ISHS Acta Horticulturae 573: International Symposium on Techniques to Control Salination for Horticultural Productivity
INFLUENCE OF SALINITY ON MICROBIAL RESPIRATION AND ENZYME ACTIVITY OF SOILS |
| Authors: | N. Okur, M. Çengel, S. Göçmez |
| Keywords: | Saline water, potassium fertilizer, microbial respiration, β- glucosidase activity, phosphatase activity |
| Abstract:
Detrimental effects of salts on microbial activity may be due to the toxicity of specific ions, elevation of osmotic pressure or the increase in alkalinity which may restrict the availability of water or influence cellular physiology and metabolic pathways. In this study, the effects of irrigation with saline water (S0=0.65, S1=2.0, S2=3.5, S3=5.0 and S4=6.5 dS m-1) and fertilization with potassium (K0, K1=100 and K2=200 g tree-1) on the microbiological characteristics of an alluvial soil were studied. The experiment was established in 1994 to determine the effects of salinity on yield and quality of Satsuma mandarin budded on Poncirus trifoliata and to test the interaction of fertilizer K with salinity. Soil samples were taken on September 1999 and analyzed for their soil respiration and the activities of phosphatase and  -Glucosidase.The increase in soil salinity had a negative effect on soil's microbiological activity. Soil microbial respiration and the two enzyme activities were inhibited even at low salinity levels, but the addition of potassium decreased the toxic effects. In the Ko parcel, the reductions in soil respiration, phosphatase and -Glucosidase were 70 %, 61.5 % and 61 %, respectively, when the salinity of the irrigation water was increased from 0.65 to 6.5 dS m-1. The reductions for the same indices were lesser at K1 (58%, 52% and 53%) and K2 parcels (54%, 47% and 51%), respectively.
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