A simple evaluation of soil quality of waterlogged purple paddy soils with different productivities.

Zhanjun Liu,Ping He,Guoqing Liang,Jialong Lv,Wei Zhou,Hui Jin,Jingdong Mao

doi:10.1371/journal.pone.0127690

Abstract

Evaluation of soil quality can be crucial for designing efficient farming systems and ensuring sustainable agriculture. The present study aimed at evaluating the quality of waterlogged purple paddy soils with different productivities in Sichuan Basin. The approach involved comprehensive analyses of soil physical and chemical properties, as well as enzyme activities and microbial community structure measured by phospholipid fatty acid analysis (PLFA). A total of 36 soil samples were collected from four typical locations, with 12 samples representing high productivity purple paddy soil (HPPS), medium productivity purple paddy soil (MPPS) and low productivity purple paddy soil (LPPS), respectively. Most measured soil properties showed significant differences (P ≤ 0.05) among HPPS, MPPS and LPPS. Pearson correlation analysis and principal component analysis were used to identify appropriate soil quality indicators. A minimum data set (MDS) including total nitrogen (TN), available phosphorus (AP), acid phosphatase (ACP), total bacteria (TB) and arbuscular mycorrhizal fungi was established and accounted for 82.1% of the quality variation among soils. A soil quality index (SQI) was developed based on the MDS method, whilst HPPS, MPPS and LPPS received mean SQI scores of 0.725, 0.536 and 0.425, respectively, with a ranking of HPPS > MPPS > LPPS. HPPS showed relatively good soil quality characterized by optimal nutrient availability, enzymatic and microbial activities, but the opposite was true of LPPS. Low levels of TN, AP and soil microbial activities were considered to be the major constraints limiting the productivity in LPPS. All soil samples collected were rich in available N, K, Si and Zn, but deficient in available P, which may be the major constraint for the studied regions. Managers in our study area should employ more appropriate management in the LPPS to improve its rice productivity, and particularly to any potential limiting factor.

Highlights

Waterlogged paddy soil is a common soil type associated with low productivity, and occupies a large area putting constraints on crop production in southwest China
Our results indicate that the rate of basic N fertilizer may be overused and, the basal: topdressing ratio (2:1) needs adjustment to make N fertilizer application more timed to coincide with the period of rapid N uptake by plants
An minimum data set (MDS) including total nitrogen (TN), available phosphorus (AP), acid phosphatase, total bacteria and arbuscular mycorrhizal fungi (AMF) was established for evaluating soil quality of waterlogged paddy soil in acidic purple soil region

Summary

Introduction

Waterlogged paddy soil is a common soil type associated with low productivity, and occupies a large area putting constraints on crop production in southwest China. While numerous studies on soil quality evaluation have concentrated on soil physical and chemical properties [10,11], biological variables can be important and have been increasingly used as indicators of soil quality owing to their rapid response and high sensitivity to changes in soil management [12,13]. Little information is available in the literature that evaluates soil quality aiming at any special soil type in terms of productivity on a regional scale [4,14,15], to the purple paddy soil In this way, a comprehensive assessment of soil quality integrating soil physical, chemical and biological properties would be greatly desired

Objectives

Methods

Results

Conclusion