不同腐熟剂对麦秸腐解率与稻田水环境的影响

Effects of Different Decomposing Agents on Decomposition Rate of Wheat Straw and Water Environment in Rice Field

为探明麦秸还田条件下施用腐熟剂对秸秆腐解效果、稻田水环境风险的影响,选用4种腐熟剂(标识为DA1、DA2、DA3和DA4)进行水稻季麦秸腐解试验。结果表明,施用4种腐熟剂均加快还田后4周内秸秆腐解速度,其中,还田后2周为麦秸快速腐解期,且腐熟剂DA3和DA4促进麦秸腐解的效果更佳,腐解率达36.5%~37.4%,较麦秸还田无腐熟剂处理(CFS)增加了5.1~6.0个百分点。与CFS处理相比,4种腐熟剂处理提高了麦秸还田后3周内田面水化学需氧量(COD)及氮磷含量,增加了水稻生长初期的水环境风险。其中,DA2、DA3和DA4这3种腐熟剂处理后3周内田面水环境风险相对较高,而DA1与CFS处理间水环境风险差异不显著。可见,稻田施用腐熟剂会加速麦秸腐解,同时会增加水稻生长初期的水环境风险,建议南方水网区水稻季谨慎施用腐熟剂。

The effects of applying four kinds of decomposition agents(DA1,DA2,DA3 and DA4)on straw decomposition and water environmental risk in paddy field under the conditions of returning wheat straw to the field were studied.The results showed that the decomposition rate of wheat straw was increased by different decomposition agents in the first four weeks,and the first two weeks was the rapid decomposing period.In addition,DA3 and DA4 had better effect on promoting the decomposition of wheat straw.The decomposition rate of wheat straw of DA3 and DA4 were 36.5%~37.4%in the first two weeks,which was 5.1~6.0 percentage points higher than that of CFS treatment(31.4%).Compared with the CFS treatment,the four treatments increased the COD(chemical oxygen demand),nitrogen and phosphorus contents of field surface water within 3 weeks after wheat straw returning to the field,which increased the water environment risk in the early stage of rice growth.Among them,DA2,DA3 and DA4 treatments had relatively high risk of surface water environment within 3 weeks after returning wheat straw to the field,while there was no significant difference between DA1 and CFS treatments.It can be seen that the application of decomposition agent can accelerate the decomposition of wheat straw and increase the water environment risk in the early stage of rice growth.Therefore,it is recommended to apply decomposing agent carefully in the rice season in the southern water network area.