粉碎和添加菌剂对红壤区自然堆沤条件下稻秆养分释放的影响

Straw nutrient releasing regularity under comminution and addingstem rot agent in red soil region

通过对新鲜稻秆进行粉碎或添加菌剂处理,探索在红壤区气候条件下,稻秆加速腐化的技术措施及其N、P、K养分释放特征,为合理利用秸秆的养分资源提供科学依据。在每个60cm×120cm的200目尼龙滤布袋装入5kg新鲜水稻秸秆,设置原状、粉碎、粉碎+腐熟剂和粉碎+农家肥等4种处理,尼龙滤布袋置放在田间自然条件下堆沤,在处理后的第0、10、28、35、51、74天和91天采集样本测定秸秆的干物质、水分和氮、磷、钾养分含量,求算秸秆的干物质腐解及养分释放规律。经过91d自然堆沤置放后,粉碎过的稻秆,干物质腐解率比不处理的水稻秸秆提高4.2%(绝对值,下同),N、P、K养分释放率提高10.4%、6.8%、12.2%;在粉碎的基础上,添加菌剂后的干物质腐解率提高6.3%—7.3%,N、P、K养分释放率提高1.0%—5.8%、11.6%—14.9%、2.2%—5.3%;粉碎后的水稻秸秆在腐解20d内P素养分的释放强度在腐解高峰期明显受到抑制,但添加菌剂后,则消除了对P素释放的抑制作用。秸秆粉碎后加入腐熟剂或农家肥均促进秸秆的腐解和氮磷钾的释放,商品腐熟菌剂若无针对性,则对水稻秸秆的腐熟无明显效果。

Finding methodsto accelerate the straw decompositionprovides a scientific basis for straw utilization in red soil region.An experiement was conducted to compare the effects of straw treated with comminution and added stem rot agent on the nutrient releasing regularity of N, P and K.Four treatmentswere designed including in-site （CK） , crushing, crushing ＋ stem rot agent and crushing ＋farmyard manure.Each of five kg offresh rice straw was packed in 200 mesh nylon filter bag with a size of 60 cmxl20 cm, then placed in the field conditions. The dry matter, moisture and N, P, K nutrient of straw were measured in 0, 10, 28, 35, 51, 74 and 91 days. The results showed that crusting treatment increased the straw decomposition rate by 4.2% compared with CK in 91th day, and the N, P and K nutrient release accordingly increased by 10.4%, 6.8% and 12.2%, respectively. Under crusting combined withstem rot agent treatment, the straw decomposition rate was increasedsignificantly by 6.3%-7.3%, and N, P and K nutrient release increased by 1.0%--5.8%, 11.6%- 14.9% and 2.2%-5.3%, respectively. However, P release was obviously inhibited in 20 days under crushing treatment,while crushing ＋microbes treatment did eliminated this inhabitationphenomenon. Rice straw treated with crushing combined with stem rot agent or farmyard manure could promote strawdecomposition and nutrient release, but the promotion effect is not significant when combined with non-specific stem rot agent.