The diversity of prokaryotic communities in soil is shaped by both biotic and abiotic factors.  However, little is known about the major factors shaping soil prokaryotic communities at a large scale in agroecosystems.  To this end, we undertook a study to investigate the impact of maize production cropping systems, soil properties and geographic location (latitude and longitude) on soil prokaryotic communities using metagenomic techniques, across four distinct maize production regions in China.  Across all study sites, the dominant prokaryotes in soil were Alphaproteobacteria, Gammaproteobacteria, Betaproteobacteria, Gemmatimonadetes, Acidobacteria, and Actinobacteria.  Non-metric multidimensional scaling revealed that prokaryotic communities clustered into the respective maize cropping systems in which they resided.  Redundancy analysis (RDA) showed that soil properties especially pH, geographic location and cropping system jointly determined the diversity of the prokaryotic communities.  The functional genes of soil prokaryotes from these samples were chiefly influenced by latitude, soil pH and cropping system, as revealed by RDA analysis.  The abundance of genes in some metabolic pathways, such as genes involved in microbe–microbe interactions, degradation of aromatic compounds, carbon fixation pathways in prokaryotes and microbial metabolism were markedly different across the four maize production regions.  Our study indicated that the combination of soil pH, cropping system and geographic location significantly influenced the prokaryotic community and the functional genes of these microbes.  This work contributes to a deeper understanding of the composition and function of the soil prokaryotic community across large-scale production systems such as maize.

Phosphorus (P) is one of the most widely occurring nutrients for development and growth of wheat. In this study; the effects of P application amount on grain yield; protein content; and phosphorus use efficiency (PUE) were studied by agronomic management of P fertilizer on spring weak-gluten wheat (Triticum aestivum L.) grown under field conditions for  yr. The experiments were performed at five levels of PO application amount; including ; ; ; ; and  kg ha-. As a result; with increase in P fertilizer; grain yield; and P agricultural efficiency (AEP) increased in a quadratic equitation; but partial factor productivity of P (PFPP) decreased in a logarithmic eq. When  kg ha- PO was applied; the grain yield reached the highest level; but the protein content in gain was lower than .%; a threshold for the protein content to evaluate weak-gluten wheat suitable for production of cake and biscuit. Yangmai  and Ningmai  could tolerate to higher P level of soils than Yangmai  that had more loss in grain yield when P fertilizer was over-applied. AEP had a concomitant relationship with grain yield and was a better descriptor for P use efficiency in the wheat. A high P use efficiency resulted in leaf area index (LAI); increased chlorophyll content and photosynthetic rate; and stable acid phophatase (APase) activity to accumulate more dry matter after anthesis; which explained that the optimum P fertilizer increased grain yield and improved grain quality of weak-gluten wheat.