耕地表面三维结构对小麦苗期根系生长的影响及其定量化描述

As the main growing environment of wheat roots, all the properties of soil may have influences on the root system. The soil surface structure is an important factor that affect the soil temperature, water, gas and nutrients and it is bound to have great influence on the growth of wheat seedling roots. This project aims to achieve a quantitative description of 3D surface structure of cultivated land(T3D) through three-dimensional reconstruction techniques, and to ascertain how the soil surface structure affects the growth of wheat roots. Sequential images of tillage were obtained by unmanned aerial vehicle to reconstruct the three-dimensional tillage. This reconstruction process includes image mosaic, 3D point cloud processing. The evaluation criteria of T3D will be set based on ISO-25178-2-2012. In the field experiment, the first step is to set up experimental plots with different surface structures by the artificial design. The wheat group with different structures is constructed by using the seeding method and density way. The soil properties, root morphology, root physiology and wheat topological characteristics are investigated by the grid method. This study can ascertain T3D’s effects on the wheat roots growth. Finally, the field-plowing test is to be verified the results. This study plans to clarify the effects of T3D on wheat root growth, and to explain the relationship between the root growth and T3D according to the soil temperature, water, gas and nutrients affected by T3D. The results could provide theoretical basis and technical support for improving the tillage quality and sowing quality.

耕地表面结构是改变耕层土壤水、肥、气、热的重要因子，影响播种和出苗、麦苗生长环境，对小麦生长意义重大。前期已证明耕地表面结构对小麦出苗、幼苗地上部特性有着显著影响，但对根系生长的影响尚不清楚。本项目以人工筛土微区和机器耕翻田块为试验对象，首先利用图像序列获取、图像拼接、三维点云提取等技术实现耕地表面三维结构（T3D）的重建，并参照ISO标准制定T3D定量化描述准则；其次通过播种方式和种植密度构建不同的小麦群体，利用方格法调查土壤特性、根系形态、根系生理及地上部农艺性状，来探明T3D对耕作层土壤水分、温度等特性以及小麦根系生长状况的影响。研究在实现T3D定量化描述的前提下，从T3D改变耕层土壤水、肥、气、热状况的角度出发，对根系生长与T3D的关系做出机理上的解释，明确T3D对根系生长的影响程度。研究结果可为改善耕地表面结构及提高播种质量提供理论依据和技术支撑。

本项目通过三维重建技术实现耕地表面三维结构（T3D）的定量化描述，并探明了其对小麦根系生长的影响。T3D的重建通过无人机和三维传感器低空获取图像序列，再利用三维点云处理等技术实现T3D的描述，并参照ISO标准制订T3D量化准则。田间试验通过人工设计不同耕地表面结构的小区，利用播种方式、种植密度构建不同的小麦群体，利用方格法调查出苗情况、土壤特性、根系形态、根系生理及地上部特性，探明了T3D对小麦根系及地上部生长的影响，并通过大田翻耕试验进行验证。研究结果为耕地情况评价和整地质量的快速获取提供了新的技术手段，量化了小麦的高产栽培研究中整地环节的影响。主要成果包括：（1）构建了基于无人机平台及三维传感器的耕地三维结构快速定量化描述技术手段；（2）探明了耕地表面结构对小麦根系生长发育的影响，并从机理上进行了解释；（3）明确了不同耕地表面结构对小麦出苗状态的影响，并构建了出苗状况监测方法；（4）研究成果发表在《Agricultural and Forest Meteorology》、《Plant Methods》、《Remote Sensing》和《Journal of Integrative Agriculture》等杂志上，累计发表论文15篇，其中SCI论文6篇; (5)申请发明专利15项，授权7项，获授权软件著作权1项；（6）培养研究生3人，协助培养博士生2人。