Nitrogen addition enhances seed yield by improving soil enzyme activity and nutrients

Area of Science:

• Agricultural Science
• Soil Science
• Plant Science

Background:

• Nitrogen (N) addition is a common method to increase plant productivity.
• Mechanisms linking N concentrations to soil enzyme activity, nutrient levels, and seed yield in Festuca kirilowii remain unclear.
• Festuca kirilowii Steud cv. Huanhu is the sole domesticated variety in the Festuca genus (Poaceae family).

Purpose of the Study:

• To investigate the impact of nitrogen fertilizer application on soil enzyme activities, soil nutrients, and seed yield of Festuca kirilowii.
• To determine the optimal nitrogen fertilizer concentration for maximizing seed production in F. kirilowii.
• To understand the regulatory mechanisms of nitrogen on soil properties and yield in the Qinghai-Tibet Plateau.

Main Methods:

• Two-year field experiments were conducted on F. kirilowii in the Qinghai-Tibet Plateau.
• Investigated the effects of varying nitrogen fertilizer concentrations on soil properties and seed yield.
• Utilized membership function analysis to identify optimal nitrogen treatment levels.

Main Results:

• Nitrogen input significantly altered soil nutrients, including pH, total nitrogen, organic matter, and total phosphorus.
• Soil enzyme activities (urease, catalase, sucrase, nitrate reductase) increased with nitrogen application, influencing nutrient conversion.
• Seed yield and yield components (tillers, fertile tillers) were enhanced by nitrogen addition.

Conclusions:

• Nitrogen fertilizer application stimulates soil enzyme activity, accelerating nutrient conversion and improving Festuca kirilowii seed yield.
• The optimal nitrogen fertilizer treatment was identified as 75 kg·hm⁻² (N4) for both experimental years.
• This study provides practical recommendations for optimizing Festuca kirilowii seed production on the Qinghai-Tibet Plateau.