莱州湾海涂海水灌溉菊芋的磷肥效应的研究

在连续3年莱州湾海涂海水灌溉试验的基础上,2003年就不同浓度海水灌溉菊芋的磷肥效应进行了田间试验研究。结果表明,在海水灌溉下,磷肥对菊芋的增加产量与增产幅度均高于淡水灌溉,在50%海水浓度范围内,随着灌溉海水浓度增加磷肥的增产效应也逐渐提高,以50%浓度海水灌溉磷肥增产效应最大;海水灌溉下,施磷肥能显著促进菊芋对K+、Ca2+和Mg2+等有益离子的吸收与运输,尤其是明显提高菊芋在海水灌溉下的SK,Na,而抑制菊芋对Na+及Cl-等有害离子的吸收;在75%的海水浓度范围内,灌溉的海水浓度越高,磷肥对上述离子的影响强度越大;海水灌溉下,施用磷肥明显促进菊芋根部氮的含量,P3(P2O560kg/hm2)与P1(P2O50kg/hm2)处理相比较,在淡水、25%海水、50%海水、75%海水灌溉处理下,菊芋根部含氮量增加0.43、0.64、0.64、0.51个百分点。

Effect of phosphate fertilizer on yield and nutrient uptake by girasole(Helianthus tuberosus ) under irrigation with seawater in Laizhou' sea beach

Seawater irrigating agriculture is one of effective measures in reasonable using and exploitating seawater, saline soils and salt-tolerant plants. In 2003, the field experiments were carried out to study the effect of phosphate fertilizer on girasole (Helianthus tuberosus) irrigated with different concentration of seawater in mudflat along the coast of Laizhou (Shandong Province). The results were as follows: 1) The increased yields of tuber and aerial parts were more in the treatment with phosphorus fertilizer with the seawater irrigation than in the treatment with the fresh water. The effect of phosphate fertilizer on yield increased with increasing of seawater concentration and was largest in the treatment with irrigation of 50% seawater (W_3). For example, the tuber yield in the treatments with P_2 (P_2O_5 30 (kg/hm~2)), P_3 (P_2O_5 60 (kg/hm~2)) and P_4 (P_2O_5, 90 (kg/hm~2)) was 39.2%, 105.3%, 73.0% higher than that of the treatment with P_1 (P_2O_5 0 (kg/hm~2)) under W_3 (50% seawater) irrigation respectively. 2) Phosphorus fertilizer could enhance absorption of K~ , Ca~(2 )and Mg~(2 ), especially the selectivity ratio of S_(K,Na) (root/stem) and S_(K,Na) (root/leaf) and decline the absorption of Na~ and Cl~-. And the effect increased significantly with the augments of seawater concentrations up to 75% seawater. The contents of K~ , Ca~(2 )and Mg~(2 ) were higher in leaves than in stems and in roots, while the contents of Na~ and Cl~- were higher in roots than in stems and leaves. The selectivity ratio, S_(K,Na) (root/leaf), in the treatment of P_3 (P_2O_5 60 (kg/hm~2)) was, respectively, 52.7%, 65.8%, 68.5% and 68.9% higher than in control ( P_2O_5 0 (kg/hm~2), P_1) under irrigation with W_1 (fresh water), W_2 (25% seawater), W_3 (50% seawater) and W_4 (75% seawater). 3) Phosphate fertilizer significantly increased N content in roots of girasole (Helianthus tuberosus). For example, the N contents in roots in the treatment of P_3 (P_2O_5 60 (kg/hm~2)) was 0.43%, 0.64%, 0.64%, 0.51% higher than in control (P_2O_5, 0 (kg/hm~2), P_1) under irrigation with W_1(fresh water), W_2 (25% seawater), W_3 (50% seawater) and W_4 (75% seawater), respectively.