Browsing by Author "Usha Mathew"

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Assessment and management of micronutrient deficiencies in Onattukara
(Department of soil science and agricultural chemistry, College of agriculture, Vellayani, 2015) Mini, V; Usha Mathew
Assessment of soil health and status of heavy metals in the certified organic farms of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2019) Greeshma, P R; Usha Mathew
The study entitled “Assessment of soil health and status of heavy metals in the certified organic farms of Kerala” was conducted from 2017 to 2019. The objective of the study was to assess and compare the soil health parameters and heavy metal status of the inputs and produce of certified organic farms and conventional farms of Kerala. Samples of soil, inputs and plant produce were collected from different locations of Kerala representing Northern, Hill, Central and Southern zones. The organic farms selected for study were under NPOP certification for more than 10 years. The rate of application of manures in organic and conventional farms were 30 t ha-1 and 2 t ha-1 respectively. The first part of investigation was conducted to comparatively evaluate the effect of organic and conventional farming on soil health, for which composite soil samples from 2 depths (0-15 cm and 15-30 cm) were collected from 10 numbers each of certified organic farms and conventional farms. The collected soil samples were analysed for physical, chemical and biological properties from which soil quality index was calculated for each sample and an in situ enumeration of earthworms and arthropods was conducted by excavating 1 m3 soil in all the farms from where soil samples were collected. Among the physical and chemical properties analysed, available N, K, Ca, Zn and Cu at 0-15 cm depth were significantly higher in soils from organic farms than conventional farms. Bulk density was found to be lower in soils of organic farms which is a good soil quality attribute. pH was significantly lower in soils of organic farms at 0-15 cm depth. Total as well as available content of heavy metals were (Ni, Cd and Pb) were not significantly different among the organic and conventional soil samples. Unlike physical and chemical properties, all biological properties were significantly higher in soils of organic farms than conventional farms. Bacterial, fungal, actinomycetes count, earthworms, soil arthropods and dehydrogenase activity were found to be significantly higher in soils of organic farms than in conventional farms at both depths and respiratory activity was found to be significantly higher in organic farms at 0-15 cm depth. Soil quality index was calculated from various physical, chemical and biological soil properties and the highest index (61.1 per cent) was obtained in the surface soils of hill zone under both management. However the highest soil quality index was observed only in soils of organic farms in Northern and Southern zones. The second part of investigation was input analysis in which inputs used in organic and conventional farms, available at the time of sampling were analysed for Zn, Cu, Cd, Ni and Pb. The results revealed that except for the content of Cu in manures and fertilizers, other heavy metals were not observed to be significantly different in manures and fertilizers. The third part of investigation was plant study, in which edible parts of 10 crops were collected from both organic and conventional farms and analysed for Zn, Cu, Cd, Ni and Pb. Except for Zn, other heavy metals were found to be very much within the limit of food safety standards. Zn was found to be high in amaranthus from both organic (96 mg kg-1) and conventional (105.6 mg kg-1) farms. Content of Zn in yard long bean, salad cucumber and curry leaf from organic farms (60-64 mg kg-1) and was found to be just exceeding the safe limit (60 mg kg-1). Zn in plants was found to be significantly affected by management practices also. A significant positive correlation have been observed between the content of Zn in plants and available Zn in soil in both conventional and organically managed soils. From the study it may be concluded that soil quality was found to be generally high in hill zone soils compared to other zones irrespective of the management practice and in all other regions, organic farming was found to be increasing the soil quality. Heavy metals in inputs and plant produce analysed were very much within safety standards. Zn content of amaranthus in organic and conventional farms exceeded the food safety limit. A significantly higher biological properties of soils in organic farms clearly manifests the long term sustainability of organic farming in Kerala’s climatic condition.
