Browsing by Author "Moossa, P P"

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Absorption and translocation of 32P by root (wilt) affected coconut palms
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2016) Beena George, S; Moossa, P P
An investigation entitled “Absorption and translocation of 32P by root (wilt) affected coconut palms” was conducted in the Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara. Two separate experiments were conducted in farmers’ fields at Mannarkkad, Chittur, Chavakkad, Kayamkulam and RARS, Pattambi. Three types of palms namely healthy, apparently healthy and diseased palms were identified from three soil types of Kerala (laterite, sandy and black cotton soil), where root (wilt) disease was prevalent. Four morphologically uniform palms of same age were selected from each group of palms and soil samples were collected from two depths; 0-20 cm and 20-40 cm from the basin. Index leaf samples (14th leaf) were also collected from the experimental palms. Soil samples were characterized for different physico-chemical properties and plant samples for N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B, Cl and Na. Absorption and translocation of nutrients in coconut palm were studied using radioactive phosphorus in laterite soil. Before 32P application, in order to make homogeneous soil conditions, soil and plant samples were analysed and soil test based fertilizer combinations including organic manures and micronutrients were applied. Three months after fertilizer application, soil and plant samples were again collected and analysed. Three different methods (cotton pad technique, root feeding and soil injection) were employed for 32P application. The index leaf samples were collected at 24 hours, 15 and 30 days after application and radioassayed. The result of basic characterisation of soil showed that all the physico-chemical properties varied significantly among different soil types. Laterite soil recorded the highest value for available P, K, Fe, Mn, Cu and B. High values of EC, Cl, Na and AEC were obtained for sandy soil. Black cotton soil registered the highest values for pH, organic carbon, Ca, Mg, S, Zn and CEC. Among soils under different palms within same soil type, there was significant variation in the content of Mg, B, Zn and Cu. Among different palms K accumulated more in the foliage of diseased palms, while the concentrations of N, Ca, Mg, Fe, Mn, Zn, Cu and B were more in the foliage of healthy palms, indicating nutritional imbalance in the root (wilt) affected palms. Before application of fertilizer in laterite soil, the contents of nutrients were not homogeneous among soils under different palms. After fertilizer application, the soil became more or less similar with respect to the nutrient content. The contents of N, Ca, Mg, Fe, Mn, Zn and Cu were significantly more in the foliage of healthy palms and K was more in the foliage of diseased palms before fertilization. Even after application of fertilizer same trend was observed. Though there was a slight increase in nutrient status of diseased palms after fertilizer application, the rate of increase was comparatively less with respect to healthy palms. This showed that integrated nutrient management targeting soil application cannot fully manage the root (wilt) disease. In absorption and translocation studies using 32P, it was observed that the absorption of radioactive phosphorus was more for healthy palms compared to diseased palms, after 24 hours, 15 days and 30 days of application. For healthy palms, the count rate was more for root feeding method, while in diseased palms highest count rate was obtained by using cotton pad technique. The count rate in the foliage after 15 days was more when compared to 24 hours after application and it tended to decrease 30 days after application. Nutrient imbalance was one of the major problems noticed in root (wilt) affected palms, so it should be corrected first by proper method of application. Among the different methods tested, cotton pad technique can be a promising technique of delivery of nutrient into root wilt affected palms especially for micro nutrients, which needs less quantity compared to major nutrients.
