Regulation Effects of Humus Active Components on Soil Cadmium Availability and Critical Threshold for Rice Safety

Organic materials containing humic acids (HAs) play important roles in regulating the bioavailability of cadmium (Cd) in soils and thus its accumulation in crops. The effects of the two active components of HAs, humic acid (HA) and fulvic acid (FA), in organic materials and their different ratios (HA/FA) on Cd uptake and accumulation in rice were investigated using a field plot experiment, and their relationships with the Cd fractions and availability in paddy soil as influenced by the use of these organic materials were analyzed in combination with the fractionation method of chemical continuous extraction. The results showed that the effects of HAs on Cd availability in soil and Cd accumulation in rice grains were controlled by the ratios of the active components in the organic materials. The treatments with an HA/FA ratio ≥ 4/6 had a passivating effect on soil Cd, resulting in a significant reduction in Cd availability. Compared with that in the control without the application of HAs (CK), rice grain Cd concentration was reduced by 15.2%-33.3%, whereas those with an HA/FA ratio ≤ 2/8 activated Cd in soil, and the available Cd content was significantly increased. Compared with that in CK, rice grain Cd concentration was increased by 24.2%-42.4%. The ratios of HA/FA in HAs affected the morphological transformation of soil Cd. Compared with the CK treatment, the treatments with ratios of HA/FA ≥ 4/6 promoted the transformation of soil Cd from the exchangeable form (EX-Cd) with high activity to the carbonate bound form (CA-Cd) and Fe and Mn oxide-bound forms (FM-Cd) with low activity, whereas those with ratios of HA/FA ≤ 2/8 showed the opposite effects. The effects of HA and FA on soil pH and available sulfur concentration differed. Soil pH had a significant positive correlation with HA addition but a negative correlation with FA addition, and soil available sulfur content had a significant positive correlation with FA addition at the rice tillering stage. Therefore, to ensure the quality and safety of rice, organic materials with an HA/FA ratio ≥ 4/6 should be selected. The results provided a scientific basis for the directed utilization of organic materials containing HAs.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:45

Enthalten in:

Huan jing ke xue= Huanjing kexue - 45(2024), 1 vom: 08. Jan., Seite 439-449

Sprache:

Chinesisch

Beteiligte Personen:

Hu, Xiu-Zhi [VerfasserIn]
Song, Yi [VerfasserIn]
Wang, Tian-Yu [VerfasserIn]
Jiang, Zhen-Mao [VerfasserIn]
Wei, Shi-Qiang [VerfasserIn]

Links:

Volltext

Themen:

00BH33GNGH
70FD1KFU70
Cadmium
Cadmium concentration in rice
Cadmium fractions
Critical threshold
English Abstract
Humic Substances
Humic acids(HAs)
Journal Article
Soil
Soil Pollutants
Soil available cadmium
Sulfur
The ratio of humic acid to fulvic acid(HA/FA)

Anmerkungen:

Date Completed 15.01.2024

Date Revised 15.01.2024

published: Print

Citation Status MEDLINE

doi:

10.13227/j.hjkx.202301012

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM367070405