Effect of application of zinc and copper on the yield of rice
(Kerala Agricultural University, 2000) Usha Mathew; Beena, C; Balachandran, P V
Effect of submergence on the soil testing parameters of paddy soils
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1986) Usha Mathew; Alice Abraham
Laboratory incubation studies were conducted to quantify the changes in pH, EC, lime requirement and availability of important nutrients such as N, P, K, Ca & Mg due to submergence of alluvial, acid saline acid sulphate and saline rice soils of Kerala, The study has revealed that pH of all the soil types increased Immediately after flooding of the air dried soils, reached a maximum and remained more or less steady throughout the period of three months submergence. Consequent to the increase in pH, a corresponding decrease in lime requirement was observed in all the soils. Maximum reduction in lime requirement was noticed for the saline and acid saline soils. A rise in EC was observed in all the soil types due to submergence during the first four to six weeks. It showed a decreasing tendency afterwards. All the soils showed a progressive increase in available nitrogen content with increase in the period of flooding. The increase was in the range of 75 - 395$ for the various soil types. Maximum increase was recorded by saline soils (395$) and minimum by alluvial soils (75%). The levels of available phosphorus recorded for the four soil types in the air dried state were in The low to medium range for rice. Submerging of these soils has resulted in a manifold increase in the content of available phosphorus. The increase was maximum for acid saline soils (700$) and minimum (55$) for alluvial soils. The availability of exchangeable cations like potassium, calcium and magnesium, however, showed a periodical increase and decrease on flooding in all the four soil types. The results of the study have clearly brought out the magnitude of the changes that result in the status of each nutrient upon flooding of soils for wetland paddy cultivation. The manifold increase in the status of major nutrients like N and P upon flooding of soils indicates that addition of fertilizer N and P under such conditions is not likely to produce any significant effect on rice unless the rice varieties are highly responsive to these nutrients. The feasibility of reducing The quantity of fertilizers to be applied or even skipping of fertilizers for one or two seasons may be considered taking into account the responsiveness of the rice variety as well as other economic factors.
Evaluation of fortified humic acids from grow bag mixtures as phytotonic in okra [Abelmoschus esculentus (L.) Moench.]
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2017) Dhanesh Kumar, T V; Usha Mathew
Magnesium and boron nutrition for yard long bean (Vigna unguiculata subsp. sesquipedalis (L). verdcourt) in southern laterites of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2015) Emil Jose; Usha Mathew
The study entitled “Magnesium and boron nutrition for yard long bean (Vigna unguiculata subsp. sesquipedalis (L). Verdcourt) in southern laterites of Kerala” was carried out at College of Agriculture, Vellayani during August to December, 2014 to standardize the method and time of application of fertilizers of Mg and B in the Agro Ecological Unit -8 using yard long bean as test crop. The experiment was laid out in the Instructional Farm Vellayani in Randomized Block Design with ten treatments and three replications. The treatments included a combination of magnesium as magnesium sulphate and boron as borax and were applied either in soil or as foliar at different times. Treatments were applied over and above the use of lime and NPK based on soil test and FYM as per package of practices recommendations of Kerala Agricultural University, as one time soil application as basal, one time soil application between basal and top dressing, one time soil application at top dressing, soil application in two equal splits as basal and top dressing, soil application at fortnightly intervals in equal splits. Foliar application of treatments were done at first flowering, active flowering and fortnightly intervals. Combined application of soil with half of adhoc recommendations of Mg and B as basal and foliar at active flowering was also one of the treatments. The study revealed that the use of magnesium and boron in soil and foliar application had a significant effect on the vegetative and yield characters. Foliar application of Mg and B as 2 per cent MgSO4 and 0.25 per cent borax at fortnightly intervals along with soil test based package of practices recommendations of NPK (T9) recorded the highest yield and it was on par with T8 which received foliar application of Mg and B twice at first flowering and active flowering along with soil test based package of practices recommendation. The highest cop duration (96 days) was observed in T9 and the lowest crop duration of 84 days was recorded by T1. The highest harvest index also was recorded by T9. The treatment