| Rice is one of the main food crops in China.In rice production,nitrogen fertilizer is required to meet the needs of rice at different growth stages mainly through fractional nitrogen fertilizer application.This multiple fertilizer application method increases labor input,and farmers are not able to grasp the correct fertilization time.Simultaneous application of urea also increases the loss of nitrogen fertilizer,resulting in low utilization of crop fertilizers,causing serious resource and environmental problems.Therefore,accelerating the construction of fertilizer application technologies that are suitable for high yield,high quality,and high efficiency is an important part of advancing structural reforms on the agricultural supply side and accelerating agricultural modernization.A field experiment was performed in 2015-2016 with three types of CRNF(bulk blending fertilizer(BBF),polymer-coated urea(PCU)and sulphur-coated urea(SCU))with two fertilizer placements(a single basal application with broadcasting(B)and banded-placement fertilizer use by mechanical side-dressing fertilization(S)).Conventional high-yield fertilization(four split applications of urea at 216 kg N ha-1(CK))as controls.The experiment was conducted at a farm belonging to Nanjing University,Yanling Town of Danyang City,Jiangsu Province,China.In this study,we studies the effect of controlled release fertilizer on the yield,nitrogen absorption and quality of machine-transplanted rice by different fertilization methods The impact of the formation.The main results were as following:1.Effect of controlled-release fertilizer on rice yield and nitrogen absorptionThe results suggest that the N release curve of BBF is similar to that of the CK treatment for both years as a result of balanced N supplies during tillering and from panicle initiation to the heading stage.A single basal application of SCU and PCU with broadcasting cannot meet rice plant N demand over the entire growth stage.The banded placement of CRNF contributes to a corresponding increase in NH4+-N concentrations and prolongs the duration of N availability of rhizosphere soils(approximately 2 cm from rice plants)compared with broadcast fertilizer application.Relative to the broadcast application,the banded placement of SCU significantly increased grain yields by 22.86%,and NRP levels by 80.92%.No yield advantage from S-PCU accompanied the significant 24.32%increase in the NRF for both years.No significant differences in rice yields and their components from BBF were obtained between the two fertilization placement conditions for both years.Combining banded placement with BBF presented no significant benefits regarding rice yields and NRF levels compared with B-BBF.Overall,our results suggest that the banded placement of fertilizers using SCU and BBF serve as a promising alternative to the use of urea high-yield fertilization with spilt application,generating increased grain yields and NRFs of machine-transplanted rice.2.Effects of controlled-release fertilizer on rice qualityAmong the different treatments using CRNF,different N release patterns had significant influence on the carbon and nitrogen metabolism during grain filling,and it had effects on the appearance(chalkiness),processing,nutrition and palatability of rice.Overall,compared with CK,the application of CRNF effectively improved quality of eating and cooking in rice,but reduced the nutritional quality,and the impacts on the appearance and processing quality of different CRNF types and fertilization methods were not consistent.Through a comparison of different CRNF types,we can see that SCU had the highest rice-eating quality and processing quality,but the lowest nutritional and appearance quality(chalky grain rate and degree of chalkiness),and the chalky grain rate and degree of chalkiness were significantly higher than CK.Compared with PCU,the application of BBF had higher nutritional and eating quality(higher disintegration values and lower digestion values).Compared with spreading,the utilization of SCU and PCU on side-dressing fertilization decreased the amylopectin content,improved the protein components and total protein content,and ultimately reduced the viscosity and palatability of rice.The use of PCU cut down the rate of brown rice and head rice.By using BBF on side-dressing fertilization,although nutrient quality decreased slightly,there was no significant difference in other quality indicators.Therefore,we believed that BBF can achieve the same appearance,processing quality,and higher cooking and eating quality as compared with conventional high-yield fertilization under two fertilization methods.Considering comprehensively the rice yield,quality,absorption and utilization of nitrogen fertilizer,this study believes that SCU and BBF under side stick fertilization is a way to effectively replace conventional fractionated fertilization. |
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