Leaf litter dynamics in acacia and eucalyptus plantations
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1997) Moossa, P P; Venugopal, V K
An investigation entitled “Leaf litter dynamics in Acacia and Eucalyptus plantations” was undertaken to study the leaf litter production, litter decomposition and nutrient release characteristics, and impact of Eucalyptus and Acacia monoculture plantations on the soil physico-chemical and biological characteristics during 1994-97. One hectare each of Acacia auriculiformis, Eucalyptus tereticornis and a moist deciduous forest coming under the Kulathupuzha range of Kerala Forest Department were selected for the study. Field experiment were conducted to determine the leaf litter production and decomposition characteristics of plantation and natural forest. Leaf litter collected at monthly intervals showed that highest litter production was in Acacia (9.4 t ha-1 year-1) followed by natural forest (6.67 t ha-1 year-1) and Eucalyptus (4.68 t ha-1 yaer-1). Pattern of litter production was unimodal in Acacia and natural forest while in Eucalyptus it was bimodal. Chemical analysis of litter samples of plantations and natural forest revealed that with respect to nutrient content fresh and leaf litter of Acacia and Eucalyptus is superior to natural forest whereas litter quality in terms of water soluble components, polyphenols, lignin and cellulose were superior in natural forest. Annual dry matter loss of leaf litter by decomposition followed the order natural forest > Acacia > Eucalyptus. Nutrient release pattern of major and micro nutrients were also worked out for the leaf litter during the process of decomposition and natural forest litter recorded the highest mobility for all the nutrients on decomposition. Improvement in soil physico-chemical properties were noticed due to leaf litter decomposition in the monoculture plantation and natural forest. Biological activity in terms of earthworm and nematode under monoculture plantation was significantly lower than that of adjacent natural forest. Microbial content of soil below the litter bag during different months of decomposition were low in Eucalyptus and Acacia. Chemical analysis of the profile samples of various plantations revealed lower nutrient status in respect of major and micronutrients compared to natural forest. The physical properties of the soil also recorded as unfavourable change in the monoculture plantations as compared to the adjacent natural forest. Proximate anlysis of soil organic matter and humus characterization of the soil organic matter separated from various plantations indicated a low rate of humification and condensation under Eucalyptus. Low humic acid and fulvic acid content in humus and dominance of fulvic acid over humic acid was also noticed in Eucalyptus plantations. Functional group analysis of humic acid and fulvic acid showed that humic material separated from natural forest contained higher quantity of total acidity, contributed by COOH and phenolic group compared to plantation soils. UV, IR, DTA and TGA analysis of humic acid and fulvic acid separated from various plantations showed no variation with respect to natural forest. Allelopathic effect of fresh leaf and leaf litter extract of various plantations on the germination and growth of rice and cowpea followed the order Eucalyptus > Acacia > natural forest and as the concentration decreased from 1: 2 to 1: 10, the allelopathic inhibition also decreased significantly. Allelopathic effect of soil extract also followed the order Eucalyptus > Acacia > natural forest. Thus it can computed that though the leaf litter production and litter quality of monoculture plantations are comparable with that of natural forest, leaf litter decomposition and nutrient released were significantly lower than that of natural forest. Soil physico-chemical properties, soil fertility and biological activities were also adversely affected by monoculture plantations.
Modelling of carbofuran movement and sorption in soils with varying physico-chemical properties
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1994) Moossa, P P; Rajendran, P
An experiment was conducted at the College of Agriculture, Vellayani, during 1992 – 93 for modelling carbofuran movement and sorption in soils with varying physic – chemical properties. Undisturbed vertical and horizontal soil columns were used for the study. Five major locations of the state cropped to banana were selected for the study viz. Malappuram (Ultisol), Chengannur (Inceptisol), Kayamkulam (Entisol), Nedumangad (Mollisol) and Kuttanad (Entisol). The soils exhibited wide variation in the major physico – chemical properties such as texture, water holding capacity, bluk density, particle density, hydraulic conductivity, CEC, AEC and organic matter. The mineralogy of the clay samples had revealed the occurrence of Kaolinite, quartz and smetite as major minerals in these soils. Distribution of carbofuran in the vertical soil columns showed high concentration of carbofuran at lower depths in the first observation for the Inceptisol of Chengannur and the Entisol of Kayamkulam. While in the 6th observation, the Ultisol of Malappuram, Entisol of Kuttanad and the Mollisol of Nedumangad showed higher concentrations in the lower layers due to higher adsorption. Horizontal distribution of carbofuran was very low though significant differences were observed between soils. Maximum horizontal distribution was observed in the Entisol of Kuttanad and the least for the Entisol of Kayamkulam. Regression equation of soil properties on carbofuran content indicated significant influence for organic matter and clay content. Path coefficient analysis of soil properties revealed significant direct positive effect for organic matter and significant direct negative effect for clay content. Indirect negative effects expressed through pH, clay content, Bulk density and AEC with respect to organic matter was not strong enough to counteract the direct positive effect. Similarly the indirect positive effect contributed by clay through organic matter, CEC and sesquioxide was also not sufficient to overcome the direct negative effect. Concentration of carbofuran in the leachate showed highest values for the Inceptisol of Chengannur followed by the Entisol of Kayamkulam, both having low CEC, organic matter and clay content. The Ultisol of Malappuram with high organic matter, CEC and clay had given the lowest value for carbofuran in the leachate. Persistence of carbofuran of was maximum in the Mollisol of Nedumangad with high organic matter, clay content and CEC. Persistence was poor in the Inceptisol of Chengannur and the Entisol of Kayamkulam which are low in organic matter, clay content and CEC. Persistence was poor in the Inceptisol of Chengannur and the entisol of Kayamkulam which are low in organic matter, clay content and CEC. The only transformation product identified was 3 – keto carbofuran observed in the surface soil of Ultisol of Malappuram and Mollisol of Nedumanged in the last observation made at 80 days after application.
