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Updated: Jun 23, 2026
08:44
Microplot Design and Plant and Soil Sample Preparation for 15Nitrogen Analysis
Published on: May 10, 2020
[Soil soluble organic nitrogen in different horticultural production systems]
Ti-Da Ge1, Dong-Mei Tang, Shi-Wei Song
1School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China. sjtugtd@gmail.com
Summary
Organic horticultural systems significantly increase soil soluble organic nitrogen (SON) and free amino acids (FAA) compared to conventional systems. Management practices in horticultural production systems directly impact soil nitrogen content and characteristics.
Area of Science:
- Soil Science
- Agronomy
- Environmental Science
Background:
- Soil nitrogen is crucial for plant growth and ecosystem health.
- Different horticultural production systems (organic, transitional, conventional) employ distinct management practices that can influence soil properties.
- Understanding the dynamics of soil nitrogen fractions, such as soil soluble organic nitrogen (SON), dissolved organic nitrogen (DON), and free amino acids (FAA), is essential for assessing soil fertility and quality.
Purpose of the Study:
- To quantify and compare the levels of SON, DON, and FAA in organic (OS), transitional (TS), and conventional (CS) horticultural production systems.
- To investigate the correlations between these nitrogen fractions and other key soil properties.
- To evaluate how different horticultural management practices affect soil nitrogen composition.
Main Methods:
- Employed ultra-centrifugal technique and KCl extraction for soil sample analysis.
- Determined the concentrations of soil soluble organic nitrogen (SON), dissolved organic nitrogen (DON), and free amino acid (FAA).
- Conducted correlation analysis between nitrogen fractions and soil properties like total nitrogen, total carbon, nitrate-nitrogen (NO3(-)-N), and ammonium-nitrogen (NH4(+)-N).
Main Results:
- SON content followed the order: OS > CS > TS. Organic systems showed significantly higher SON ratios relative to total soluble nitrogen (TSN) and total nitrogen (TN).
- DON content was highest in OS, followed by CS and TS, with varying proportions of TSN and TN across systems.
- FAA content decreased in the order CS > TS > OS and constituted a notable percentage of both TSN and SON. TSN, SON, and FAA were significantly correlated with soil total N, total C, NO3(-)-N, and NH4(+)-N.
Conclusions:
- Organic horticultural production systems demonstrably enhance soil soluble organic nitrogen and free amino acid content compared to conventional and transitional systems.
- Management practices within horticultural systems play a pivotal role in altering the quantity and characteristics of soil soluble organic nitrogen.
- The findings highlight the importance of organic farming practices for improving soil nitrogen availability and overall soil health.
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