施肥和混播对人工草地土壤速效养分含量的影响

Responses of Soil Available Nutrients Content in Legume-grass Mixture Grassland to Fertilization and Mixed Sowing Ratio

以紫花苜蓿与无芒雀麦混播草地为对象,研究不同氮(N)磷(P)钾(K)肥组合、混播比例以及茬次对土壤速效养分含量的影响。结果表明,施肥对0~30cm土壤碱解氮、速效磷和速效钾含量影响极显著(P<0.01)或显著(P<0.05);在0~15cm土层,第1茬收获时的土壤碱解氮、速效钾和速效磷含量以及第2茬收获时的速效钾和速效磷含量受混播比例影响极显著(P<0.01);在0~30cm土层,第1~3茬收获时的土壤碱解氮和第1~2茬收获时的速效磷含量受施肥与混播比例互作影响极显著(P<0.01)。0~15cm土层速效钾、速效磷含量与磷钾肥施量呈极显著正相关(P<0.01),碱解氮含量与氮肥施量没有显著相关性。高氮处理(N_(420)P_(250)K_(120))第1茬0~15cm土壤碱解氮含量比高钾处理(N_(350)P_(100)K_(360))低18.41%(P<0.05),第2茬比高钾和高磷处理(N_(140)P_(300)K_(300))低29.45%和17.27%(P<0.05)。缺磷处理(N_(210)P_(0)K_(240))1~3茬土壤碱解氮含量比高磷处理低18.29%、36.09%和17.00%(P<0.05)。豆禾1∶2混播第1茬0~15cm土壤碱解氮和速效钾含量比2∶2混播高17.55%和17.62%(P<0.05),1~3茬速效磷含量比2∶2混播高11.39%、7.23%和12.86%(P<0.05)。

This experiment was conducted to analyze the effect of different nitrogen(N),phosphorus(P),potassium(K)fertilizer combinations,mixing ratios,and cutting times on soil available nutrient content in mixed grassland of alfalfa(Medicago sativa)and smooth brome(Bromus inermis).The results showed that fertilization had a significant effect on the contents of alkali-hydrolyzable nitrogen,available phosphorus and available potassium in 0~30cm soil layer(P<0.01 or P<0.05);in 0~15cm soil layer,the contents of alkali-hydrolyzable nitrogen,available potassium and available phosphorus in the first cutting and the content of available potassium and available phosphorus in the second cutting were significant affected by the mixed sowing proportion(P<0.01);in 0~30cm soil layer,the soil alkali-hydrolyzable contents at 1st~3rd cutting and available phosphorus content at 1st~2nd cutting were significantly affected by the interaction of fertilization and mixed sowing ratio(P<0.01).The contents of available potassium and available phosphorus in 0~15cm soil layer were positively correlated with the application rate phosphorus and potassium fertilizer(P<0.01),and the content of alkali-hydrolyzable nitrogen was not significantly correlated with the application rate of nitrogen fertilizer.The content of alkali-hydrolyzable nitrogen in 0~15cm soil layer in the first cutting of high nitrogen(N_(420)P_(250)K_(120))treatment was 18.41%lower than that of high potassium(N_(350)P_(100)K_(360))treatment(P<0.05),and 29.45%and 17.27%lower than that in the second cutting of high potassium and high phosphorus(N_(140)P_(300)K_(300))treatment(P<0.05).The content of alkali-hydrolyzable nitrogen at 1st~3rd cutting of phosphorus deficiency(N_(210)P_(0)K_(240))treatment was 18.29%,36.09%and 17.00%lower than that of high phosphorus treatment(P<0.05).At the first cutting,the content of alkali-hydrolyzable nitrogen and available potassium in the 0~15cm soil layer with a mixed sowing ratio of 1∶2 was 17.55%and 17.62%higher than those with 2∶2 mixed sowing ratio(P<0.05),and the content of available phosphorus in 1~3 cutting was 11.39%,7.23%and 12.86%higher than those with 2∶2 mixed sowing ratio(P<0.05).