长期化肥和有机肥施用对双季稻根茬生物量及养分积累特征的影响

摘要

[Objective]Rice root returned to soil not only promotes mineral nutrients returned to soil, but also improves soil fertility. However, little information is reported about the root biomass and root nutrients accumulation.[Method] Based on the long-term field experiment started from 1981, four treatments were chosen, (1) no fertilizer treatment (CK), (2) nitrogen (N), phosphorus (P) and potassium (K) fertilizers (NPK), (3) Double rates of NPK fertilizers (2NPK), (4) NPK + manure (NPKOM). The soil and plant were sampled and measured in 2012. The changes of rice root biomass and their N, P, K contents were analyzed, then, the response of soil fertility factor to root were explored.[Result] Rice root biomass, nutrient accumulation and their proportions in whole plant were shown that early rice was significantly higher than that of late rice among all treatments, meanwhile, application of chemical and organic fertilizers increased significantly root biomass and nutrient accumulation in both rice growing seasons than other treatments. Compared with NPK, the root biomass and N, P and K accumulation in early rice growing season increased by 20.58%, 17.34%, 270.66% and 37.89%, respectively; and correspondingly the values in later rice season were 23.85%, 17.88%, 262.55% and 37.96%, respectively. However, compared with early rice, the proportions of root biomass, N and K accumulation in whole plant in NPKOM treatment in the late rice growing season decreased by 22.18%, 33.90% and 26.70%, respectively; and correspondingly the values in NPK treatment were 4.91%, 39.41% and 27.06%, respectively. Conversely, the proportions of root P accumulation in whole plant in NPKOM treatment in late rice growing season showed an increase tread in comparing with early rice growing season. Further, its multivariate regression analysis showed that soil total P and available P contents were key factors in the increase of rice root biomass and the accumulation of N, P, K in root.[Conclusion] Long-term application of organic and inorganic fertilizers increased rice root biomass and nutrient accumulation, but decreased the proportions of rice root N and K accumulation in whole plant. Moreover, soil P content played an important role in rice root growth and nutrient accumulation.%[目的]作物根茬还田不仅促进作物吸收的养分归还农田系统,而且可以培肥土壤.然而,在双季稻区,有关不同施肥措施下根茬生物量的变化及养分积累特征则仍不明确.[方法]基于1981年开始的进贤双季稻长期定位试验,于2012年分别采集早晚稻成熟期不施肥(CK)、氮磷钾肥(NPK)、2倍的氮磷钾肥(2NPK)和氮磷钾肥与有机肥配施(NPKOM)处理的水稻秸秆、籽粒、根茬和土壤样品,分析不同施肥处理下根茬生物量及氮磷钾养分积累量的变化趋势,探讨影响根茬生物量及养分积累量的关键肥力因子.[结果]根茬生物量和养分积累量及占总植株的比例均呈现出早稻季明显高于晚稻季,且有机无机肥配施处理可以显著提升水稻的根茬生物量及氮磷钾养分积累量.与NPK处理相比,NPKOM处理的早稻根茬生物量及氮磷钾积累量分别增加了20.58%、17.34%、270.66%和37.89%,晚稻季根茬生物量及氮磷钾积累量的增幅为23.85%、17.88%、262.55%和37.96%.但是,在早稻季,NPKOM处理的根茬生物量及氮钾养分积累量占总植株的比例则分别比NPK处理降低了22.18%、33.90%和26.70%,晚稻季NPKOM处理的降幅分别为4.91%、39.41%和27.06%,而根茬磷素的比例则呈增加趋势.进一步通过多元回归分析发现,在所有肥力指标中,土壤全磷和有效磷是影响水稻根茬生物量及氮磷钾养分积累量的关键肥力因子(P<0.05).[结论]长期有机无机肥配施可以显著增加根茬生物量及氮磷钾养分积累量,但却显著降低了根茬氮钾养分占总植株的比例.且当其他条件相同的情况下,施肥措施主要通过土壤磷含量调控早晚稻的根茬生物量及养分积累量.