| The objective of this study was to quantify the effects of water saving irrigation on inbred rice and aerobic rice growth, P efficiency and water productivity, as well the effects of different phosphorus level on aerobic rice growth, P efficiency and water productivity Basing on the research of water saving irrigation for inbred rice both inland and abroad, the experiment was carried out in 2002 at experimental field of Huibei Water Science Experimental Station, Henan, following a split-plot plan. The main plots were four water treatments (irrigate only when soil dries out until SWP at 15cm depth exceeds -10kPa, -30kPa, -70kPa, and the rainfed with survival irrigation). The subplots consisted two varieties (inbred, farmers' variety: 90247; aerobic variety: HD502). As to another experiment, the main plots were two water treatments (irrigate only when soil dries out until SWP at 15cm depth exceeds -lOkPa, -70kPa), the subplots was three phosphorus levels (P0: no phosphorus application; P50: 50kgP/hm2; P100: 100kgP/hm2). The main results were as follows:1. Soil water regime could change the environment of P nutrition and its absorption and utilization by inbred rice. Generally, P content and accumulation in inbred rice decreased as the declination of SWP (SWP). Which exactly showed that P content and accumulation in inbred rice root, stem, filled grain at high SWP treatments was higher than that in low ones at the tillering and panicle initial (PI) stages. P accumulation of inbred rice root and stem at higher SWP was higher than that in lower SWP. The PER of W4 treatment was the lower than others.2. Soil water regime could change the absorption and utilization or P by aerobic rice At PSO level water intimidation could raise P content of aerobic root. As to other organs the change of P content and accumulation of aerobic rice was similar with inbred rice, which declined as SWP decreased. While at the same water regime, it increased as more P was applied, which were more significantly at lower SWP. The PER of aerobic rice increased as SWP increased and P application decreased.3. The water regime could change bio-character of inbred rice, then affect the aspect and yield of plant. Severe water intimidation could decrease inbred rice biomass, effective tiller number and tiller rate at rear growing stage. The leaf biomass increased firstly and then decreased, and reached the climax at flowering stage; there was significant difference between water regimes. At high SWP the LAI of inbred rice increased more quickly than low SWP, which is good to get high yield; the LAI of W4 was the lowest at PI stage, flowering stage and maturation stage.4. The water regime and P level could change the bio-character of aerobic rice, then affect the aspect of plant and yield. At P50 level, severe water intimidation could decrease root biomass and LAI at tillering stage and PI stage, there was significant difference between W1 and W4.regimes. Water intimidation at rear growing period decreased the plant height of inbred rice and aerobic rice. At high SWP, P application could increase root and leaf biomass and plant height, but excess P application led to the inversely result; at low SWP, there was apparent effect of P application at front growing period. The biomass of aerobic rice stem at medium and high P level was higher than PO. At high SWP, the number of tillers per meter square of PO was lowest, P50 afford the biggest contribution to tillers increasing at front growing period; at low SWP, the NO. of tillers per meter square increased as P application.5. At PO, the A.P. content of low SWP was higher than that of high SWP; the P50 mitigated the requirement of soil A.P. for aerobic rice at PI stage, the soil A.P. at PO increased firstly, reached the climax at PI stage and then decreased, and there's no significant difference between high and low water regimes. At PI00, high SWP could increase soil A.P. at rear growing period, while low SWP led the inverse result.6. Low SWP could decrease the yield o...
|
PDF Full Text Request