Welcome to Acta Prataculturae Sinica ! Today is Share:

Acta Prataculturae Sinica ›› 2021, Vol. 30 ›› Issue (4): 99-110.DOI: 10.11686/cyxb2020467

Previous Articles     Next Articles

Herbage production and forage quality responses to cutting height and fertilization of legume-grass mixtures in the Hexi region

Xin-you WANG1(), Wen-xia CAO1(), Xiao-jun WANG1, Yu-zhen LIU2, Rui GAO1, Shi-lin WANG1, Hai-tao AN1, Xiu-xia DENG1, Wen-hu WANG1   

  1. 1.College of Grassland Science,Gansu Agricultural University,Grassland Ecosystem Key Laboratory of Ministry of Education,Sino-U. S. Research Centers for Sustainable Grassland and Livestock Management,Lanzhou 730070,China
    2.Animal Science and Veterinary Medicine,Qinghai University,Xining 810000,China
  • Received:2020-10-19 Revised:2020-12-14 Online:2021-04-20 Published:2021-03-16
  • Contact: Wen-xia CAO

Abstract:

Mowing and fertilization are extremely important field management decisions in the cultivation of legume-grass mixtures. Appropriate stubble height at mowing and optimal application rates of nitrogen and phosphorus fertilizers can enhance the productivity of mixed grassland. This research was conducted in the Hexi Corridor area and explored the effects of different stubble heights and fertilizer application rates on the yield and quality of a three-year-old perennial legume-grass mixture comprising Medicago sativaBromus inermis and Elytrigia elongata at a planting ratio of 1∶1∶1. The experiment used a split-plot design with three stubble heights as main plots: 5 cm (A1), 8 cm (A2) and 11 cm (A3). Six fertilizer treatments were included as sub-plots: no fertilization (CK, B1), single phosphorus (150 kg P2O5·ha-1, B2), low nitrogen and high phosphorus (75 kg N·ha-1+225 kg P2O5·ha-1, B3), equal nitrogen and phosphorus (150 kg N·ha-1+150 kg P2O5·ha-1, B4), single nitrogen application (150 kg N·ha-1, B5), high nitrogen and low phosphorus application (225 kg N·ha-1+75 kg P2O5·ha-1, B6). The leguminous forages in the mixed grassland were mowed at the early-flowering stage, and fertilized after the first mowing. It was found that: the A3B3 treatment combination had the highest annual yield (19626 kg·ha-1); and the A2B2 treatment combination had the lowest annual yield (14342 kg·ha-1). Increasing the stubble height reduced the crude protein content of alfalfa to some extent, and adding nitrogen enhanced the crude protein levels of poaceous forages. The relative forage value (RFV) of herbage was increased by increasing nitrogen and decreasing phosphorus, and the forage RFV was also decreased when the fertilizer application rate was too high. The optimal combination of nitrogen and phosphorus fertilizer was 150 kg N·ha-1+150 kg P2O5·ha-1. Based on the combined results for yield and quality, the appropriate application rate of phosphate fertilizer application significantly improved the nutritional quality of forage grass. Using the TOPSIS comprehensive evaluation model to evaluate the yield of mixed grassland and the nutritional quality of each mixed forage, the 8 cm stubble height and 150 kg N·ha-1+150 kg P2O5·ha-1 is the optimal combination of stubble height and fertilizer application for the mixed forage cropping of M. sativa+B. inermis+E. elongata in the Hexi Corridor.

Key words: legume-grass mixtures, stubble heights, combination of N and P, grassland yield, forage quality