为探究腐殖酸与生物质炭配施化学磷肥对酸性土壤磷素活化及甘蔗生长的影响.采用盆栽试验,探究了2个施磷水平和2种磷素活化剂的施用对土壤养分、磷素转化及甘蔗生长的影响.结果表明,腐殖酸与生物质炭单独施用或配合施用提高了土壤速效磷、磷素活化率、有机质、有效钾、碱解氮的含量及磷酸酶的活性,且甘蔗株高、茎粗、全磷含量、磷积累量及磷肥利用率也有所提高,但显著降低了土壤无机磷O-P的含量,其中0.1 g/kg磷肥+2 g/kg腐殖酸处理(P1F)的土壤O-P含量显著低于单施0.1 g/kg磷肥处理(P1)49.35％,腐殖酸与生物质炭配施处理(P1FS)较空白对照处理(CK)的土壤有机质含量和磷酸酶活性分别显著提高了29.31％和42.11％.在2个施磷水平下,腐殖酸与生物质炭的施用对土壤无机磷形态含量增加的效果从大到小依次为Fe-P>Ca-P>Al-P>O-P.表明施用腐殖酸与生物质炭提高了土壤的速效养分、磷素含量、磷酸酶活性,促进了土壤磷素转化,进而影响了甘蔗对磷素的吸收利用.

【Objective】The study was conducted to explore the effects of humic acid and biomass carbon on soil phosphorus activation and inorganic phosphorus form transformation with a view to providing theoretical basis for the research and development of synergistic phosphorus fertilizers.【Method】Taking humic acid and biomass carbon as the test materials, with the ratio of 1 g/kg and 2 g/kg soil and phosphate fertilizer and fully mixing with the test soil, a soil culture test was carried out for 60 days to study the effects of humic acid and biomass carbon on the activation of soil phosphorus and the transformation of various forms of inorganic phosphorus.【Result】Compared with CK2 and CK1 treatments, soil available phosphorus content, phosphorus activation coefficient and Fe-P and Al-P contents of soil inorganic phosphorus components increased, while the contents of Ca-P and O-P decreased to varying degrees. On the 18th, 30th and 45th day of the soil culture test, each treatment had a significant effect on the content of soil available phosphorus compared with CK2 and CK1. The content of available phosphorus in P2S2 treatment was significantly higher than that in CK2 treatment by 20.67%, and that in P1F2 treatment was significantly higher than that in CK1 treatment by 69.83%. On the 30th, 45th and 60th day of the test, the content of soil Al-P in P2S2 treatment was significantly higher than that in CK2 treatment by 61.40%, 14.79%, and 17.77%;. Correlation analysis showed that soil available phosphorus had a very significant positive correlation with phosphorus activation coefficient and Al-P. Under the action of different ratios of humic acid and biomass carbon, the proportion of inorganic phosphorus in each form ranked as Fe-P>Ca-P>Al-P>O-P.【Conclusion】Under two phosphorus application levels, both humic acid and biomass carbon can increase the content of soil available phosphorus and phosphorus activation coefficient, promote the contents of Fe-P and Al-P of inorganic phosphorus components in soil, and activate the fixed phosphorus in soil, which is conducive to the conversion of O-P to the available state and significantly improves the availability of soil phosphorus.

为探究不同C/N有机碳肥对铝矿复垦地的土壤培肥及桑树生长的影响,以广西百色市平果县坡造镇伏琴村蚕桑复垦土为供试土壤,采用盆栽试验研究了2个施肥量和4个C/N有机碳肥的施用对复垦土壤的pH、有机质、氮磷钾养分、土壤酶活性及桑树生长的影响.结果表明,施用化肥和不同C/N有机碳肥处理的土壤pH缓慢上升,有机质、氮磷钾养分和土壤酶活性均显著增加,显著促进了桑树的生长;N2水平施肥处理较N1施肥水平处理增加明显;增加碳施入量(C/N=10、20、30)较纯化学肥料对土壤pH、有机质、氮磷钾养分和土壤酶活性的提升作用显著,桑树的株高、径围和生物量也显著增加,并以C/N为20～30的处理提高作用好.综合分析,施肥是短时间内快速培肥复垦土壤的有效措施,且增大有机碳肥投入的培肥效果优于化肥,以C/N为20～30的有机碳肥与N2水平施肥量的配合施用对培肥复垦土及桑树生长效果最佳.

[目的]探究锰胁迫对酸性土壤氮素转化、酶活性及甘蔗氮素吸收利用的影响,为酸性土壤上甘蔗的合理施肥提供参考依据.[方法]在室内开展模拟酸性土壤锰胁迫培养试验,在玻璃温室中进行甘蔗盆栽试验,测定、分析锰胁迫下土壤氮素组分含量、pH和土壤酶活性的差异及其与甘蔗氮素吸收累积的关系.[结果]锰胁迫可使土壤铵态氮含量和净氨化速率显著提高(P＜0.05,下同),土壤硝态氮含量和净硝化速率显著降低,并显著提高土壤净矿化速率;同时,锰胁迫显著降低土壤脲酶活性和显著提高土壤转化酶活性,但对土壤蛋白酶活性无显著影响(P＞0.05).相关分析结果表明,土壤脲酶活性与土壤铵态氮含量和pH分别呈显著和极显著(P＜0.01,下同)正相关;土壤蛋白酶活性与土壤铵态氮含量呈显著正相关,与土壤硝态氮含量和净硝化速率分别呈极显著和显著负相关.在锰胁迫下,甘蔗的株高、生物量、植株氮素累积量和氮素吸收效率均显著降低.[结论]锰胁迫能抑制酸性土壤的硝化作用,减少铵态氮向硝态氮转化,同时使土壤脲酶活性降低,土壤转化酶活性升高,从而减少酸性土壤中甘蔗可利用氮素含量,使甘蔗对氮的吸收利用减少.