Effect of biological and reduced rates of chemical fertilizers on forage yield (quantity and quality) in Persian clover

In order to achievement to Low Input Sustainable Agriculture (LISA) this study has carried out in experimental fields of Borujerd agricultural research station (Lorestan province –Iran) in 2011. Two factorial experiments (RCBD) with three replications have been studied. Experimental treatments including: four levels of chemical fertilizers: (nitrogen & phosphorus) F0=N0+P0, F1=N25 (25k/h Urea 46%nitrogen) + P50(50k/h Super phosphate triple 46% P2O5), F2=N50 +P100 and F3=N75 +P150. The biological fertilizers including: control, PGPR (Pseudomonas florescence11168 strine), native Rhizobium (Rhizobium legominosarum bv.trifolli RTB2) and co-inoculation. Results showed that the location effect was significantly (p<0.01) affected on green yield, height, regrow rate and (p<0.05) on CP and ADF. The most parameters were more in location 2 than that of location 1.The CP, DMD and height were not significant under chemical and biological treatments. The highest green yield (76.16 t/ha) was observed in Pseudomonas and native Rhizobium at highest rate of chemical fertilizers (B2F4 and B3F4). The efficiency of F2B in comparison to F3B0 treatments was increased green yield (0.33 percentage), Crud Protein (2.6 percentage), chlorophyll content (1.9 percentage), regrow rate (4.69 percentage), Ash (3.97 percentage) and decrease of CF (-0.15 percentage). CP tended (r= -0.35; α=0.1) and (r=-0.73; α=0.01) negatively correlated with ADF and CF respectively. It seems that application of reduced chemical fertilizers integrated with biological fertilizers (specially native rhizobium) can positively interact on yield as well as forage quality leading to decrease chemical