生物炭添加对黄土旱区土壤水肥环境及谷子产量形成的影响

Effect of biochar addition on soil water and nutrient contents and yield formation of millet in loess arid region

黄土旱区土壤有机质含量偏低,有限水肥资源难以高效利用。生物炭具有调节土壤孔隙环境和水肥有效性的潜力。有关生物炭调节黄土旱区土壤水肥运移,提升特色作物谷子产量的关联机制值得深入分析。为明确生物炭添加对陕北黄土旱区土壤水肥环境和谷子产量形成的影响,探讨生物炭在该地区的增产增效潜力,本研究以“晋谷21号”为材料,设置CK(0 t·hm^(-2))、C1(2 t·hm^(-2))、C2(4 t·hm^(-2))、C3(8 t·hm^(-2))、C4(16 t·hm^(-2))5个梯度的施炭处理,连续等量施炭2年,开展大田定位试验。结果表明:(1)添加适量生物炭能有效提升土壤含水量,但高施炭量不利于土壤水分的储存利用。连续施炭2年,谷子拔节期和成熟期C3土壤含水量较CK分别显著提升21.4%、30.5%,C4较C3分别降低8.83%、7.25%,但无显著差异。(2)连续2年增施生物炭,C4处理土壤pH值、有机质、氨态氮、硝态氮和速效钾含量较CK提升4.28%~29.4%;土壤速效磷含量随增施生物炭的剂量先增后减,C4速效磷含量较CK显著下降7.27%。(3)添加生物炭能有效提升谷子生物量和产量,C3施炭条件下,谷子成熟期地上部生物量较CK显著提升17.8%,谷子产量相较于CK显著提升16.9%。综上,添加适量生物炭能有效改善陕北黄土旱区土壤水肥环境,调节谷子生物量积累,促进碳水化合物转化,提升谷子产量。

The content of soil organic matter in loess arid region is low,and the limited resources of water and fertilizer in dry farmland lead to low water and nutrient use efficiencies.Biochar has the potential to regulate the soil porosity environment and the availability of water and fertilizer.Therefore,the related mechanisms of biochar promoting the grain yield and regulating the soil water and fertilizer transport in loess arid region are worthy of in-depth exploration.In order to clarify the effect of biochar addition on soil water and nutrient contents,and yield formation of millet in loess arid region in northern Shaanxi Province,"Jingu 21"was used in this study.Five levels of biochar application were applied,i.e.CK(0 t·hm^(-2)),C1(2 t·hm^(-2)),C2(4 t·hm^(-2)),C3(8 t·hm^(-2))and C4(16 t·hm^(-2)),and the same amount of carbon for each level was applied consecutively for 2 years.The results showed that(1)Adding proper amount of biochar could effectively increase soil water content,but excessive addition of biochar was not conducive to soil water storage and utilization.The soil water content under C3 at the jointing and maturing stages was significantly increased by 21.4%and 30.5%compared with CK,and of the water content under C4 decreased by 8.83%and 7.25%for respective growth stages compared with C3,but there was no significant difference.(2)Soil pH value,organic matter,ammonium,nitrate and avail-able potassium contents under C4 increased by 4.28%-29.4%compared with CK after two years of biochar application.The soil available phosphorus content increased first and then decreased with the increase of biochar application,and the available phospho-rus content under C4 decreased by 7.27%compared with CK.(3)The addition of biochar effectively improved the biomass and yield of millet.Under C3,the above-ground biomass of millet at the mature stage increased by 17.8%compared with CK,and the yield of millet increased by 16.9%compared with CK.In conclusion,appropriate amount of biochar application can effectively improve the soil water and fertilizer nutrient contents in the loess arid region in northern Shaanxi,and consequently favorite the accumulation of grain biomass,the transformation of carbohydrate and yield gain.