Study on Vetiver’s Purification for Wastewater from Pig Farm

Abstract: Nitrogen, phosphorus and heavy metals from pig farms are key sources of water pollution. Wastewater contains nitrogen and phosphorus which are the most important plant nutrients, but is harmful when applied to agricultural land in excess amounts, thereby leading to pollution of ground water by nitrates, surface water by phosphorous (causing eutrophication) and soil by heavy metals such as copper which are used as growth promoters in the feed stuff. The main objective of this paper was to investigate the effects of vetiver (Vetiver zizanioides) in purifying wastewater from pig farms and design a purifying system for pig farms with a Vetiver bamboo float. The results showed that Vetiver had a very high capacity to purify wastewater. It’s ratio of uptake and purification to Cu and Zn> 90%, to As and N> 60%, to P was between 59–85%, to Pb was between 30–71%, and to Hg was between 13–58%. The purifying effects of Vetiver to heavy metals, N, and P from pig farms were ranked as Zn> Cu> As> N> P> Pb> Hg. It is powerful to remove the elements of Cu, Zn, As and N for pig farms

Differential Assembly and Shifts of the Rhizosphere Bacterial Community by a Dual Transgenic Glyphosate-Tolerant Soybean Line with and without Glyphosate Application

Modern agriculture has gained significant economic benefits worldwide with the use of genetically modified (GM) technologies. While GM crops provide convenience to humans, their biosafety has attracted increasing concern. In this study, the Illumina MiSeq was used to perform a high-throughput sequencing of the V3-V4 hypervariable regions of 16S rRNA gene (16S rDNA) amplicons to compare the rhizosphere bacterial communities of the EPSPS/GAT dual transgenic glyphosate-tolerant soybean line Z106, its recipient variety ZH10, and Z106 with glyphosate application (Z106G) during flowering, seed filling, and maturing stages under field settings. At each of the three stages, the alpha and beta diversity of rhizosphere bacterial communities revealed no significant differences between ZH10, Z106, and Z106G. However, some bacterial taxa demonstrated a greater proportional contribution, particularly the nitrogen-fixing rhizobium Ensifer fredii, in the rhizospheric soil of Z106 at the seed filling and maturing stages, when compared to ZH10 and Z106G. The present study therefore suggests that the EPSPS/GAT dual transgenic line Z106 and exogenous glyphosate application have a minimal effect on the composition of the soybean rhizosphere bacterial community but have no impact on the structure of the rhizosphere microbial community during a single planting season

The host niches of soybean rather than genetic modification or glyphosate application drive the assembly of root‐associated microbial communities

Abstract Plant roots significantly influence soil microbial diversity, and soil microorganisms play significant roles in both natural and agricultural ecosystems. Although the genetically modified (GM) crops with enhanced insect and herbicide resistance are thought to have unmatched yield and stress resistance advantages, thorough and in‐depth case studies still need to be carried out in a real‐world setting due to the potential effects of GM plants on soil microbial communities. In this study, three treatments were used: a recipient soybean variety Jack, a triple transgenic soybean line JD321, and the glyphosate‐treated JD321 (JD321G). Three sampling stages (flowering, seed filling and maturing), as well as three host niches of soybean rhizosphere [intact roots (RT), rhizospheric soil (RS) and surrounding soil (SS)] were established. In comparison to Jack, the rhizospheric soil of JD321G had higher urease activity and lower nitrite reductase at the flowering stage. Different treatments and different sampling stages existed no significant effects on the compositions of microbial communities at different taxonomic levels. However, at the genus level, the relative abundance of three plant growth‐promoting fungal genera (i.e. Mortierella, Chaetomium and Pseudombrophila) increased while endophytic bacteria Chryseobacterium and pathogenic bacteria Streptomyces decreased from the inside to the outside of the roots (i.e. RT → RS → SS). Moreover, two bacterial genera, Bradyrhizobium and Ensifer were more abundant in RT than in RS and SS, as well as three species, Agrobacterium radiobacter, Ensifer fredii and Ensifer meliloti, which are closely related to nitrogen‐fixation. Furthermore, five clusters of orthologous groups (COGs) associated to nitrogen‐fixation genes were higher in RT than in RS, whereas only one COG annotated as dinitrogenase iron‐molybdenum cofactor biosynthesis protein was lower. Overall, the results imply that the rhizosphere host niches throughout the soil–plant continuum largely control the composition and function of the root‐associated microbiome of triple transgenic soybean