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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
Quality assessment of pokkali soils under different land uses
(Department of Soil Science and Agricultural Chemistry,College of Horticulture, Vellanikkara, 2014) Chris, Joseph; KAU; Sreelatha, A K
The present study entitled ‘Quality assessment of Pokkali soils under different land uses’ was undertaken to evaluate the soil and water quality of acid saline Pokkali soils under different land uses and to develop geo-referenced database and maps on soil characterization. For this purpose, surface soil samples and water samples were collected from the selected panchayaths representing five land use pattern in the Pokkali tracts. Initial survey was conducted on Pokkali area and five panchayaths were selected from Ernakulam district namely, Kuzhippally, Nayarambalam, Elamkunnappuzha, Edavanakkadu and Kottuvally with all the selected land use patterns. The land use patterns under study were i) paddy alone ii) paddy – shrimp iii) shrimp alone iv) fallow and v) mangroves. The soil samples were analysed for their physical (texture, bulk density, soil moisture constants, aggregate stability), chemical (pH, EC, CEC, base saturation, available N, P, K, Ca, Mg, Fe, Cu, Mn, Zn, S, B) and biological (organic carbon, dehydrogenase activity, microbial biomass carbon) attributes. Water samples were also characterized for parameters like pH, EC, TSS and heavy metals. Measured attributes were analyzed by one-way analysis of variance using statistical package MSTATC to examine the effect of land use type on soil properties. Soil quality evaluation was done by the method described by Andrews et al. (2002). Three main steps of this technique includes, i) selection of minimum data set (MDS), ii) scoring of the MDS indicators based on their performance of soil functions, and iii) integration of the indicator scores into a comparative index of soil quality. Analysis of variance revealed that land uses have significant effect on most of the measured attributes except fine sand percent, base saturation percent, content of Mg, Zn, organic carbon and dehydrogenase activity. The statistical analysis resulted in selection of minimum data set which highly influenced the quality of the soil. Indicators in the MDS included available water content, pH, fine sand percent, aggregate stability, silt percent, available Mg, bulk density, available S, microbial biomass carbon, available Mn, organic carbon, base saturation and EC. The highest soil quality index (4.92) was observed in paddy- shrimp land use system in Nayarambalam panchayath and least value (2.07) was observed in shrimp alone land use pattern in Kottuvally panchayath. The observed soil quality index value was in the order, paddy- shrimp> paddy alone> fallow> mangrove> shrimp alone. Based on the relative soil quality index value, all land uses were categorized into three groups, ie, poor, medium and good. Paddy- shrimp land use system in Nayarambalam panchayath was the only one land use system coming under the ‘good’ category. For all the panchayaths and RRS, Vyttila GIS based soil quality index maps were prepared.
Open Access
Wet soil analysis for nutrient prescription in paddy soils
(Department of Soil Science and Agricultural Chemistry,College of Horticulture, Vellanikkara, 2014) Irene, Elizabeth John; KAU; Sureshkumar, P
Three locations from 7 agro ecological units dominated by rice crop were identified namely, Onattukkara sandy soil(AEU 3), Kuttanad(AEU 4), Pokkali(AEU 5), Kole(AEU 6), north central laterite(AEU 10), Palakkad central plains (AEU 22) and Palakkad eastern plains (Black soils )(AEU 23). Geo-referenced soil samples were collected at 3 stages: before cropping season, at active tillering and visual panicle initiation. Plant samples were also collected during the above stages and analyzed for nutrient contents. Initial characterization was done with air dried samples while samples during crop growth period were collected by maintaining the wet anaerobic conditions and analyzed as such as well as after drying. Submergence resulted increase in pH both under wet and dry analysis. The pH on the basis of wet analysis was higher than that by dry analysis. EC decreased during flooding and dry analysis gave higher values than by wet analysis. The (C: N) 1 ratio (based on total carbon and total nitrogen) varied from 9.32 :1 in Onattukarasandy soil to 18:1 in Kuttanad on the basis of wet analysis. Analysis after drying recorded a (C: N) 1 ratio ranging from 10.84 inPalakkad central plains to 22 in Kuttanad. Comparison of wet and dry analysis of other available nutrients indicated that higher values were recorded for P, K, Ca, Mg