Effects of chemical fertilizer combined with organic manure and rhizobium inoculation on growth，feeding quality and nutrient absorption of Dolichos lablab L .

Dolichos lablab L. is a legume forage with highyield and good feeding quality. Fertilization is one of the most important factors affecting the growth and feeding quality of forage. Our objective was to investigate the effects of different fertilization on Dolichos lablab L. Chemical fertilizer combined with organic manure (CK, F, F0.75M0.25, F0.5M0.5，F0.25M0.75, M) were used to investigate the influences of fertilizer treatments on nodulation, growth, photosynthesis, feeding quality, nutrient absorption by Dolichos lablab L. and as well as soil enzyme activities. The results show that the growth, yield and quality of D. lablab L. are better under the F0.5M0.5 and F0.75M0.25, those under the F and F0.5M0.5 are good, and those under the M and CK are the worst. Compared with the F, the yields of F0.5M0.5 and F0.75M0.25 are increased by 19.46% and 16.49%, respectively. Plants under the F and CK form fewer nodules (19-26 No./basin) and lower nodule weight (0.58-1.56 g/basin), while the nodule number and nodule weight of the plants are increased with the increase of manure proportion. When the proportions of the organic fertilizer are increased from 25% to 100%, the nodule numbers are increased from 54 to 109 nodule/basin, and the nodule weight are from 3.13 to 3.90 g/basin. The net photosynthetic rates of the four fertilizer treatments included organic manure are similar ［ 14.39-15.32 CO2 mol/(m2s)］，and are significantly higher than those of the F and CK ［10.07-10.27 CO2 mol/(m2s) ］. The organic fertilizer could improve the contents of crude protein, crude fat, crude ash, nitrogen, phosphorus and potassium of D. lablab L., and thus improve feeding quality. The ground biomasses of the F0.5M0.5 and F0.75M0.25 are the highest, of which the contents of protein, crude fat, crude ash, soluble sugar yield and nitrogen, phosphorus, potassium, calcium, magnesium absorptions are also the highest. Compared with the pure chemical fertilizer, the organic manure could improve the soil enzyme (catalase, invertase, urease) activities. The results of the correlation analysis show the shoot biomass (R2=0.6758), nitrogen (R2=0.7269), phosphorus (R2=0.9759) and potassium (R2=0.9488) absorptions are positively correlated with the nodule weight. The nodule formation could improve nitrogen, phosphorus and potassium nutrition; promote the growth, increase biomass and quality to some extent. In cultivation practice in Chongqing, the selection of chemical fertilizer combined with organic manure and rhizobium inoculation could increase the yield and improve the quality of D.lablab L.