不同玉米栽培模式对中温带典型暗棕壤腐殖质组成的短期影响

为探讨不同玉米栽培模式对中温带典型暗棕壤腐殖质组分数量及结构的短期影响,以吉林省磐石市实施3 a的定位栽培试验为供试对象,分别研究高光效休耕轮作栽培(HPE)、地膜覆盖的高光效休耕轮作栽培(PM-HPE)、宽窄行交替休闲栽培(WNR),以及农民等垄宽常规栽培(CC)下各栽培模式的种植带和休耕带两个功能区对暗棕壤总有机碳、水溶性物质、胡富质量分数比(w(C_(HA))∶w(C_(FA)))、胡敏素以及胡敏酸、富里酸溶液光学性质(E_4/E_6与△log K值)差异的影响,结果表明:(1)休闲栽培措施在短期内易使暗棕壤总有机碳发生矿化,但其对水溶性物质及其占总有机碳中比例的提高具有促进作用,其中PM-HPE模式对水溶性物质的保蓄效果最佳。休闲栽培下密植玉米的种植带对水溶性物质含量有所消耗,使更多水溶性物质固存在休耕带;(2)休闲栽培更有利于暗棕壤胡敏酸质量分数的消耗以及富里酸组分的累积,使其腐殖质活性增加、品质降低。适度休耕能够在一定程度上缓解胡敏酸相对比例的损失,更有利于腐殖质品质的稳定。休耕有利于腐殖质结构向简单化方向进行,而在种植带,暗棕壤富里酸分子有进一步缩合的趋势;(3)高光效栽培促进了微生物对胡敏素的矿化分解。

Short-term Effect of Different Corn Cultivation Modes on the Compositions of Humic Substances Extracted from A Typical Dark-brown Soil in Middle Temperate Region

We studied the differences in the contents of total organic C (TOC), water soluble substance (CWSS), humin (CHu), the ratios of humic acid (HA)/fulvic acid (FA) (CHA/CFA) and E4/E6, the△logK values from the HA and FA alkaline-solutions based on the four cultivation types including the fallow rotation cultivation with a high photosynthetic efficiency (HPE), the plastic mulched fallow rotation cultivation with a high photosynthetic efficiency (PM-HPE), the alternating leisure cultivation of wide-narrow row (WNR) and the conventional cultivation (CC).The cultivation experiments men-tioned above was implemented continuously for 3 a in Panshi City of Jilin Province served as our tested objects for exploring the short-term effects of different corn cultivation modes on the compositions and structural properties of humic substances extracted from a typical Dark-brown soil in middle temperate region .In this process , two functional areas of the planting zone and fallow area were discussed separately .The application of short-term fallow cultivation were more likely to acceler-ate the mineralization process of TOC , but the content of CWSS and its proportion in the TOC could be enhanced , in which the retention of CWSS by PM-HPE was the best.The planting zone from the fallow cultivation could consume a large number of CWSS , making much more CWSS exist in the fallow area .The fallow cultivation was more conducive to the consumption of CHA and the accumulation of CFA extracted from the dark-brown soil, and simultaneously could improve the activity of hu-mus and lower its quality .The moderate fallow farming methods could prevent a loss in the relative proportion of CHA , which was more advantageous to the stability of humus quality .The fallow cultivation could make the structure of humus simple, but at the planting zone , it could promote a tendency to further condensation of FA extracted from the dark -brown soil.The fallow rotation cultivation with a high photosynthetic efficiency could promote the microbial decomposition and mineralization of CHu .