Effects of three planting patterns on soil microbial community composition

Abstract

Aims Planting patterns have direct effects on soil microorganisms.Because of different plants and human activities,planting patterns change soil fertility.Our objective is to understand the effects of different planting patterns on soil microbial community structure.Methods We carried out a long-term field experiment at Jilin Agriculture University that used phospholipid fatty acid analysis method to study the effects of three planting patterns of corn:continuous cropping,non-continuous cropping and uncultivated.Important findings Different planting patterns affected soil microbial community structure.Continuous cropping of corn had the lowest total phospholipid fatty acids and bacterial phospholipid fatty acids(33.12 nmol·g-1 and 18.09 nmol·g-1,respectively).Fungal phospholipid fatty acids and fungi/bacteria with non-continuous cropping were 0.61 nmol.g-1 and 3.06%,respectively,and were significantly lower than with uncultivated and continuous cropping(p 0.05).But the ratio of gram positive phospholipid fatty acids/gram negative phospholipid fatty acids was greater with non-continuous cropping.The uncultivated treatment had greater total and bacterial phospholipid fatty acids(42.98 nmol·g-1 and 24.68 nmol·g-1,respectively),higher contents of gram positive phospholipid fatty acids and gram negative phospholipid fatty acids,and a lower ratio of gram positive phospholipid fatty acids/gram negative phospholipid fatty acids.Principal component analysis showed that soil microbial community structure with cropping was significant different(p 0.05) with that of uncultured in first principal component.Non-continuous cropping and continuous cropping were negatively positioned in first principal component with principal component scores of-2.48 and-1.84,respectively.Uncultivated was in a positive position in first principal component with a principal component score of 2.31.Redundancy analysis of soil microbial community structure and environmental variables showed that soil pH and soil-water stable aggragates had the strongest positive correlation with phospholipid fatty acids and that total nitrogen and available phosphorus were also positively correlated with phospholipid fatty acids.