Silica availability in soils and river water in two watersheds on Java Island, Indonesia

Abstract

Silicon is a beneficial element for rice plants and is one of the major factors affecting the sustainability of rice production. We investigated silica (Si) availability and dynamics in soils of sawah, other land uses, and also in river and canal water in two watersheds in Citarum and Kaligarang, Java Island, Indonesia. The term sawah refers to a leveled and bounded rice field with an inlet and an outlet for irrigation and drainage, respectively. In the present study, we examined Si content in soils, plants and river water in relation to factors influencing the Si content, such as parent material and land use. The available Si content in sawah was found to be deficient at two sites and low at 10 sites out of 16 sites investigated in the Citarum watershed. In the Kaligarang watershed, no sawah site was classified as deficient and nine out of the 15 sawah sites were determined to be low for rice plant growth. A survey of Si content in rice flag leaves in some selected rice fields showed that seven out of 12 samples had contents less than 125 g SiO 2 kg -1 ; these rice samples with low Si contents were those in sawah classified as low in Si contents. In the Citarum watershed, sawah soils developed from the accumulation of lake and clay sediment contained relatively little available Si, while sawah soils in the Kaligarang watershed that were mainly developed from tuff and volcanic ash contained relatively more available Si. In the Citarum watershed, the type of land use influenced Si availability in the soils via a large amount of litter accumulation of pine trees in the case of pine plantations, and acidification in the soils in the case of tea plantations and maize fields. In general, the Si content in river and canal water was higher in the Kaligarang watershed than in the Citarum watershed, and this appears to be affected by the type of parent material. In addition to the type of parent material, Si depletion occurring in dams might also influence Si content in the lower stream of river or canal water in the Citarum watershed.

Silicon elution from three types of steel slag fertilizers in a paddy field analyzed by electron probe micro-analyzer (EPMA)

“…Si is transported to stems and leaf blades and used to form silica body cells (Sato et al 1990). The formation of silica body cells depends on Si supply from soil and irrigation water (Husnain et al 2008). It is well known that deficiency of Si causes pathogenic disease like brown spot disease and blast (Datnoff et al 1997;Hayasaka et al 2008).…”

Silicon Biogeochemistry and Bioavailability in Soil

“…Neal et al ( 2005 ) also reported that dissolved Si concentrations for waters were signifi cantly affected by temperature, pH and the type of crystalline Si with which equilibrium was established. Husnain et al ( 2008 ) reported that in Citarum River, Indonesia, the average Si concentration ranged from 22 to 37 mg SiO 2 L −1 in the upper stream and from 13 to 25 mg SiO 2 L −1 in the middle and lower streams, while in the Kaligarang River, the average Si concentration ranged from 34 to 54 mg SiO 2 L −1 in the upper stream and from 23 to 39 mg SiO 2 L −1 in the middle and lower streams, showing the difference was affected by the geological condition of the watersheds. Kawaguchi and Kyuma ( 1977 ) summarized that the average soluble Si concentrations in rivers on Java Island are 42.3, 30.2, 18.2 and 28.6 mg SiO 2 L −1 , respectively, with the geological substrate being volcanic ash, marl, lime and acid tuff loam.…”

“…At pH 2-9, especially at physiological pH values, Si in soil is mainly present as monosilicic acid and conversion of monosilicic acid into ionic silicates is possible only at pH >9. The main factors infl uencing soil Si availability or Si-supplying power include types of soil and parent material, historical land-use change, soil pH, soil texture, soil Eh, organic matter, temperature and accompanying ions (Kawaguchi and Kyuma 1977 ;He and Li 1995 ;Cai et al 1997 ;Sumida 2002 ;Husnain et al 2008 ;Struyf et al 2010a , b ).…”

“…Kawaguchi and Kyuma ( 1977 ) reported that the soil-available Si content in tropical Asia ranged from 104 to 629 mg SiO 2 kg −1 and the available Si content was reported to be the highest in soils of Indonesia among Asian countries (Kawaguchi and Kyuma 1977 ). However, recent studies indicate that 12 sawah sites out of 16 in Citarum and 9 sawah out of 15 were low or defi cient in available Si contents for rice growth (Husnain et al 2008 ).…”

Influence of Water Management and Silica Application on Rice Growth and Productivity in Central Java, Indonesia

“…Darmawan et al (2006) reported that over the past three decades, soil Si availability has decreased by 11-20%. Husnain et al (2008) reported that dissolved Si concentration in irrigation water in Indonesia has also decreased by 10-20% in the same period. Husnain et al (2011) stated that paddy soils contained available Si less than 300 mg SiO 2 kg -1 , a deficiency criterion proposed by Sumida (1992), in 76% out of total 92 paddy soils examined in West Sumatra, and 22.5% out of total 59 paddy soils in West Java, while in Central Java and East Java, it was less than 3% out of total 43 paddy soils in both provinces.…”