Sulphur Fractions in Acid Soil Continuously Fertilized with Chemical Fertilizers and Amendments under Maize-Wheat System

A long-term fertilizer experiment on maize-wheat cropping system was initiated in 1972–1973 on a Typic Hapludalf at Research Farm of Palampur which comprised of ten treatments up to 1980–1981. The eleventh treatment, consisting of 100% NPK(−S) was introduced in kharif 1981. After twenty-six years of continuous cropping (kharif 1981 to rabi 2007–2008), the effect of different chemical fertilizers and amendments with or without sulphur (S) application was studied on different forms of S. Continuous application of chemical fertilizers and amendments improved all the S fractions in soil except where S was not applied. Integrated use of balanced dose of chemical fertilizer with farmyard manure (FYM) or lime sustained higher yields of maize in comparison to inorganic fertilizer alone. Accordingly, S uptake was also higher when FYM or lime was applied in conjunction with 100% NPK. Continuous application of urea (100% N) alone resulted in no yield. Significant positive relationship amongst the different forms of S in soil (0–15 cm) indicated the existence of equilibrium among themselves. All the S fractions exhibited significant positive relationship with yield and S uptake by maize.