Effects of Water Management and Soil Aggregation on the Growth and Nutrient Uptake of Rice1

Abstract

AbstractFlooding is considered essential for the optimum growth and yield of rice (Oryza sativa). The benefits of flooding are not well understood, even though they have been associated with a reduction in soil moisture stress, alteration of root development, increased availability of plant nutrients, control of weeds, and a modified microclimate environment. Since modification of soil aggregation may also influence some of the same plant responses as flooding, these effects were examined.The growth and development of rice, cv. ‘Calrose,’ was closely observed from seedling stage to maturity in a controlled greenhouse environment. At harvest the yield components, total yield of grain and straw, root production and distribution, and total uptake of N, P, K, Ca, Mg, Mn, Zn, Fe, and Si were determined. Rice plants grown under flooded conditions were superior to nonflooded plants except for the first 40 days after planting. Soil aggregation had little effect on the growth and development of flooded rice, but nonflooded rice was benefited by the puddled soil. Flooded roots developed predominately near the soil surface while nonflooded roots permeated the soil profile more uniformly to depths of 30 cm. Puddled, nonflooded soil greatly reduced root development because of apparent high soil bulk density. Flooded plants were superior in grain yield, straw yield, total dry matter production, panicles per plant, grains per panicle, and percent of filled florets. Except for lower total dry matter production on the 5 to 15‐mmdiameter flooded soil soil aggregates, there were no significant effects of aggregation on yield or yield components. Nonflooded plants were superior on the puddled soil treatment. Flooded plants absorbed more P, Fe, and Si than nonflooded treatments and the latter showed higher accumulation of K, Mn and Zn.The growth and development of rice, cv. ‘Calrose,’ was closely observed from seedling stage to maturity in a controlled greenhouse environment. At harvest the yield components, total yield of grain and straw, root production and distribution, and total uptake of N, P, K, Ca, Mg, Mn, Zn, Fe, and S| were determined. Rice plants grown under flooded conditions were superior to nonflooded plants except for the first 40 days after planting. Soil aggregation had little effect on the growth and development of flooded rice, but nonflooded rice was benefited by the puddled soil. Flooded roots developed predominately near the soil surface while nonflooded roots permeated the soil profile more uniformly to depths of 30 cm. Puddled, nonflooded soil greatly reduced root development because of apparent high soil bulk density. Flooded plants were superior in grain yield, straw yield, total dry matter production, panicles per plant, grains per panicle, and percent of filled florets. Except for lower total dry matter production on the 5 to 15‐ramdiameter flooded soil aggregates, there were no significant effects of aggregation on yield or yield components. Nonflooded plants were superior on the puddled soil treatment. Flooded plants absorbed more P, Fe, and Si than nonflooded treatments and the latter showed higher accumulation of K, Mn and Zn.The growth and development of rice, cv. ‘Calrose,’ was closely observed from seedling stage to maturity in a controlled greenhouse environment. At harvest the yield components, total yield of grain and straw, root production and distribution, and total uptake of N, P, K, Ca, Mg, Mn, Zn, Fe, and S| were determined. Rice plants grown under flooded conditions were superior to nonflooded plants except for the first 40 days after planting. Soil aggregation had little effect on the growth and development of flooded rice, but nonflooded rice was benefited by the puddled soil. Flooded roots developed predominately near the soil surface while nonflooded roots permeated the soil profile more uniformly to depths of 30 cm. Puddled, nonflooded soil greatly reduced root development because of apparent high soil bulk density. Flooded plants were superior in grain yield, straw yield, total dry matter production, panicles per plant, grains per panicle, and percent of filled florets. Except for lower total dry matter production on the 5 to 15‐ramdiameter flooded soil aggregates, there were no significant effects of aggregation on yield or yield components. Nonflooded plants were superior on the puddled soil treatment. Flooded plants absorbed more P, Fe, and Si than nonflooded treatments and the latter showed higher accumulation of K, Mn and Zn.