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Acta Prataculturae Sinica ›› 2021, Vol. 30 ›› Issue (5): 52-64.DOI: 10.11686/cyxb2020202

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Effects of nitrogen and phosphorus addition on production performance and nutritive value of pasture species in Northern Tibet

Yan PENG1,3(), Jing-yuan SUN2, Su-jie MA3, Xiang-tao WANG3, Lei SUN3(), Xue-hong WEI3()   

  1. 1.College of Life Science,Huazhong Normal University,Wuhan 430079,China
    2.Resources & Environment College,Tibet Agricultural and Animal Husbandry University,Nyingchi 860000,China
    3.Animal Science College,Tibet Agricultural and Animal Husbandry University,Nyingchi 860000,China
  • Received:2020-05-11 Revised:2020-09-08 Online:2021-05-20 Published:2021-04-16
  • Contact: Lei SUN,Xue-hong WEI

Abstract:

The development of snow pastures is an effective means to relieve rangeland degradation and improve grassland productivity. Rational fertilization is a key measure for ensuring the sustainable development of degraded alpine meadows. Therefore, we conducted field experiments and laboratory analyses to evaluate the effects of different fertilization treatments on the main agronomic traits, nutritional value, and total outputs of cultivated pasture species. This study was conducted at Namache, in the North Tibetan Autonomous Region of Naqu Prefecture. We focused on the effects of the nitrogen(N) and phosphorus(P) fertilizers on the production performance and nutritive value of pasture species to for provide a theoretical basis for the establishment of artificial grassland. The experiment had an orthogonal design with three factors (plant variety, fertilization and mixture of plant varieties). The four pasture species were Secal cerealeAvena sativa, Vicia sativa and Vicia tibetica, five fertilization treatments were no fertilizer (CK); 75 kg·ha-1 urea (N);375 kg·ha-1 NH4H2PO4(P); 22500 kg·ha-1 organic manure (OM) and 75 kg·ha-1 urea+375 kg·ha-1 NH4H2PO4+22500 kg·ha-1 organic manure (NPOM). Data for the sown pastures were evaluated by grey associative analysis, membership function analysis, and similar priority ratio analysis, principal component analysis. The four models and their evaluation results were subjected to a weighted analysis. We analyzed 16 main traits: plant height, growth rate, fresh-dry weight ratio, stem-leaf ratio, number of tillers/branches, sowing rate, stem diameter, total vegetation cover, crude protein content, crude fat content, crude fiber content, ash content, water content, non-nitrogenous components content, calcium content, phosphorus content and dry yield on sown pasture to explore the effects of main traits on dry yield. Then, we used simple correlation analysis and partial correlation analysis to determine which traits were most closely related to dry yield. The results showed that: 1) Compared with CK, the N, P, OM and NPOM fertilization treatments significantly affected the production performance and nutritive value of pasture species. In general, N and P addition advanced the phenological development of pasture species by 1 to 12 days. 2) Plant height, sowing rate, stem-leaf ratio, number of tillers/branches, total vegetation cover and yield showed positive partial correlations with dry yield. 3)The highest dry weight of pasture species was under the N and NPOM treatments. The optimal fertilization schemes were NP and NPOM. The top four pasture species/fertilization combinations were ranked, from highest productivity to lowest, S. cereale +V. tibetica (NOPM)>A. sativa (NP)>S. cereale +V. tibetica (NP)>A. sativa+V. sativa (NOPM). Therefore, at an appropriate planting density, these pasture species are suitable for the development of high-yielding artificial grassland in Northern Tibet. The results indicated excellent performance of A.sativa+ V. tibeticaunder NPOM and S. cereale +V. tibetica NP, the multivariate evaluation indicated that their yield was stable and that they are suitable for wide utilization in Tibet.

Key words: Northern Tibet, sown pasture, nitrogen and phosphorus addition, correlation analysis, comprehensive evaluation