Mineral nutrients in floodwater and floating rice growing at water depths up to two metres

Abstract

Concentrations of N, P and K were measured in floodwater and in floating rice cultivars growing at up to 2 m water depths in the central flood plain of Thailand. Concentrations of N, P and K in floodwater were often higher than those reported for oligotrophic lakes, nevertheless the floodwater contained 4-45 times less K and 15-90 times less N than concentrations reported in most soil solutions. P concentrations were similar in the floodwater and in most soil solutions.Concentrations of nutrients in leaves indicated there may be deficiencies of P at two sites and a deficiency of N at one of two sites. Data are discussed in terms of reduced nutrient uptake in rice fields at low 02 concentrations which have recently been measured in these areas.

Benefits of flooding-induced aquatic adventitious roots depend on the duration of submergence: linking plant performance to root functioning

“…may not contain such high concentrations of P as in our nutrient solution (e.g. P concentration varied between 0Á3 and 2 mmol L À1 in the floodwater of rice fields; Setter et al, 1987), the continuous exposure of the roots to these concentrations may still lead to substantial uptake. Therefore, being able to take up nutrients through the aquatic adventitious roots from the floodwater may substantially improve plant survival and performance during partial submergence and play a major role in increased plant performance upon aquatic adventitious root formation.…”

Flooding tolerance: suites of plant traits in variable environments

“…Uptake of nutrients by shoots of completely submerged plants might be necessary to overcome constraints on root-to-shoot transport imposed by a lack of transpiration, although xylem guttation driven by root-pressure can provide some flow in aquatic species when completely submerged (Pedersen 1993). Floodwater in a deepwater rice region of Thailand contained higher concentrations of N, P and K than found in oligotrophic lakes, but these concentrations are still considered low compared with those found in most soil solutions (Setter et al 1987).…”

Seedling Nutrient Status before Submergence Affects Survival after Submergence in Rice

“…The adverse effects of flooding constitute a complex phenomenon that varies with genotype and pretreatments, carbohydrate status of the plant before and after submergence, developmental stage of the plant when flooding occurs, duration and severity of flooding, and degree of turbidity of floodwater (Setter et al, 1995; Ramakrishnayya et al, 1999; Jackson and Ram, 2003; Das et al, 2005). Setter et al (1987a) reported that the environmental factors associated with flooding are variable in different locations, even over short distances.…”