Transformation of zinc in soil and zinc nutrition in lowland rice under different levels of Phosphorus
(Department of Soil Science and Agricultural Chemistry, College of Agriculture,Vellanikkara, 2021) Najiya Rinthas, K; Moossa, P P
Phosphorus and zinc are two important essential elements required by the plants for various metabolic activities, functions and associated with membrane structure. Continuous use of phosphatic fertilisers with less zinc, aggravates zinc shortage also phosphorus applied will be accumulated in the soil leading to formation of zinc phosphate complex that affect zinc translocation to various plant parts. There are contradictions regarding phosphorus zinc interaction that is controlled by native P and Zn status. In this context an investigation entitled “Transformation of zinc in soil and zinc nutrition in lowland rice under different levels of phosphorus” was conducted. Two separate experiments were carried out at Regional Agricultural Research Station, Pattambi. In the first experiment, fractions of Zn under different P levels was studied in Long Term Fertilizer Experiment (LTFE) with six treatments on rice in RBD with four replications. The soil samples were taken after the paddy harvest of kharif 2020 and sequential extraction of Zn (water soluble + extractable, organically bound Zn, amorphous sesquioxide Zn and crystalline sesquioxide Zn) and P (sol-P, Al-P, Fe-P, sesquioxide occluded P and Ca-P) were carried out. In the second experiment phosphorus and zinc interactions was studied using pot culture experiment on rice in factorial CRD with 3 replications. Samples from different locations of Palakkad district having native P <12, 12- 24, >24 kg ha-1 and native Zn <1, 1-3, >3 mg kg-1 were collected. Sixteen treatment combinations were applied with 4 levels of P (0, 25, 50,100 mg kg-1 ) as KH2PO4 and 4 levels of Zn (0, 5, 10, 15 mg kg-1 ) as ZnSO4.7H20 through solution for studying the nutrient uptake and yield. The results of fractionation study showed that continuous use of inorganic fertilisers with organic manures in T5 (100% NPK + FYM) increased various Zn fractions except amorphous sesquioxide Zn fraction which was highest in the control. Even though the increase in P application increased different P fractions significantly higher content was observed in 100% NPK+ FYM and these were proved to be beneficial towards increasing different P fractions. But Ca-P fraction was more in the lime treated plot. Correlation study concluded that most of the phosphorus fractions have negative impact on different zinc fractions. The results of the pot experiment elucidated that P and Zn application increased number of productive tillers and thousand grain weight but higher zinc application decreased plant height. Among different soils, soil type S2 (P > 24 kg ha-1 ) registered higher grain and straw yield, P in grain and straw, total P uptake of paddy, but Zn uptake and Zn in grain and straw were more in soil type S3 (Zn > 3 mg kg-1 ). Combined application of 100 mg kg-1 P and 10 mg kg-1 Zn recorded higher grain (57.27 g pot-1 ) and straw yield (66.82 g pot-1 ). Phosphorus application significantly increased the P content in grain and straw but zinc addition had antagonistic effect on them and treatment combination of P100Zn0 registered higher P content in grain (0.26%) and straw (0.214%). The Zn in grain and straw significantly increased by the application of zinc, but phosphorus was having an adverse effect and treatment combination of P0Zn15 registered higher Zn content in grain (61.28 mg kg-1 ) and straw (44.19 mg kg-1 ). Total P and Zn uptake of paddy increased by the application of both phosphorus and zinc with higher content obtained at P100Zn15 (28.47 mg pot-1 ) and P50Zn10 (0.458 mg pot-1 ) treatment combination. Correlation study concluded that phosphorus and zinc application affected P and Zn uptake in high zinc containing soil (S3) and high P soil (S3), respectively. In future this work can be used to study the changes in various P and Zn fractions under continuous crop removal, various management practices to mobilise fixed P in high phosphorus containing soil and also to study Q/I relationship of both phosphorus and zinc.