Soil water content during and after plant growth influence nutrient availability and microbial biomass

Abstract

Two experiments were conducted to study the effect of soil water content on soil respiration, microbial biomass and nutrient availability in planted and unplanted soil. In the first experiment, wheat was grown in pots for four weeks in soil that was kept dry between one and four weeks. In the second experiment, soil was maintained at 50% of water-holding capacity (WHC) for four weeks and either planted with wheat or left unplanted. After removal from the pots, soil was kept at 50% WHC or quickly dried to 40, 30, 20 or 10% of WHC. The soils were incubated four weeks during which soil respiration, microbial biomass and nutrient availability were measured. In the first experiment, shoot and root biomass and microbial biomass carbon were higher in constantly moist than constantly dry soil, but the reverse was true for available N. In the second experiment, cumulative respiration was two-fold higher in planted than unplanted soil and decreased with water content, with a smaller decrease in planted soil. Microbial biomass carbon on days 5 and 10 was higher at 10% than at 50% WHC in planted soil, but not affected by water content in unplanted soil. We conclude that soil microbes can maintain higher respiration at low water content despite low biomass because activity per unit biomass is high.

Climate Change-Induced Agricultural Drought over Moist-Cool and Moist-Warm Climatic Zones: A Case Study in Ale and Adami-Tulu Woredas, in Oromia National Regional State, Ethiopia

“…The stresses resulting from drought during the above critical times can influence the normal physiological process of the plant and cause damage, as the result of abnormal metabolism and may reduce growth, plant death or plant development (Fathi and Tari, 2016). The shoot and root biomass of the crop plants are higher in moist soil than in dry soil (Xue et al, 2017…”

Slope aspect influences plant biomass, soil properties and microbial composition in alpine meadow on the Qinghai-Tibetan plateau

“…Increasing plant species richness can diversify soil microbial community via effects on soil nutrient pool and nutrient cycling rate, especially the distribution and cycling of C and N (Chung et al, 2007). Plant and root residues also provide substrates for microbial community (Xue et al, 2016;Xue et al, 2017). Therefore, plant community is one of the most important factors when investigating the size and composition of microbial community in soil at sites with different slope aspects.…”

Efficacy of Woodchip Biochar and Brown Coal Waste as Stable Sorbents for Abatement of Bioavailable Cadmium, Lead and Zinc in Soil

“…Throughout the experiment, soil water content was adjusted to 50% of the WHC estimated for each of the treatments. Such water content was chosen because it has been shown to be suitable for plant growth in light soils (Xue et al 2017). The pots were set up on tables in a well-ventilated laboratory at room temperature for 9 weeks of incubation to ensure maximum sorption and equilibrium.…”