Studies On Effects Of Long-term Different Fertilization On Soil Fertility,bacterial Community Characteristics,grain Yield And Quality In Reddish Paddy Field

To reveal the internal relationship between long-term different fertilization,soil properties and grain yield components,moreover,provide theoretical basis and technical support for efficiently fertilizing and cultivating based on sustainable production in central southern reddish paddy soil.The long-term experiment of different combined application of manure and chemical fertilizer that initiated 1982 and established by Hengyang red soil experimental station of Chinese Academy of Agricultural Sciences,which contains 7treatments:?1?Manure?M?;?2?combined application of Nitrogen,Phosphorus,Potassium and Manure?NPKM?;?3?combined application of Nitrogen,Phosphorus and Potassium?NPK?;?4?combined application of Nitrogen,Potassium and Manure?NKM?;?5?combined application of Nitrogen,Phosphorus and Manure?NPM?;?6?combined application of Phosphorus,Potassium and Manure?PKM?;?7?No Fertilization?NF?,was conducted to study the effects of long-term different fertilization regimes on soil nutrients,physicochemical properties,bacterial community structures and diversities,grain yields and qualities,nutrients uptaking and accumulation in late rice season.The main results were listed as follows:?1?Long-term different fertilization regimes enhanced the SOC,DOC,TN,AN,TP,AP and AK in different degree,among them,all the properties of NPKM treatment were highest than that in other treatments,the relative values were 24.65 g/kg,1.31 g/kg,2.26 g/kg,213.01 mg/kg,1.25 g/kg,43.63 mg/kg and 178.6 mg/kg,respectively.Moreover,the SOC/TN?10.92?of which was significantly higher than other treatments.Additionally,the contents of SOC,DOC,TN,AN and AK in M treatment enhanced compared with the NPK treatment under the same NPK input.?2?Compared with the pH value?5.97?before the experiment,the pH values of NF and NPK treatments declined by 0.06 and 0.27.However,manure application increased pH values in different degree.Among them,M and PKM were best,the pH values of them increased by 0.11,0.10 than that before experiment,respectively.These indicated that long-term NPK application promoted acidification but manure application alone or combined with PK effectively alleviated soil acidification in reddish paddy soil.Additionally,the cellulase activity of M treatment was the highest?0.27 mg Gluose/g dry soil/72 h?,followed by NPKM treatment,and no significant differences were detected among them,but they all significantly higher than other treatments.Meanwhile,the activities of urease and sucrase in NPKM treatment were highest,0.27 mg NH3-N/g dry soil/24 h and 21.09 mg Glucose/g dry soil/24 h,respectively.The activity of acid phosphatase?4.49 mg Phenol/g dry soil/24 h?in NPKM just lower that in NPM treatment.Moreover,the E-K⁺?E-Na⁺and EBC of NPKM treatment were the highest,the relative values were 0.34,0.35,5.23 cmol/kg,respectively,and the CEC?14.07 cmol/kg?in NPKM treatment was just lower than that in PKM treatment.These indicated that NPKM treatment had the best effects on synergistically improved four enzymes activities,E-K⁺,E-Na⁺,EBC and CEC,and then,more fertile than other treatments.?3?There were no significant effects of long-term different fertilization regimes on the bacterial phyla in paddy soil.The top four phyla were Proteobacteria,Acidobacteria,Chloroflexi and Nitrospirae,which account for more than 70%of soil bacteria.However,different fertilization regimes had shaped the differential rhizospheric bacterial community structures,the E-Mg²⁺,SOC and AN were the key factors that driving the formation of specific bacterial community structures.Additionally,the treatments of M and NPKM facilitated higher soil bacterial bio-diversities compared with NF treatment,the relative Shannon indexes were 9.79 and 9.83,respectively.However,Shannon index and Chao1reduced by 0.07 and 183.83 in NPK treatment,among them,the Chao1 was significantly lower than that in other treatments.Meanwhile,the abundance of phylum Actinobacteria was significantly increased in NPKM than that in other treatments.?4?The significant differences of grain yield,effective panicles and Spikelet per panicle were detected among long-term different fertilization regimes,the grain yield of NPKM was highest?7.72 t/hm²?,which significantly higher than that of other treatments,and the corresponding effective panicles and Spikelet per panicle were 293.33×10⁴/hm²,188.88No./panicle,respectively,both of them were highest than that of other treatment.Moreover,the grain yield and the ratio of grain to straw in M treatment were increased by 6.25%and14.78%compared with NPK treatment,otherwise,the straw declined by 6.78%,which indicated that M treatment promoted the photosynthetic assimilation products transferring from straw to grain,and then,formed grain yield.Additionally,NPKM treatment promoted N,P,K uptaking and accumulation in aboveground plant,the relative accumulated values were 135.20,39.59,183.11 kg/hm²,respectively.Among them,The effect of N on K uptaking and accumulation was higher than that of P?increased by 10.04 kg/hm²?,similarly,the effect of P on N uptaking and accumulation was higher than that of K in aboveground plant?increased by 14.42 kg/hm²?.Moreover,combined application of N and K promoted P uptaking and accumulation?29.44 kg/hm2?,but increasing P input still inhibited the P uptaking and accumulation when N deficiency?27.74 kg/hm²?.?5?Fertilization enhanced the milled and head rice rates,gel consistency,amylose and protein contents by 7.73%?12.35%,2.05%?10.19%,2.48%?6.83%,1.14%?3.04%,0.61%?7.93%in different degree,respectively,and declined the chalky grain rate and chalkiness by 1.82%?6.81%?4.41%?10.29%.Among them,The NPKM treatment had the highest milled and head rice rates,gel consistency,amylose and protein contents,and the lowest chalky grain rate and chalkiness,the relative values were 70.50%,61.76%,86 mm,13.55%,8.85%,30.80%,3.05,respectively,and it's grain qualities were better than others.?6?Balanced using of manure and NPK fertilizers greatly increased soil nutrients,SOC,DOC and CEC,significantly improved enzyme activates,alleviated soil acidification and increased the abundance of Actinobacteria,synergistically improved the effective panicles and Spikelet per panicle,further filled the grain yield.What's more,it dramatically enhanced the milled and head rice rates,gel consistency,amylose and protein contents but greatly declined the chalky grain rate and chalkiness,integrally improved the machining,external,flavor and nutrition qualities.It could be recommended as a scientific fertilizing regime for high-efficiency fertility and sustainable production in reddish paddy fields of Central Southern China.