Mineral soil conditioner requirement and ability to adjust soil acidity

Xiangdong Yang,Yashuang Feng,Dan Qiao,Xiaohong Zhang,Xiaoyan Li,Mingxue Sun,Juan Li

doi:10.1038/s41598-020-75192-5

Abstract

Mineral soil conditioners (MSCs) are used to regulate soil acidity and improve soil quality; they are often made in sintering potassium feldspar, limestone, or dolomite, and are alkaline materials rich in silicon, calcium, potassium, and magnesium. The key point of how to apply them into farmlands is their ability to adjust soil acidity and the MSCs requirement (MSCR). In this study, inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis and X-ray diffraction (XRD) were firstly used to determine the elemental and phase compositions of the MSCs in order to establish its equivalent relationship for the depletion of soil activity (H+) and its conversion relationship with CaCO3. Secondly, the soil culture method and the improved Shoemaker Mclean Peatt–Double Buffer (SMP–DB) method were compared using a group of 14 typical acid soils in MSCR. It is investigated that the MSCs contained four alkali/alkaline earth–metal elements: Ca, Mg, K, and Na in the bound aluminosilicate form (Ca2MgAlSi2O7, Ca3(SiO3)3, KAlSiO4, and KAlSi2O6); and the depletion of 2.31 mol of H+ required 100 g of MSCs and the amount of Si–Ca–K–Mg MSC needed to deplete the same quantity of H+ was only 0.87 times that of CaCO3. Based on the calculations by using the SMP-DB method and the soil culture method, the MSCR for treating the 14 typical acid soils were in the range of 0.56–8.27 t hm−2 and 0–10.8 t hm−2, respectively. Data from both methods were highly correlated with each other and there was a good linear correlation between them, and the equation: {{MSC}_{R}}^{{prime}}=30.29d-0.77 could be used to calculate the MSCs requirement. The recommended MSCR was approximately 4–8, 2–6, and 1–3 t hm−2 when soil pH < 4.50, 4.50 < pH < 5.50, and pH > 5.50, respectively. The experimental and computational methods established in this study could serve as the scientific basis and theoretical guidance for the production and agricultural use of MSCs.

Highlights

The mineral nutrient bioavailability, ability to adjust soil acidity, and the application amount in fields should be investigated firstly if we want to evaluate the performance of a new type of soil conditioner such as MSCs
L i15 set up 6 M SCR treatments with 0, 0.6, 0.9, 1.2, 1.5 and 1.8 t hm−2 respectively in the water spinach experiments in Fujian Province of China, and they concluded that 1.5 t hm−2 was the optimal application amount considering the crop’s yield and economics of production at the same time. Ji14 found that the application of 1.5–1.85 t hm−2 of Si–Ca–K–Mg MSCs elicited positive results among 5 MSC treatments at 0, 0.75, 1.125, 1.5 and 1.875 t hm−2 application amounts in paddy soil in Jiangxi Province of China
The MSCs used in this study mainly contain four alkaline earth elements: Ca, Mg, K, and Na, and these elements exist in bound aluminosilicate forms, namely Ca2MgAlSi2O7, Ca3(SiO3)3, KAlSiO4, and KAlSi2O6 by using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and X-ray diffraction (XRD) analyses. 100 g MSCs was needed to deplete 2.31 mol of H+ due to that the SMP-DB buffer solution deplete 0.139 meq of H+ per unit increase in pH

Summary

Introduction

The mineral nutrient bioavailability, ability to adjust soil acidity, and the application amount in fields should be investigated firstly if we want to evaluate the performance of a new type of soil conditioner such as MSCs. existing studies mainly focus on their effects on crop y ield[14,15] and its role in reducing Cd pollution[16]. The purpose of this work was to evaluate the MSCs’ ability to adjust soil acidity, and to establish the experimental method for assessing the appropriate application amount of MSCs into soils.

Objectives

Methods

Results

Discussion

Conclusion