Manure substitution improves maize yield by promoting soil fertility and mediating the microbial community in lime concretion black soil

Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidification,groundwater contamination and biodiversity reduction.Meanwhile,organic substitution has received increasing attention for its ecologically and environmentally friendly and productivity benefits.However,the linkages between manure substitution,crop yield and the underlying microbial mechanisms remain uncertain.To bridge this gap,a three-year field experiment was conducted with five fertilization regimes:i)Control,non-fertilization;CF,conventional synthetic fertilizer application;CF_(1/2)M_(1/2),1/2 N input via synthetic fertilizer and 1/2 N input via manure;CF_(1/4)M_(3/4),1/4 N input synthetic fertilizer and 3/4 N input via manure;M,manure application.All fertilization treatments were designed to have equal N input.Our results showed that all manure substituted treatments achieved high soil fertility indexes(SFI)and productivities by increasing the soil organic carbon(SOC),total N(TN)and available phosphorus(AP)concentrations,and by altering the bacterial community diversity and composition compared with CF.SOC,AP,and the soil C:N ratio were mainly responsible for microbial community variations.The co-occurrence network revealed that SOC and AP had strong positive associations with Rhodospirillales and Burkholderiales,while TN and C:N ratio had positive and negative associations with Micromonosporaceae,respectively.These specific taxa are implicated in soil macroelement turnover.Random Forest analysis predicted that both biotic(bacterial composition and Micromonosporaceae)and abiotic(AP,SOC,SFI,and TN)factors had significant effects on crop yield.The present work strengthens our understanding of the effects of manure substitution on crop yield and provides theoretical support for optimizing fertilization strategies.

Transcriptome analysis suggests mechanisms for a novel flowering type: Cleistogamous wheat

Wheat is one of the most important staple crops worldwide.Fusarium head blight severely reduces wheat yield and quality.Cultivation of a novel type of cleistogamous wheat mutant,ZK001,which was created by static magnetic field treatment,is a new strategy for controlling Fusarium head blight.However,little is known about the mechanism of cleistogamy in wheat.The present study demonstrated that anthers of ZK001 were retained on the glumes at all flowering stages,whereas those of YM18 were extruded from the paleae and lemmae.There was a clear difference in the morphological characteristics of lodicules between YM18 and ZK001.Lodicule calcium and potassium contents were significantly higher in YM18 than in ZK001 from white to yellow anther stages.In Fusarium head blight resistance,the diseased kernel rate and deoxynivalenol content of ZK001 were markedly lower than those of YM18 and QM725.Comparative transcriptome analysis of YM18 and ZK001 was performed to identify regulatory mechanisms of cleistogamy.The main differentially expressed genes identified in the spikelets of YM18 and ZK001 at the green anther stage were associated with cell walls,carbohydrates,phytohormones,water channel,and ion binding,transport,and homeostasis.These differentially expressed genes may play an important role in regulating cellular homeostasis,osmotic pressure,and lodicule development.The results indicate that ZK001 lost the ability to push the lemmae and paleae apart during the flowering stage because of the thin lodicules.ZK001 was speculated to provide structural barriers for Fusarium head blight during the flowering stage.The thin lodicule of ZK001 results from low levels of soluble sugar,calcium ions,and potassium ions in the lodicules.These levels are regulated by differentially expressed genes.