Efficacy of Soil Conditioners in Improving Properties of Lime Concretion Black Soil and Their Consequence for Summer Maize Yield

Abstract

【Background】 Lime concretion black soil is widely distributed in central China including Henan and Anhui provinces. Apart from its low fertility, it is also hard and less porous for roots to penetrate. These combine to hinder crop growth and comprise crop yield. Traditional remediation methods including deep tillage to loosen the soil are effective but are tedious and laborious. As an alternative, soil conditioners have been increasingly used over the past years to improve the properties of the black soil to sustain its productivity. 【Objective】 The objective of this paper is to compare the effectiveness of different soil conditioners in improving soil properties and the consequence for crop growth and yield. 【Method】 We took summer maize as an example and the soil was plowed using conventional tillage after maize harvest but before winter wheat was drilled. There were three treatments: rotary tillage + application of root promoter (RT+RP), rotary tillage + application of soil remediating agent (RT+RA), rotary tillage + soil improvement agent (RT+SI). Traditional deep tillage was taken as the control (CK). In each treatment, we measured the changes in soil properties and fertility, enzyme activity, as we as the resistance of the maize against lodging and the eventual yield. 【Result】 Compared to CK, all treatments increased soil water content and reduced soil bulk density although the change varied with treatments; they also boosted the activity of soil enzymes including urease, sucrase and neutral phosphatase, and improved the contents of available P, ammonium N and nitrate N in the soils, as well as plant height and stem diameter. All improvements and increases were at significant level (p<0.05). These together improved the cross breaking strength of the third shoot node, thereby enhancing the resistance of the maize against bending loading. Compared with CK, RT+RP, RT+RA and RT+SI increased crop yield by 15.73%, 9.02% and 8.82%, respectively, and the economic benefit by 12.05%, 5.40% and 3.37%, respectively. 【Conclusion】 Amending the lime concretion black soil with soil conditioners is more effective than deep ploughs in improving soil properties and crop yield. Of the three treatments we studied, rotary tillage combined with root-promoting agent was most effective in improving soil water contents, enzymatic activity and summer maize yield.

Keywords

• lime concretion black soil
• soil nutrients
• soil enzyme activity
• lodging resistance
• yield