An agronomic and physiological re-evaluation of the potassium and sodium requirements and fertilizer recommendations for sugar beet
An agronomic and physiological re-evaluation of the potassium and sodium requirements and fertilizer recommendations for sugar beet
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对甜菜钾和钠需求以及肥料建议的农艺和生理重新评估
DOI：
10.1017/s0021859607007630
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
P. Barraclough
中科院分区：
文献类型：
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作者：
G. Milford;P. Jarvis;J. Jones;P. Barraclough
摘要在2000年至2005年的6年系列试验中，使用长期存在的交换性表土钾（Kex）差异的参考地块，重新检查了甜菜对钾（K）和钠（Na）的需求。两组地块的表土浓度Kex范围为40-550毫克/公斤，每个位于一个单独的领域，一个粉质粘壤土在Rothamsted和其他对比桑迪壤土在Woburn。在Rothamsted研究了表层土壤Kex与施用的N、K和Na肥料之间的相互作用。在这些明确规定的条件下，在表层土壤Kex浓度为120-150 mg/kg，即土壤K指数为2-时，调整后的净甜菜的最大产量为55-71 t/ha，两种土壤之间的差异很小，这是由于交换性土壤Na和下层土壤Kex的差异造成的。有没有新施钾肥的产量反应，即使在低钾地块的反应可能是预期的。它的结论是，英国甜菜钾肥使用的现有建议不需要调整，以允许现代作物的更高产量。在Rothamsted（土壤含15-20 mg Na/kg）的任何表层土壤Kex水平下，对NaCl肥料没有产量反应，但在Woburn（桑迪壤土仅含5-10 mg Na/kg）的低Kex地块上，产量增加。土壤交换性钾、钠的状况对施用NaCl肥料后的钠吸收有很大影响。在低钠土壤沃本，几乎所有的应用钠被甜菜种植的地块与低浓度的表土Kex和一半的地块有足够的浓度的表土Kex相比，三分之二和五分之一，分别在较高的钠含量的土壤在Rothamsted。植株将0.75的K和0.95的Na分配到地上部，其余分配到贮藏根。这种分布模式是一致的网站，季节和土壤钾供应。通过测定茎和贮藏根组织水中K和Na的毫摩尔浓度（mmol/kg），研究了K和Na之间的生理相互作用。在地上部的K的组织水浓度的渐近增加与浓度的Kex在表土中，K浓度的增加是伴随着相应的减少组织水浓度的Na。最大浓度的钾在拍摄组织水（和最低浓度的钠）时，表土含有最低的200毫克Kex/公斤。最适生理组织水Na浓度为c。90-100 mmol/kg;维持这一水平需要表层土壤中交换性钠至少为25 mg/kg。在不受土壤Kex限制的情况下，植物的总组织水浓度维持在c。地上部K+Na为300-350 mmol/kg。这是实现与80 mmol的钠和230 mmol的K/kg的组织水的高钠含量的土壤在Rothamsted，和40 mmol的钠和275 mmol的K/kg的组织水的低钠土壤在Woburn。在工厂配糖室和那些使用标准的实验室化学分析和工厂之间的估计交付的甜菜和表土Kex的组织水中的K的浓度之间的测量甜菜K之间建立了显着的相关性。使用这些关系来估计钾在收获的甜菜，并提供反馈给种植者对他们的土壤中的钾的状态，和英国甜菜上使用钾和钠肥料的研究的影响进行了讨论。
SUMMARY The potassium (K) and sodium (Na) requirements of sugar beet were re-examined in a 6-year series of experiments between 2000 and 2005 using reference plots with a wide range of long-established differences in exchangeable topsoil K (Kex). Two groups of plots with a topsoil concentration Kex range of 40–550 mg/kg were used, each situated within an individual field, one on a silty clay loam at Rothamsted and the other on a contrasting sandy loam at Woburn. The interactions between topsoil Kex and applied N, K and Na fertilizers were studied at Rothamsted. Under these well-defined conditions, maximum yields of 55–71 t/ha of adjusted clean beet were achieved with a topsoil Kex concentration of 120–150 mg/kg, i.e. at Soil K Index 2–, with a small difference between the two soils being accounted for by differences in exchangeable soil Na and subsoil Kex. There were no yield responses to freshly applied fertilizer K, even on low K plots where responses might be expected. It is concluded that the existing recommendations for K fertilizer use on UK sugar beet do not need to be adjusted to allow for the higher yields of modern crops. There were no yield responses to NaCl fertilizer at any level of topsoil Kex at Rothamsted (where the soil contained 15–20 mg Na/kg), but yields were increased on low Kex plots at Woburn whose sandy loam contained only 5–10 mg Na/kg. The uptake of Na from the applied NaCl fertilizer was strongly influenced by the exchangeable K and Na status of the soil. On the low Na soil at Woburn, almost all of the applied Na was taken up by sugar beet grown on plots with low concentrations of topsoil Kex and half of it on plots with adequate concentrations of topsoil Kex compared with two-thirds and one-fifth, respectively, on the higher Na-content soil at Rothamsted. Plants partitioned 0·75 of their K and 0·95 of their Na to the shoot and the balance to the storage root. This pattern of distribution was consistent across sites, seasons and soil K supply. The physiological interactions between K and Na were studied by examining their millimolar concentrations in the tissue-water (mmol/kg) of the shoots and storage roots. The tissue-water concentrations of K in the shoot increased asymptotically with the concentration of Kex in the topsoil, and the increase in K concentration was accompanied by a corresponding decrease in the tissue-water concentration of Na. Maximum concentrations of K in shoot tissue-water (and minimum concentrations of Na) were achieved when the topsoil contained a minimum of 200 mg Kex/kg. The optimal physiological tissue-water concentration of Na in shoots was estimated to be c. 90–100 mmol/kg; maintenance of this level required a minimum of 25 mg/kg of exchangeable Na in the topsoil. When not limited by soil Kex, plants maintained a total tissue-water concentration of c. 300–350 mmol/kg of K+Na within the shoot. This was achieved with 80 mmol of Na and 230 mmol of K/kg of tissue water on the high Na-content soil at Rothamsted, and with 40 mmol of Na and 275 mmol of K/kg tissue water on the low-Na soil at Woburn. Significant correlations were established between measurements of beet K made in the factory tarehouse and those made using standard laboratory chemical analyses and between factory estimates of the concentrations of K in the tissue-water of delivered beet and the topsoil Kex. The uses of these relationships to estimate the off-takes of K in the harvested beet and provide feedback to growers on the K status of their soils, and the implications of the study for the use of K and Na fertilizers on UK sugar beet are discussed.