# Root System and Its Relations with Soil Physical and Chemical Attributes in Orange Culture
## 1 Introduction  
Brazil is the world's largest exporter of orange juice, which makes citrus growing very economically important for the country. Its sales represent more than 80% of international trade, even supplying the internal market [1]. During the 2019/20 orange harvest, 390 million 40 kg boxes were produced throughout the citrus area of the state of Sao Paulo and southwest Mineiro [2]. Among the main varieties of orange cultivated, Valencia (_Citrus sinensis_) stands out, which, grafted with the Swingle citrumelo rootstock (_Citrus paradsi_ vs. _Poncirus trifoliata_), presents a higher volume of canopy and fruit productivity compared to use of Cravo and other citrumelos as rootstock [3].  
In the citrus industry, the installation and formation of orchards presents great variability due to the management and soil tillage adopted in the area [4]. The management of soil with the use of subsoils allows the rupture of deeper layers, reaching up to 0.70 m, in addition to affecting breathing of the soil, increasing the porosity and reducing its bulkdensity [5]. Minimum tillage has been used by producers due to the contribution of organic matter that is maintained as soil protection, and promotes an increase in the values of macroporosity [6], allowing greater root development of the crop. The growth of the roots is related to the physical quality of the soil and the effects caused by its structure according its tillage, resistance of the superficial layer, water content and intensity of traffic of machines and equipment [7].  
Agricultural management systems for the establishment and management of orchards can affect soil physical resources and, consequently, chemical resources [8]. According to [PERSON] et al., [9], the indicators most used to measure soil quality in orange groves are pH, cation exchange capacity, bulk density, macroporosity, phosphorus content and organic matter.  
Changes in soil attributes, mainly related to structure, can compromise the development of roots in citrus [10]. In general, the density and length of the root system of plants are characteristics that determine the potential of the crop to absorb water and nutrients [11] and, consequently, develop properly and produce good quality fruits. Therefore, the knowledge of their distribution along the soil is important for making rational and sustainable soil and water management decisions, in addition to fertilization [12].  
Thus, companies sought and developed alternatives for soil tillage for the establishment of orchards aiming at the preservation of their quality. The triple operation implement was developed with the objective of providing planting, furrow fertilization, subsoiling and construction of beds, promoting improvements in the physical conditions of the soil and, consequently, in the root development of citrus culture.  
In this context, the following hypothesis was considered: the use of the triple operation implement for soil tillage results in the best physical and chemical conditions and, consequently, greater root volume of the orange crop. Therefore, the objective of this study was to identify the physical and chemical attributes that have the greatest influence on the root growth of the orange crop under different soil tillage systems.