| To evaluate the effects of the System of Rice Intensification (SRI) on grain yield andeco-environment, 3-year field experiments were conducted at the Agriculture Experimental Farmof Zhejiang University in Hangzhou, Zhejiang province, China, with one rice crop annually. In2004, the treatment was SRI, traditional flooding (TF), non-flooded plastic film mulching (PM),no plastic film mulching and no flooding (NM) and the system of rice intensification with plasticmulching (PMSRI), and there were three transplanting density in PMARI treatment: 25 cm×17 cm,25 cm×25 cm, 25 cm×30 cm. In 2005, the treatments were the System of Rice Intensification(SRI) and traditional flooding (TF). The experimental design in 2004 and 2005 was completerandomized blocks with three replications. In 2006, the experiment was a randomized split blockdesign with three replications. The main plots were two cultivation systems: traditional flooding(TF) and the System of Rice Intensification (SRI). Subplots include four nitrogen application rates:NO (no fertilizer N), N1 (80 kg N ha-1), N2 (160 kg N ha-1) and N3 (240 kg N ha-1) as urea. Bycontrast with TF, the growth characteristics of rice and yield traits under three water-savingcultivation systems (SRI, PM, UM) were studied; the ammonia volatilization from rice field, soilbiological properties, and water-saving effect and water use efficiency, nutrient uptake andutilization and nitrogen use efficiency under SRI was also studied; and primary study on grainyield effect of the system of rice intensification with plastic mulching was conducted. The resultswere as follows:1. Compared to TF, tiller number, plant height, chlorophyll contents of functional leaves, drymatter accumulation, dry weight of roots, effective panicles, seed setting rate and 1000-grainweight was significantly decreased due to serious drought stress to rice under UM, and the grainyield was decreased by 44.8%. PM improved the rice tillering capability; however, grain yield wasdecreased by 23.9% compared to TF, which was due to lower rate of tiller and 1000-grain weightand smaller spike. At mature stage, the plant height was significantly decreased under PM,however, chlorophyll contents of functional leaves, dry matter accumulation and dry weight ofroots was not significant difference compared to TF. Compared with TF, SRI improved the ricetillering capability and significantly increased the effective panicles, dry weight of roots, drymatter of one plant and chlorophyll contents of functional leaves during the late growth stage,however, the plant height was not difference. Results showed that grain yield was increased by26.4%, 11.5% and 6.4%～48.4% in 2004, 2005 and 2006, respectively, compared to TF. SRI havesmaller spike than TF, however, the seed setting rate and 1000-grain weight was not significantdifference.2. Yield-increasing was decreased with N application rate increased under both of TF and SRItreatments. The maximum grain yield under SRI was in NI level and there was not significantdifference between with N2, however, the maximum grain yield under TF was in N2 level. Compared to TF, SRI significantly increased grain yields in N0 and N1, however, there was nosignificantly in N2 and N3 level.3. SRI significantly increased nutrients (N, P, and K) uptake by rice and could promote (N, P,and K) transfer to the panicle. At mature stage, the amount of absorption and accumulation of N, Pand K in different organs (leaves, stem and sheaths and panicle) under SRI was higher than TF.Compared with TF, the ratio of panicle N, P and K to total N, P and K was increased by 5.0%,2.0% and 3.0%, and the ratio of leave N, P and K to total N, P and K was decreased by 6.7%,7.3% and 12.2%, respectively. The internal nutrient efficiency of N, P and K under SRIsignificantly increased by 21.9%, 19.3% and 17.0% compared to TF, respectively.4. As N rate increased, the amount of N uptake by rice plant increased, however, N in paniclewas up to the maximum in N2 level then decreased under both SRI and TF, and N use efficiency(ANUE, agronomic N use efficiency; PFP, partial factor productivity of applied N) under bothSRI and TF significantly decreased. Results showed that higher agronomic N use efficiency beingachieved at a relatively low N fertilizer rate (80 kg N ha-1) with SRI and it increased by 47.9%compared to TF; however, it was lower 44.7%, 70.9% than TF at 160 and 240 kg N ha-1,respectively. Among N treatments, partial factor productivity of applied N was increased underSRI compared to TF. Results also showed that the interaction between cultivation and nitrogenapplication rates on nitrogen use efficiency were significantly difference.5. Compared with TF, ammonia volatilization was significantly increased with SRI; however,the dynamic changes in ammonia volatilization rate under different stage were similar in bothtreatments. The greatest ammonia volatilization loss was at basal stage, next was at tillering stageand the smallest was at booting stage. The total amount of ammonia volatilization loss during therice growth stage under SRI was higher 25.2% than TF.6. Compared with TF, PM and NM resulted in 672.8 mm and 631.0 mm of total waterconsumtion in 2004, respectively, moreover, water use efficiency significantly increased by PM,but the total water use efficiency under NM was no significantly difference. SRI resulted in anirrigation water saving of 461.5 mm, 476.5 mm and 830.3 mm in 2004, 2005 and 2006,respectively, a reduction of 33.9%, 26.9% and 36.9%, compared to TF. Compared with TF, totalwater use efficiency increased by 91.3%, 54.5% and 93.5% in 2004, 2005 and 2006, respectively,with SRI practices, and irrigation water use efficiency increased by 195.6%, 90.1% and 130.5% in2004, 2005 and 2006. Water use efficiency significantly increased by optimum amount of Nfertilizer application.7. Treatment SRI was significantly higher than the control in population of cultureablemicroorganisms (bacteria, fungi, actinomycetes), microbial biomass C and N, and microbialbiomass P in the late growth stage, regardless of sampling date. Compared with TF, the activity ofurease, alkaline phosphatase, invertase and catalase in soil at the tillering stage was increased by12.6%, 30.0%, 15.1% and 13.8%, respectively. The treatment SRI was also higher than the controlin soil available N, and however, showed no significant difference in soil available P. 8. Compared with TF, the system of rice intensification with plastic mulching (PMSRI)improved the rice tillering capability and significantly increased the effective panicles, however,the grain number per spike and 1000-grain weight was decreased. Dry matter one plant underPMSRI was higher than TF and population dry matter weight was higher or equal. Results showedthat effective panicle, seed setting rate and grain number per spike decreased with the plantingdensity increasing, and dry matter one plant increased and population dry matter weight decreased.Compared with TF, grain yield under PMSRI with transplanting plant of 25 cm×25 cm and 25cm×30 cm. was increased by 10.3%, 3.7%, respectively, and decreased by 1.2% withtransplanting plant of 25 cm×17 cm.In a word, SRI improved the rice tillering capability and significantly increased the effectivepanicles compared to TF, and there were well developed root system under SRI. Results alsoshowed that SRI had higher chlorophyll contents of functional leaves during the late growth stagethan TF. Compared with TF, SRI increased the nutrients uptake by rice plant and improvednutrients transfer to the panicle and increased the grain yield. Moreover, yield-increasing wassignificantly at lower level of nitrogen. It is most important to the sustainable development of riceproduction due to significant water-saving effect with SRI and SRI was helpful to improve thebiological characteristics of soil. However, ammonia volatilization loss from rice field wasincreased by SRI and the reasonable nitrogen management was very important under SRI.
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