Skip to main content
Open Access Publications from the University of California

Department of Plant Sciences

UC Davis

Contribution of soil organic sulphur fractions to Marandu palisadegrass sulphur nutrition


Sulphur (S) deficiency in plants is widespread throughout the world. In soil S can be found in organic and inorganic forms. The contribution of the S organic fractions in meeting plant requirements in S is not well known. This study aimed to evaluate the variation of the mineral and organic S fractions in an Entisol where Marandu palisadegrass (Brachiaria brizantha) was fertilized with N and S. A fractionated 52 factorial experiment was carried out in a greenhouse, in a randomized block design, with four replications. Combinations of five N rates with five S rates, supplied as NH4NO3 and CaSO4.2H2O, were studied. Plants were harvested three times and the soil was sampled at each harvest. The total S content in the plant material was determined. Four soil S fractions were determined: inorganic SO4 S, ester bonded S, carbon-bonded S, and residual S. The 400-40 mg dm-3 N-S combination resulted in more S removed from the soil by the grass than the treatments with N or S supply alone. Inorganic SO4 S in the soil was increased by S application. The carbon-bonded S did not change in the soil, in any sampling time, with any N-S combination. The ester bonded S was increased, and apparently did not follow any N and S fertilizations. Except for the combination 400N-0S, the residual S fraction decreased as the time progressed. The variations of the S organic fractions in soil indicate that part of the S requirement of Marandu palisadegrass may be supplied by the residual S fraction.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View