水肥耦合效应对栓皮栎苗木生长的影响

Coupling effects of soil water and fertilizer application on the growth of Quercus variabilis seedlings

【目的】探讨栓皮栎Quercus variabilis当年生苗木的苗高、地径、单株叶面积、根干质量、生物量积累对水肥耦合的响应规律,并确立最佳的灌溉施肥组合。【方法】采用4因素5水平二次回归通用旋转组合设计(RCCD),建立各指标与土壤含水率、施氮量、施磷量和施钾量回归模型,分析各因子的主效应、单因素和耦合效应对生长的影响。【结果】①对苗高、地径、单株叶面积、根干质量、生物量的方差分析表明,各指标的不同处理间存在显著差异(P<0.05),处理8、处理16、处理18苗木生长情况较好。②模型检验结果表明:土壤含水率和施氮量对5个指标均有显著正效应,施磷量对地径无显著效应,施钾量对各指标均无显著效应,主效应从大到小依次为土壤含水率、施氮量、施磷量和施钾量。③单因素效应表明:各指标随着施肥量的增加均呈现出类似"抛物线"的变化趋势,生长速率随着土壤含水率的增加而增加,到一定程度时速率减缓。④耦合效应表明:土壤含水率×施氮量对苗高、生物量、叶面积、根干质量有显著正效应,土壤含水率×施磷量对苗高、地径、根干质量、生物量有显著正效应,土壤含水率×施钾量对生物量有显著正效应,施氮量×施磷量对叶面积、根干质量、生物量有显著正效应,施氮量×施钾量对地径有显著负效应,水肥间的耦合效应大于肥料间的耦合效应。【结论】栓皮栎苗期水肥需求量从大到小依次为土壤含水率、施氮量、施磷量和施钾量,适宜的水分和施肥配比可促进苗木生长。高水、高氮、高磷、低钾条件下苗木生长情况更好。水肥调控的最佳组合为:土壤含水率为田间最大持水量的79%,氮、磷、钾用量分别为215.3、46.0、18.1 mg·株^-1,苗木的苗高可达到45.14 cm,地径达到4.40 mm,根干质量达到6.30 g,生物量达到11.70 g,单株叶面积可达460.83 cm^2。图3表2参30。

[Objective]The aim is to investigate the response of stem height,ground diameter,leaf area,root weight and biomass accumulation of the seedlings of Quercus variabilis to the coupling of water and fertilizer,and to establish optimal combination of irrigation and fertilization.[Method]The four-factor-five-level quadratic regression general rotatable central composite design(RCCD)was employed to establish the regression model of each index and soil moisture(W),nitrogen(N),phosphorus(P)and potassium(K),with an analysis conducted of the main effect,monofactor and coupling effect of each factor on growth.[Result](1)With the variance analysis of the stem height,ground diameter,leaf area,root weight and biomass,it was found that there is a significant divergence in the treatment of various factors(P<0.05)and the growth of seedling 8,16 and18 is the most favorable.(2)The model test results show that W and N have significant positive effect on all 5 indexes,P has no significant effect on ground diameter,K has no significant effect on any indexes,and there is a decrease of the main effect:W>N>P>K.(3)In terms of monofactor effect,it was shown that all the indexes presented a trend of first increase and then decrease with the increase of fertilizer application,in the path of a parabola.There was a gradual growth of the seedling with the increase of W before the a drop occurred in the growth rate.(4)With the anlaysis of the coupling effect,it was found that W×N has significant positive effects on stem height,root weight,biomass and leaf area,W×P has significant positive effects on stem height,ground diameter,root weight and biomass,W×K has significant positive effects on biomass,and N×P has significant positive effects on root weight,leaf area and biomass,N×K has significant negative effects on the ground diameter and the coupling effect between water and fertilizer is greater than that between fertilizers.[Conclusion]In conclusion,the water and fertilizer demand in the seedling stage of Q.variabilis is W>N>P>K,and suitable water and fertilizer ratio can promote the growth of seedlings.Seedlings grow better with conditions of high water,high nitrogen,high phosphorus and low potassium fertilizer.The optimal combination of water and fertilizer regulation was as follows:soil water content was 79%of the maximum field moisture capacity,nitrogen application was 215.3 mg·plant^-1,phosphorus application was 46.0 mg·plant^-1,potassium fertilizer application was 18.1 mg·plant^-1,with seedling height reaching 45.14 cm,ground diameter reaching 4.40 mm,root weight reaching 6.30 g·plant^-1,biomass reaching 11.70 g·plant^-1,and leaf area reaching 460.83 cm^2.[Ch,3 fig.2 tab.30 ref.]