effect was statistically 131 not significant for the quality characters like fibre content and keeping quality of pod. However the protein content was significantly influenced by the treatment. The incidence of Fusarium wilt and aphids were noticed during the crop period. But the treatments had no significant influence on them. The results of the soil analysis before and after the experiment revealed a general increase in available nutrient content and pH as a result of the treatments. The soil application of Mg and B at fortnightly intervals recorded the highest value for available Mg and B. Critical level of Mg (>120 ppm) for sufficiency in soil was attained in all soil application treatments. In the case of B, critical level of sufficiency (> 0.5 ppm) was not attained either through soil or foliar application. Application of Mg and B as soil and foliar application had a significant effect on the contents of N, P, Ca, Mg, S, Fe, Cu, Zn, Mn and B in the pod of the yard long bean. However the effect of treatments on the content of K in the pod was not significant. Whole plant analysis revealed that, the treatment had significant effect on the contents of N, P, Ca, Mg, S and B. But K, Fe, Cu, Zn, Mn were not significantly influenced by the treatments. It is concluded that, both the soil and foliar application of Mg and B significantly improved the nutrient uptake, pod yield and yield characteristics of yard long bean. The highest benefit cost ratio was noted in the treatment T8 which consisted of soil test based NPK and farm yard manure along with foliar application of 0.25 per cent borax and 2 per cent magnesium sulphate twice at first flowering and active flowering.
Status and impact of heavy metals in selected soils and crops of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1999) Usha Mathew; Alice Abraham
Status of Cu, Zn, Ni, Pb and Cd in samples of selected soils, fertilizers, manures and crops were estimated. A critical analysis of the total content of these heavy metals in the soils studied here revealed that Cu arid Cd are existing beyond the critical level in the some of the samples. In the wetland soils, content of all heavy metals was lowest for phytotoxicity and food safety in samples from absolute control plots of rice PME at Pattambi, Moncompu and Kayamkulam and highest in samples from plots receiving maximum quantity of organic manures and inorganic fertilizers. The DTPA extractable form is only a very minor part of their total content. The heavy metal load of the commonly used P fertilizers in Kerala is found to be highly variable. Zn is the highest contaminant followed by Pb, Ni, Cd and Cu. With respect to manures commonly used in Kerala, Zn is the most abundant among the five elements studied followed by Cu. Retention of heavy metals was found to be more in the roots of all plants compared to the above ground portions except Zn in amaranthus. The grain, straw and root of rice plants collected from PME plots which were receiving organic manures and inorganic fertilizers continuously for several years had a distinctly higher content of all heavy metals compared to the samples obtained from absolute control plots. The content of Cu in rice samples and that of Zn and Cu in the fodder samples from sewage farm exceeded the critical level to express phytotoxicity. In some of the samples of amaranthus and cowpea, content of Zn, Pb and Cd exceeded the food safety standards prescribed in Germany. Studies on the pattern of retention of applied Cd and Ni in undisturbed soil columns of important soil types of Kerala showed that retention of Cd and Ni was more in the top than in the bottom layers. Higher retention and lower leaching loss of applied Cd and Ni was observed in the columns not treated with FYM. Pot culture studies have shown a significant reduction in yield of rice, sesame and cowpea at various levels of Cd and Ni with and without FYM. Nutrient content of seed, shoot and root showed variations but did not reveal any specific pattern in various crops. In cowpea, low levels of Cd and Ni in the absence of FYM stimulated nodulation and nitrogen content. Intake of Cd and Ni in various plant parts of rice, sesame and cowpea was in the order root> shoot> seed. It was more in the presence of FYM than in its absence. The toxic effects of Ni on growth and yield parameters were of lesser magnitude compared to Cd especially in rice and cowpea. Maximum accumulation of Cd in edible portions was recorded by sesame with no ill effect on germination. However a moqerate accumulation of Cd in rice seeds resulted in significant reduction in germination. An alarming observation obtained from the study was that almost all samples of rice grains exceeded the food safety standard of 1 mg Cd kg-1 indicating that rice, the staple food of the people of Kerala is contaminated with Cd, the most hazardous heavy metal for human health. This pioneer study on the heavy metal status of selected soils and crop plants of Kerala has brought out the need for conducting detailed studies on these aspects.
