河西灌区麦茬免耕对春玉米田土壤微生物量氮和磷的影响

2004~2005年,在甘肃河西走廊的黑河灌区,设计20 cm留茬压倒(NPS20)、40 cm留茬压倒(NPS40)4、0 cm立秆(NS40)2、0 cm立秆(NS20)和传统耕作(CT)5个耕作处理,I1(5 400 m3/hm2)和I2(3 600 m3/hm2)2个灌溉水平,研究了春小麦不同留茬高度、不同留茬方式对春玉米田在不同灌水水平下土壤微生物量N和P的季节性变化的影响.结果表明:土壤微生物量N春种前有表聚的现象,土壤微生物量P则在整个耕层分布比较均匀;留茬免耕可显著增加播种前0~5 cm土层土壤微生物量N和P含量,10~20 cm土层则变化较小;连续免耕2 a后,春种前0~5 cm土层土壤微生物量N和P的增殖,分别以20 cm留茬压倒免耕处理(NPS20)和40 cm留茬压倒免耕处理(NPS40)的最高,分别增加了23.97%和148.80%,且土壤水分对表土层及耕层的土壤微生物量P的影响较土壤微生物量N显著.

Effects of no-tillage with stubble on soil microbial biomass N and P in irrigated oasis of the Hexi Corridor

During 2004 to 2005,a field experiment was carried out to study the effects of different spring wheat stubble staying treatments(NPS_(20)、NPS_(40)、NS_(40)、NS_(20)、CT) and 2 irrigation level(5400(m~3/hm~(2)) and 3600 m~3/hm~(2))in no-tillage with stubble on soil microbial biomass N and P.The results showed that soil microbial biomass N(SMB-N) was collected in soil surface layer before seedling time while soil microbial biomass P(SMB-P) was averaged.Conservation tillage increased SMB-N and SMB-P in 0～5 cm soil layer,while that in 10~20 cm soil layer had no significant difference during sowing stage.Compared with the result of the last year,the highest increased quantity of SMB-N and SMB-P in 0～5 cm soil layer appeared in NPS_(20) and NPS_(40) respectively,which reached to 23.97 % and 148.80 %,and soil water had more evident effect on SMB-P than on SMB-N.