Identification and crop performance of acid sulfate soil-tolerant rice varieties

Abstract

The present study aims to: 1) identify acid sulfate soil (ASS)-tolerant rice varieties from the genetic stock of Korean rice (Oryza sativa L.) varieties under ASS conditions; 2) to evaluate their yield performance, and elucidate the physiological mechanism for ASS tolerance with the identified tolerant varieties. Two hundred sixty-six rice varieties were screened for ASS tolerance, and we identified two japonica-indica hybrid varieties, Geumgang (GG) and Pungsan (PS), as having high tolerance under ASS paddy conditions (pH 3). We first conducted a yield trial of GG and PS grown in Wagner pots to determine their potential yields under ASS conditions. A yield trial under paddy field condition followed. In the pot experiment, the ASS-tolerant varieties, GG and PS, showed significantly higher yields than PT-1, which is a local reference variety in mildly improved soil pH conditions (pH 4.1-4.6). Al and Fe content in GG and PS were significantly lower than that of PT-1, so there might be some mechanism that inhibits the absorption of toxic metal ions in the tolerant varieties. In the paddy conditions, the grain yields more than 5 t ha -1 of the two tolerant varieties under mildly improved soil pH condition were significantly higher than PT-1. Dry matter weights of above ground parts also showed the same trend as grain yield. The study demonstrated that the ASS-tolerant japonica-indica rice varieties with high yielding potential could contribute to the improvement of rice yield in ASS regions, and will be good materials for the development of acid soil-tolerant rice varieties.

Characteristics of the acidity and sulphate fractions in acid sulphate soils and their relationship with rice yield

“…The tillage measures used for rice cultivation influence the acidity and sulphate content of ASS which subsequently affects crop growth (Husson et al 2000;Mathew et al 2001;Shamshuddin et al 2004;Kang et al 2010). The acidity-producing capability of ASS is a major consideration and has a lasting effect on the main characteristics of these soils (Fanning 2002).…”

“…Acidity directly damages rice and also adversely affects rice growth by mobilizing many potentially toxic metals or limiting the bioavailability of essential nutrients (Ljung et al 2009). Most of the metals ions, particularly Al, in the soil are mobilized in excess when the soil pH is <4, thereby inhibiting rice growth (Kinraide 1997;Kang et al 2010). Phosphorus-sorption in ASS is greatly influenced by Al-oxides, Fe-oxides and Mn, which are governed by soil pH (Krairapanond et al 1993).…”

“…2004; Kang et al . 2010). The acidity-producing capability of ASS is a major consideration and has a lasting effect on the main characteristics of these soils (Fanning 2002).…”

“…Therefore, rice cultivation is regarded as an appropriate use for ASS in the Pearl River Delta (Lin 1999). However, even though rice can grow in ASS with pH <4•0 (Kang et al 2010), production in these soils is often severely limited as a result of the high acidity (Krairapanond et al 1993). With the oxidation of Fe-sulphide in ASS and the acidification of ASS, many metals (e.g.…”

“…However, even though rice can grow in ASS with pH <4·0 (Kang et al . 2010), production in these soils is often severely limited as a result of the high acidity (Krairapanond et al . 1993).…”