and Fe in wet analysis while the values for availableS, Mn, Zn and B were higher in dry analysis. Data on analysis after drying, recorded significant negative correlation of pH with organic carbon (0.36**) and available S (-0.37**) due to accumulation of organic acids and SO 42-ions under aerobic condition. Antagonistic interaction of available P with available Ca was attributed to significant negative correlation obtained between them in dry analysis. Wet analysis gave significant positive correlation of pH with available Ca (0.35**) and significant negative correlation with available S (-0.28*). All the C: N ratios computed on the basis of, total carbon and total nitrogen (C: N) 1, total carbon and available nitrogen (C: N) 2, organic carbon and total nitrogen (C: N) 3 and organic carbon and available nitrogen(C: N) 4 were significantly correlated with total and available nitrogen at different stages both under wet and dry analysis. Four soil types namely, Onattukara sandy, Kuttanad, north central laterites and Palakkad eastern plains were used for an incubation study to unravel the pattern of decomposition of added organic matter and to identify the C: N ratio at equilibrium. Changes in pH and redox potential during submergence indicated slight increase in pH after 7 days of submergence and redox potential was constantly decreasing with increasing period of submergence. The (C: N) 1 ratio was found to stabilize at 9.6:1 after 3 months of incubation with organic matter while it was stabilized at 7.6:1 without organic matter in Onattukara soil. In Kuttanad soils it was 18.3:1 and 17:3 respectively. In Chittor soils it stabilized at 10:1. The (C: N) 3 also showed similar trends. However, available nutrient did not give any significant correlationwith the corresponding plant content of the respective nutrient. This focusesto the importance of future studies with more number of samples from eachAEU’s as each of the fertility parameters are highly varying in these units.
Open Access
Characterization, conversion and evaluation of selected lignocellulosic biomass
(Department of Soil science and Agricultural Chemistry, College of Agriculture, Vellayani, 2014) Anushma, S; KAU; Aparna, B
The study entitled “Characterization, conversion and evaluation of selected lignocellulosic biomass” was conducted during the period 2013-14 at the Department of Soil Science & Agricultural Chemistry, College of Agriculture, Vellayani. The main objectives of the study were the characterization of the lignocellulosic biomass from selected plant sources, assessment of various microbial and enzymatic sources for degrading the lignocellulosic biomass into compost and evaluation of the resultant compost for assessing its manurial value. The experiment was completed in three stages. Representative samples of water cabbage (L. flava), coir pith, water hyacinth (E. crassipes) , and farm wastes (dried leaves and pseudostem of banana) were collected and analysed for bio-chemical composition. Water cabbage recorded 2.74 per cent N, 0.30 per cent P, 0.33 per cent K, 16.98 C:N ratio, and no detectable levels of heavy metals except Ni (0.55 ppm) and inferred as the best substrate in terms of nutrient content followed by water hyacinth, farm wastes and coir pith respectively. The substrates were converted to composts using various inoculants viz. T. reesei, P. sajor-caju, Composting Inoculum and commercial enzyme cocktail (cellulase/pectinase and lactase) and physico- chemical and biological characteristics were analyzed. A mixture of water cabbage and Composting Inoculum) was concluded as the best in terms of nitrogen content , cellulase activity, maturity period, C:N ratio and no detectable levels of heavy metals except Ni (0.414 ppm) followed by the mixture of Water hyacinth and Composting Inoculum had comparable N, P , K, EC , C:N ratio, and heavy metal content below the detectable limit. Considering the effect of inoculants on different substrates, Composting Inoculum was concluded as the best in terms of moisture content, EC,N, P, K, dehydrogenase activity, cellulase activity, maturity period and C:N ratio. The resultant composts from the previous stage were evaluated for their performance as manure in a pot culture experiment with test crop amaranthus (variety - Arun). Application of 100 % N as compost water hyacinth and Composting Inoculum was noticed as the best treatment in terms of yield, plant height, number of branches, girth of stem, soil properties viz. water holding capacity, available N, available P, available K, available Mn, available Cu, bacteria population and plant content of micronutrients viz. Mn, Cu, and B. Major enzymes viz. dehydrogenase, urease and aryl sulphatase imposed significance on yield and yield attributes. Application of 100 % N as compost from water cabbage and Composting Inoculum was found to be good and on par with T13 in many of the characters. Application of various composts did not result any heavy metal accumulation in the soil Thus it was inferred from the study that water cabbage was the best substrate in terms of their chemical composition followed by water hyacinth. water cabbage + Composting Inoculum was recorded as the best compost followed by water hyacinth + Composting Inoculum. 