Quantification of Amorphous Silicon by Optimizing the 1% Na 2 CO 3 Method from Intensively Cultivated Rice and Sugarcane
- PDF / 670,571 Bytes
- 15 Pages / 595.276 x 790.866 pts Page_size
- 97 Downloads / 119 Views
ORIGINAL PAPER
Quantification of Amorphous Silicon by Optimizing the 1% Na2CO3 Method from Intensively Cultivated Rice and Sugarcane Soils in a Tropical Climate Sabyasachi Majumdar 1
&
Nagabovanalli B. Prakash 1
Received: 17 August 2019 / Accepted: 10 January 2020 # Springer Nature B.V. 2020
Abstract The 1% Na2CO3 method used for measuring amorphous silicon (ASi) in soils was initially developed by DeMaster (1981) for measuring biogenic silica in marine sediments. Although this method is widely used for quantifying ASi content in soil, it has a few limitations which requires specific attention in case of the digestion period. In this study, we quantified the ASi content by optimizing the extraction of ASi from tropical soils collected from an intensively cultivated area with rice and sugarcane by using the 1% Na2CO3 method. The results of batch experiments suggested that a 3 to 5 hour digestion period as recommended by DeMaster (1981) is not sufficient for ASi determination in tropical soils. Hence, we recommended that the same method can be adopted for tropical soils with a modified digestion period of up to 3 to 6 hour instead of 3 to 5 hour. The results revealed that ASi content varied from 0.62 to 2.94 and 0.60 to 3.77 g kg−1 in rice and sugarcane soil, respectively. We also focused on the effect of vegetation on ASi content in the soil and observed that ASi content was higher in southern transition zone and coastal zone soils of sugarcane than rice, which indicates extent of recycling of crop residues mainly influence ASi content of soils. Our results also reflected that clay can act as a major source of ASi content in rice and sugarcane soils. Keywords Amorphous silicon . Digestion time . Rice . Sugarcane . Wet alkaline method
1 Introduction Silicon (Si) is the second ubiquitous element in the earth’s crust followed by oxygen [1–4]. Besides crystalline silicates, the Si pool in soil also includes an amorphous fraction [5, 6]. In terrestrial soils, huge quantities of Si are deposited in amorphous form than mineral origin [7]. The amorphous silicon (ASi) comprises of biogenic silicon (BSi) [8] and pedogenic Si forms [6] with the dominance of former. Due to higher solubility of ASi than crystalline minerals, ASi is expected to play a crucial part in bio-availability and cycling of Si in soil [8]. Numerous studies revealed that the solubility of ASi and BSi is greater compared to quartz [1, 9–12]. The quantity of ASi in soil generally varies from 2500 and < 600 mm yr−1, respectively. In general, eight profiles each from rice and sugarcane sites were collected. The details of soil sampling locations and taxonomical classifications of the soils are presented in Table 1. In case of sugarcane growing areas, sugarcane trash was burnt and mixed into the soil, whereas rice straw was usually removed from the field at the time of harvesting. From each profile, soil samples were collected at three different depths (0–30, 30–60 and 60–90 cm). Soil samples were shipped from the field to laboratory in a separate plastic
Data Loading...
