Novel Weighting Method for Evaluating Forest Soil Fertility Index: A Structural Equation Model

Abstract

Understanding nutrient quantity and quality in forest soils is important for sustainable management of forest resources and maintaining forest ecosystem services. In this study, six soil nutrient indicators, including soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) were measured in five different aged stands of Chinese fir forests in subtropical China. A structural equation model (SEM) was developed based on these soil nutrients indicators in order to better evaluate the soil fertility index (SFI) in these studied forests. The results show that soil nutrient contents changed with the soil depth in different age groups. The SOM decreased in a specific order: over mature > mature > near mature > middle > young stands. The TN content of the soil gradually decreased with increased soil depth throughout all age groups. The SEM indicated that the TN had the highest weight of 0.4154, while the TP had the lowest weight at 0.1991 for estimating the SFI. The weights of other indicators (AN, SOM, AP, and AK) ranged 0.2138–0.3855 in our study. The established SEM satisfied the fitness reference values and was able to accurately describe the forest soil nutrient status through the SFI. The overall SFI values were significantly higher in over mature stands than in young-aged stands and in topsoil than in deeper soil in all examined forests. Soil TN, AP, and AK were the most important nutrient indicators to the evaluation of the SFI in the study sites. The results confirmed that the SEM was suitable to estimate the weights of the SFI and better describe the soil nutrient status in forests. Our research provides an innovative approach to assess a soil nutrient status and soil fertility and provides a scientific basis for accurate implementation of soil nutrient assessment in forest ecosystems.

Potential of Chromolaena odorata, Ipomoea carnea and Eichhornia crassipes as green manures on soil fertility index and rice production on vertisols

“…Soil fertility is closely related to the nutrients contained in the soil. According to the research of Zhao et al (2023), the soil fertility index is a method that is commonly used for making a comprehensive evaluation of soil fertility. Using fertilizer in correct proportions will increase crop production, and the foundation of organic farming lies in the health of the soil.…”

Soil Fertility Evaluation and Fertilizer Requirements of Nitrogen, Phosphorus and Potassium for Wheat Production (Sharq El-Owainat – Western South Egypt)

“…The visible and near-infrared spectroscopy used to assessment soil fertility index (Yang et al, 2020) and development by Munnaf and Mouazen (2021). Zhao et al (2023) applied a novel weighting method for forest soil fertility index evaluation. There was a significant positive correlation between soil fertility index and soil suitability for Arabica coffee (Coffea arabica L.) in Pacitan District, Indonesia (Irawan et al, 2022).…”

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“…Therefore, mobile forms of nutrients are used to assess the fertility of agricultural land on which the crop is forming during one growing season, while the total forms of nutrients are often used (Gao et. al., 2022;Zhao et. al., 2023) to assess the productivity of forest soils.…”