CARBON DYNAMICS IN SALT - AFFECTED CALCAREOUS SOILS IN SOUTH EAST TURKEY

Abstract

Secondary salinity is a significant problem in irrigated agricultural lands. Investigation of the amount of the CO2-C (g kg(-1) day(-1)) quantity released to atmosphere through the application of different carbon resources into soil that is under the effect of secondary salinity is highly important in terms of global warming. This study has been conducted in a laboratory environment to measure the amount of CO2-C (g kg(-1) day(-1)) released to atmosphere for a period of 15 weeks by soil under the effect of different electrical conductivity (EC) (EC:0-2-4-6 dS m(-1)) and applied with corn biochar (CBC) and corn stalk wastes (CSW). Both on a daily basis and cumulatively, when compared with the control group (C-0) at the end of the study, the amount of CO2-C released by soil applied with corn biochar and salt concentration (CBC+EC) has been observed to be lesser than that released by soils applied with corn stalk wastes and salt concentration (CSW+EC). When the amount of CO2-C released to atmosphere is compared with C-0 with the increase in EC values, a reduction has been observed in the emission level of soils applied with both CBC and CSW. This reduction has been observed at a higher level in soils applied with CBC+EC. As a result of the application of CBC+EC, dosages, weeks and CBC+ECx week interaction are observed to have a significant effect on CO2-C emission, on the basis of repeated measures analysis of variance result (p<0.05). Following the CSW+ECx application, weeks are observed to have a significant effect on CO2-C emission (p<0.05), while CSW+ECx week interaction is observed to have no significant effect (p>0.05). According to CBC+EC salt application dosages and in terms of the effect on CO2-C emission, and based on Tukey HSD multiple-comparison test, CBC+EC0 dose (2.05 +/- 0.19a) has been observed to be highest, while CBC+EC6 (1.58 +/- 0.13b) dosage has been observed to be the lowest (p<0.05). CSW+EC4 (4.18 +/- 0.41a) the highest dosage, while CSW+EC0 (3.63 +/- 0.43b) the lowest result dosage yielded (p<0.05). Looking at Tukey HSD multiple-comparison tests; CO2-C release from the CBC+EC applied soil was highest on 3rd week (3.12 +/- 0.16a), while the lowest figure was on the 15th week (0.21 +/- 0.02g) (p<0.05). Then in soils applied with CSW+EC, the highest figure has been observed on the 3rd week (7.07 +/- 0.11A), while the lowest has been observed on the 15th week (0.46 +/- 0.07D) (p<0.05).