| Applying chemical fertilizer is one of the most important and efficient approach to increase rice yield. Although the enhancement effect from a single nutrient component chemical fertilizer is straight forward, the direct run-off together with low utilization efficiency and frequent application lead to a significant increase in production and environmental cost. Fortunately, the application of slow-release compound fertilizer is reportedly to be an effective approach to resolve this issue. Zhongdong Lujuneng (ZDLJN) compound fertilizer, a new type of slow-release fertilizer, is widely used in rice production across Jiangsu province recently and showed yield enhancement effect. Nevertheless, systematic study on the effect of ZDLJN fertilizer utilization in rice high yielding cultivation is still missing, including its effects on rice growth and development, yield formation, root formation, grain quality and application of the fertilizer per se. To clarify these issues, this study integrated two sets of experiment in pot and paddy field, employing an early season late maturity japonica rice cultivar Wuyunjing 23.Pot experiment (including comparative test, application rate test, application timing test) aimed to clarifying the effects on tiller dynamic, growth habit, source-sink relationship, dry matter production and distribution, root system, yield and yield components. Field experiment (including manual transplanting and mechanic transplanting) aimed to clarify its effects on yielding components and major grain quality index. These experiments clarified the effect of ZDLJN compound fertilizer on the aforementioned agronomic characters, and the physiological foundation of high yielding, good grain quality, and high fertilizer utilization efficiency. Outlines of the application technical package for ensuring high yielding, good grain quality, and high utilization efficiency of the ZDLJN were also summarized.The main results are as following:1. On the aspect of yield, we found that applying ZDLJN compound fertilizer could efficiently increase the rice production of Wuyunjing 23. Compared to the control group, grain yield of ZDLJN treatment increased 19.12% in the pot experiment, whereas this number was 3.28% in the field experiment. Application rate experiment revealed that higher application rate produced more grain yield. The yield increased more when ZDLJN was applied at an earlier stage, and the best timing was application as a basal fertilizer. In paddy field application, a combination of basal 45 and promoting 15 achieved significantly more grain yield.As to the yield component, application of ZDLJN compound fertilizer increased panicle number of Wuyunjing 23 by 16.5% in pot experiment, whereas by 22.04% in field experiment. Higher application rate and earlier application timing achieved more panicle number. The effect on spikelet number per panicle was inconsistent in treatment, whereas the grain weight decreased in treatments with ZDLJN application.2. On the aspect of source-sink relationship, application of ZDLJN compound fertilizer increased rice plant effective leaf area, efficient leaf area, total leaf area at heading time and maturity time total area. Compared to control group, the leaf area increased 25.86%,21.63%, 27.78% and 59.46% respectively. However, the specific leaf weight at maturity decreased by 13.87%. Higher application rate led to higher effective, efficient, total leaf area at heading, and total leaf area at maturity; and earlier application of ZDLJN led to a reduced the leaf area at heading and maturity period.Application of ZDLJN increased the sink capacity of Wuyunjing 23 by 18.86%. The sink capacity increased more when application rate of the compound fertilizer was higher; and the earlier application led to bigger sink capacity.3. On the aspect of dry matter production and distribution, application of ZDLJN compound fertilizer enhanced the dry matter accumulation at heading stage, biomass yield and economic coefficient at maturity, by 5.31%,6.68% and 8.71%, respectively. The biological yield slightly increased at higher application rate of ZDLJN compound fertilizer. And earlier application of ZDLJN produced more biological yield, and achieved higher economical coefficient.4. On the aspect of nitrogen absorption and utilization, application of ZDLJN enhanced total nitrogen absorption at heading and maturity by 17.72% and 24.9%, respectively; The more and earlier the ZDLJN applied, the higher the nitrogen absorption at maturity. The application of ZDLJN compound fertilizer boosted the nitrogen harvest index, nitrogen recovery efficiency, nitrogen agronomy efficiency and nitrogen partial factor productivity. Higher application rate of ZDLJN also led to a higher nitrogen recovery efficiency, nitrogen agronomy efficiency and nitrogen partial factor productivity.5. In root system, compared with the control group, results showed that the adventitious root number, adventitious root length, root dry weight, total absorption area and active absorption area of single plant after fertilizer application was lower than those in control at 30 day-post-transplanting, while the root activity, longest root and the number of longest root were much higher in ZDLJN application treatment. The upper layer root characters at heading were superior in ZDLJN application treatment to that of the control, but shoot and root dry matter ratio was inferior to the control group. At maturity stage, shoot and root dry matter ratio was higher than that in the control. Combined with the results of relative analysis and path analysis, we concluded that the fertilizer could improve the root appearance and root lengthening, the increase in the number of adventitious roots and the dry root weight of a single plant in the earlier stage, boosting the shoot and root dry matter ratio and roots vigor in the middle to late stages, which contributed to the increase in the yield of Wuyunjing 23.6. On the aspect of grain processing and brown rice appearance quality, application of ZDLJN compound fertilizer increased the brown rice rate, milled rice rate and head rice rate, with a respective increment of 0.23%,1.60% and 1.75%. Split application was better than a single application. The chalky kernel percentage and chalky area in ZDLJN application zone were 30.31% and 31.43% respectively lower than those of the control, except in treatment of applying ZDLJN 30Kg as a basal fertilizer. The grain length-width ratio did not change significantly.7. As to the nutritional quality and eating quality after cook, application of ZDLJN compound fertilizer reduced the amylose content in the polished rice by 3.33% than that of control; whereas the rice gel consistency and protein content in polished rice increased by 5.24% and 8.45%, respectively. Split application of ZDLJN contributed to the reduction in amylose content and increase of gel consistency and protein content in the polished rice, increased the element concentration of Ca, Mg, Fe, Mn and Zn by 26.14%,29.33%,12.14%,6.69% and 2.66%, respectively; on the contrast, K and Cu reduced by 13.65% and 7.45% respectively. P concentration showed no observable change among the treatments.8. On the aspect of RVA properties, the peak viscosity and breakdown value of grains from ZDLJN compound fertilizer application treatments were higher than that of the control; while the final viscosity, setback viscosity and pasting temperature were lower than that of the control. Application of ZDLJN led to the rice grain being much gooey showing a higher breakdown value, smaller setback viscosity and lower pasting temperature, attaining to a better taste quality. |
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