Effect of manure, zeolite and irrigation on soil properties and seed yield of sunflower (Helianthus annuus L.)

In order to investigate the effect of different levels of zeolite and farmyard manure, as environmental friendly fertilizers on soil properties and yield and quality of sunflower, a field experiment was carried out in a split -factorial layout based on completely randomized blocks design in three replications in the faculty of agriculture, Tarbiat Modarres University, Tehran, Iran, during 2014 and 2015. Treatments included irrigation regimes (irrigation after depleting 40, 60 and 80% of soil water content) as main factor and the combinations of nutrition systems (100% organic, 50% organic + 50% chemical and 100% chemical fertilizer) and zeolite (0, 5 and 10 ton.ha-1 of zeolite) in factorial layout. Results showed that using organic sources increased organic carbon, nitrogen, phosphorus, potassium, and electrical conductivity of soil, while decreased bulk density at the end of the growth season. Due to the high amount of organic carbon, organic sources accompanied with zeolite improved the organic carbon content of the soil and led to the highest seed yield (1781 kg.ha-1) and water productivity (3.01 and 3.3 kg.ha-1.mm-1 in the first and second years, respectively). In first year, the highest oil content of seed (37.9%) was obtained in 10 ton.ha-1 zeolite with 50% farmyard manure + 50% chemical fertilizer under full irrigation treatment. At all irrigation regimes, application of 100% organic sources or combined chemical and organic sources with 5 or 10 ton.ha-1 of zeolite led to greater seed yield and water productivity. Overall, the results of this experiment revealed that under the most irrigation regimes, application of farmyard manure and zeolite may increase the availability of water and nutrients for plant and may led to increase yield and oil content of seed and water productivity in sunflower.