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Acta Prataculturae Sinica ›› 2024, Vol. 33 ›› Issue (11): 172-185.DOI: 10.11686/cyxb2024013

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Determination of optimal input levels of nitrogen, phosphorus and potassium for high yield and quality of hydroponic barley forage based on response surface methodology

Ming-hui HOU1(), Yan-liang SUN1, Kai-xin YANG1, Jun-cang QI2, Qian-bing ZHANG1()   

  1. 1.College of Animal Science & Technology,Shihezi University,Shihezi 832003,China
    2.College of Agriculture,Shihezi University,Shihezi 832003,China
  • Received:2024-01-04 Revised:2024-03-15 Online:2024-11-20 Published:2024-09-09
  • Contact: Qian-bing ZHANG

Abstract:

By analyzing the effects of different levels of nitrogen, phosphorus and potassium on the fresh grass yield and crude protein of barley forage, the optimal levels of nitrogen, phosphorus and potassium suitable for hydroponic cultivation of barley forage were identified, with a view to providing a theoretical basis and data reference for the optimal use of this resource. The range of values of nitrogen addition, phosphorus addition and potassium addition were determined by a single-factor experiment, a quadratic polynomial regression model was constructed by the response surface optimization method, and different levels of nitrogen, phosphorus and potassium were added in hydroponic cultivation through a central composite rotational design. The nitrogen addition rates were 3.30, 5.00, 7.50, 10.00 and 11.70 mmol·L-1; the phosphorus addition rates were 0.66, 1.00, 1.50, 2.00 and 2.34 mmol·L-1, the potassium addition rates were 1.98, 3.00, 4.50, 6.00 and 7.02 mmol·L-1, and fresh grass yield and crude protein content were selected as the optimization criteria. It was found that the quadratic effects of fresh grass yield and crude protein content were extremely significant (P<0.01), with determination coefficients of 0.97; the surface effect of potassium on fresh yield was extremely significant (P<0.01). The interaction effect of nitrogen and potassium on fresh yield was extremely significant (P<0.01), while the interaction between phosphorus and potassium on fresh yield was also significant (P<0.05). The response surface effects of nitrogen-potassium and phosphorus-potassium on crude protein content were extremely significant (P<0.01). The response surface indicated the optimal combination of the three nutrients was nitrogen addition of 9.19 mmol·L-1, phosphorus addition of 1.08 mmol·L-1, and potassium addition of 3.99 mmol·L-1. At this nutrient combination, the modeled fresh yield was maximized at 12.07 kg·plate-1, and the predicted crude protein content was 19.35%DM.

Key words: hydroponics, barley forage, fresh grass yield, crude protein, response surface analysis