Compost effects on microbial biomass and soil P pools as affected by particle size and soil properties

Abstract

Previous studies have shown that finer composts release nutrients more quickly than coarse composts, but little is known about the nutrient release from different size fractions of a compost. To assess if compost size fractions differ in their effect on microbial biomass and soil P pools, a compost from garden waste was separated by sieving into different particle size fractions (> 5 mm, 3-5 mm and < 3 mm) and then mixed into three different soils (referred as soil A, B and C) at a rate of 50 mg total P kg -1 . These soils were chosen because the size of soil P pools could be affected by soil properties which may also influence how the P pools respond to compost addition. Cumulative soil respiration, microbial biomass and soil P pools were determined after 25 and 50 days. Compost addition increased soil respiration and micobial biomass C and P, with the greatest increase in respiration with the > 5 mm fraction and in microbial biomass C and P with the < 3 mm fraction. The size of the P pools was mainly affected by soil type, the compost fractions had similar effects on soil P pools except for a greater increase in available P concentration by the finest fraction compared to the coarser size fractions. Soil A with the highest organic matter content had the highest concentrations of Fe/Al associated P (NaOH-P) and organic P whereas Ca-associated P (HCl-P) dominated in the alkaline soil C. The size of most P pools, even the so-called stable P pools changed over time in amended and non-amended soils. It can be concluded that the size of P pools is more strongly affected by soil properties such as organic matter content, texture and pH than by the compost fractions.

Effect of particle size on rotary drum composting of garden waste and their ranking using analytical hierarchy process

“…The rotation of garden waste in the reactor provides adequate aeration accountable for the rise in pH value and increased degradation of GW due to hydrogen ions release during aeration. The result is supported by Verma and Marschner, (2013) where garden waste compost for particle size >5 to <3 mm also showed no differences in pH values.…”

“…Particle size is also an important factor for the e cient degradation of GW. Smaller particle size leads to larger surface areas and makes it easier for bacteria to degrade effectively as the majority of the bacterial invasion occurs on or near the surface (Lata Verma & Marschner, 2013). Particle size distribution of the feedstock material effects degree of compaction and porosity favouring aeration of materials (Liu, Wang, Guo, Zhao, & Zhang, 2017).…”

Effect of organic amendments on maize cultivation under agricultural drought conditions in Central Java, Indonesia

“…The experimental plots were treated with 20 t ha -1 of wet organic amendments based on the practices of local dairy farmers and mixed in the root zone (20-25 cm soil depth) 3 days before seeding. The particle size of CP and RA ranges 3-5 mm (compost garden waste) and 4.75-13.20 mm (burnt rice husk ash), respectively (Verma and Marschner, 2013;Nguyen et al, 2013). In this study, SB was applied without any pre-treatment and the particle size was more than 5 mm.…”

Total and Hot-Water Extractable Organic Carbon and Nitrogen in Organic Soil Amendments: Their Prediction Using Portable Mid-Infrared Spectroscopy with Support Vector Machines

“…As a consequence of different material origin and material treatment during the production process, organic C and N pools of compost and BCS products can vary in their chemical composition and particle size distribution. Both can affect potential carbon turnover in soils [12]. Chemical composition can be characterized by the determination of total organic carbon (TOC) and total nitrogen (TN) and the respective CN ratios.…”