Utilisation of dairy industry solid waste as an organic source in soil productivity
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 2004) Indu, B; Usha Mathew
Zinc and boron availability in soils and impact of carriers on crop productivity
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2005) Jyolsna, V K; Usha Mathew
A study entitled “Zinc and boron availability in soils and impact of carriers on crop productivity” was carried out at College of Agriculture, Vellayani 2003-2005 to monitor the effect of moisture levels with and without FYM on the availability of B and Zn in three types of soil viz., red, laterite and Onattukara sandy and the influence of carriers of Zn and B on tomato. The experiment consisted of two parts viz., incubation study and separate pot culture experiments with B and Zn. The physico-chemical analysis of soils used for incubation study was done using suitable analytical procedures. Incubation study was conducted at the laboratory to monitor the availability of B and Zn in red, laterite and Onattukara sandy soils. Two kg of each type of soil was taken in earthern pots of uniform size and incubated for two months at three moisture levels viz., air dry, field capacity and full saturation with and without FYM. The experiment was laid out in CRD with six treatments. They were, T1 – Air dry, T2 – Field capacity, T3 – Full saturation, T4 – T1 + FYM, T5 – T2 + FYM and T6 – T3 + FYM. Soil samples were drawn at fortnightly intervals and analysed for the available content of boron and zinc following standard analytical procedures. Separate pot culture experiments were conducted to study the influence of B and Zn using laterite soil on growth, yield and quality of tomato. They were laid out in CRD with treatments viz., T1 – fertilizers alone as per POP, T2 – fertilizers and FYM as per POP, T3 - T1 + B/Zn @ 0.5 /2.5 kg ha-1, T4 – T1 + B/Zn @ 1.0/5.0 kg ha-1, T5 – T1 + B/Zn @ 1.5/10 kg ha-1, T6 – T2 + B/Zn @ 0.5/2.5 kg ha-1, T7 – T2 + B/Zn @ 1.0/5.0 kg ha-1 and T8 – T2 + B/Zn @ 1.5/10.0 kg ha-1. Observation on various biometric and yield parameters had been recorded. Soil, plant and fruit analysis were done using standard analytical procedures. From the incubation study, it can be seen that B availability was more at full saturation condition than at air dry and field capacity moisture regimes in all the three soils. It was minimum at air dried state of soil. Available Zn recorded maximum value at air dried state than at field capacity and full saturation moisture regimes. The influence of B and Zn on the growth, yield and quality of tomato can be clearly understood from the pot culture experiments. Plant height and number of primary branches showed significant increase with B and Zn application. Yield, B : C ratio and quality parameters were higher in the treatments which comprise B/Zn along with FYM. Available K in soil after pot culture increased with increase in levels application of boron. The same trend was shown by DTPA-extracted Zn and Cu. Available Fe and Mn decreased by B application. Soil B increased with increase in level of B application. Plant content of these nutrients showed the same trend as that of soil content. Available P, Fe, Mn and Cu decreased with increase in levels of Zn application in the pot culture experiment with Zn. Soil available Zn increased with increase in level of application of Zn. Plant nutrient content showed considerable variations. There was an increasing trend for uptake of nutrients from T1 to T8 as there was an increase in total dry matter production in both the experiments. From the results cited above it can be confirmed that B and Zn fertilization has an important role in improving yield and quality of tomato. The highest yield, quality and B : C ratio were obtained when B was applied @ 1.5 kg ha-1. This indicates that further experiments may be conducted by raising the level of B above 1.5 kg ha-1 to verify its effect on contributing to further increase in yield. In the experiment with Zn, though the yield was the highest in T8, the B : C ratio was higher in T7 than in T8 . This indicates that economic yield was obtained when Zn was at 5 kg ha-1. For the purpose of formulating recommendations on application of B and Zn, more field studies need to be conducted.