木薯氮素营养状况的SPAD仪诊断..docVIP

木薯氮素营养状况的SPAD仪诊断 柳红娟1，刘子凡1*，黄洁2 (中国热带农业科学院热带作物品种资源研究所 海南 儋州 571737；海南大学农学院海南 海口 570228) 块根形成期、块根膨大期和块根工艺成熟期分别为45.19、43.09、40.6344.31、42.49、40.51。在块根形成期块根膨大期和块根工艺成熟期0.63和1.34Tropical Crops Genetic Resources Institute, CATAS, Hainan Danzhou 571737, China) Abstract: In this paper, taken the cassava variety of SC8 as tested materials, the change of cassava leaf SPAD value, fresh cassava yield and starch yield during different growing period were studied with nitrogen supply. The results showed that (i)at the root initiation stage and the root bulking stage, the leaf SPAD value varied with nitrogen fertilization levels in linear-plateau regression modes, and in linear regression modes at the root technical maturity stage.(ii) Fresh cassava yield and starch yield varied with the leaf SPAD value in a quadratic-function modes at root initiation stage, root bulking stage and the root technical maturity stage, threshold SPAD values of different growth stages of cassava were obtained, which were critical for the instruction of nitrogen fertilization in cassava by SPAD-502. when fresh cassava yield was the highest,SPAD values were 45.19,43.09,40.63,respectively; when starch yield,and 44.31,42.49,40.51,respectively. (iii) when the observed SPAD value was less one unit than the critical SPAD value at the three stages,and the amount of nitrogen apply was less than 1.98 kg/667m2, the increasing amount of nitrogen apply were 0.42, 0.63 and 1.34 kg/667m2 in the three stages; the amount of nitrogen apply was more than 1.98 kg/667m2, the additional apply amount would be reseached in advance. Key Words: Cassava; SPAD values; Nitrogen nutrition diagnose 木薯是世界大薯类作物，我国第大热带作物。[3~7]等特点，即使在非常贫瘠的土壤上，也能获得一定的产量[8]。另一方面，木薯对肥料的施用又非常敏感，比如施肥量、肥料施用时期等[9~13]。SPAD-502是一种便携的叶绿素检测仪，其读数可以较好地反映植物叶片叶绿素的浓度[14~17]，而且与植株氮素浓度以及产量均有较好的相关，并可作为氮肥追肥的依据[18~20]。然而，SPAD-502叶绿素仪应用在木薯上的本文主要研究不同木薯的高产栽培提供理论依据。 供试材料为华南8号，由中国热带农业科学院热带作物品种资源研究所提供。 1.2 试验方法 1.2.1 试验地条件试验于2011年212月在中国热带农业科学院热带作物品种资源研究所基地进行，试验地土壤基本情况：土壤为砖红壤，p