Preparation of biochar from solid waste of saline-alkaline aquaculture and its effect on sulfate saline-alkaline soil amendment
The shortage of fresh water resources,air pollution and soil salinization are the environmental problems perplexing all countries in the world.China has a relatively high degree of land salinization.There are a large number of saline-alkaline lands in China,mainly distributed in the northeast,north,northwest of China and some coastal areas.The total saline-alkaline land area in China is about 99.13 million hm2,Research shows that aquaculture in saline-alkaline land can not only produce high-quality protein,but also play an important role in the improvement of saline-alkaline land.In recent years,the comprehensive utilization model of fishery and agriculture in saline-alkaline land has largely solved the problem of difficult utilization of saline-alkaline land(water),and provided a new way for the comprehensive utilization of low-lying saline-alkaline land.In addition to the characteristics of high salinity and alkalinity,soil infertility is also a bottleneck problem that restricts the utilization of saline-alkaline land.Whether the solid wastes generated during aquaculture process can be recycled is crucial for maintaining the sustainable development of aquaculture in saline-alkaline soil.To explore the utilization methods of solid wastes from saline-alkaline aquaculture,pyrolysis and hydrothermal carbonization were selected to produce pyrolysis biochar fish manure(BFM)and hydrothermal fish manure(HFM).BFM,HFM and aquaculture solid waste(FM)were used as three amendments to evaluate their effects on sulfate saline-alkaline soil.Three doses(2％,5％,8％)of amendments were added to saline-alkaline soil for 30 d of soil incubation.The physicochemical parameters and particle size of the soil were measured,and the improvement effects of amendments on saline-alkaline soil were evaluated by a rice pot trial.The results showed that BFM and HFM were rich in nutrients,a large number of functional groups such as hydroxyl group on the surface were retained,and the agglomeration degree of hydrothermal biochar was greater than that of pyrolytic biochar.After 30 d soil incubation,with the dose increase of BFM,HFM and FM from 2％to 8％,soil available nitrogen increased by 9.00％,10.21％-78.58％and 27.64％-67.39％respectively.The soil total phosphorus increased by 14.98％-42.90％,16.62％-39.68％and 14.70％-42.25％respectively.After amendment application,the soil pH did not change significantly,and salt content increased with the increase of the dosage.While the salinity,pH and main ions of soil in HFM group remained at a low level.On the third day,the germination rates of 5％BFM,5％HFM and 2％FM,increased to 28.33％,33.33％and 28.33％compared with the control group(20％).When the dosage of amendment reached 8％,it significantly decreased the germination rate of rice(P＜0.05).In conclusion,hydrothermal carbon as an amendment is better than pyrolytic carbon and raw material,and the application dose should be less than 5％.This study provides a theoretical basis for the recycling of solid wastes from saline-alkaline aquaculture.
万方数据
维普
