生物炭的10年土壤培肥效应

大量短期的室内试验和田间试验研究表明,施用生物炭可以增加土壤碳固定,提升土壤肥力和作物产量,然而关于生物炭的长期土壤肥力效应尚不明确。为此,依托持续10年的生物炭的田间定位试验4个处理:对照(CK)、生物炭4. 5 t·hm-2·年-1(B4. 5)、生物炭9 t·hm-2·年-1(B9. 0)、秸秆还田(SR)],研究了长期施用生物炭对土壤肥力状况的影响。结果显示,与对照相比,长期施用生物炭和秸秆还田对土壤p H值没有显著影响,但容重降低了2. 2%～8. 2%,施用生物炭的土壤电导率降低了1. 5%～7. 8%,而秸秆还田处理土壤电导率提高了4. 7%～13. 4%。施炭和秸秆还田使土壤有机质(SOM)含量增加57. 7%～123. 1%,总氮含量提高11. 3%～21. 9%,总磷没有显著性变化。不同处理土壤NH+4-N含量的差异不显著,而施用生物炭和秸秆还田土壤NO-3-N含量增加3. 8%～67. 1%,且高炭处理的效果显著。土壤有效磷含量显著降低了23. 1%～42. 0%,速效钾含量上升了2. 0%～23. 1%。总体而言,长期施用生物炭提升了土壤肥力,尤其是对土壤有机质的提升有显著的效果。

A 10 year field experiment on biochar amendment:effects on soil fertility

A large number of short term laboratory and field trails show that biochar amendment can increase soil carbon sequestration,improve soil fertility and crop yields.However,little is known about its long term effect on soil fertility.Therefore,the aim of this study was to assess the long term effect of biochar amendments on soil fertility based on a 10 year field experiment.Four treatments were set up:control(CK),biochar 4.5 t·hm-2·yr-1 (B4.5),biochar 9.0 t·hm-2·yr-1(B9.0)and straw retention(SR).Results showed that biochar treatments and straw retention did not significantly affect soil pH,but decreased soil bulk density by 2.2%~8.2%,soil conductivity was decreased sharply by 1.5%~7.8% with increasing application rates in biochar treatments,and was increased by 4.7%~13.4% in straw retention,respectively compared to control.Soil organic matter and total nitrogen contents were enhanced by 57.7%~123.1% and by 11.3%~21.9%,respectively,and total phosphorus content did not significantly change under the biochar and straw treatments.Soil ammonium(NH+4-N)content did not show significant difference between the treatments,but nitrate(NO-3-N)content was increased by 3.8%~67.1% under the biochar and straw treatments and this difference was statistically significant under the higher biochar application rate.The biochar and straw treatments significantly reduced soil available phosphorus content by 23.1%~42.0%,but increased available potassium content by 2.0%~23.1%.In general,the long term biochar application enhanced soil fertility,especially significantly increased soil organic matter.