**1. Introduction**

Desertification is a common type of land degradation in ecologically fragile areas [1,2]. It can threaten regional environmental security and is becoming an important barrier that hinders the global economy and the transition to a sustainable society [3]. In general, desertification refers to land degradation that is dominated by sand or gravel due to natural and human factors under various climatic conditions [4]. Sandy land refers to the land formed by the process of desertification, and the surface is mainly sand (or gravel) material. Research shows that desertification may be caused by natural or human factors, among which human factors play an important role in the process of land desertification [5,6]. In arid and semiarid areas, unreasonable land use will lead to the decline of vegetation coverage and the destruction of soil structure, which will lead to desertification [7,8]. Excessive reclamation is an important inducer of land desertification [9]. The growing coverage of sandy land is becoming an important issue and poses a serious threat to the sustainability of human habitation, especially in China [10]. Therefore, the protection and management of desertification land and the sustainable utilization of desertification land resources have attracted extensive attention from government departments and researchers [11,12].

There are two different views on the utilization of sandy land in the existing research. One is to protect the sandy land and abandon it completely, so that some sandy land that

**Citation:** Xu, Y.; Cai, Z.; Wang, K.; Zhang, Y.; Zhang, F. Evaluation for Appropriate Tillage of Sandy Land in Arid Sandy Area Based on Limitation Factor Exclusion Method. *Land* **2022**, *11*, 807. https://doi.org/10.3390/ land11060807

Academic Editors: Bangbang Zhang, Yongsheng Wang, Qi Wen and Dazhuan Ge

Received: 20 April 2022 Accepted: 24 May 2022 Published: 30 May 2022

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**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

can be improved by engineering, is suitable for farming, and that can produce food has not exerted its production potential [13,14]. Second, there is a lack of supervision to include sandy land in the reserve resource pool of cultivated land. The disorderly and excessive development of sandy land destroys the balance of regional water resources and accelerates the speed of land wind erosion and desertification [15–17]. The existing studies on land desertification mainly focus on the process and causes of desertification [18,19], the desertification degree evaluation method and evaluation index system [20,21], desertification risk analysis [22,23], dynamic monitoring of land desertification [24,25], and sand control [26]. In addition, under the climate conditions of arid and semiarid areas, sandy soil flows in the wind because its sand particles are non-cohesive and single granular, resulting in rapid changes in land cover and landform [27,28]. As a result, the evaluation objects of existing studies on sandy land are mostly aeolian sandy soil or sandy land, which cannot cover all sandy soils [29,30]. Obviously, the evaluation and explanation of suitable sandy land in the existing research is insufficient, and it is necessary to carry out more detailed and targeted research to scientifically and rationally promote the protection and sustainable use of sandy land.

Therefore, this study defined suitable arable sandy land as sandy land suitable for crop growth, depending on natural conditions or with certain artificial measures. Based on the above characteristics of unstructured and wind-eroded sandy soils in arid and semiarid areas, the evaluation object of arable sandy soil was determined as all sandy soils without considering surface cover (land use type), and the study area is Hangjin Banner, Inner Mongolia, which is an arid and semiarid area with an obvious current land use structure. Then, the limitation factor exclusion method was used to carry out the investigation and evaluation of arable sandy soil in arid and semiarid areas, determine the quantity and distribution of arable sandy soil in the region, treat the development and protection of sandy soil from the perspective of ecological security, and put forward the direction and measures of arable sandy land development. We hope that the research results can provide a valuable reference for the sustainable development and utilization of arable sandy land and desertification control in arid and semiarid areas.

#### **2. Materials and Methods**

### *2.1. Study Area*

Hangjin Banner is located in southwestern Inner Mongolia, northwest Ordos city, with a total area of 1.89 × 104 km2 (Figure 1). It is located in a mid-temperate monsoon continental climate with low annual rainfall and an uneven regional distribution of rainfall. The average annual rainfall is 281 mm, decreasing from southeast to northwest. The rainfall is concentrated from June to August, and the interannual variation is large. The annual evaporation is 2630 mm, which belongs to the arid and semiarid area. The topography of Hangjin Banner consists of alluvial plains of the Yellow River, sandy deserts, wavy high plains, and hills inlaid and arranged, with an obvious zonal distribution pattern (http://www.hjq.gov.cn/, 1 April 2022). The soil type is mainly aeolian sandy soil, which is distributed along the northern edge of the Kubuqi Desert and the Mu Us Sandy Land, accounting for 58.7% of the total area of Banner. Other soil types, such as fluvo-aquic soil, saline soil, brown calcium soil, chestnut soil, and grey desert soil, are sporadically distributed. Due to the large variability in annual precipitation and the loose sandy substances in sediments, Hangjin Banner will have a large risk of desertification with unreasonable development. In 2020, Hangjin Banner's Gross Domestic Product (GDP) was 12.8 × <sup>10</sup><sup>9</sup> Chinese Yuan (CNY), a 2.3% increase from 2019, and the per capita disposable income was 33,084 CNY, a 3.5% increase from 2019 (The Government of Hangjin Banner, 2021). In addition, because of the limitation of natural and socioeconomic conditions in Hangjin Banner, the current structure of land use is embodied in the high proportion of grassland and unused land (sand land), accounting for 50.0% and 28.8%, respectively, and the proportion of cultivated land and forestland is low, 3.5% and 9.2%, respectively (http: //nmggky.cn/ 1 April 2022). Because Hangjin Banner has obvious regional differences in

land use, with obvious differences between the planting areas along the Yellow River in the north and the high plains and sandy animal husbandry areas in the central and southern parts, it was selected as a typical case for empirical research.

**Figure 1.** Location of the research area.

#### *2.2. Data Source and Process*

Hangjin Banner has a vast area and requires three remote sensing images to cover the entire administrative area. The strip numbers on the OLI-TIRS remote sensing images were 128/032, 129/032, and 128/033. Summer is the best time to extract information on sand, grassland, and other land types because vegetation grows luxuriantly. Therefore, the acquisition time of the Hangjin Banner Landsat 8 remote sensing images was from 1 August 2020 to 1 September 2020. At the same time, the cloud cover of the three remote sensing images was less than or equal to 4%. The pre-processing of remote sensing images includes radiometric correction, atmospheric correction, and image mosaicking and cropping. The data of soil, meteorological, socioeconomic, and land use came from the second soil census in Hangjin Banner, the daily value dataset of climate data in the past 30 years, "Hangjin Banner's National Economic Statistics (2004–2020)", and the land of Hangjin Banner in 2020 Utilize change investigation database (1:10,000), "Hangjinqi Salinization Grade Map" (1:250,000).
