【摘要】 [目的]探究切根改良后配合氮、磷肥混施对科尔沁草原羊草割草场土壤养分的影响。[方法]在切根基础上对羊草割草场进行不同浓度的氮、磷肥添加试验,设置4个氮、磷添加梯度处理,分别为CK(对照)、NP1(尿素75 kg/hm~2+磷酸二铵45 kg/hm~2)、NP2(尿素150 kg/hm~2+磷酸二铵90 kg/hm~2)和NP3 (尿素225 kg/hm~2+磷酸二铵135 kg/hm~2)。每个处理设置3个区组作为重复,共12个试验小区。2014年8月中旬,在每个小区随机设置一个1 m×1 m样方,齐地面刈割植物样品后采集土壤样品,随机设置3个取样点,采用凯氏定氮法、碱解法、钼锑抗比色法、酸溶—钼锑抗比色法、氢氧化钠熔融法、乙酸铵浸提—火焰光度法、重铬酸钾滴定法分别测定土壤氮、磷、钾含量和土壤有机质含量。[结果]与CK相比,NP3处理导致10～20 cm土壤层的全氮含量显著(P<0.05)降低;3个施肥处理均可显著(P<0.05)提高0～10 cm和10～20 cm土壤层的速效氮含量;NP3处理可显著(P<0.05)提高0～10 cm土壤层的全磷和速效磷含量,NP2处理可显著(P<0.05)提高0～10 cm和20～30 cm土壤层的速效磷含量;NP2和NP3处理导致10～20 cm和20～30 cm土壤层的全钾含量显著(P<0.05)降低,NP3处理导致0～10 cm土壤层的速效钾含量显著(P<0.05)降低;3个施肥处理均可显著(P<0.05)提高不同土壤层的有机质含量。[结论]综合考虑施氮、磷肥后土壤养分含量变化情况,在对羊草割草场改良过程中,需要配施一定量的钾肥,有利于改善科尔沁草原羊草割草场土壤养分状况。更多还原

【Abstract】 [Objective]To investigate the effects of combinative application of nitrogen(N) and phosphorus(P) fertilizers based on improvement by root cutting on soil nutrient of Leymus chinensis mowing meadow in Horqin grassland. [Method]On the basis of root cutting, a field experiment of adding N and P fertilizers at different concentrations was conducted in the Leymus chinensis mowing meadow. Using a randomized block design, four treatment levels of N and P fertilizers, including CK(control), NP1(urea75 kg/hm~2+diammonium phosphate 45 kg/hm~2), NP2(urea 150 kg/hm~2+diammonium phosphate 90 kg/hm~2), and NP3(urea 225 kg/hm~2+diammonium phosphate 135 kg/hm~2), were set. There were 3 blocks as repeats for each treatment, and there was a total of12 experimental plots. In mid-August 2014, a 1 m × 1 m quadrat was randomly set in each plot, and the soil samples were collected after cutting the plant samples at 0 cm stubble; three sampling points were randomly chosen, and the contents of soil N,P and potassium(K) as well as soil organic matter were determined by Kjeldahl method, alkaline hydrolysis method,molybdenum-antimony anti-colorimetric method, acid dissolution-molybdenum-antimony anti-colorimetric method, sodium hydroxide fusion method, ammonium acetate extraction-flame photometric method, and potassium dichromate titrimetric method.[Result]Compared with CK, NP3 treatment induced the significant(P<0.05) reduction of total N content in 10-20 cm soil layer;the 3 fertilization treatments significantly(P<0.05) increased the available N content in 0-10 cm and 10-20 cm soil layers; NP3 treatment significantly(P<0.05) increased the contents of total P and available P in 0-10 cm soil layer, and NP2 treatment significantly(P<0.05) increased the available P contents in 0-10 cm and 20-30 cm soil layers; NP2 and NP3 treatments induced the significant(P<0.05) reduction of total K contents in 10-20 cm and 20-30 cm soil layers,and NP3 treatment induced the significant(P <0.05)reduction of available K content in 0-10 cm soil layer; the 3 fertilization treatments significantly(P <0.05) increased the organic matter contents in different soil layers. [Conclusion]Considering the changes in soil nutrient contents after applying N and P fertilizers, a combinative application of K fertilizer at a certain level is necessary to improve the soil nutrient status of the Leymus chinensis mowing meadow in Horqin grassland.更多还原