氮磷运筹对环青海湖地区寒生羊茅种子生产的影响OA

The aim of this study was to investigate the effects of combined nitrogen(N)and phosphorus(P)application on the seed yield of Festuca kryloviana,with an overall goal to provide a theoretical basis and technical support for its seed production.A field experiment with a two-factor randomized complete block design was conducted over two consecutive years in the Qinghai Lake region.F.kryloviana was cultivated under four nitrogen application levels and three phosphorus application levels,and the seed yield,its component factors,and economic benefits of 3-year-old(2023)and 4-year-old(2024)F.kryloviana were determined and analyzed.The results show that the combined application of N and P significantly improved the agronomic traits of F.kryloviana.All treatment groups showed increases in plant height,stem diameter,hay yield,and spike length compared with the control,although the magnitude of these increases varied.Specifically,under optimal treatments in 2023 and 2024,the maximum plant height reached 107.4 and 110.5 cm,respectively;the stem diameter reached 1.1 and 1.3 mm,respectively;the hay yield reached 6.27 and 6.41 t·ha-1,respectively;and the spike length reached 14.5 and 15.9 cm,respectively.The combined application of N and P also significantly affected seed yield components.The number of reproductive branches initially increased and then decreased as the N application rate increased,and in 2023 and 2024 shoot numbers were increased by 71.8%and 49.6%,respectively,in the optimal treatments compared with the control group.The 1000-seed weight showed a significant response to P application,with increases of 23.58%and 13.98%in 2023 and 2024,respectively,in the optimal treatments compared with the control group.Correlation analyses indicated that the actual seed yield had extremely significant positive correlations with the number of reproductive branches and 1000-seed weight(P<0.01).Furthermore,different seed yield indexes(potential seed yield,expressed seed yield,and actual seed yield)were all regulated by N and P.Each year,the seed yields were obvious higher in the optimal treatments than in the control group.The actual seed yield reached 0.92 t·ha-1 in the optimal treatment in 2023 and 0.78 t·ha-1 in the optimal treatment in 2024.In terms of economic benefits,in 2023,the maximum yield increase was 5.72×10³ CNY·ha-1,and the maximum fertilizer contribution rate was 38.96%;in 2024,the maximum yield increase was 2.80×10³ CNY·ha-1,and the maximum fertilizer contribution rate was 23.26%.Notably,the treatment with 120 kg·ha-1 N combined with 600 kg·ha-1 P resulted in stable and high economic benefits in both years.A membership function analysis of seed yield and its components revealed that the combined application of 120 kg·ha-1 N and 600 kg·ha-1 P is the optimal fertilization scheme for this crop in this study area.