| Soil water potential (SWP) was examined rigorously with negative pressure soil moisture tensiometer. Both field and pot experiments were carried out to study effects of water-controlling from 2007 to 2008. Intermittent controlling water treatments (ICWT) at-20KPa and -10KPa of SWP were carried out from re-green to mature. The effects of soil moisture on growth and development, yield and quality of rice were studied systematically in cold region.The results are as follows:The results of field experiments in 2007 and 2008 years showed that ICWT at-10KPa of SWP carried out were beneficial to improve the rice yield of different regions. The yield increasing ranges of different varieties in Daxing and Qingan were 1.60-7.67% and 1.51~6.95% respectively. The results of potted experiments showed that the per panicle weight enhanced 11.4%, primary rachis-branches numbers of J and D variety increased 2.15% and 4.49% respectively, second rachis-branches numbers of two varieties increased 4.00% and 4.02% respectively. Panicles per hill of two varieties was decreased under the condition of controlling-water treatment, and D variety reached the extremely significant level; Grain numbers of superior and middle-position of J variety and middle and inferior-position of D variety were increased; Kernel seting rate of two varieties were increased, the increasing ranges of middle and inferior-position of J variety reached the significant level, kernel seting rate of superior, middle and inferior-position of D variety increased 4.86%, 5.42% and13.30% respectively. Biomass of J variety was increased, biomass of D variety was signficantly decreased, economic indexs of two varieties increased 5.73% and 3.21% respectively; Economic yield of J variety increased 14.47%, economic yield of Dvariety was decreased.When ICWT at -8~-10KPa of SWP were carried out from re-green to mature, the height of the two varieties was increased; The reason was that the first and forth internode length counted from the top of J variety and the first internode length counted from the top of D variety was significantly increased. Moverover, the second and third internode length counted from the top of D variety were incresed in different degrees. The stem numbers of two varieties were decreased, the difference between DS and DCK had reached to the strong significant level.When ICWT at -8~-10KPa of SWP were carried out from re-green to mature, chlorophyll contents of two varieties were accelerated, the increasing range reached significant level at booting stage; leaf nitrogen contents of two varieties were incrased at later developmental stage; Dry weight of J was higher than its of the JCK at different growth stages, dry weight of D was higher than its of the DCK before flowering stage, contrary to it after flowering stage; Exportation percentage (EP) and transformation percentage (TP) of dry matter in sheath of two varieties increased 6.21%, 22.58%, 4.01% and 7.77% respectively.When ICWT at -8~-10KPa of SWP were carried out from re-green to mature, the process of grain filling of J variety was accelerated; grain filling rate peak appearing time of inferior grains of J variety was delayed; G ,Gmax, I and Wmax.G of superior grains, middle grains and inferior grains of J variety was raised respectively, the growing period of J variety were shorten, reaching to 8.78%, 0.47% and 40.14% respectively.The results of field experiments showed that ICWT at -8~-10KPa of SWP carried out from re-green to mature was beneficial to increase head rice rate and improve external quality and increase the evaluation of white rice taste of rice of different ecological regions. The result of potted experiments showed that head rice rate, amylose contents of different position-grains, fat contents of middle position and evaluation of white rice taste decreased, protein content and fragrant value of two varieties incresed.ICWT at-10KPa of SWP were carried out in different eclogical regions, the rates of water saving were all above 20%. |
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