水位管理对稻田地表水总磷的影响

通过蒸渗仪进行水稻水位管理试验,研究了稻田施肥后和水稻各生育阶段不同淹水深度的地表水总磷(TP)质量浓度变化.结果表明:施肥后,淹水深度和淹水时间对TP质量浓度均有影响,随着淹水时间的延长,TP质量浓度不断增加;在水稻同一生育阶段,TP质量浓度随淹水深度增加而减少,但淹水越深,单位面积释放出的TP越多;在水稻不同生育阶段,TP释放量乳熟期最大,抽穗开花期次之,拔节孕穗后期最小;在水稻各生育阶段的淹水处理中,温度和淹水深度对TP释放量均有影响,当2个因素同时变化时,淹水深度对TP释放量影响明显.

Influence of water level management on total phosphorus concentration of surface water in paddy fields

Through the experimental tests on paddy rice water level management by use of lysimeters,change of the total phosphorus(TP) concentration of surface water was studied at different water levels during various growth stages of the paddy rice after fertilizer application.The results show that,both the flooding time and flooding depth have influence on the TP concentration,and the TP concentration of surface water increases with time.At the same growth stage of the paddy rice,the TP concentration decreases with the increase of the flooding depth,but the larger the flooding depth,the more the TP release amount per unit area.At different growth stages of the paddy rice,the TP release amount at the milky ripe stage is the largest,that at the heading-flowering stage is the second and that at the later period of the jointing-booting stage is the least.As for the treatment of flooding of the paddy rice at different growth stages,both the temperature and the flooding depth have influence on the TP release amount,and the latter has obvious influence on the TP release amount when the two factors simultaneously change.