[Situation Analysis and Trend Prediction of the Prevention and Control Technologies for Planting Non-Point Source Pollution].

The contribution of crop planting to agricultural non-point source pollution should not be underestimated in China. Although many modern technologies have been developed to prevent non-point source pollution in recent decades, their impacts on pollution control in farmland are far from expectation. The application of technologies for non-point source pollution control for crop farming has been delayed due to unclear technical parameters and application effectiveness. Therefore, based on studies of the non-point source pollution control for crop farming in China and abroad that were published in the last 20 years, the present research was carried out to determine the development process of planting non-point source pollution control technologies and to illuminate the framework construction. The technologies in different fields and directions were compared by their effects on fertilizer input,yield, and pollutant emission. The development trend in the field of prevention and control technologies for planting non-point source pollution was subsequently predicted. In addition, a technical framework was developed with 3 fields (pollutant source reduction, pollutant interception in the migration process, and nutrient recycling) and 14 directions. The analysis showed that the technologies for reducing pollutants from the source have attracted the most (and increasing) concern with many research directions, and that many of the studies in this field have focused on the regulation of fertilizer application. On the contrary, there is a lack of technologies in the fields of pollutant process interception and nutrient recycling. Promoting nutrient-use efficiency, regulating nutrient transformation, and using soil supplements will be the main entry points for non-point source pollution control for crop farming. Furthermore, technologies will operate better with the help of farmland infrastructure and downstream purification systems.

Transformation of inorganic P fractions of soil and plant growth promotion by phosphate-solubilizing ability of Penicillium oxalicum I1.

The solubilization of tricalcium phosphate is often considered as the standard for screening of most phosphate-solubilizing microorganisms (PSMs). However, usually the effect of large-scale application of PSM on the promotion of crop growth varies. This study presents an efficient method for screening and testing phosphate-solubilizing fungus that enhance plant growth. A fungus Penicillium oxalicum I1 (P-I1) was isolated and identified that had high ability of phosphate-solubilization and could utilize maize root exudates as sources, and propagate well in vitro and in soil. P-I1 excreted oxalic acid and reached 593.9 µg/ml, and the pH value was decreased from 6.90 to 1.65 in 26 h. The amount of P-I1 increased by 48-fold in 28 d and was maintained for 49 d in soil. PSM showed selectivity on the transformation of the different forms of phosphorus, a wide range of insoluble phosphates, such as Ca8H2(PO4)6·5H2O, AlPO4, FePO4, and Ca10(PO4)6(OH)2, were converted to soluble CaHPO4in soil, and CaHPO4was also inhibited from being converted into insoluble phosphate by P-I1. The Ca2-P content reached 27.11 µg/g soil on day 28 at 20°C, which increased by 110.32%, and plant growth promotion was tested and verified, the results showed that maize yield increased remarkably than control after inoculated P-I1, maize yield increased maximum by 14.47%. The data presented that P-I1 appear attractive for exploring their plant growth-promoting activity and potential field application.

Characterization of bacterial consortium and its application in an ectopic fermentation system.

This study aimed to develop an ectopic fermentation system (EFS) to reduce the pollution of cow wastewater and to provide a basis for the production of biofertilizer with fermentation residues. Six thermophilic strains, three of which have efficient cellulose-degrading abilities and the other have good ammonia-N utilizing abilities, were chosen as the microbial inocula. The results showed that EFS inoculated with microbial consortium brought higher temperature and more wastewater was needed to ensure continuous fermentation. The pH values decreased in the early stage of fermentation, and then increased during the process. It caused increases in total Kjeldahl nitrogen, total phosphorous, and total potassium content. Decreases in organic matter content and C/N ratio were also observed. The high level of nutrients indicated the suitability of the paddings after fermentation for agronomic uses. It firstly attempted to combine cow wastewater treatment and bio-organic fertilizer production by EFS with mixed microbial culture.