Abstract
Soil nutrients are essential factors that reflect farmland quality. Nitrogen, phosphorus, and potassium are essential elements for plants, while silicon is considered a “quasi-essential” element. This study investigated the spatial distribution of plant nutrients in soil in a hilly region of the Pearl River Delta in China. A total of 201 soil samples were collected from farmland topsoil (0–20 cm) for the analysis of total nitrogen (TN), available phosphorus (AP), available potassium (AK), and available silicon (ASi). The coefficients of variation ranged from 47.88% to 76.91%. The NSRs of TN, AP, AK, and ASi were 0.15, 0. 07, 0.12, and 0.13, respectively. The NSRs varied from 0.02 to 0.20. All variables exhibited weak spatial dependence (R2 < 0.5), except for TN (R2 = 0.701). After comparing the prediction accuracy of the different methods, we used the inverse distance weighting method to analyze the spatial distribution of plant nutrients in soil. The uniform spatial distribution of AK, TN overall showed a trend of increasing from northeast to southwest, and the overall spatial distribution of AP and ASi showed that the northeast was higher than the southwest. This study provides support for the delimitation of basic farmland protection areas, the formulation of land use spatial planning, and the formulation of accurate farmland protection policies.
Highlights
Soil nutrients are important indicators of cultivated land quality, which is determined by two aspects: soil fertility and spatial location [1]
Based on the notion that the sampling interval should be less than half the range of the variogram [34] and the principle that sample numbers are usually a compromise between the accuracy required and the resources available for investigation, these results indicated that the sampling design was adequate for determining the spatial variability of soil nutrients in the study area [30]
The results showed that total nitrogen (TN) is moderately enriched and available phosphorus (AP) is deficient in the study area, which was consistent with the geochemical survey results
Summary
Soil nutrients are important indicators of cultivated land quality, which is determined by two aspects: soil fertility and spatial location [1]. Soil fertility, which is closely related to the concentrations of soil nutrient elements, is the foundation of soil productivity [2]. Soil nutrient elements can be classified into essential, beneficial, and toxic elements. Beneficial elements, which usually include sodium, silicon (Si), and cobalt, are vital for some specific plant species growing under certain environmental conditions [4]. A sufficient supply of soil nutrients allows plants to grow and develop normally, and the abundance and chemical form of nutrients directly determines whether the soil is fertile [5]. It is essential to measure the concentrations of soil nutrient elements to estimate farmland quality
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