Mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea

Soil fertility depletion is one of the main factors for yield stagnation in tea cultivation in Sri Lanka for last few decades. Organic material (OM) incorporation has been identified as the sustainable technique to restore soil fertility in degraded tea fields even though research information is...

Full description

Saved in:
Bibliographic Details
Main Author: Liyanage, Liyana Rallage Mahesh Chaminda
Format: Thesis
Language:English
Published: 2022
Subjects:
Online Access:http://psasir.upm.edu.my/id/eprint/103942/1/LIYANA%20RALLAGE%20MAHESH%20-%20IR.pdf
Tags: Add Tag
No Tags, Be the first to tag this record!
id my-upm-ir.103942
record_format uketd_dc
spelling my-upm-ir.1039422023-06-02T07:53:20Z Mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea 2022-07 Liyanage, Liyana Rallage Mahesh Chaminda Soil fertility depletion is one of the main factors for yield stagnation in tea cultivation in Sri Lanka for last few decades. Organic material (OM) incorporation has been identified as the sustainable technique to restore soil fertility in degraded tea fields even though research information is scanty. A series of experiments were carried out to investigate the carbon (C) and nitrogen (N) mineralization dynamics and the effects of OMs, such as Gliricidia (GLI), compost (CMP), tea waste (TW), biochar charged with nutrients (CBC) and raw biochar (RBC) without nutrient charging, on bio-availability of nutrients. Experiments were conducted in completely randomized design at the Universiti Putra Malaysia. The potential for partial substitution of inorganic N fertilizers by aforesaid OMs was tested in split plot design under field condition in Sri Lanka using mineralization and bio-availability indicators. The parallel first-order kinetic model fitted well (R2>0.99) with the C mineralization dynamics demonstrating different C pools in added OMs. All the materials enhanced the soil microbial biomass carbon (MBC) and nitrogen (MBN) over 79 and 70%, respectively. Catalase and dehydrogenase activities were also improved by more than 76%. The carbon mineralization rate was highest in GLI (k=0.7 day-1) and it was lowest in RBC (k=0.01 day-1). Gliricidia showed the highest mineralizable C content of 15,350 mg kg-1, which rapidly promoted the soil's biological activities. The CBC behaved similarly to compost in improving soil health. Gliricidia had faster released of N amounting to 94% of added N in N, P and S mineralization study. Even though CBC increased urease, protease, dehydrogenase and phosphatase activity by 157, 376, 500 and 75%, respectively, CBC probably immobilized/fixed N in the soil making unavailable for plants. It was confirmed by the bioavailability of mineralized products trial evaluated by implementing the exhaustive cropping technique with Napier grass. Approximately, 47% of the mineralized N from GLI was taken up by the plant, and the rest may have been lost or immobilized by microbes. Consequently, GLI showed the highest apparent nutrient recovery (NAR) of 47%. It should be mandatory to fortify biochar with a nutrient solution in order to maximize the utilization of biochar for soil health restoration. The study of different ratios of OMs to inorganic fertilizers based on N requirements showed that all the tested OMs had the potential to replace the inorganic N fertilizer to an extent of 30%. In conclusion, GLI and CBC can be applied to restore fertility and health status respectively in degraded tea lands. Charged biochar showed the maximum benefits for the restoration of degraded soil with the ability to replace inorganic fertilizer by at least 20% for mature tea cultivation, invariably subsequent to supplementary future investigations. Crops and soils Crops - Nutrition Soil fertility 2022-07 Thesis http://psasir.upm.edu.my/id/eprint/103942/ http://psasir.upm.edu.my/id/eprint/103942/1/LIYANA%20RALLAGE%20MAHESH%20-%20IR.pdf text en public doctoral Universiti Putra Malaysia Crops and soils Crops - Nutrition Soil fertility Musa, Mohamed Hanafi
institution Universiti Putra Malaysia
collection PSAS Institutional Repository
language English
advisor Musa, Mohamed Hanafi
topic Crops and soils
Crops - Nutrition
Soil fertility
spellingShingle Crops and soils
Crops - Nutrition
Soil fertility
Liyanage, Liyana Rallage Mahesh Chaminda
Mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea
description Soil fertility depletion is one of the main factors for yield stagnation in tea cultivation in Sri Lanka for last few decades. Organic material (OM) incorporation has been identified as the sustainable technique to restore soil fertility in degraded tea fields even though research information is scanty. A series of experiments were carried out to investigate the carbon (C) and nitrogen (N) mineralization dynamics and the effects of OMs, such as Gliricidia (GLI), compost (CMP), tea waste (TW), biochar charged with nutrients (CBC) and raw biochar (RBC) without nutrient charging, on bio-availability of nutrients. Experiments were conducted in completely randomized design at the Universiti Putra Malaysia. The potential for partial substitution of inorganic N fertilizers by aforesaid OMs was tested in split plot design under field condition in Sri Lanka using mineralization and bio-availability indicators. The parallel first-order kinetic model fitted well (R2>0.99) with the C mineralization dynamics demonstrating different C pools in added OMs. All the materials enhanced the soil microbial biomass carbon (MBC) and nitrogen (MBN) over 79 and 70%, respectively. Catalase and dehydrogenase activities were also improved by more than 76%. The carbon mineralization rate was highest in GLI (k=0.7 day-1) and it was lowest in RBC (k=0.01 day-1). Gliricidia showed the highest mineralizable C content of 15,350 mg kg-1, which rapidly promoted the soil's biological activities. The CBC behaved similarly to compost in improving soil health. Gliricidia had faster released of N amounting to 94% of added N in N, P and S mineralization study. Even though CBC increased urease, protease, dehydrogenase and phosphatase activity by 157, 376, 500 and 75%, respectively, CBC probably immobilized/fixed N in the soil making unavailable for plants. It was confirmed by the bioavailability of mineralized products trial evaluated by implementing the exhaustive cropping technique with Napier grass. Approximately, 47% of the mineralized N from GLI was taken up by the plant, and the rest may have been lost or immobilized by microbes. Consequently, GLI showed the highest apparent nutrient recovery (NAR) of 47%. It should be mandatory to fortify biochar with a nutrient solution in order to maximize the utilization of biochar for soil health restoration. The study of different ratios of OMs to inorganic fertilizers based on N requirements showed that all the tested OMs had the potential to replace the inorganic N fertilizer to an extent of 30%. In conclusion, GLI and CBC can be applied to restore fertility and health status respectively in degraded tea lands. Charged biochar showed the maximum benefits for the restoration of degraded soil with the ability to replace inorganic fertilizer by at least 20% for mature tea cultivation, invariably subsequent to supplementary future investigations.
format Thesis
qualification_level Doctorate
author Liyanage, Liyana Rallage Mahesh Chaminda
author_facet Liyanage, Liyana Rallage Mahesh Chaminda
author_sort Liyanage, Liyana Rallage Mahesh Chaminda
title Mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea
title_short Mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea
title_full Mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea
title_fullStr Mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea
title_full_unstemmed Mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea
title_sort mineralization of organic materials and bioavailability of nutrients to partially replace the inorganic fertilization for tea
granting_institution Universiti Putra Malaysia
publishDate 2022
url http://psasir.upm.edu.my/id/eprint/103942/1/LIYANA%20RALLAGE%20MAHESH%20-%20IR.pdf
_version_ 1776100384078561280