氮磷肥配施对苦荞根系生理生态及产量的影响

以苦荞品种‘迪庆’为材料,在盆栽试验条件下,研究了氮(纯氮用量分别为0g/kg、0.1g/kg、0.2g/kg)、磷(P2O5用量分别为0.1g/kg和0.2g/kg)配施对苦荞根系生长、生理指标及其产量的影响,旨在为黄土高原苦荞高产优质栽培提供理论依据。结果表明:(1)在相同施磷量条件下,苦荞幼苗的株高、茎粗、茎叶干重、主根长、根表面积、根系体积、根系直径、根系干重以及壮苗指数等均随施氮量的增加而呈先升后降的趋势,但根冠比随施氮量的增加而呈先降后升的趋势;叶片叶绿素含量以及根系活力、酸性磷酸酶(Apase)活性、可溶性蛋白含量和植株氮积累量随施氮量的增加呈抛物线变化趋势,根系硝酸还原酶(NR)活性和植株氮含量随施氮量的增加而增加;而根系可溶性糖含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、丙二醛(MDA)含量和游离脯氨酸含量等指标均随施氮量的增加而呈先降后升的趋势,0.1g/kg施氮处理各指标均显著低于其他处理;成熟期单株粒重、百粒重随施氮量的增加呈先升后降的趋势,0.1g/kg施氮处理各指标均显著高于其他处理。(2)在相同施氮量条件下,随着施磷量的增加,苦荞根系酸性磷酸酶(Apase)活性、SOD活性、POD活性、MDA含量、可溶性糖含量、可溶性蛋白以及游离脯氨酸含量等指标均降低,其余各指标则呈增加趋势。(3)无论施磷量条件如何,0.1g/kg的施氮处理下苦荞产量最高,与其他施氮处理相比,在低磷和高磷处理下的增产幅度分别为7.04%~37.40%和14.73%~68.26%;在施氮量一定的情况下,高磷处理比低磷处理增产15.96%~42.00%。(4)在该试验条件下,适当的氮磷肥配施表现出了明显的正加和效应,但过量施肥也有可能导致增产幅度下降,中氮高磷(施纯N量0.1g/kg,施P2O5量0.2g/kg)配施效果最优。

Root Physio ecological Indices and Yield of Fagopyrum tataricum with Combining Application of Phosphorus and Nitrogen Fertilizer

In order to provide theoretical basis for high yield and good quality cultivation of Fagopyrum tataricum in the Loess Plateau, we determined the effects of combining different nitrogen (N application rates of 0 g/kg, 0.1 g/kg and 0.2 g/kg) and phosphorus fertilizer (P₂O₅ application rates of 0.1 g/kg and 0.2 g/kg) conditions on the root physio ecological indices and yield during the growing period of F. tataricum under experimental pot conditions. The results showed that: (1) under equal phosphorus fertilizer treatments, plant height, stem diameter, shoot dry weight, main root length, root surface area, root volume, root average diameter, root dry weight and seedling index initially increased and then decreased with increasing nitrogen application rate while root shoot ratio decreased initially and then increased with increasing nitrogen application rate. Chlorophyll content, root activity, acid phosphatase activity, soluble protein content, plant N accumulation show the parabola changes with the increase of nitrogen application rate. Root NR activity and plant N content increased with increasing nitrogen rate while SOD, POD activities and MDA content in root, soluble sugar content and free proline content decreased initially and then increased with increasing nitrogen application rate. Weights per plant and 100 seed weight initially increased and then decreased with increasing nitrogen application rate. (2) Under equal nitrogen fertilizer treatments, root Apase, SOD and POD activities, soluble sugar, soluble protein and MDA contents decreased with increasing phosphorus application rate. The other above indices increased under high phosphorus treatment compared with low phosphorus treatment. (3) Among the three nitrogen levels, yield of F. tataricum was the highest under 0.1 g/kg nitrogen application. It increased respectively by 7.04% and 37.40% compared with 0 g/kg and 0.2 g/kg nitrogen treatments under low phosphorus condition. It also increased respectively by 14.73% and 68.26% compared with 0 g/kg and 0.2 g/kg nitrogen treatments under high phosphorus condition. In addition, the yield of F. tataricum was higher in high phosphorus treatment. It also increased, respectively by 15.96% and 42.00% compared with low phosphorus treatment under equally nitrogen fertilizer treatment. (4) In this study, reasonable application of nitrogen and phosphorus fertilizer showed a positive additive effect, but over application of fertilizer could reduce yield. F. tataricum was more suitable for production at suitable nitrogen fertilizer (0.1 g/kg N application) and high phosphorus fertilizer condition (0.2 g/kg P₂O₅ application).