The Effect of Sulfur and Manure on Quantitative and Qualitative Characteristics of Sesame Varieties (Sesamum indicum L)

Oil seeds had an important role in supplying food, heat and pharmaceutical needs. Today oil seeds are considered as the strategic agricultural products in the world.  Providing of essential elements for crops, especially micro-nutrients play an important role in increasing the quality of produced food and improving community health. Sulfur is one of the essential elements required for plants, which has been underestimated in recent years. In oil seeds, sulfur plays an important role in seeds quality and growth. These plants usually need more sulfur for suitable growth and higher yield. Synthesis of some essential proteins and vitamins in crops has been faced difficulty due to sulfur deficiency. The addition of organic matter with sulfur in soils with high acidity is an appropriate option for reducing acidity and dissolving the required elements of crops.

The limiting factors in crop production are high soil pH and its effect on availability of nutrients and also organic matter shortages. This research was conducted at Kerman Agricultural and Natural Resources Research and Education Center to determine the effect of sulfur and cattle manure on quantitative and qualitative characteristics of sesame varieties (Sesamum indicum L.) in a factorial experiment with completely randomized block design with 3 replications in 2016. The treatments consisted of powdered sulfur at four levels (0, 2, 4 and 8 t.ha-1), Cow manure at two levels (0 and 20 t.ha-1) and included two Jiroft-13 and Jiroft local varieties. After soil preparation the cultivars were planted on the rows with 50 cm distance. Grain yield, Harvest index, Oil and Protein Content, phosphorus and leaf sulfur content of sesame varieties were measured at the end of the growing season.

The results indicated that the highest level of sulfur (8 t.ha-1) except for harvest index caused a significant increase in the investigated traits compared to the control treatment. The interactions of Cattle manure and sulfur were significant on some traits and the highest grain yield belonged to the Jiroft-13 cultivar in the highest level of sulfur and Cattle manure. The Jiroft-13 cultivar had the highest grain oil and protein content and harvest index as compared to Jiroft local variety. Effects of sulfur and Cattle manure treatments on grain oil and protein were significant and the highest amount was observed in combined application of sulfur and manure. Application of sulfur increased the concentration of this element in sesame leaves and also due to local reduction of soil acidity, it had a significant effect on increasing phosphorus uptake. The results indicate that the integrated use of sulfur and cattle manure as an ecological solution in order to increase growth and quantitative and qualitative production of oil crops, especially in alkaline soils could be considered.

In general, the results of this study indicate that sulfur application had a significant effect on the quantitative and qualitative characteristics of sesame varieties and soil improvement. Application of cattle manure improved physical and chemical properties of soil, resulted yield increase and provided the sulfur oxidation conditions. In alkaline soils, animal fertilizers can be used to release phosphorus and fixed micronutrients. Considering the positive effect of sulfur on soil pH reduction and increasing accessibility to phosphorus and micronutrients, consumption of this substance with animal fertilizers, will make each one more effective. Large amounts of sulfur are produced in the country's oil and gas industries which can play an important role in increasing the quality of oilseed crops. According to the experimental conditions and the obtained results in the absence of cow manure, using 8 t.ha-1 of sulfur is recommended. However, under application of 20 t.ha-1 of cow manure, while using lower levels of sulfur, favorable results can be obtained.  Jiroft-13 had a higher yield than local variety and is recommended for Kerman climatic conditions.