Evaluation of Integrated Nutrition on Quantitative and Qualitative Yield of Asparagus (Asparagus officinalis L.) Cultivars in Dezful

Asparagus is a perennial crop that is well-suited for small-scale and part-time farming operations, and it is considered a healthy food with a high content of bioactive compounds. This study was conducted to investigate the effect of different fertilizer treatments on the yield and agricultural characteristics of various cultivars of Asparagus plants at Safi Abad Dezful Agricultural Research. The experiment was done as a split-plot design based on completely randomized block design with three replications. The main factor consisted of three cultivars of asparagus (Mary Washington, Linda and Mike), while the sub-factor included five fertilizer levels (1-Manure fertilizer, 2-Basic chemical fertilizers + manure fertilizer, 3- Basic chemical fertilizers + manure fertilizer + sulfur, 4- Basic chemical fertilizers + manure fertilizer + calcium and 5- Basic chemical fertilizers + manure fertilizer + calcium + sulfur). The results indicated significant effects of both cultivar and fertilizer treatment on the fresh and dry yield of the edible stem and the daily growth of the stem. Furthermore, the interaction between cultivar and fertilizer had a significant effect on fresh and dry yield of the edible stem, stem daily growth, amount of nitrogen and protein percentage. The study revealed a significant variation between the different asparagus cultivars and fertilizer treatments concerning the measured traits. Specifically, the Mary Washington cultivar exhibited the highest number of stems per plant (14.8), while Mike cultivar had greatest stem diameter (11.2 mm). The usage of manure fertilizer along with chemical fertilizers, sulfur, and calcium in the Mary Washington cultivar resulted in the highest yields of edible and dry stems, measuring 2758 and 665 kg.ha-1, respectively. Moreover, results demonstrated that simultaneous application of manure fertilizer and basic chemical fertilizers led to the highest nitrogen content (7.41%) and protein content (46.25%) in the Linda cultivar. Based on the findings of this research, for achieving the highest yield of edible and dry stems in asparagus plants in the Dezful region, it is recommended to choose the Linda cultivar and apply a combination of manure fertilizer with chemical fertilizers, sulfur, and calcium.