100 % N as compost (water hyacinth + Composting Inoculum) was noticed as the best treatment in pot culture. With regards to inoculants used on different substrates,Composting Inoculum was found to be the most effective for composting the agrowastes.
Open Access
Zinc bioinfortification for enhancing yield and quality of yard long bean (vigna unguiculata subsp.sesquipedalis (L) verdcourt) in ferralitic soils
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2014) Dhanya, G; KAU; Manorama Thampatti, K C
The study titled ‘Zinc biofortification for enhancing yield and quality of yard long bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt) in ferralitic soils’ has been carried out at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani during 2013-14. The above investigation was under taken to study the effect of zinc biofortification through mineral fertilization on pod yield and quality of yard long bean and bioavailability of zinc. The experiment was laid out in Instructional Farm, Vellayani in Randomized Block Design with ten treatments and three replications during October, 2013 to January, 2014. The treatments included two methods of Zn fertilizer application viz., soil application of Zn @ 2.5 kg ha-1 and 5 kg ha-1 and foliar application of ZnSO4 @ 0.025 per cent and 0.05 per cent along with Package of Practices Recommendations of KAU (POP) and Soil Test Based Recommendations (STBR). The treatment effect was statistically not significant for the biometric characteristics of yard long bean. Regarding the pod yield, foliar application of ZnSO4 @ 0.05 per cent along with STBR (T10) recorded the highest yield per plant. The same treatment showed the highest value for single pod weight plant-1 and number of seeds pod-1as well as B:C ratio and total dry matter production. However, the harvest index was highest for the T5 (POP + ZnSO4 foliar @ 0.025 %) which on par with all other treatments except T1 (POP). The results of the soil analysis at the time of final harvest revealed a general increase in available nutrient content compared to that of initial status. The soil application of Zn @ 5 kg ha-1 along with POP (T4) recorded the highest value for available Zn followed by the treatment with STBR + Zn @ 5 kg ha-1 (T8). The chemical analysis of pods revealed that, foliar application of ZnSO4 @ 0.05 per cent along with STBR (T10) recorded the highest concentration of Zn and lowest value for phytate. The increase in Zn content was 41.47 per cent over its counterpart without Zn application. The same treatment (T10) showed the lowest phytate P: Zn ratio indicating highest bioavailability of Zn. The performance of treatment T1 (POP) was comparatively poor in these aspects. The Zn content of bhusa showed a different pattern with POP based treatments receiving foliar application of Zn showed highest values. Evaluating the performance on methods and levels of Zn application for biofortification in yard long bean var. Vellayani Jyothika, it was observed that, the treatment receiving STBR based N, P and K fertilizers along with 0.05 per cent ZnSO4 foliar spray at branching and flowering stages (T10) recorded the highest pod yield, B:C ratio and Zn content with lowest values for phytate and phytate: Zn ratio. Considering the lowest nutrient input addition and more benefit, the same was found to be the best treatment. However, the treatment receiving POP based N, P and K recommendation with Zn as foliar treatment at 0.05% (T6) was also found to be equally effective in all aspects with slightly lesser values but statistically on par with the above. The foliar application of ZnSO4 @ 0.05 per cent to yard long bean at branching and flowering stages was able to increase pod yield and zinc density and can reduce the phytate content of pods, both at POP and STBR based treatments of N, P and K fertilizers. Hence it can be concluded that whatever be the rate of application for N, P and K, i.e. either POP or soil test based recommendation, the foliar application of ZnSO4 @ 0.05 per cent at branching and flowering stages was found to be the best as regards to pod yield, Zn content and quality compared to other methods and rate of zinc application.
