Sulfur in Nonirrigated and Irrigated Chestnut Soils and Evaluation of Increasing Doses of Sulfur Fertilizers (with NPK) for Potatoes

Abstract

It was found that low humus content and low biological activity of virgin chestnut soils of Western Transbaikalia cause a low gross amount of sulfur. The distribution of sulfur along the profile gradually decreases with some accumulation in the carbonate horizon. Prolonged irrigation caused by an increase in humus content and biological activity contributed to an increase in the amount of sulfur, which practically increases with the depth of the profile. The stock of mobile sulfates irrigated in a layer of 0–20 cm was three times higher than in virgin soil (7.3 and 2.4 kg/ha, respectively); it also was 1.3 times higher in the 0–50 cm layer and 2.9 times higher in the 0–100 cm layer. According to the content and reserves of mobile sulfur, chestnut soils in a layer of 0–20 cm are classified as low-income. After 3 years of using increasing doses of sulfur fertilizers (against the background of NPK) for irrigated potatoes, the content of all forms of sulfur in the soil increased depending on the dose size. The following pattern was revealed: the amount of S_org in the soil and the enrichment of humus with it increased with an increase in the dose and the ratio C : S_org decreased. A negative sulfur balance was found in the control and in the background versions. The introduction of the lowest dose of S15 has already formed a positive balance, but it is necessary to apply a dose of S30 (against the background of NPK) in compliance with irrigation standards because chestnut soils are depleted of mobile sulfur.