Effects of N-fertilizers,straw, and dry fallow on the nitrogen balance of a flooded soil planted with rice |
| |
Authors: | Teresita Santiago-Ventura Marjorie Bravo C. Daez V. Ventura I. Watanabe A. A. App |
| |
Affiliation: | (1) The International Rice Research Institute, Los Banos, Laguna, Philippines;(2) Boyce Thompson Institute at Cornell University, 14853 Ithaca, NY, USA;(3) Present address: The Rockefeller Foundation, 1133 Avenue of the Americas, 10036 New York, NY, USA |
| |
Abstract: | Summary Nitrogen balance studies were made on rice (Oryza sativa) grown in flooded soil in pots. A low rate of fertilizer (5.64 mg N. kg−1 soil) did not depress the N gain, but a high rate (99.72 mg N. kg−1 soil) elminated the N gain. Soil N loss was negligible since15N applied as ammonium sulfate and thoroughly mixed with the soil was recovered from the soil-plant system after 3 crops. The observed N gain, therefore, was caused by N2-fixation, not by a reduction of soil N loss. Straw enhanced N gain at the rate of 2–4 mg per g straw. However, this gain was not observed when soil N availability was high. Dry fallow between rice crops decreased the N gain. |
| |
Keywords: | Dry fallow N-balance Oryza sativa Paddy soils Rice Straw |
本文献已被 SpringerLink 等数据库收录! |
|