Open Access
Quality assessment of pokkali soils under different land uses
(College of Horticulture, Vellanikkara, 2014) Chris, Joseph; KAU; Sreelatha, A K
The present study entitled ‘Quality assessment of Pokkali soils under different land uses’ was undertaken to evaluate the soil and water quality of acid saline Pokkali soils under different land uses and to develop geo-referenced database and maps on soil characterization. For this purpose, surface soil samples and water samples were collected from the selected panchayaths representing five land use pattern in the Pokkali tracts. Initial survey was conducted on Pokkali area and five panchayaths were selected from Ernakulam district namely, Kuzhippally, Nayarambalam, Elamkunnappuzha, Edavanakkadu and Kottuvally with all the selected land use patterns. The land use patterns under study were i) paddy alone ii) paddy – shrimp iii) shrimp alone iv) fallow and v) mangroves. The soil samples were analysed for their physical (texture, bulk density, soil moisture constants, aggregate stability), chemical (pH, EC, CEC, base saturation, available N, P, K, Ca, Mg, Fe, Cu, Mn, Zn, S, B) and biological (organic carbon, dehydrogenase activity, microbial biomass carbon) attributes. Water samples were also characterized for parameters like pH, EC, TSS and heavy metals. Measured attributes were analyzed by one-way analysis of variance using statistical package MSTATC to examine the effect of land use type on soil properties. Soil quality evaluation was done by the method described by Andrews et al. (2002). Three main steps of this technique includes, i) selection of minimum data set (MDS), ii) scoring of the MDS indicators based on their performance of soil functions, and iii) integration of the indicator scores into a comparative index of soil quality. Analysis of variance revealed that land uses have significant effect on most of the measured attributes except fine sand percent, base saturation percent, content of Mg, Zn, organic carbon and dehydrogenase activity. The statistical analysis resulted in selection of minimum data set which highly influenced the quality of the soil. Indicators in the MDS included available water content, pH, fine sand percent, aggregate stability, silt percent, available Mg, bulk density, available S, microbial biomass carbon, available Mn, organic carbon, base saturation and EC. The highest soil quality index (4.92) was observed in paddy- shrimp land use system in Nayarambalam panchayath and least value (2.07) was observed in shrimp alone land use pattern in Kottuvally panchayath. The observed soil quality index value was in the order, paddy- shrimp> paddy alone> fallow> mangrove> shrimp alone. Based on the relative soil quality index value, all land uses were categorized into three groups, ie, poor, medium and good. Paddy- shrimp land use system in Nayarambalam panchayath was the only one land use system coming under the ‘good’ category. For all the panchayaths and RRS, Vyttila GIS based soil quality index maps were prepared.
