The Effects of Biological Fertilizers, Chemical Fertilizers and Manure Application on Some Qualitative Characteristics of Vicia villosa Roth Forage under Greenhouse Condition

Introduction Fertilizer management plays an important role in successful crop production. The biological fertilizers have been suggested not only to elimination or significant reduction of chemical fertilizer dependency but also increase of soil fertility and improvement of crop yield and quality. Materials and Methods This experiment was conducted in a completely randomized design with three replications at the Research Greenhouse of Ferdowsi University of Mashhad. The experimental treatments included 1- mycorrhizae arbuscular (Glomus mosseae), 2- mycorrhizae arbuscular (Glomus mosseae) + vermicompost (M+V), 3- mycorrhizae + nitroxein (included bacteria Azospirillum sp. and Azotobacter sp.) (M+N), 4- mycorrhizae arbuscular + Rhizobium (R. legominuzarum) (M+R), 5-mycorrhizae arbuscular + NPK Chemical fertilizer (40-40-20) (M+NPK) and 6- Control (without fertilizer, C). In bio-fertilizer treatments, seeds were inoculated by mycorrhizae and Rhizobium immediately before planting, according the standard conditions and company recommendations. Chemical fertilizer and vermicompost were applied directly into the soil. The first irrigation was done immediately after planting and an additional irrigation was also done 4 days after planting to improve the seedling emergence. Subsequent irrigations were conducted at 10-days interval. Forage samples were collected at stage of 10% open bud. The samples were oven-dried in 70°C for 48 h and then weighed before being ground to pass through a 1-mm sieve. Both chemical analysis and in vitro digestibility assessments were performed in triplicate. Crud protein (CP), Ash, neutral detergent fiber (NDF) and acid detergent fiber (ADF) content of forages were measured by standard methods. An in vitro gas production method was conducted to determine the dry matter (DM) and organic matter (OM) digestibility. All data were subjected to ANOVA using the GLM procedure of SAS (SAS 9.1) and means were compared by using LSD-test at 5% probability level. Results and Discussion The results showed that in vitro DM digestibility was significantly (P < 0.5) affected by experimental treatments. The highest in vitro digestibility of dry matter (73.44%) was observed in the combination of Nitroxin bio-fertilizer and mycorrhiza whereas forages in mycorrhiza + NPK treatment had lowest (67.39%) in vitro DM digestibility. However, experimental treatments had a trend to significant (1.0 > P > 0.5) effect on in vitro organic matter digestibility. The highest and the lowest in vitro OM digestibility values were observed in the Rhizobium + mycorrhiza (77.86%) and control (66.48%), respectively. Similarly, the results of previous studies indicated that forage quality significantly improved by inoculation with mycorrhizal fungi fertilizer in comparison with control. There was a significant difference between experimental treatments for percentage of crude protein. All fertilizer treatments increased CP content of forages as compared to that control. The effect of M, M + V and M+NPK treatments on CP was similar and the highest CP was associated to M + These effects of fertilizer treatments may be related to increasing the nitrogen fixation and absorption capacity of plant. Although a negative correlation has been reported between CP and fiber content of forages, the results of our study showed a low non-significant impact of fertilizer treatments on fiber content of forage expressed as NDA and ADF. Moreover, the percentage of Ash for all fertilizer treatments was similar to control, except for Rhizobium + mycorrhiza treatment that showed a higher significant Ash content than control. In this experiment, a significant effect of fertilizer treatments was also observed for dry matter yield of forage. In comparison with control, the combination of mycorrhizal and Rhizobium increased forage dry matter yield by 37.89%. These results are in agreement with. Conclusions The use of biological and organic fertilizers improves availability of nutrients for plant without negative impact on soil and environment. In the present study, we showed an increase in qualitative and quantitative characteristics of Vicia villosa Roth forage by bio-fertilizers application under greenhouse condition. However, a combination of mycorrhiza and Rhizobium had the highest positive impact on forage yield and quality of Vicia villosa Roth. Further studies may be need to evaluation of the effects of these bio-fertilizers and/or their combinations with other organic and chemical fertilizer on specific crops and conditions