Effects of Straw Incorporation on Soil Nutrients, Enzymes, and Aggregate Stability in Tobacco Fields of China

Yi Wang,Guodong Bo,Jiguang Zhang,Zhongfeng Zhang,Guoming Shen,Fanyu Kong

doi:10.3390/su8080710

Abstract

To determine the effects of straw incorporation on soil nutrients, enzyme activity, and aggregates in tobacco fields, we conducted experiments with different amounts of wheat and maize straw in Zhucheng area of southeast Shandong province for three years (2010–2012). In the final year of experiment (2012), straw incorporation increased soil organic carbon (SOC) and related parameters, and improved soil enzyme activity proportionally with the amount of straw added, except for catalase when maize straw was used. And maize straw incorporation was more effective than wheat straw in the tobacco field. The percentage of aggregates >2 mm increased with straw incorporation when measured by either dry or wet sieving. The mean weight diameter (MWD) and geometric mean diameter (GMD) in straw incorporation treatments were higher than those in the no-straw control (CK). Maize straw increased soil aggregate stability more than wheat straw with the same incorporation amount. Alkaline phosphatase was significantly and negatively correlated with soil pH. Sucrase and urease were both significantly and positively correlated with soil alkali-hydrolysable N. Catalase was significantly but negatively correlated with soil extractable K (EK). The MWD and GMD by dry sieving had significantly positive correlations with SOC, total N, total K, and EK, but only significantly correlated with EK by wet sieving. Therefore, soil nutrients, metabolic enzyme activity, and aggregate stability might be increased by increasing the SOC content through the maize or wheat straw incorporation. Moreover, incorporation of maize straw at 7500 kg·hm−2 was the best choice to enhance soil fertility in the tobacco area of Eastern China.

Highlights

In China, farmers traditionally incorporated straw into soil to improve soil fertility, but in recent years, most straws have been burned to save labor, which was a waste of nutrient resources, affected road safety due to reduced visibility, and caused air pollution [1]
Soils with maize or wheat straw incorporated at 7500 kghm2 (M3, W3) had the highest values of most soil nutrients
The accumulation of soil organic carbon (SOC) and its related soil nutrients were higher when the tobacco planting soil was incorporated with maize straw than with the same amount of wheat straw

Summary

Introduction

In China, farmers traditionally incorporated straw into soil to improve soil fertility, but in recent years, most straws have been burned to save labor, which was a waste of nutrient resources, affected road safety due to reduced visibility, and caused air pollution [1]. Soil enzymes can catalyze innumerable reactions necessary for life processes of soil microorganisms, decomposition of organic residues, cycling of nutrients, and formation of organic matter and soil structure [9]. They are synthesized, accumulated, inactivated, or decomposed in soil; and play important roles in soil nutrient cycling and seem to be an important indicator of soil quality [10,11]. Straw incorporation has significant roles in improving the activity levels of soil enzymes and soil microbial biomass [13,14]. Straw incorporation could be an important way to improve soil fertility from the point view of soil enzyme

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Results

Discussion

Conclusion