化肥与有机肥结合对旱地覆膜春小麦产量形成和土壤碱解氮累积影响

Effects of the Combination of Chemical and Organic Fertilizer on Spring Wheat Grain Yield Formation and Soil Available Nitrogen Accumulation Under Plastic Mulched Rain-fed Area

针对黄土高原半干旱地区瘠薄的土壤、较低的氮肥固持率和传统的一次性基施化肥制度造成覆膜小麦生育期内土壤氮供需不平衡,引起早衰和水分生产潜力限制的问题。于2016—2017年,在陇中雨养农业地区进行大田试验,化学肥料氮磷钾肥按照传统施肥量相同基施的情况下,布置全膜覆土(PMS)、全膜覆土+高量有机肥(PMO)、裸地(CK)处理,研究不同处理对小麦干物质积累特征、土壤碱解氮变化和产量形成的影响。结果表明:干物质积累特征方面,PMO较PMS全生育期干物质累积量平均提高11.93%,进一步提高拔节—抽穗和灌浆—成熟阶段干物质量累积速率,干物质累积量最大增长速率及生育期平均增长速率分别提高11.53%和11.42%,快速生长期无显著延长;PMO较PMS和CK处理0—30 cm土层土壤有机质(SOM)含量分别平均提高42.79%和43.73%,0—50 cm土层土壤碱解氮(SAN)含量分别平均提高110.67%和42.80%;PMO较PMS播前至收后0—50 cm土层SAN累积量降低幅度减少111.15%和增加SAN下移趋势;与PMS相比,PMO进一步优化产量构成,显著提高春小麦籽粒产量和生物产量,但显著降低氮素偏生产力和增加收后土壤SAN累积量。因此,化肥和高量有机肥基施可提高半干旱区覆膜小麦干物质累积速率和耕层土壤碱解氮含量,降低扬花后低氮素限制,促进增产,但增加土壤氮素残留量,可以通过合理减施措施加以调控。

The poor soil fertility,lower nitrogen fertilizer retention and total fertilizer application before sowing,are the key factors which result in the nitrogen imbalance between soil supplying and crop requirement,causing the wheat presenility and the limited soil water productivity potential on the semiarid rain-fed loess plateau.A field experiment was conducted in 2016 and 2017 on the rain-fed central Gansu province,to understand the effects of different treatments on the wheat dry matter accumulation,soil available nitrogen changing dynamics and yield formation.The three treatments were:(1)Whole field mulched by soil-plastic(PMS),(2)PMS with organic fertilizer application,and(3)without soil-plastic mulching and organic fertilizer application(CK),the chemical nitrogen(N),potassium(P)and phosphate(K)were applied before sowing totally in all treatments and with same amount.The results showed that the dry matter of PMO averagely increased by 11.93%in the whole growth period,further increased the dry matter accumulation rate in jointing-heading and filling-harvesting stages,as compared with PMS.Correspondingly,the max growth rate and average growth rate of dry matter increased by 11.53%and 11.42%,but the rapid growth stage did not significantly differ between PMO and PMS.The soil organic matter(SOM)content in 0—30 cm profile of PMO increased by 42.79%and 43.73%compared with PMS and CK,respectively.The soil available nitrogen(SAN)content in 0—50 cm profile correspondingly increased by 110.67%and 42.80%.The decrease extent of soil nitrogen accumulation in 0—50 cm profile from sowing to harvesting stage of PMO decreased by 111.15%but increased the SAN down-transporting,as compared with PMS.Compared with PMS,PMO optimized the grain yield component factors,significantly increased grain yield and biomass.However,it decreased the nitrogen fertilizer partial productivity and increased the SAN accumulation at harvesting stage.Consequently,the chemical fertilizer with organic fertilizer increased wheat biomass,dry matter accumulation rate and relieved nitrogen limitation in post-flowering stage,resulting in the higher grain yield.However,the SAN accumulation risk also occurred,which should be regulated by decreasing fertilizer application amount.