低锌旱地土壤水分对小麦产量和锌利用的影响

【目的】西北旱地土壤有机质含量低,pH和碳酸钙含量高,导致土壤有效锌含量低,加之水分缺乏,不仅制约冬小麦生长和产量,还严重影响小麦锌的吸收利用。本研究选取西北旱地典型缺锌区,在土施锌肥的基础上,设置了2年的补充灌水田间试验,进一步研究水分对土壤锌有效性、 小麦生长、 产量以及锌和相关元素吸收利用的影响。【方法】田间试验于2010~2012年在陕西永寿县进行,采用裂区设计,锌肥为主处理,在不施锌与施锌(ZnSO4·7H2O)50 kg/hm2的基础上,设置在冬小麦关键生长期补充和不补充灌水2个副处理。在成熟期采集植株样品,测定了小麦产量、 生物量,各器官部位的锌及氮、 磷、 钾、 铁的含量; 采集0—40 cm土层土壤,测定了土壤有效性锌含量。【结果】在返青期、 孕穗期补灌20~30 mm水分对小麦产量、 土壤有效锌含量无显著影响,却有提高小麦各部位锌含量、 锌肥利用率的趋势,不施锌和施锌条件下,灌水比不灌水处理小麦籽粒锌含量分别提高3.8%~16.3%、 3.8%~13.1%,灌水使锌肥利用率提高21.2%~177.8%。灌水量和灌水时期的不同也影响锌在小麦各器官部位的分配与累积,第一季施锌和不施锌条件下,灌水比不灌水处理锌收获指数分别降低5.1%和2.0%,而第二季锌收获指数分别提高2.1%和2.7%。两季灌水对小麦籽粒中铁及大量元素氮磷钾含量的影响亦各不相同。【结论】在旱地缺锌土壤上,小麦生长关键期灌水对小麦产量、 土壤有效锌含量无显著影响,却有提高小麦各部分锌含量、 锌肥利用率的趋势,说明水肥结合对旱地石灰性土壤锌和锌肥有效性的影响应引起进一步重视,这对提高旱地缺锌地区作物和人体锌营养水平具有潜在意义。

Effects of soil moisture on wheat grain yield and zinc utilization in zinc-deficient dryland soil

Objectives] Zinc-deficient in dryland soil caused by low organic matter, high pH and calcium carbonate contents, along with the deficiency of water supply not only constrains the winter wheat growth and yield, but also uptake and utilization of zinc( Zn) .Therefore, a two-year field experiment was carried out on a typical Zn-deficient dryland soil with irrigation to the Zn-applied winter wheat in the northwest part of China to investigate the effects of soil moisture on soil Zn availability, wheat growth, yield formation, uptake and utilization of Zn and other relevant elements.Methods]The field experiment was conducted in Yongshou County of Shanxi Province during 2010-2012.A split plot design was used with the Zn application rates of 0 and 50 kg/hm2 as the main plot factors, the addition and no addition of supplemental irrigation as subplot factors.At mature stage, samples were collected and measured, which included grain yield, crop biomass, contents of Zn, nitrogen(N), Phosphorus(P), potassium (K)and Ferrum(Fe)in different organs or parts of crops.Zn content was also determined for 0-40 cm layers of soil.Results] Results showed that irrigation of 20 to 30 mm water at jointing or booting stage had no significant effects on grain yield and soil available Zn(DTPA-Zn).However, it tended to increase grain Zn contents and Zn fertilizer use efficiency.The grain Zn contents increased by 3.8%-16.3%and 3.8%-13.1%, when supplemental was irrigation under no Zn and Zn application treatments, respectively.Zn use efficiency under supplemental irrigation was increased by 21.2%-177.8%.Supplemental irrigation amount and time also affected the Zn accumulation and distribution in different organs or parts of winter wheat.The Zn harvest index of Zn and no Zn application treatments was decreased by 5.1% and 2.0% in 2010-2011, increased by 2.1% and 2.7% in 2011-2012, respectively. Effects of supplemental irrigation on Fe and macro-element N, P and K were also different in both years.Conclusions] On Zn-deficient dryland soil, supplemental irrigation showed no significant effects on winter wheat grain yield and soil available Zn contents, however, it increased the Zn contents in different organs or parts and Zn fertilizer use efficiency.This indicates that integrated management of water and fertilizer with increasing the availability of soil Zn and fertilizer Zn should be given special attentions.Especially in dryland area with Zn-deficient soils it is of potential significance for the improvement of Zn nutrition levels for local crops and people.