Soil carbon storage and nitrogen dynamics in certified organic farms of Kerala (Record no. 289366)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 05275nam a22001817a 4500 |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | 631.4 |
| Item number | NAY/SO PG |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Nayana, M V |
| 245 ## - TITLE STATEMENT | |
| Title | Soil carbon storage and nitrogen dynamics in certified organic farms of Kerala |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Place of publication, distribution, etc | Vellayani |
| Name of publisher, distributor, etc | Department of Soil Science and Agricultural Chemistry, College of Agriculture |
| Date of publication, distribution, etc | 2021 |
| 300 ## - PHYSICAL DESCRIPTION | |
| Extent | 134p. |
| 502 ## - DISSERTATION NOTE | |
| Dissertation note | M Sc |
| 520 ## - SUMMARY, ETC. | |
| Abstract | The study entitled “Soil carbon storage and nitrogen dynamics in certified organic farms of Kerala” was carried out to assess the influence of organic farming on the various physical, chemical and biological properties and also the carbon and nitrogen pools of the soil. A field survey was conducted and ten certified organic (certified for more than 10 years) and nearby conventional farms representing Northern zone (Kannur), hill zone (Wayanad), central zone (Palakkad) and Southern zone (Thiruvananthapuram) were selected for the study. Two composite samples each from two depths (0-15 cm and 15-30 cm) were collected and analyzed for soil properties, organic carbon pools and fractions, organic matter fractions and nitrogen fractions. Various carbon indices like carbon pool index, lability index and management index were worked out. For studying the temporal variation of nitrogen, samples were collected from two certified organic farms and nearby conventional farms of College of Agriculture, Vellayani during February, May, August and November and analyzed for various nitrogen fractions. The soils under study belong to sandy loam, loamy sand, sandy clay and loam textural classes. The bulk density was found to be the lowest in the organic soils (1.15 Mg m-3 ) than the conventional. Other physical properties like porosity (41.32%), water holding capacity (52.68%), water stable aggregates (73.59%) were found to be higher in the surface soils of organic farms than the conventional farms. Macro aggregates constituted greater proportion than micro aggregates. The soil acidity (pH 5.71), EC (0.09 dSm-1 ) and CEC (5.98 C mol (p+ ) kg-1 ) were found to be more in the organic farms. Soil biological properties like soil enzyme dehydrogenase (25.21 g TPF g-1 soil 24 h-1 ) and soil protein glomalin (12.31 mg g-1 ) were also found to be higher in organic farms and decreased with depth. The different pools of organic carbon like active (0.60%), slow (0.29%) and recalcitrant (0.51%)) pools were found to be higher in organic farms at both depths. A higher total organic carbon of 7.59% was registered in organic farm and it decreased with depth. Other carbon fractions like water soluble carbon (157.79 mg kg-1 ), labile carbon (2.57 mg g-1 ), particulate organic carbon (0.76%) and microbial biomass carbon (187.80 mg kg-1 ) were also found to be higher in the organic soil when compared to the conventional. Aggregate associated carbon was 166 also found to be higher in organic soil and more carbon was associated with macro aggregates than micro aggregates. The organic matter fractions like fulvic acid (5.45%), humic acid (3.56%) and humin (0.47%) were dominated in organic soils. Total nitrogen content (0.46%) was the highest in organic soils. Other nitrogen fractions like total soluble nitrogen (257.60 mg kg-1 ), soluble organic nitrogen (159.3 mg kg-1 ), particulate organic nitrogen (0.51 g kg-1 ), ammoniacal (121.20 mg kg-1 ) and nitrate (51.80 mg kg-1 ) nitrogen and microbial biomass nitrogen (88.76 mg kg-1 ) were found to be higher in organic farm than the conventional. Total free amino acids (5.28 mg N kg-1 ) and soluble protein (52.48 mg N kg-1 ) were also found to be the highest in organic soils. C:N ratio of the organic soil was found to be 16:1. Various carbon indices like carbon pool index (0.82), lability index (0.64), management index (0.53) and soil organic carbon stock (130.93 Mg ha-1 ) were higher in organic soils than conventional. The seasonal/temporal dynamics of nitrogen studied revealed that the highest concentration of all the N fractions was observed during May and the least during November at both the depths. Also a higher concentration was noticed in the organic soils than the conventional. From the study it is concluded that the organic farming significantly contributed to soil carbon storage as different pools distributed in different sized aggregates of soil due to increased organic carbon addition and aggregate dynamics. The organic matter fractions, nitrogen fractions, carbon and nitrogen mineralization were also positively and significantly influenced by organic management system. The soil organic carbon stock and indices were increased by organic management system indicating the improvement in the quality and sustainability of the system. The seasonal dynamics of various nitrogen forms and fractions were also significantly influenced by organic farming demonstrating the interactive effect of management system and climate change which increased nitrogen availability from organic nitrogen sources. |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name as entry element | Soil Science and Agricultural Chemistry |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name as entry element | Soil carbon storage |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name as entry element | Organic farms |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Gladis, R (Guide) |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | |
| Item type | Theses |
| Not for loan | Collection code | Permanent location | Current location | Shelving location | Date acquired | Full call number | Barcode | Date last seen | Koha item type |
|---|---|---|---|---|---|---|---|---|---|
| Reference Book | KAU Central Library, Thrissur | KAU Central Library, Thrissur | Theses | 2022-04-23 | 631.4 NAY/SO PG | 175306 | 2022-04-23 | Theses |