协同实现小麦高产优质和环境友好的根层土壤锌调控机制

Zinc (Zn) is an essential element for crop growth and human health. Zinc deficiency in agricultural production and human body in China, however, is under severe conditions and thus being one of the important limiting factors for grain yield and quality in the current high-yielding wheat production system. Therefore, using multiple years field experiment combination with the laboratory analysis, this project aims to investigate the effects of different Zn application levels on the growth and development of the above-ground and root, yield components, Zn concentrations in shoot and grain, grain Zn bioavailability and grain quality of wheat, as well as soil Zn speciation, soil available Zn, and microbial diversity in soils. With that, the project will explore the role of Zn in the establishment and functioning of wheat population, as well as the potential mechanism of high Zn use efficiency by root system and biological processes in the rhizosphere. The project will also identify the critical Zn concentrations for population structure and functioning of high-yielding wheat system. The project will further explore the effect of root-zone Zn management on wheat grain quality and environment friendly. The overall objective is to establish the effective root-zone regulation for Zn fertilizer management for achieving high-yielding wheat system, thus provide the theoretic and technical support for high yield, high quality and friendly environment simultaneously, and finally achieve the food security and human health.

锌是作物生长和人体发育必需的营养元素，我国农业生产和人群缺锌状况都十分严重。在目前的高产小麦生产体系中，锌缺乏已经成为产量和营养品质进一步提高的重要限制因子之一。本项目拟以高产小麦为研究对象，以多年田间定位试验为基础，结合室内分析试验，通过研究不同施锌水平对高产小麦地上部和根系生长、产量形成、植株和籽粒锌含量、籽粒锌有效性、营养品质、土壤锌形态和有效性、土壤微生物群落组成和结构等的影响，揭示集约化高产条件下锌在小麦地上群体构建和功能中的作用及锌高效利用的地下根系/根际过程；明确支撑高产小麦群体的锌的临界需求；探明根层锌调控对小麦籽粒锌营养品质和环境的影响；建立以根层调控为核心的高产小麦体系锌肥的有效调控途径，从而实现作物高产与优质、环境友好的协同，为实现粮食安全和人体健康提供理论依据和技术支撑。

锌是作物生长和人体发育必需的营养元素，我国农业生产作物和人群缺锌状况均十分严重。本项目以高产小麦和玉米为研究对象，依托锌水平长期定位试验，深入研究了不同施锌水平对高产小麦和玉米地上部和根系生长、产量形成、植株和籽粒锌含量、营养品质、土壤锌形态和有效性、重金属风险、土壤微生态等的影响，结果表明：(1) 土施锌肥显著增加了所有土壤形态锌含量，土壤交换态锌和铁氧化物结合态锌在全锌中所占的比重,当土壤中每盈余1 kg Zn/ha，土壤DTPA-Zn含量增加0.06 mg/kg;（2）土施锌肥可以通过提高光合速率和叶面积指数，增加小麦成穗率及穗粒数、减少玉米秃尖实现产量增加；（3）建立了实现冬小麦和夏玉米高产的DTPA-Zn临界浓度（2.0和4.7 mg/kg）和植株锌临界浓度（29.4和33.5 mg/kg）; (4) 合理的锌肥施用（5.7-11.4 kg/ha）促进了小麦玉米根系的生长及在耕层土壤中的分布，增加根系锌吸收和花后植株锌吸收量，提高了小麦和玉米籽粒锌含量和生物有效性及其他籽粒营养品质，其中标准粉和精粉中锌生物有效性更高；（5）土施锌肥显著增加了小麦籽粒锌、镉、铅含量，同时降低籽粒砷含量。合理的锌肥用量（5.7 kg Zn/ha）既能实现小麦籽粒锌强化，同时又不会增加重金属健康风险，而过量施用锌肥会带来籽粒重金属健康风险;（6）合理施锌（5.7 kg Zn/ha）可以提高土壤脲酶、蔗糖酶、转化酶、过氧化氢酶的活性，同时又不会降低微生物群落的α-多样性，实现农业微生态系统的可持。综上所述，合理土施锌肥 (5.7-11.4 kg Zn/ha) 既可以增加小麦、玉米产量和籽粒营养品质，改善人体健康，又不会对人体产生重金属健康风险；同时还能提高土壤酶的活性、保持土壤微生物群落结构的多样性, 实现小麦玉米生产的高产、优质、环境友好的协同，为实现粮食安全和人体健康的锌肥施用技术提供理论依据和技术支撑。