Co-incorporation of Chinese milk vetch(Astragalus sinicus L.)and chemical fertilizers alters microbial functional genes supporting short-time scale positive nitrogen priming effects in paddy soils

Nitrogen(N)priming is a microbially mediated biochemical process as affected by different incorporation practices.However,little information is known about the microbial mechanisms driving the response of N priming to co-operation of Chinese milk vetch(CMV,Astragalus sinicus L.)and different rates of chemical fertilizers in paddy soils in South China.Here,an anaerobic incubation experiment was conducted to study N priming effects(PE)and their relationships with soil microbial functional genes after CMV incorporation alone(M),co-incorporation of CMV with 100%(normal dosage)chemical fertilizers(MC100),and co-incorporation of CMV with 80% chemical fertilizers(MC80).Co-incorporation of CMV and chemical fertilizers enhanced the short-time scale(the first 20 d of incubation)positive PE of N,while no significant differences existed among the three treatments on day 60 or 90 of incubation(P>0.05).Compared with the M treatment,gross priming effect(GPE)in the MC100 and MC80 treatments significantly increased by 34.0% and 31.3%,respectively,and net priming effect(NPE)increased by 47.7% and 47.8%,respectively,during the first 20 d of incubation(P<0.05).This was likely attributed to soil nutrient availability and added substrate quality.The MC100 and MC80 treatments increased the gdhA gene abundance by 5.0% and 9.8%,increased the gdh2 gene abundance by 12.7% and 45.7%,and increased the nasB gene abundance by 9.5% and 41.4%,respectively,in comparison with the M treatment on day 20 of incubation.Correlation analyses indicated that soil microbial functional genes involved in N mineralization(gdhA and gdh2),assimilatory nitrate reduction(nasB),and nitrification(amoB)were significantly correlated with N priming under different incorporation practices during the incubation period(P<0.05).Thus,co-incorporation of CMV and chemical fertilizers can regulate soil microbial community functional gene structure,which may accelerate mineralization and assimilatory nitrate reduction and inhibit nitrification,thereby increasing the short-term positive PE of N in the present study.

ADDRESSING FINANCIAL OBJECTIONS TO SUSTAINABLE DESIGN AND CONSTRUCTION

We have the tools and the knowledge to create much healthier,economical,and ecologically responsible buildings at little or no incremental cost over that of conventional buildings.Unfortunately,both actual and perceived financial barriers are preventing widespread adoption of sustainable design,construction,and maintenance practices.Often organizations express a commitment to sustainable design and construction,but limit the actual implementation to only low-hanging fruit and ignore any significant investment.We need to be able to explain the benefits of sustainable design,construction,and facilities management in a more compelling fashion.In addition to talking about important features of green building,such as decreased use of energy,water,and other natural resources,we need to emphasize the benefits of green building in terms that resonate with key decision makers,such as higher net profits,increased asset values,enhanced image and reduced risk.This article provides useful information that could help you address some barriers to sustainable initiatives:•Every executive that you speak to is aware that data can be manipulated and may be skeptical of studies conducted by organizations that could benefit from a particular set of results.So I’ve included information on independent third-party studies.•In challenging economic times,people are particularly concerned about short-term cash flow.So I’ve included information on programs developed by the Building Owners and Management Association(BOMA)International to maximize asset values without sacrificing shorter-term profits.•Often people are risk-averse and feel more comfortable in the middle of the pack than on the cutting edge.So I’m including information on some potential risks of not going green,including decreased asset values and increased operating costs.Many aspects of sustainable design and construction are based upon proven technology and are being increasingly incorporated into best practices for the design and construction industries,which might lead to legal problems for those who do not include the more widely accepted sustainability measures in their projects.It can be difficult to find and navigate through existing incentives for energy efficiency.So I’m including information on a tool to help you find what initiatives are available and some expert advice on how to use this type of tool.•Often an executive may be far more concerned with the next quarter’s financial results than in the long-term profitability of an organization that he or she may very well not be working for in 20 years.Currently accepted financial accounting methods encourage this short-term focus.So I’m including information on the efforts of leaders in the finance sector to change accounting principles to accommodate considerations of long-term profitability.•Normally,people tend to accept the opinions of acknowledged leaders in their own fields.So I’m including examples of how sustainable initiatives are contributing to the bottom lines of several highly respected organizations.I’m also including information about efforts to create a globally accepted framework for accounting for sustainability that brings together financial,environmental,social,and governance information in a single integrated reporting format by a coalition including the Big Four accounting firms-PricewaterhouseCoopers,Deloitte Touche Tohmatsu,Ernst&Young and KPMG.