油稻免耕种植模式的土壤理化特性和酶活性

Soil physical and chemical properties and enzyme activities of rape and rice planting patterns under no-tillage

2016年,在湖南省益阳市南县免耕试验基地开始设计不同种植模式处理;2018—2020年,采集冬闲–稻(IR)、冬闲–稻–稻(IRR)、油–稻(OR)、油–稻–稻(ORR)等4种油稻种植模式的土壤样品,测定土壤的容重、微团聚体、养分和酶活性,探究免耕条件下不同油稻种植模式对土壤理化特性和酶活性的影响。结果表明:2018、2019年,同一年内不同油稻种植模式土壤容重间的差异无统计学意义;2020年,IR和IRR的土壤容重显著高于OR和ORR的;2020年,OR和ORR的0.250~1.000 mm粒级微团聚体质量分数较2018年的分别降低了52.04%和49.41%,不同种植模式对大粒级(>0.010 mm)微团聚体质量分数的影响较大,对小粒级(<0.010 mm)的影响较小;2018、2019年,同一年内4种种植模式土壤有机质质量分数间的差异无统计学意义,2020年,ORR的土壤有机质质量分数显著高于其他模式的;同一年内,OR、ORR的土壤速效钾质量分数显著低于IR、IRR的,ORR的土壤纤维素酶、磷酸酶活性均较IRR的高。可见,免耕条件下,油–稻和油–稻–稻种植模式可减缓土壤的紧实度,改变土壤微团聚体组分,延缓有机质含量降低速率,提高土壤纤维素酶和磷酸酶活性。

The study began to design different planting pattern treatments in the rape season at Nanxian no-tillage experimental base in Yiyang City,Hunan Province in 2016.In order to study the effects of different rape and rice planting patterns on soil physical and chemical properties and enzyme activities under no-tillage conditions,soil samples of four planting patterns were collected,including winter idle-rice(IR),winter idle-rice-rice(IRR),rape-rice(OR),rape-rice-rice(ORR),and soil bulk density,microaggregates,nutrients and enzyme activities were determined from 2018 to 2020.The results showed that there was no difference in soil bulk density between different rape and rice planting patterns in 2018 and 2019,and the soil bulk densities of IR and IRR patterns were significantly higher than those of OR and ORR patterns in 2020.In 2020,the mass fractions of soil microaggregates in the 0.025-1.000 mm size of OR and ORR patterns decreased by 52.04%and 49.41%compared with 2018.The effects of different planting patterns on the mass fractions of large grain microaggregates(>0.010 mm)were greater than those of small grain microaggregates(<0.010 mm).There was no difference in soil organic matter mass fraction among the four patterns in 2018 and 2019.The soil organic matter mass fraction of ORR patterns in 2020 was significantly higher than the other three patterns.In the same year,the soil available K mass fractions of OR and ORR patterns were significantly lower than those of IR and IRR patterns,and the soil cellulase and phosphatase activities in ORR pattern were higher than those in IRR pattern.In conclusion,rape-rice and rape-rice-rice patterns under no-tillage could slow down soil compaction rate,change soil microaggregate composition,delay the decrease rate of organic matter mass fraction,and improve soil cellulase and phosphatase activities.