不同施肥方式与保水剂互作对河西地区黄芪土壤微环境及产量的影响

Effects of Different Fertilization Methods and Water Retaining Agents on Soil Microenvironment and Yield of Astragalus mongholicus in Hexi Region

土壤干旱缺水和有机质亏缺是限制甘肃河西地区黄芪产业发展的关键因素。为探索促进河西地区土壤蓄水保肥和土壤微环境改善的施肥措施,通过连续2年大田试验,设置保水剂+有机肥+普通尿素(B+OM+N)、保水剂+有机肥+缓释尿素(B+OM+HN)、保水剂+普通尿素(B+N)、有机肥+普通尿素(OM+N)、有机肥+缓释尿素(OM+HN)和单施普通尿素(CK)6个处理,探讨了不同施肥方式与保水剂互作对黄芪土壤水分、养分等微环境指标的影响,并分析了其与产量之间的相关性。结果表明:随着土层深度的加深,土壤水分含量先升后降,有机质、速效氮磷钾及微生物生物量碳、氮(MBC、MBN)含量逐渐降低,NH_(4)^(+)-N和NO_(3)^(-)-N含量逐渐增加,MBC/MBN比先增后减;随着生育期的推进,土壤水分、NH_(4)^(+)-N和NO_(3)^(-)-N含量逐渐降低,有机质、MBC、MBN含量和MBC/MBN比逐渐增加,碱解氮、速效钾含量先升后降,有效磷含量波动式下降;不同土层深度、不同生育期各养分指标及黄芪芦头直径和单株根重均以B+OM+HN处理表现最高。相关性分析显示,土壤养分指标间及其与黄芪产量指标显著正相关。综上,有机肥、缓释尿素、保水剂的施用提升了黄芪土壤养分,改善了土壤微环境,进而提高了黄芪产量,其中以氮减量1/3的基础上配施有机肥、缓释尿素与保水剂处理对河西灌区土壤微环境改善和黄芪产量提升效果最佳。

Soil drought and lack of organic matter are the key factors limiting the development of astragalus industry in Hexi region of Gansu Province.This study aimed to explore the fertilization methods for soil water storage and fertilizer conservation and soil microenvironment improvement in Hexi region of Gansu Province,in which six treatments were designed for two consecutive years of field experiments,including water retaining agent+organic fertilizer+common urea(B+OM+N),water retaining agent+organic fertilizer+slow-release urea(B+OM+HN),water retaining agent+common urea(B+N),organic fertilizer+common urea(OM+N),organic fertilizer+slow-release urea(OM+HN)and single application of common urea(CK).The effects of different fertilization methods and water retaining agents on soil moisture and nutrient indexes of Astragalus mongholicus were investigated,and their correlation with yield were analyzed.The results show that with the deepening of soil depth,soil moisture is increased first and then is decreased,organic matter,available nitrogen,phosphorus and potassium,MBC and MBN are decreased gradually,NH_(4)^(+)-N and NO_(3)^(-)-N are increased gradually,and MBC/MBN is increased first and then is decreased.With growth period,soil moisture,NH_(4)^(+)-N and NO_(3)^(-)-N are decreased gradually,organic matter,MBC,MBN and MBC/MBN are increased gradually,alkali-hydrolyzable N and available K are increased first and then are decreased,and available P is decreased in a fluctuation pattern.B+OM+HN show the highest performance in all nutrient indexes,reed head diameters and root mass per plant of astragalus in different soil depths and different growth stages.Correlation analysis shows that there is significant positive correlation between soil nutrient indexes and yield indexes of Astragalus mongholicus.In conclusion,the application of organic fertilizer,slow-release urea and water retaining agent can improve soil nutrients and microenvironment,and then increase the yield of Astragalus mongholicus.The interaction treatment of slow-release urea and water retaining agent combined with organic fertilizer based on reducing 1/3 nitrogen has the best effect on improving soil microenvironment and increasing yield of Astragalus mongholicus in Hexi irrigation area.