CAJ | 학술논문

以黄土丘陵区2、6、10、15龄旱作枣林(Ziziphus jujube cv.Junzao)为研究对象,采用根钻法,距树干0.5、1、1.5 m处、分层(0.2 m)钻取土样,分析了旱作枣林细根随树龄的变化特征.结果表明:随着枣林树龄增大,枣林细根根长密度增加,比根长减小;2龄枣树细根主要分布于径向1.5 m以内和垂向1.6 m以上,10、15龄枣树细根分布超过径向1.5 m和垂向3 m以上,并在株间形成根系高密度区,6龄枣树细根径向分布范围大于2龄,垂向分布与10龄和15龄接近;不同树龄枣林细根根长密度均随土层深度增加而减小,且主要集中在0~0.6 m土层中;随着树龄增加,细根根长密度径向分布无差异(10、15龄).研究表明:2、6龄枣林应靠近树干地表处施肥,而理论上成熟期10、15龄枣林可在林内任意位置施肥;同时为防止枣林减产和退化,需增加枣林管理措施以有效降低枣树自身奢侈性耗水和非生产性耗水.
이황토구릉구2、6、10、15령한작조림(Ziziphus jujube cv.Junzao)위연구대상,채용근찬법,거수간0.5、1、1.5 m처、분층(0.2 m)찬취토양,분석료한작조림세근수수령적변화특정.결과표명:수착조림수령증대,조림세근근장밀도증가,비근장감소;2령조수세근주요분포우경향1.5 m이내화수향1.6 m이상,10、15령조수세근분포초과경향1.5 m화수향3 m이상,병재주간형성근계고밀도구,6령조수세근경향분포범위대우2령,수향분포여10령화15령접근;불동수령조림세근근장밀도균수토층심도증가이감소,차주요집중재0~0.6 m토층중;수착수령증가,세근근장밀도경향분포무차이(10、15령).연구표명:2、6령조림응고근수간지표처시비,이이론상성숙기10、15령조림가재림내임의위치시비;동시위방지조림감산화퇴화,수증가조림관리조시이유효강저조수자신사치성모수화비생산성모수.
Fine roots (roots≤2 mm in diameter) are the primary organ of absorbing water and nutrients in forest systems. Since the initiation of the large-scale ecological rehabilitation project (known as "Grain for Green" project) by the Chinese central government in 1999, the acreage of the jujube orchard has been increased rapidly on the Loess Plateau mainly for conserving soil plus water and raising economic benefits. However, the knowledge of fine roots dynamics during stand development is lacked to guide management practices for rain-fed jujube plantations, and most studies focused on the vertical dynamic of fine roots, with the method of random sampling and missed characterizing the radial distribution of fine roots. The objective of this study was to investigate the characteristics of fine roots in a rain-fed jujube plantation (Ziziphus jujube Mill. cv. Lizao) with a range of stand ages (2, 6, 10, and 15 years) in Qingjian County in Shaanxi Province (37°15′N, 118°18′E). Specifically, the fine root length density (FRLD), and the specific root length (SRL) in different age classes of a rain-fed jujube plantation at different radial distances were characterized. The distribution of the jujube trees was relatively uniform in 2 m between rows with the distance of 3 m between plants in each row, and the fine root samples were collected at 0.2 m increments to a depth of 3 m in trisection radiation from the representative tree trunk (0, 120, and 240°) at 0.5 m, 1 m, and 1.5 m radial distance in October 2014. The soil samples were collected with a root auger, which included a long cylindrical steel auger with an internal diameter of 0.09 m. The results showed that the fine root length density increased with the stand age increasing, and the surface soil had the highest fine root length density values in the 0-0.6 m surface soil layer, representing 60%-90% of the total fine root length density (from 0 to 3 m) in all study sites. The fine roots of the 2-year-old jujube plantation were distributed mainly in a range of 1.5 m, horizontally, within a thickness of 1.6 m, vertically; while those the 10 and 15-year-old jujube trees have exceeded 1.5 m in the radial direction and 3 m in the vertical direction, and a high-density region of fine roots were observed in the middle of the inter-row in 10, and 15-year-old jujube trees. This suggested that through ten years of fine root system development in the dense rain-fed jujube plantation, the fine roots were overlapped between neighboring jujube trees, and there was no difference of fine root length density in the radical distribution in the mature jujube trees (10 and 15 years,p>0.05). Stand age had a significant effect on the specific root length (p<0.05), and the average values of the specific root length were 6.08 m/g, 4.80 m/g, 4.50 m/g, and 3.80 m/g in 2, 6, 10, and 15-year-old jujube trees, respectively. This implied that the younger stands (2 and 6 years) had relatively "thinner" fine roots compared with the mature stands in the rain-fed jujube plantation, which likely occurred because young stands could take advantage of scarce moisture and nutrients. Our results quantified the extent and magnitude of fine root distribution in the soil layers during a chronosequence, which may reflect an increase in the concentration of fertilizer in these soil layers. The outcomes suggest that fertilizer can be placed closing to the main trunk in young stands, whereas fertilizer can be more evenly distributed in mature stands, and local farmers should conduct necessary measurement strategies for soil moisture conservation in the rain-fed jujube plantation.