石灰性土壤上豆科绿肥活化锌及促进冬小麦籽粒锌吸收营养机制

Zinc (Zn) is an essential element for humans, and Zn deficiency causes various kinds of diseases. For the Zn bioavailability is low in calcareous soil, most of grain Zn concentration of wheat produced in these area are less than recommended grain Zn concentration. Field experiments results indicated that legume green manure rotation (LGM) increased winter wheat grain Zn significantly which could be a possible solution for improving Zn uptake for local residents. Rootbox, incubation test and field experiments are designed in present study to investigate the mechanisms of two different legume green manure root extrudates and the decomposition products enhance the bioavailability of Zinc in the soil and to explore how LGM influences Zn absorption, transport and remobilization in wheat for the purpose of optimizing the biofortification strategy of Zn in wheat through LGM, and improving the Zn status in crops and humans.

锌是人类必需的微量元素，缺锌会引起人体多种疾病，而我国石灰性土壤有效锌含量很低，多数产区小麦籽粒锌含量低于推荐含量，无法满足人体锌营养需求。本项目以田间试验豆科绿肥轮作能够显著提高后茬冬小麦籽粒锌含量为切入点，拟进一步通过根箱试验、室内培养及田间试验，从不同豆科绿肥根系分泌物成分、数量和腐解产物对土壤锌形态转化及生物有效性的影响，绿肥轮作后冬小麦根系生长发育、小麦锌的吸收、转运及再分配过程的变化方面，揭示豆科绿肥对土壤锌的活化及促进冬小麦籽粒锌吸收的营养机制。研究结果将为以种植绿肥作为生物强化手段提高我国小麦籽粒锌含量，改善作物和居民锌营养提供科学依据。

锌是人类必需的微量元素，缺锌会引起人体多种疾病，而我国石灰性土壤有效锌含量很低，小麦籽粒锌含量严重低于推荐含量，无法满足人体锌营养需求。本项目通过陕西渭北长武、永寿典型低锌土壤上的田间试验夏闲期种植不同种类绿肥，研究测定了绿肥-小麦各生育期植株、土壤有效锌变化规律；通过田间不同绿肥腐解试验监测了养分释放规律，研究结果澄清了绿肥对小麦茎叶-籽粒锌的转移过程无显著影响，揭示了怀豆、黑麦豆绿肥是通过其自身强大的吸锌能力，将锌富集其体内，然后在还田后腐解阶段，快速腐解释放锌，大量增加土壤中有效锌含量，进而提高了小麦籽粒锌含量。本研究同时还为渭北地区筛选出了怀豆、黑麦豆两种生物量大、吸锌能力强，锌释放速率高，残留率低适宜渭北地区种植，并能有效提高小麦锌含量的绿肥品种。绿肥轮作可作为渭北低锌旱地培肥土壤，提高小麦锌含量的农艺措施。