施用生物炭对红壤和潮土种植小白菜氮素利用的影响

Effect of biochar application on crop nitrogen utilization in red and fluro-aquic soil

研究了施用不同剂量(0%、0.5%、1%、2%、4%)花生壳生物炭对红壤和潮土种植小白菜(Brassica rapa L.chinensis)生长及氮素养分利用效率的影响。利用淋溶土柱装置、根系扫描仪明确各处理小白菜生物量、根系形态指标,收获后土壤残留氮素养分含量,氮素利用效率,淋溶液氮含量等指标,探讨生物炭对不同类型土壤作物生长和养分利用的影响特征和机制。结果显示:与空白对照和单施氮肥处理相比,施用生物炭在潮土上显著降低小白菜地上和地下生物量,降幅分别达59.1%~77.2%、70.6%~80.6%,但在红壤上却显著增加小白菜地上和地下生物量,增幅分别达35.7%~69.0%、63.0%~77.1%。此外,生物炭对其根系形态指标亦影响显著,随生物炭施用量的增加,在潮土中施用生物炭,小白菜主根长降低了11.5%~30.1%,根表面积降低45.6%~55.9%,根冠比呈先增加后降低的趋势;而在红壤中施用生物炭,对小白菜根长影响不显著,根表面积增加47.5%和56.7%,根冠比显著降低。说明施用生物炭在红壤上促进小白菜根系发育,而在潮土上抑制小白菜根系发育。在潮土中施用生物炭,降低小白菜氮素吸收效率64.7%~73.5%,氮肥偏生产力降低65.1%~79.3%;在红壤中施用生物炭则提高了小白菜氮素吸收效率44.7%~59.6%,氮肥偏生产力增加了32.0%~63.2%。同时,施用生物炭显著降低小白菜植株硝酸盐含量,降幅分别达40.9%~84.6%和18.8%~75.0%。在红壤中施用生物炭,通过促进小白菜根系发育,提高其产量,降低红壤氮素残留,提高氮肥的利用效率,具有良好的生态效益;而对潮土施用生物炭,则抑制小白菜根系发育,降低其产量,降低其氮肥的利用效率,生物炭对潮土的高效安全施用仍需进一步探讨。

The aim was to study the effect of different peanut shell biochar(0%,0.5%,1%,2%,4%)on the Pakchoi(Brassica rapa L.chinensis)growth and nitrogen use efficiency in red and fluvo-aquic soil.We used the leaching columns,root scanner and analysis software to identify the Pakchoi biomass,root morphology,residual soil nutrient content,nitrogen use efficiency,solution nitrogen content,and discuss the effects of biochar on growth and nitrogen utilization of crops in two soils.The results showed that the biochar amendments significantly reduced the aboveground and underground biomass of Pakchoi planted in fluvo-aquic soil,with a decrease of 59.1% ~ 77.2%,70.6% ~ 80.6%,but significantly increased the aboveground and underground biomass of Pakchoi planted in red soil,with an increase of 35.7% ~ 69.0%,63.0% ~ 77.1%.In addition,the biochar had a significant effect on its root morphology.Biochar application reduced the root length and the root surface area of Pakchoi by 11.5% ~ 30.1% and 45.6% ~ 55.9% in fluvo-aquic soil.The ratio of root to shoot showed a trend of increasing firstly and then decreasing,the biochar amendments in red soil had no significant effect on the root length of Pakchoi,which increased the root surface area by 47.5% and 56.7%,decreased the ratio of root to shoot.The results indicated that the biochar application promoted the Pakchoi root growth in red soil;and inhibited the Pakchoi root growth in fluvo-aquic soil.The biochar amendments decreased the nitrogen absorption efficiency,nitrogen partial productivity of Pakchoi by 64.7% ~ 73.5%,65.1% ~ 79.3% in fluvo-aquic soil.And biochar amendments increased the nitrogen absorption efficiency,and the nitrogen partial productivity of Pakchoi by 44.7% ~ 59.6%,and 32.0% ~ 63.2% in red soil.At the same time,biochar application significantly reduced the nitrate content of Pakchoi by 40.9% ~ 84.6% and 18.8% ~ 75.0%,respectively.Biochar application can promote the Pakchoi growth,increase its yield,reduce the nitrogen residue in red soil,and improve the nitrogen utilization efficiency.It has good ecological benefits.But biochar applation in fluvo-aquic soil can inhibit Pakchoi root development,reducing its yield,and nitrogen fertilizer utilization efficiency,the effective and safe application of biochar in fluvo-aquic soil still needs further exploration.