A straw-soil co-composting and evaluation for plant substrate in BLSS

摘要

Material closure is important for the establishment of Bioregenerative Life Support System, and many studies have focused on transforming candidate plant residues into plant culture medium. For the limitations of using wheat straw compost as substrate for plant cultivation, a straw-soil co-composting technique was studied. The changes of pH, C/N value, germination index, cellulose, lignin and so on were monitored during the co-composting process. The maturity was evaluated by the C/N value and the germination index. The result showed that after 45 days' fermentation, the straw-soil final co-compost with inoculation (T1) became mature, while the co-compost without inoculation (TO) was not mature. In the plant culture test, the Tl substrate could satisfy the needs for lettuce's growth, and the edible biomass yield of lettuce averaged 74.42 g pot~(-1) at harvest. But the lettuces in TO substrate showed stress symptoms and have not completed the growth cycle. Moreover, the results of nitrogen (N) transformation experiment showed that about 10.0% and 3.1% N were lost during the Tl co-composting and plant cultivation, respectively, 23.5% N was absorbed by lettuce, and 63.4% N remained in the Tl substrate after cultivation.