Bacterivorous Nematodes Correlate with Soil Fertility and Improved Crop Production in an Organic Minimum Tillage System

Jan H. Schmidt,Maria R. Finckh,Johannes Hallmann

doi:10.3390/su12176730

Jan H. Schmidt, Maria R. Finckh + Show 1 more

Open Access

https://doi.org/10.3390/su12176730

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Journal: Sustainability	Publication Date: Aug 19, 2020
Citations: 13	License type: CC BY 4.0

Affiliation: University of Kassel, Julius Kühn-Institut

Abstract

Reduced nutrient mineralization rates under minimum tillage are usually compensated by mineral fertilizer application. These, however, cannot be applied in organic farming systems. We hypothesized that an organic minimum tillage system based on frequent cover cropping and application of dead mulch would improve soil fertility and compensate for the potential negative effects of minimum tillage. Two long-term field experiments were set up in 2010 and 2011 to compare plowing versus minimum tillage including the application of transferred mulch. A second factor, the application of compost versus mineral potassium and phosphorus, was also compared. In 2019, soils were analyzed for soil pH, organic carbon, macro- and micronutrients, microbial biomass, microbial activity, and total nematode abundance. In addition, performance of pea in the same soils was determined under greenhouse conditions. Across both experiments, macronutrients (+52%), micronutrients (+11%), microbial biomass (+51%), microbial activity (+86%), and bacterivorous nematodes (+112%) increased in minimum tillage compared to the plow-based system. In the greenhouse, pea biomass was 45% higher in the soil that had been subjected to minimum tillage compared to the plow. In conclusion, soil fertility can be improved in organic minimum tillage systems, which include intensive cover cropping and the application of dead mulch, over plow-based systems.

Highlights

Organic farming systems are generally based on intensive soil tillage for seed bed preparation and weed control, which, in the long run, often lead to reduced soil fertility [1]
We hypothesized that an organic minimum tillage system based on frequent cover cropping and application of dead mulch would improve soil fertility and compensate for the potential negative effects of minimum tillage
In 2019, soils were analyzed for soil pH, organic carbon, macro- and micronutrients, microbial biomass, microbial activity, and total nematode abundance

Summary

Introduction

Organic farming systems are generally based on intensive soil tillage for seed bed preparation and weed control, which, in the long run, often lead to reduced soil fertility [1]. Minimum tillage generally tends to delay soil warming in spring; N mineralization rates are often too low to meet crop demands, especially in temperate climates [6]. For this reason, the application of conservation agriculture methods—i.e., the simultaneous application of minimum tillage, crop rotations, and residue retention—to organic farming systems may not necessarily improve soil fertility, even after 10 years of adaptation to the system [7]. Organic minimum tillage systems need to be modified in order to provide sufficient levels of nutrients and weed control at the same time [8]

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Discussion

Conclusion