Modification of total and phosphorus mineralizing bacterial communities associated with Zea mays L.through plant development and fertilization regimes

Harnessing the rhizospheric microbiome,including phosphorus mineralizing bacteria(PMB),is a promising technique for maintaining sustainability and productivity in intensive agricultural systems.However,it is unclear as to which beneficial taxonomic group populations in the rhizosphere are potentially associated with the changes in soil microbiomes shifted by fertilization regimes.Herein,we analyzed the diversity and community structure of total bacteria and PMB in the rhizosphere of maize(Zea mays L.)grown in soils under 25 years of four fertilization regimes(compost,biocompost,chemical,or nonfertilized)via selective culture and Illumina sequencing of the 16S rRNA genes.Plant development explained more variations(29 and 13%,respectively)in the composition of total bacteria and PMB in the rhizosphere of maize than the different fertilization regimes.Among those genera enriched in the rhizosphere of maize,the relative abundances of Oceanobacillus,Bacillus,Achromobacter,Ensifer,Paracoccus,Ramlibacter,and Luteimonas were positively correlated with those in the bulk soil.The relative abundance of Paracoccus was significantly higher in soils fertilized by compost or biocompost than the other soils.Similar results were also observed for PMB affiliated with Ensifer,Bacillus,and Streptomyces.Although plant development was the major factor in shaping the rhizospheric microbiome of maize,fertilization regimes might have modified beneficial rhizospheric microbial taxa such as Bacillus and Ensifer.

Integrating phosphorus management and cropping technology for sustainable maize production

Achieving high maize yields and efficient phosphorus(P)use with limited environmental impacts is one of the greatest challenges in sustainable maize production.Increasing plant density is considered an effective approach for achieving high maize yields.However,the low mobility of P in soils and the scarcity of natural P resources have hindered the development of methods that can simultaneously optimize P use and mitigate the P-related environmental footprint at high plant densities.In this study,meta-analysis and substance flow analysis were conducted to evaluate the effects of different types of mineral P fertilizer on maize yield at varying plant densities and assess the flow of P from rock phosphate mining to P fertilizer use for maize production in China.A significantly higher yield was obtained at higher plant densities than at lower plant densities.The application of single superphosphate,triple super-phosphate,and calcium magnesium phosphate at high plant densities resulted in higher yields and a smaller environmental footprint than the application of diammonium phosphate and monoammonium phosphate.Our scenario analyses suggest that combining the optimal P type and application rate with a high plant density could increase maize yield by 22%.Further,the P resource use efficiency throughout the P supply chain increased by 39%,whereas the P-related environmental footprint decreased by 33%.Thus,simultaneously optimizing the P type and application rate at high plant densities achieved multiple objectives during maize production,indicating that combining P management with cropping techniques is a practical approach to sustainable maize production.These findings offer strategic,synergistic options for achieving sustainable agricultural development.

Influence of bean rhizosphere on the biological properties and phosphorus fractionation in the calcareous soils amended with municipal sewage sludge

The biological and chemical conditions of the rhizosphere are known to considerably differ from those of the bulk soil, as a consequence of a range of processes that are induced either directly by the activity of plant roots or indirectly by the stimulation of microbial population and activity in the rhizosphere. Information about phosphorus （P） fractionation in the rhizosphere soils amended with municipal sewage sludge （MSS） is limited, were We carried out greenhouse experiments using a rhizobox in order to evaluate the effects of bean rhizosphere on the various inorganic P （Pi） fractions, organic P （Po）, P in particulate fraction （PF-P）, Olsen-P, dissolved organic C （DOC）, microbial biomass P （MBP） and alkaline phosphatase （ALP） enzyme in 10 calcareous soils amended with MSS （10 g MSS was added to 1 kg soil）. Non-occluded P, occluded P, calcium phosphate and residual P were also quantitated. The results showed that DOC, MBP and ALP activity strongly increased and PF-P and Olsen-P de- creased in the rhizosphere soils compared with in the bulk soils （P〈0.05）. The contents of non-occluded P, oc- cluded P and residuaI-P fractions in the rhizosphere soils were lower than in the bulk soils, while the contents of calcium phosphate and organic P in the rhizosphere soils were higher than in the bulk soils. Simple correlation coefficients showed that P uptake had positive relationship with non-occluded P, occluded P, calcium phosphate fractions and PF-P in the rhizosphere soils. The results suggest that the short-term application of MSS to the cal- careous soils may increase Po and calcium phosphate fractions in the rhizosphere soils, and calcium phosphate fraction is potentially available to crops.

Key minerals influencing apple quality in Chinese orchard identified by nutritional diagnosis of leaf and soil analysis

We investigated the correlation between leaf/soil minerals and fruit quality in apple trees grown in orchards,with the ultimate goal of improving the latter.Leaf mineral nutrients;soil nutrients in the 0-20,20-40,and 40-60 cm layers;and fruit quality traits in 32 apple orchards in China were monitored for 2 years.Significant factors associated with fruit quality were identified via correlation analysis.An analysis of leaf data revealed that leaf nitrogen（N） and leaf magnesium（Mg） levels were extremely high in 75 and 89%of the orchards,respectively.In the Bohai Gulf region,94%of the orchards showed significantly higher values than the standard.The soil pH values of the orchards in eastern China like eastern Shandong or Liaoning were lower than 7.0,while the pH values in the Loess Plateau of northwestern China like Shaanxi were much higher than 7.Soil alkali-hydrolyzable N levels in 47%of the orchards were lower than the optimal level of 70 mg kg^-1.Generally,the soil alkali-hydrolyzable N levels of orchards in the Bohai Gulf region were significantly higher than those in the Loess Plateau region.The available P levels in the orchards of the Bohai Gulf region were up to three times higher than those of the Loess Plateau region.However,although the available potassium（K） in most orchards was sufficient（51.39-309.94 mg kg^-1）,leaf K content in 73%of the orchards was low,possibly due to fruit bagging or fruit overload.Approximately 63%of the orchards in Shandong and 29%of the orchards in Shannxi showed leaf Fe deficiencies.In the Loess Plateau,most orchards showed high leaf Ca levels,a strong correlation was observed between leaf and soil phosphorus/potassium（P/K）content and fruit organic acid content.The amounts of fruit soluble sugar or fructose were positively correlated with soil calcium/potassium（Ca/K） levels and leaf calcium/boron（Ca/B） levels in most orchards.The excessive leaf N levels caused by the extensive application of N fertilizers had a negative effect on fruit quality in most apple orchards in China.P,K,Ca,and B were key minerals associated with fruit quality.