间作对咖啡和澳洲坚果根系形态、分布及养分累积的影响

为探明澳洲坚果与咖啡间作对地上部生长及地下部互作效应,为生产推广复合高效栽培模式提供理论依据,布置了咖啡和澳洲坚果间作盆栽实验,以二者分别单作为对照,分析植株的生长量、生物量、养分含量、根系形态以及土壤养分的差异。结果表明：（1）间作咖啡和间作澳洲坚果根干重、茎干重、单株总干重分别为40.86、50.38、148.34 g,22.38、33.19、111.97 g,间作咖啡显著大于间作澳洲坚果,叶干重二者差异不显著;幼龄期间作条件下,咖啡生长速率快于澳洲坚果。间作咖啡、间作澳洲坚果与各自单作根、茎、叶、单株干物质累积量差异均不显著。（2）间作澳洲坚果叶氮累积量2135.27 mg显著大于间作咖啡的1957.60 mg,除此之外,间作咖啡根氮、磷、钾,茎氮、磷、钾,叶磷、钾,单株总氮、磷、钾累积量均显著大于间作澳洲坚果,表明幼龄期间作条件下,咖啡养分累积量占优势;间作澳洲坚果根氮、钾累积量742.80、103.22 mg显著大于单作的535.00、37.77 mg,可见,间作根系竞争促进澳洲坚果增加根部氮的分配,提高根钾的吸收累积。（3）间作咖啡和间作澳洲坚果根长、根表面积、根体积在本株侧面根系生态位分布量占总取样量的62.63%~65.67%,其次是在株间根系生态位分布量占总取样量的16.01%~27.53%,在对应本株近侧和对应本株远侧面2个根系生态位分布较少,可见间作后二者根系主要分布于自身根系生态位,在株间位置根系交叉重叠,未在土壤深度和广度空间形成差异分布,属于间作竞争型根系统。咖啡与澳洲坚果均属于浅根系,侧根直径小,成龄澳洲坚果是高大乔木,随着时间的推移,与咖啡间作将处于地上、地下部竞争优势。

Effect of Coffee and Macadamia Intercropping on Root Morphology,Distribution and Nutrient Accumulation

In order to explore the effects on plant growth, root morphology, distribution and nutrient accumulation based on coffee-macadamia intercropping systems, an experiment was performed with three planting patterns: monoculture coffee (MC), monoculture macadamia (MM), and coffee-macadamia intercropping (IMC). The results showed that: (1) in IMC, the coffee leaves dry weight was no significantly compared with macadamia, but the root dry weight, stem dry weight and total dry weight per plant of coffee and Macadamia were as follows 40.86, 50.38, 148.34 g and 22.38, 33.19, 111.97 g. It showed those of coffee were significantly higher than those of Macadamia. the young coffee plant growth rate was faster than that of young Macadamia plant. The dry weight of coffee root, stem, leaves and total per plant dry weight were not significantly different in MC and in IMC, and so as the macadamia. (2) in IMC, the N accumulation of macadamia leaves was 2135.27 mg, significantly higher than that of coffee (1957.60 mg). Beyond that, the N,P and K accumulation of stem and root; the P and K accumulation of leaf; total N, P and K accumulation per plant for coffee were significantly higher than those of macadamia. As a result, the young coffee plant had more nutrient accumulation compared with macadamia. The N and K accumulation of macadamia root was 742.80, 103.22 mg in IMC, higher than that of 535.00, 37.77 mg in MM, indicating that the macadamia N allocation to root increased due to the root competition between the two, and root K accumulation increased. (3) The root length, root surface area and root volume near the side of coffee and macadamia root distribution position was accounted for 62.63%~65.67% of the total sampled, The second root distribution position was between the two plants, accounted for 16.01%~27.53% of the total sampled. The least was near the side of the correspond plant and beyond the side of the correspond plant. So more root of coffee and macadamia was observed atthere-self root niche, and the root was overlapping between the two plant root space, the spatial distribution of the two plants root system was not separated in soil depth and width, showing that the two crops intercropping had a competition root system. Coffee and macadamia are shallow rooted plants with, thin root diameter. Macadamia is a large tree, so it will be in dominant position in field intercropping.