生物炭对红壤中不同铝形态及小白菜生长的影响

Effect of Biochar Application on Remission of Red Soil Aluminum Different Forms and the Growth of Pakchoi

红壤是我国南方典型的酸性土壤,具有pH值低,活性铝含量高等特点。生物炭作为新型土壤改良剂,对提高土壤肥力与pH,缓解铝毒具有明显的效果。为了研究生物炭对红壤铝形态及小白菜生长的影响,采用盆栽试验,并设置0%C(CK),1%C,2%C和3%C共4个处理,每个处理4次重复,进行土培种植小白菜。结果表明:施用生物炭会显著提高小白菜的出苗率,且生物炭处理的小白菜出苗率较CK处理提高10.8%~25.0%。另外,施用生物炭显著改善了小白菜的生长状况,提高了小白菜的生物量,且小白菜铝含量降低68.3%~82.2%。此外,施用生物炭后,土壤pH值、速效磷、速效钾和有机碳量显著提高,其中土壤pH值提高0.35~0.79个单位,而碱解氮含量却显著降低。添加生物炭能使土壤活性铝总量显著下降,且较CK下降16.9%~41.7%,而具有生物毒害的交换性Al^(3+)较CK处理降低37.4%~75.5%,施用生物炭越多,降低效果越明显。然而,不是所有形态的铝含量都下降,各形态铝之间存在转化关系,Al(OH)_2^+,Al(OH)^(2+)与胶体Al(OH)_3~0均有不同程度的上升。说明施用生物炭可以提高土壤pH值,改善肥力,降低活性铝含量,促使具有生物毒害的交换性Al^(3+)向其他形态铝转化,从而缓解铝毒效果,并且在一定范围内,效果随生物炭用量增加而增大。

Red soil is as a typical acid soil with low pH, high content of active aluminum and so on. Biochar is known as a new soil conditioner which has obvious effect on improving soil fertility and pH, even remitting aluminum toxicity. In order to study the effect on aluminum toxicity reduction in red soil and growth of pakchoi under biochar addition, this experiment set 0% C （CK）, 1% C, 2% C, 3% C treatments in pot with 4 repeats. The results showed that application of biochar could significantlyincrease the emergence rate of pakchoi. The treatments of 1%C, 2% C and 3% C increased emergence rates by 10.8% -25.0%respectively than CK treatment. The growth of pakchoi improved significantly and enhanced the biomass of pakchoi after biochar applying. Meanwhile, the aluminum contents of the pakchoi reduced by 68.3%-82.2% than CK treatment after biochar applying. The soil pH, available K, available P and organic carbon content increased significantly under biochar applying. The content of soil available N decreased significantly under biochar applying. The soil total active aluminum content decreased significantly by 16.9%-41.7% respectively under biochar applying. The exchangeable Al3＋ reduced by 37.4%-75.5%. Although total soil active aluminum decreased significantly after biochar applying, not all of the aluminum forms decreased, which they exist transformation relationship among these aluminum forms. The exchangeable Al3＋ and Al-HA decreased, meanwhile the Al （OH）2＋, Al （OH）2＋ and colloid Al （OH）30 increased in different degrees. The results showed that the application of biochar could improve soil fertility,increase the pH, make the exchangeable Al3 ＋ with biological toxicity changing in other Al forms, which leads to remit thealuminum toxicity.