水氮耦合下小粒咖啡幼树生理特性与水氮利用效率

为探明经济热作小粒咖啡幼树的水氮精准管理模式,研究了4个灌水水平(WS,75%~85%田间持水量;WH,65%~75%田间持水量;WM,55%~65%田间持水量;WL,45%~55%田间持水量)和4个施氮水平(NH,0.60 g/kg;NM,0.40 g/kg;NL,0.20 g/kg;NZ,0 g/kg)对小粒咖啡幼树生理特性及水氮吸收利用的影响。结果表明:与WL相比,增加灌水使叶绿素、类胡萝卜素、丙二醛、脯氨酸和可溶性糖含量分别降低5.8%~15.5%、6.0%~14.4%、14.2%~30.3%、27.6%~60.0%和22.6%~57.5%,使根系活力和水分利用效率分别提高15.8%~63.8%和21.6%~29.6%,降低土壤硝态氮均值21.5%~36.2%。与NZ相比,增加施氮使丙二醛降低23.8%~49.8%,叶绿素、类胡萝卜素、脯氨酸、可溶性糖、根系活力和水分利用效率分别提高49.0%~88.4%、21.9%~60.9%、509%~703%、20.7%~52.3%、23.5%~41.8%和21.6%~53.9%,同时土壤硝态氮均值增加2.73~14.44倍。NZ和NL时氮素吸收总量与灌水量显著正相关;NM和NH时水分利用效率和氮素吸收总量均随灌水量先增后减。不同灌水条件下,水分利用效率、氮素吸收总量均与施氮量呈显著二次曲线关系。NMWH组合的水分利用效率最大,同时NM和NH处理的氮素表观利用效率和氮素吸收效率最大,因此NMWH为水氮高效利用组合。

Biochemical Property and Water and Nitrogen Use Efficiency of Young Arabica Coffee Tree under Water and Nitrogen Coupling

The object was to explore precise management mode of water and nitrogen to tropical economic crop of young arabica coffee tree, using four levels of irrigation, WS (75%~85% field capacity), WH (65%~75% field capacity), WM (55%~65% field capacity) and WL (45%~55% field capacity), and four levels of nitrogen, NH (0.60g/kg), NM (0.40g/kg), NL(0.20g/kg) and NZ (0g/kg). The effect of irrigation and nitrogen on biochemical index and water and nitrogen use of arabica coffee young tree was studied. The result showed that, compared with WL, increasing irrigation amount reduced chlorophyll, carotenoid, malondialdehyde, proline and soluble sugar by 5.8%~15.5%, 6.0%~14.4%, 14.2%~30.3%, 27.6%~60.0% and 22.6%~57.5% respectively, and increased root activity and water use efficiency by 15.8%~63.8% and 21.6%~29.6%, and reduced the average value of soil NO-3-N by 21.5%~36.2%. Compared with NZ, increasing nitrogen rate reduced malondialdehyde by 23.8%~49.8%, while increased chlorophyll, carotenoid, proline, soluble sugar, root activity and water use efficiency by 49.0%~88.4%, 21.9%~60.9%, 509%~703%, 20.7%~52.3%, 23.5%~41.8% and 21.6%~53.9% respectively, and increased the average value of soil NO-3-N by 2.73~14.44 times. Total N uptake was positively correlated with irrigation amount under NZ and NL treatment, and water use efficiency and total N uptake increased at first and then decreased with irrigation amount under NM and NH treatment. Water use efficiency and total N uptake were quadratic curve relation with nitrogen rate under deferent irrigation treatment. Water use efficiency of NM/WH treatment was the largest, and N apparent recovery fraction and N uptake efficiency were the largest under NM and NH treatment. Thus combination of NM/WH was the efficient use of water and nitrogen of young arabica coffee tree.