Changes in humus content on the territory of agricultural lands in the Issyk-Kul basin of Kyrgyzstan

Abstract

The Issyk-Kul valley of Kyrgyzstan has very large diversity of soil types which is developed by complex of abiotic and biotic factors including mountain-valley landscapes and different climatic conditions. We found that there is a process of significant loss of humus content in almost all studied areas of the Issyk-Kul region, both in the upper and lower layers of the soil. The humus content has been significantly decreased in the upper layer of valley soils during the past four decades. Among them, mountain-valley chestnut and dark chestnut soils, represented in the Issyk-Kul region, showed themselves to be the most depleted. Here, the difference in humus content between the top arable and non-arable layers is 40%. More stable humus content is shown in the mountain light chestnut and mountain-valley light brown soils, presented in certain areas of the Ton, Ak-Suu and Tyup districts. Apparently significant decrease in the humus content in chestnut soils is associated with intensive long-term anthropogenic use, including non-compliance with agrotechnical standards.