Response of Sunflower to Sources and Levels of Sulfur under Rainfed Semi-arid Tropical Conditions

• Published in: Communications in soil science and plant analysis 2009-01, Vol.40 (17-18), p.2926-2944
• Main Authors: Usha Rani, K, Sharma, K.L, Nagasri, K, Srinivas, K, Vishnu Murthy, T, Maruthi Shankar, G.R, Korwar, G.R, Sridevi Sankar, K, Madhavi, M, Kusuma Grace, J
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Alfisol; Alfisols; application rate; Biological and medical sciences; chemical constituents of plants; dry matter accumulation; fertilizer application; Fundamental and applied biological sciences. Psychology; Helianthus annuus; lipid content; nitrogen; oilseeds; phosphorus; plant growth; plant response; S application; S sources; seed oil content N/S and P/S ratio; seed productivity; Soil science; sulfur; sulfur fertilizers; sunflower; tropical soils; tropics; yields
• ISSN: 0010-3624; 1532-2416
• DOI: 10.1080/00103620903175389

Sulfur (S) is one of the severely limited nutrients in rainfed semi-arid tropical Alfisols. Its application plays an important role in improving the yield and quality of oilseed crops. To identify the optimum level of sulfur for greater yield and oil content in the sunflower crop (MSFH-8) through suitable sources, a field experiment involving varying levels of S through two sources (gypsum and elemental S) in combination with standard levels of nitrogen (N) and phosphorus (P) was conducted on a sandy loam soil (Typic Haplustalf) at Hayathnagar Research Farm of Central Research Institute for Dryland Agriculture, Hyderabad, situated at an altitude of 515 m above mean sea level and on 78° 36' E longitude and 17° 18' N latitude. The response to S application in sunflower crop in terms of growth parameters, yield components, nutrient uptake, and seed oil content was conspicuous. The application of graded levels of sulfur at rates of 20, 40, and 60 kg ha-1 applied through elemental S significantly increased the seed yield of the sunflower crop over the control by 5.4, 10.7, and 18.1% respectively, whereas the corresponding increases in case of gypsum (CaSO4·2H2O) were 25.1, 28.8, and 33.9% respectively. The greatest seed yield of sunflower (1175 kg ha-1) and percentage oil content (39.7%) was obtained with 60 kg S ha-1 through gypsum under rainfed conditions. Our study clearly indicated that the application of S at relatively high levels significantly increased the uptake of N, P, and S. The percentage oil content in seed recorded a positive and highly significant relationship with the uptake of N (r = 0.958**), P (r = 0.967**), and S (r = 0.951**), signifying the importance of balanced nutrition in influencing the oil content of seed in sunflower. The application of S through gypsum at rate of 60 kg S ha-1 along with 40 kg N and 30 kg P2O5 ha-1 was most superior in enhancing the seed yield and percentage oil content in seed.