生物炭对间作体系中刨花润楠生长及土壤养分年际变化的影响

为探究生物炭对刨花润楠(Machilus pauhoi)的促生及土壤保肥的长期效应,以刨花润楠-梅叶冬青(Ilex latifolia)间作系统为研究对象,开展田间小区试验,研究0 kg(CK)、1.2 kg(T1)、2.4 kg(T2)、和4.8 kg(T3)4个生物炭用量对2015—2017年间刨花润楠生长动态及土壤养分含量年际变化的影响。结果表明:移栽前期,刨花润楠生长较慢,但16月后生长速度加快。生物炭可促进刨花润楠株高、叶长及叶宽的生长,但不同用量间差异不显著;与对照相比,T1、T2和T3处理下刨花润楠地上部干重分别增加35.71%、59.02%和31.81%,地下部干重分别增加28.02%、39.69%和20.52%;3个年份生物炭处理下0—15 cm和15—30 cm土层pH、有机质和速效钾含量均高于对照,且均随着生物炭施用量的增加而增加;生物炭处理下土壤全氮、全磷、全钾含量均略有提高。施用生物炭后,2015年和2016年0—15 cm土层碱解氮含量降低,2017年则有所增加,但影响不显著(P0.05)。15—30 cm土层碱解氮含量变化不明显;生物炭对2015年0—15 cm土层有效磷含量的影响不显著,到2016年和2017年则增加其含量,且T1和T3处理下效应最显著。生物炭可增加15—30 cm土层有效磷含量,但到后期(2017年)效应不显著(P0.05)。总体看来,不同处理下土壤各养分含量均表现为0—15 cm15—30 cm,2015年2016年2017年。刨花润楠生物量与0—15 cm土壤养分含量间存在显著正相关性,各养分含量间也存在正相关关系。适量生物炭(T2)处理促生保肥效应最佳,且具有长效性。

Effects of biochar on Machilus pauhoi growth and soil nutrient interannual variation in an intercropping system

To explore the long-term effects of biochar on growth promotion and soil nutrients of the intercropping system of Machilus pauhoi and Ilex latifolia, a field plot experiment was carried out to study the growth dynamics of M. pauhoi and inter-annual variability of soil nutrient content from 2015 to 2017 under the treatment of four biochars of 0 (CK), 1.2 (T1), 2.4 (T2), and 4.8 kg (T3). The results showed that the M. pauhoi growth rate was slow in the early stage, but accelerated after transplantation at 16 months. Biochar promoted the height, leaf length, and leaf width growth of M. pauhoi, but there was no significant difference between the different dosages. Compared with the control, the shoot dry weight of M. pauhoi under T1, T2, and T3 treatments increased by 35.71%, 59.02% and 31.81% respectively, whereas the root dry weight increased by 28.02%, 39.69%, and 20.52% respectively. The soil pH, organic matter, and available potassium content in 0-15 and 15-30 cm soil layers increased with biochar application rates over three years. After biochar application, the content of total nitrogen, phosphorus, and potassium in the soil increased slightly. The alkali hydrolysable nitrogen content in the 0-15 cm soil layer decreased in 2015 and 2016, but increased in 2017 and the increment effect was not significant (P > 0.05). There was no obvious change in alkali hydrolysable nitrogen content in the 15-30 cm soil layer. The change in available phosphorus content in the 0-15 cm soil layer in 2015 was not obvious after biochar application, but it increased in 2016 and 2017. In addition, the effect of T1 and T3 treatments were the most significant. Biochar increased the available phosphorus content in the 15-30 cm soil layer, but it was not significant later (year 2017) (P > 0.05). In general, the trend of the soil nutrient content under each treatment was: 0-15 > 15-30 cm, year 2015 > 2016 > 2017. There was a significant positive correlation between M. pauhoi biomass and the 0-15cm soil nutrient content, and different soil nutrient contents. With respect to biochar application, the effect of T2 was most pronounced with regard to promoting growth and holding fertilizer and was also long lasting.