significantly among the treatments. The highest organic carbon content of soil was recorded by T4 (75 % N as EVC + FAA 3 % soil application) and T12 (75% N as EVC + vermiwash 10 % soil application). The maximum labile carbon was recorded by T8. T5 (75 % N as EVC + panchagavya 3 % foliar spray) was rich in available N. Soil enzyme activities were influenced by the application of liquid organic manures. The treatment T5 registered the highest plant uptake of major nutrients. The treatment T3 registered the highest plant uptake of secondary nutrients. The highest value of Fe and Zn uptake was noticed in T11.(75 % N as EVC + vermiwash 10 % foliar spray). The highest value of Cu uptake was noticed in T1 (KAU PoP). The highest value of Mn uptake was noticed in T3 (75 % N as EVC + FAA 5 % foliar spray) . The lowest plant uptake of all nutrients were recorded by T13 (Absolute control). Economics of cultivation of bhindi indicated that cost benefit ratio was found higher for treatment T5, 75 per cent N as EVC + panchagavya 3 per cent foliar application (2.83) followed by T7, 75 per cent N as EVC + cow urine 10 per cent foliar spray (2.09). From the above study, it was concluded that the recommended dose of inorganics (KAU PoP) can be substituted with combined application of enriched vermicompost (enriched with azolla 10 %) to get 75 per cent N and foliar application of 3 per cent panchagavya or soil application of 10 per cent cow urine or 5 per cent fish amino acid at 10 days intervals. Soil health, in terms of physical, chemical, biological and biochemical properties of soil was more enhanced in the treatments received soil application of liquid organic manures. Liquid organic manures viz., cow urine, panchagavya, jeevamrutha, fish amino acid and vermiwash were easily preparable in the farmers’ farm, biodegradable, less expensive, eco-friendly and non-hazardous for human health and environment. From the study it was found that above liquid organic manures were very good organic sources for organic farming and sustainable agriculture.

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