Abstract:

This research aimed to identify the ideal ratio of microbial fertilizer （MF） and chemical fertilizer （CF） to promote growth of Elymus nutans. Compared with a typical CF application of 300 kg·ha^-1， this study explored fertilizer reductions of 20% or 40% （80%CF and 60%CF， respectively） and substitution with MF at rates of 60， 90， 120， 150 or 180 kg·ha^-1. Effects on agronomic characters， the root system and nutritional quality of E. nutans were evaluated. It was found that at the first harvest， 80%CF （240 kg·ha^-1） combined with 90 kg·ha^-1 MF increased E. nutans plant height， stem thickness and hay yield by 34.86%， 44.83% and 3.08%， respectively compared with CK， while 80%CF combined with 120 kg·ha^-1 MF increased the crude fat content of plants by 22.97% compared with CK and decreased acid detergent fiber content by 6.59%. 80%CF combined with 150 kg·ha^-1 MF increased plant crude protein content by 36.09% and 80%CF （240 kg·ha^-1） combined with 90 kg·ha^-1 MF decreased neutral detergent fiber content by 15.64%. At the second harvest， 80%CF combined with 60 kg·ha^-1 MF increased total plant root length by 34.77% compared with CK； 80%CF combined with 90 kg·ha^-1 MF increased plant height， stem thickness， hay yield and the total root surface area by 80.43%， 66.34%， 13.08% and 8.66%， respectively； 80%CF combined with 120 kg·ha^-1 MF increased plant crude protein and crude fat content， total root volume， underground fresh weight and underground dry weight by 25.30%， 14.61%， 45.54%， 19.39% and 51.04%， respectively； 80%CF combined with 180 kg·ha^-1MF reduced acid detergent fiber and neutral detergent fiber content of plants by 8.13% and 8.88%， respectively， compared with CK. Through principal component analysis， the combined application of 20% fertilizer reduction （240 kg CF·ha^-1） and 90 kg·ha^-1 microbial fertilizer gave the best growth promotion effect on E. nutans.

Key words: Elymus nutans, microbial fertilizer, agronomic traits, root system, nutritional quality