Evaluation of the Effect of Type and Amount of Fertilizer Management on Some Silage Characteristics of Artichoke (Cynara scolymus L.) in Isfahan

  Artichoke (Cynara scolymus L.) is an herbaceous perennial plant belongs to the Asteraceae family (Ziai et al., 2004). Artichoke silage quality was less than alfalfa silage but it is as much as corn silage with lower seed contents and was more than sorghum silage and the palatability of this plant increased after ensiling. Application of Integrated Nutrition Systems (IPNS) based on the use of biofertilizer is one of the most important factors affecting the sustainability of food production and soil fertility. Researches have shown that biological or chemical fertilizers alone cannot be used for sustainable agricultural production, and in most cases, bio-fertilizers as a supplement to chemical fertilizers can ensure the sustainability of production in agricultural systems. Regarding the importance of nutrition management in plants, the present experiment was conducted with the aim of investigating the effect of different fertilizer sources (bio-fertilizers, chemical fertilizers and their integration) on yield and artichoke silage quality in Isfahan climate conditions.
Material and This experiment was conducted as a factorial based on RCBD design with three replications at the Research Station of Isfahan Agricultural and Natural Resources, Iran, during 2014-2015. The first factor consisted of chemical fertilizers at levels of 100% chemical fertilizer (200 and 100 kg ha-1 NP), 50% chemical fertilizer (100 and 50 kg ha-1 NP), and control (no fertilizers). The second factor comprised bio-fertilizer at levels of 1 liter ha-1 Nitroxin (include Azotobacter, Azospirillium, and Pseudomonas), 100 gha-1 Barvar 2 (include Pseudomonas potida and Bacillus lenthus), 1 liter ha-1 Nitroxin +100 gha-1 Barvar 2 and control (without inoculation). Seeds were sown on 26 April 2014. Chemical fertilizer (urea and triple superphosphate) applied based on soil analysis results. The first half of the nitrogen fertilizer was utilized as strip takes under seed before sowing and the rest at 7-8 leaf stage of the crop. The plants were harvested at vegetative rosette stage. The harvested material was chopped and stored for about 75 days in laboratory silos. Wet and dry forage yield and Silage quality indices as crude protein (CP), crude fat (CF), ash, neutral detergent fiber (NDF), water soluble carbohydrates (WSC), organic matter digestibility (OMD), metabolizable energy (ME) and net energy for lactation (NEL) were measured. Analysis of variance was done using SAS ver.9.1 software and comparison of the means was conducted using by Duncan at 5% level. The results showed that soil fertilizer management systems significantly affected forage yield and silage quality of artichoke. Increasing the levels of chemical fertilizer increased wet and dry forage yield. Among the bio-fertilizer levels, combined fertilization with Nitroxin and Barvar 2 and application of Nitroxin alone had the highest forage yield. The effect of integrated fertilizer management on silage quality was higher than the single application of chemical fertilizer or bio-fertilizer. The highest CP percent (19.25 %) and lowest CP (7.68 %) were obtained by 100% chemical fertilizer + Nitroxin+ Barvar 2 and control treatment, respectively. NDF reduced with the application of chemical and biological fertilizer and 100% chemical fertilizer + Nitroxin+ Barvar 2 had the minimum values of them. The highest amount of WSC was related to 50% chemical fertilizer at all levels of bio-fertilizer. Application of bio-fertilizers increased the OMD, ME and NEL compared to control level. Also, these traits increased by the increment of chemical fertilizer application.
  Based on the results of this research, using 50% chemical fertilizer + Nitroxin+ Barvar 2 can be recommended to improve the silage quality of artichoke