Response of forage quality in Persian clover upon co-inoculation with native Rhizobium leguminosarum symbiovar (sv.) trifoli RTB3 and plant-growth promoting Pseudomonas florescence 11168 under different levels of chemical fertilizers

摘要

The excessive use of chemical fertilizers has generated several environmental problems. In order to evaluate the effects of co-inoculation of Pseudomonas, native Rhizobium with nitrogen and phosphorus levels on forage quality in Persian clover (Trifolium rosapinatum L. cv.Br73), this study was carried out in experimental fields of Lorestan Agricultural Research Center (Borujerd station) Lorestan province, Iran in 2011. A factorial experiment in the form of complete randomized block design with three replications was studied. Experimental treatments include: four levels of chemical fertilizers: F0 = N0 +P0, F1 = N25 + P50 (25 Kg/ha Urea, 46% N2) + 50 Kg/ha Super phosphate triple, 46% P2O5), F2 = N50 + P100 and F3 = N75 + P150 for sites 1 and 2. The biological fertilizers include: control (no bacterium), Pseudomonas florescence, native Rhizobium and co-inoculation (Pseudomonas + native Rhizobium). In these studies, some characteristics such as: crude protein (CP); dry matter digestible (DMD), water soluble carbohydrates (WSC), crude fiber (CF), acid detergent fiber (ADF), ash and neutral detergent fiber (NDF) were assessed. Results show that biological fertilizers were significantly (p<0.05) affected with regards to CP, WSC and ADF but chemical fertilizers were significantly (p<0.01) affected with regards to CP, DMD, ASH, CF, ADF and NDF. Interaction between chemical and biological fertilizers showed that CP (α=0.05) and WSC (α=0.01) were significant. Crude protein percentage tended (r=-0.35; α=0.1) and (r=-0.73; α=0.01) negatively correlated with ADF and CF percentages respectively. In this study, F2S3 (native rhizobium with reduced application of chemical fertilizers) treatment as compared to F2S1 (no application of biological fertilizers with recommended chemical fertilizers) increased positive indexes such as: CP (4.58%); DMD (4.38%) and ASH (3.25%) and decreased negative indexes such as CF (-0.77%) and NDF (-6.4%). Therefore, it is recommended for low input sustainable agriculture (LISA) and high quality of forage.