施氮与种植方式对北方旱作农田土壤酶活力及养分含量的影响

Effects of Nitrogen Application and Planting Patterns on Soil Enzyme Activity and Nutrient Content of Dryland in Northern China

为了解氮肥不同施用量对春麦豌豆间作、春麦单作、豌豆单作土壤特性的影响,探讨春麦豌豆间作、春麦单作、豌豆单作的最佳氮肥施用量,设置春麦豌豆间作(SI)、春麦单作(SS)、豌豆单作(PS)3种种植方式以及0(N0),90(N1),180(N2),270 kg/hm^(2)(N3)4个施氮量,于播后85 d测定土壤蔗糖酶、β-葡萄糖苷酶、脲酶、谷氨酰胺酶、磷酸酶5个酶的活性和土壤全氮、碱解氮、全磷、有效磷、有机碳5种土壤养分含量。结果表明,施氮(N2、N3)提高了PS土壤蔗糖酶活性(65.51%,57.88%),N2水平达到最大值,4个氮水平下,SI种植模式的蔗糖酶活性比PS显著提高31.25%~94.07%;N3处理显著提高了β-葡萄糖苷酶活性(17.81%);施氮提高了SS、SI土壤脲酶活性,且在N2水平达到最高,相同施氮水平下SI>SS>PS;N2显著提高SS、SI、PS土壤谷氨酰胺酶活性(分别提高26.95%,67.05%,55.03%);SS、SI、PS土壤磷酸酶均在N2水平达到最高,且SI显著高于SS和PS(分别提高128.35%,337.21%);施氮能提高土壤碱解氮、全磷、有效磷含量,其中碱解氮与有效磷在N2水平达到最高。土壤蔗糖酶与脲酶、磷酸酶活性均极显著相关,与有效磷含量显著相关;土壤脲酶活性与磷酸酶活性、碱解氮含量极显著正相关,与全氮、有效磷含量显著正相关;土壤磷酸酶活性与全氮、有效磷含量极显著正相关,与碱解氮显著正相关;土壤全氮含量与碱解氮极显著正相关;氮处理与种植模式对土壤脲酶、谷氨酰胺酶活性和磷酸酶存在极显著交互作用,对土壤全磷、有效磷含量存在显著交互作用。综上,180 kg/hm^(2)为最佳施氮量,同等施氮量水平下间作优于单作。

To investigate the effects of different application rates of nitrogen fertilizer on soil characteristics of spring wheat and pea intercropping,spring wheat monoculture and pea monoculture.Three planting methods including intercropping of wheat and pea(SI),sole cropping of spring wheat(SS)and sole cropping of pea(PS)were set,and four nitrogen application levels 0(N0),90(N1),180(N2),270 kg/ha(N3)were set.At 85 days after sowing,the activities of five soil enzymes,including sucrase,β-glucosidase,urease,glutaminase and phosphatase,and the contents of five soil nutrients,including total nitrogen,alkali-hydrolyzed nitrogen,total phosphorus,available phosphorus and organic carbon were measured.The results showed soil sucrase activity was increased(65.51%,57.88%)by N application(N2,N3)in PS soil,and N2 level reached the maximum value.Under four nitrogen levels,the sucrase activity of SI planting pattern was significantly increased by 31.25%-94.07%compared with PS.N3 treatment significantly increased SSβ-glucosidase activity(17.81%);soil urease activities in SS and SI were increased by N application,and reached the highest at N2 level,SI>SS>PS under the same fertilization;N2 significantly increased the glutaminase activities in SS,SI and PS soils(26.95%,67.05%,55.03%,respectively).Soil phosphatase of SS,SI and PS all reached the highest level in N2,and SI was significantly higher than SS and PS(increased by 128.35%,337.21%,respectively).Nitrogen application could increase soil alkali-hydrolyzed nitrogen,total phosphorus and available phosphorus contents,among which alkali-hydrolyzed nitrogen and available phosphorus reached the highest at N2 level;soil sucrase activity was very significantly correlated with the urease,phosphatase,and significantly correlated with the available phosphorus content.Soil urease activity was very significantly correlated with phosphatase activity and alkaline hydrolyzable nitrogen content,and was significantly correlated with total nitrogen and available phosphorus content.Soil phosphatase activity was very significantly correlated with total nitrogen,available phosphorus content,and significantly correlated with alkaline hydrolyzable nitrogen.The total nitrogen content of soil was very significantly correlated with alkaline hydrolyzable nitrogen.There was a significant interaction between nitrogen treatment and planting mode pattern on soil urease,glutaminase,phosphatase activities,soil total phosphorus,available phosphorus contents.In conclusion,180 kg/ha was the best nitrogen application rate,and intercropping was better than monoculture under the same nitrogen application rate.