Open Access
Biological profile of ferralitic alluvial paddy soils under long term differential fertilizer application
(College of Agriculture, Vellayani, 2014) Nikhil, K; KAU; Sumam, George
The present study on “Biological profile of ferralitic alluvial paddy soils under long term differential fertilizer application” was formulated with the objective of studying the variations in the important biological properties of ferralitic alluvial soils under long term fertilizer experiments with rice-rice cropping sequence and the relationship of these properties with yield and yield attributes. The soils of three long term fertilizer experiments at RARS, Pattambi (listed below) formed the study material 1) Permanent Manurial Trial with tall indica rice variety (PMT- Tall), 2) Permanent Manurial Trial with dwarf indica (PMT- Dwarf), 3) AICRP on long term fertilizer experiments (LTFE). For (PMT- Tall) the treatment combination T7 which is an integrated nutrient package of 10 kg N ha-1 as green leaf (GL) + 10 kg N ha-1 as cattle manure (CM) + NPK 20:20:20 kg ha-1 significantly and positively influenced most of the soil biological properties like bacteria, fungi, actinomycetes and Azotobacter, levels of soil enzymes urease, phosphatase and dehydrogenase, microbial biomass carbon (MBC), C and N mineralization potential, hot water extractable carbohydrates (HWC) and in turn plant characters like height, no. of tillers and no. of panicles plant-1 and ultimately grain and straw yield. For other characters like population of arthropods, P solubilizers and soil respiration T5 (20 kg N ha-1 as CM + NPK 20:20:20 kg ha-1) and for Azospirillum count T3 (20 kg N ha-1 as CM + 20 kg N ha-1 as GL) registered the maximum values. The same trend in favour of integrated nutrient management was observed for (PMT- Dwarf) also, T7 (22.5 kg N ha-1 as GL + 22.5 kg N ha-1 as CM + NPK @ 45:45:45 kg ha-1) registering significantly the highest values for properties like bacteria, actinomycetes, Azotobacter, soil enzymes, MBC, HWC, plant height, no.of tillers, no. of panicles plant-1 and grain yield. For characters like fungi, Azosprillum population and respiratory activity T6 (45 kg N ha-1 as GM+ NPK @ 45:45:45 kg ha-1) was the most effective as was T5 (45 kg N ha-1 as CM + NPK @ 45:45:45 kg ha-1) for P solubilizers and straw yield, T3 (45 kg N ha-1 as CM + 45 kg N ha-1 as GM) for arthropod count and N mineralization and T1 (90 kg N ha-1 as CM) for C mineralisation In LTFE T8, also an integrated nutrient package {100 percent NPK + FYM @ 5 t ha-1 (to Kharif crop only)} produced significantly the higher populations of earthworms, arthropods, bacteria, actinomycetes, fungi, Azospirillum, Azotobacter, soil enzymes, MBC, HWC, C and N minerlisation potential, no. of panicles and in turn grain yield. Only for a very few characters the other treatments had any effect like T10 {100 percent NPK + in situ growing of Sesbania aculeata (for Kharif crop only)} for straw yield and no. of tillers and T3 (150 percent NPK) for p solubilizers. In nutshell for sustenance of soil health and maximum yield, treatment T7 (10 kg N ha-1 as GL+ 10 kg N ha-1 as CM + NPK @ 20:20:20 kg ha-1) can be adjudged to be the best for (PMT- Tall). For (PMT- Dwarfl), T7 (22.5 kg N ha-1 as GL + 22.5 kg N ha-1 as CM + NPK @ 45:45:45 kg ha-1) was the best treatment and T8 {100 per cent NPK + FYM @ 5 t ha-1 (to Kharif crop only)} for LTFE.
