土壤改良剂对黄土高原旱作苹果园土壤理化性质及经济效益的影响

Effects of Soil Amendments on Soil Physical and Chemical Properties of Dryland Apple Orchards and Economic Efficiency in the Loess Plateau

土壤有机质低、保水能力差是阻碍黄土高原苹果产业良性发展的两大制约因素。本研究针对上述问题,选取生物炭、大分子保水剂、枯草芽孢杆菌和胶质芽孢杆菌作为改良剂开展了为期两年的大田试验。研究发现施加生物碳、大分子保水剂、枯草芽孢杆菌以及胶质芽孢杆菌较对照相比土壤全氮含量平均提升88.86%、49.38%、30.05%和25.35%,土壤硝态氮平均提升1.70、1.50、1.29和1.49倍,土壤铵态氮平均提升高达29.01、8.50、12.75和22.60倍;生物炭对土壤有机碳储量影响最显著,提升高达3.70倍以上。通过通径分析发现土壤pH、土壤导水率及硝态氮直接影响有机碳储量,土壤容重、铵态氮、速效钾及土壤团聚体通过影响土壤pH和土壤导水率间接影响土壤有机碳储量。土壤改良剂对果树新稍、果径、果树根系分布情况及产量均有一定影响,在0~20 cm土层深度,施加生物炭较对照处理果树根系密度提升了3.05倍。除施加生物炭外,其它改良剂对苹果产量影响不显著。通过经济效益评价分析,仅施加生物炭后改良经济效益为正,达到1149.26元/hm^(2)。建议将施用生物炭作为改良果园土壤、提高苹果产量的有效途径。

Low soil organic matter and poor water holding capacity are two major restrictive factors hindering the benign development of the apple industry in the Loess Plateau.In order to solve the above problems,biochar,Super Absorbent Polymers,Bacillus subtilis and Bacillus mucilaginosus were selected as soil amendments for two years field experiment.The results showed that biochar,Super Absorbent Polymers,Bacillus subtilis and Bacillus mucilaginosus addition increased the average total nitrogen content of soil by 88.86%,49.38%,30.05% and 25.35% compared with CK,respectively;Compared with CK,the mean of soil nitrate nitrogen was increased by 1.70,1.50,1.29 and 1.49times and soil ammonium nitrogen was increased by 29.01,8.50,12.75 and 22.60 times,respectively.Among these soil amendments,biochar has the most significant impact on soil organic carbon storage,with an increase of more than 3.70 time,compared with CK.Through path analysis,soil pH,hydraulic conductivity and nitrate nitrogen directly affect soil organic carbon storage,and soil bulk density,ammonium nitrogen,available potassium and soil aggregates indirectly affect soil organic carbon storage by affecting soil pH and soil hydraulic conductivity.Soil amendments have certain effects on the new height,fruit diameter,root distribution and yield of fruit trees.After the application of biochar,the root density of fruit trees increased by 3.05 time compared with the CK at the depth of 0~20 cm soil layer and the apple yield increased significantly compared with the control(P<0.05).Through the economic benefit evaluation and analysis,the economic benefit of the improvement after only applying biochar is positive,reaching 1149.26 yuan·hm^(-2).It is suggested that the application of biochar should be an effective way to improve orchard soil and increase apple yield.