สถานะสารหนูและการใช้ทริบเปิลซูเปอร์ฟอสเฟตลดความเป็นพิษของสารหนูในดินปลูกข้าว จากอำเภอร่อนพิบูลย์ จังหวัดนครศรีธรรมราช

Abstract

Ronphibun District, Nakhon Si Thammarat Province, was tin mining area and resulted in arsenic (As) contamination in soils. Soil properties and distance from As source on As fractionation were studied. Soil samples from 23 areas at 0.5 to 6.0 km from As source were collected. Soil properties and As fractionations were determined. Moreover, the study was aimed to investigate the effect of phosphate fertilizer on growth, As and nutrient uptake of rice. The different levels of phosphate were added to soil with different levels of As. Soil had high total As concentration when compared with critical level of As in agricultural soil in Thailand. Arsenic fractionations in topsoil were mostly partitioned in the amorphous and poorly-crystalline hydrous oxides of Fe and Al fraction and non-specifically adsorbed fraction was the lowest. Moreover, high correlation between sum of non- specifically and specifically adsorbed with specifically adsorbed fraction (r=0.997**) was found and correlation between of non-specifically and specifically adsorbed fractions with some soil properties such as organic matter, total N and available P were found. Whereas, total As, non-specifically and specifically adsorbed fractions decreased with increasing distance from As source. The results indicated that As fractions as potential release to the environment had high. The soil with high As concentration (20 mg kg1) showed As toxicity symptom in rice during tillering stage and rice was dead before the harvesting stage but in the soil with low As concentration (10 mg kg1) showed As toxicity symptom in rice during panicle initiative stage. Application of phosphate fertilizer in soil with high As concentration did not alleviate As toxicity in rice, plant growth and nutrients uptake were decreased but in soil with low As concentration found that plant growth and nutrients uptake tended to increase and As in grain decreased. Therfore, application of phosphate fertilizer to alleviate As toxicity is a suitable strategy in soil with low As concentration.