Open Access
Impact of glyphosate and chlorpyriphos on chemical and biological properties of lateritic soil
(College of Horticulture, Vellanikkara, 2014) Shitha, C R; KAU; Durga, Devi K M
The thesis entitled "Impact of glyphosate and chlorpyriphos on chemic I a d biological properties of lateritic soil" was done in the year 2012-2013 in the Dep rt e of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikara. The programme consisted of laboratory experiment viz., avoidance behaviour of earth orm, pot culture study on survival of earthworm and soil micro flora under the different pesticide treatments and two field experiments viz., application of (1) glyphosate and (2) chlorpyriphos in cropped area and lawn respectively. The laboratory and pot culture studies consisted of seven treatments. The treatme ts included two levels of application (recommended and double the recommended dose) of t 0 formulations of glyphosate (1.2 and 2.4 kg a.i. ha") and single chlorpyriphos formulati n (400 and 800 g a.i. ha") and an absolute control. Glyphosate formulations namely Roundup® and Glycel® were applied at 6 and 12 mL L-I respectively and chlorpyriphos formulation Dursban® was applied at 4 and 8 mL L-I. The main observations included in this research programme were biological properties of soil viz., earthworm count, total microbial count, dehydrogenase activity and chemical properties of soil viz., pH, organic carbon, available P, K Ca, Mg, Fe, Zn, Cu and Mn. Both laboratory and pot culture experiments were done with native earthworms. The laboratory experiment was done to understand the avoidance behavior of earthworm to t e two glyphosate formulations and chlorpyriphos. This study showed that all the chemicals were avoided by earthworms and the maximum avoidance was obtained with the application of Roundup® (12 mL L-I) followed by Glycel® (12 mL L-I) and Dursban® (8 mL L-I). Earthworm avoidance test done by two methods of application (mixing as well as spraying) showed similar trends. However, higher net response was obtained by mixing the pesticides in soil. Spraying on the surface imitated the field situation, in which the avoidance response ranged from 20.0 to 46.7 %, while in the case of mixing the pesticides with the soil, the avoidance response ranged from 33.3 to 73.3 %. When the soil was mixe with the chemicals, the earthworms had direct contact with the pesticides throughout the treated soil section and thus they had shown greater tendency to avoid the area. Pot culture studies on the survival of earthworms revealed that neither glyphosate nor chlorpyriphos had deleterious effects on their multiplication. The study also showed that both soil fungi and bacteria were affected by application of glyphosate and chlorpyriphos. The adverse effect of chemicals on the soil fungi followed the order Roundup 12 mL i.' > Dursban 8 mL r.:' > Glycel 12 mL r.:' > Dursban 4 mL i.' > Roundup 6 mL i.' > Glycel 6 mL r.'. Percent decline in the fungal population was 10.1 to 70.5 at one week and 5.8 to 62.9 at one month after application. It was noticed that Roundup and Glycel at the recommended rates of application did not cause adverse effect on soil fungi at one month after spraying, indicating that the effect was temporary. However, chlorpyriphos formulation caused a significant decline in the fungal population at both the sampling intervals. In the case of bacteria, percentage decline over control followed the order Roundup 12 mL i.' > Glycel 12 mL i.' > Roundup 6 mL r.' > Dursban 8 mL i.' > Glycel6 mL Cl> Dursban 4 mL i.', at one week after spraying and the extent of decline ranged from 14.3 to 71.6%. At one month, the effect of chlorpyriphos (Dursban) on bacteria was comparatively lower than that of glyphosate formulations at both the concentrations. Two field studies were conducted to find out the effect of application of glyphosate in cropped area (banana field) and chlorpyriphos in the lawn. Experiment in the banana field was conducted with five treatments namely Roundup® and Glycel® each at 6 and 12 mL i.' and an absolute control. The treat~ents were replicated four times. Studies with chlorpyriphos were carried out in the established lawns of the College of Horticulture, Vellanikkara with three treatments viz., Dursban® at 4 and 8 mL L-land seven replications. Both biological and chemical properties were studied. It was found that application of . glyphosate caused short term inhibitory effect on soil fungus up to 30 days after spraying, where as application of chlorpyriphos caused short term inhibitory effect on soil bacteria (up to 30 DAS). Population of soil micro flora did not vary between treatments at 60 days after spraying glyphosate and chlorpyriphos formulations. Dehydrogenase activity and available nutrients in the soil were unaffected by the application of glyphosate and chlorpyriphos formulations used in the study.
Open Access
Physico-chemical properties of rain water harvested under different situations in lateritic soils
(College of Horticulture, Vellanikkara, 2014) Abdu Ibrahim Hassen; 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.

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