Mitigating Potassium Leaching from Muriate of Potash in a Tropical Peat Soil Using Clinoptilolite Zeolite, Forest Litter Compost, and Chicken Litter Biochar

Kavinraj Krishnan,Latifah Omar,Audrey Awing Ngerong,Maru Ali,Adiza Alhassan Musah,Karen Ahim,Osumanu Haruna Ahmed

doi:10.3390/agronomy11101900

Abstract

Using muriate of potash (MOP) as a source of potassium (K) is a cost-effective method for crop production in tropical peat soils. However, exchangeable K commonly leaches from tropical peat soils because of high rainfall and a lack of clay to retain this cation. Potassium retention as exchangeable K could inhibit K loss through leaching to increase K availability. Clinoptilolite zeolite (CZ), forest litter compost (FLC), and chicken litter biochar (CLB) can be used to retain K from MOP in tropical peat soils for crop use because of the high affinity of CZ, FLC, and CLB for K ions. These approaches can be used as innovative and sustainable alternatives for the frequently used lime (CaCO3). However, information on using CZ, FLC, and CLB for MOP K retention is limited. Thus, CZ, FLC, and CLB were tested in a leaching study to determine their effects on MOP K retention in tropical peat soil. The use of CZ and FLC at rates of 100% and 75% of the recommended rate for pineapple cultivation (a commonly grown fruit crop in tropical peat soils in Malaysia) improved the K availability, pH, and CEC of the peat soil because of the high CEC of CZ and the humic substances (humic acids, fulvic acids, and humin) of FLC, which have a high affinity for K ions. The CLB did not improve K retention because of the competition between K, Ca, Mg, and Na ions, which are inherently high in this soil amendment. Instead of liming, which only replaces a few of the leached cations, such as calcium, the results of this study suggest an alternative method of retaining peat cations, such as K, that reduce peat acidity. This alternative method of retaining peat soil cations, especially K ions, is a practical and sustainable approach for improving peat soil productivity.

Highlights

Tropical peat soils are high in organic matter and provide nutrients for crops through their decomposition to produce, for example, ammonium nitrate, phosphate, and sulfur
This study provided information on K availability from the combined use of different amounts of muriate of potash (MOP), Clinoptilolite zeolite (CZ), forest litter compost (FLC), and chicken litter biochar (CLB), which was reflected by the amount of K in the leachate, the total soil K, and the exchangeable soil
Over the years, liming has been a temporal solution in increas- SC2 had yield

Summary

Introduction

Peat soils in Sarawak, Malaysia have low pH levels (3.5–4.0) [2]. As such, they are not able to retain significant amounts of macro-and micronutrients. The leaching of most of these plant nutrients in peat soils is due to low levels or the absence of clay, which holds cations in deep peat soil. Clay has a large specific surface area with predominantly negatively charged exchange sites that adsorb and retain nutrients against leaching. These negative charges react with H+ and Al3+ ions to create a buffering condition against extreme pH changes. A lack of clay in tropical peat soils causes porosity

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Methods

Conclusion