Element uptake of sugar beet (Beta vulgaris L.) on calcareous chernozem soil

In 1981, in the 8th year of a long-term NPK fertilisation experiment set up on calcarcous loamy chernozem soil, the effect of different nutrient suppl y levels and their combinations were examined on the yield components and e lement uptake of sugar beet. The soil of the growing site contained satisfa ctory supplies of Mn, Mg and Cu, moderate supplies of N and K and poor supp lies of P and Zn. The experiment consisted of 4N x 4P x 4K = 64 treatments, on a total of 128 plots. The main results can be summarised as follows: 1. Compared to the control extreme supplies of NPK led to a doubling of the young leaf-blade mass and an increase of 3-4 times in the mass of the leaf -stalk. The minimum and maximum values of yield components at harvesting, a s a function of the nutrient supply, were as follows: beet/foliage ratio 2. 1 and 6.7, plant density 53 and 92 thousand/ha, mean beet mass 490 and 910 g/beet, beet yield 42 and 56 t/ha, foliage yield 10 and 25 t/ha. 2. Parameters of industrial quality also changed. deteriorating drastically on over-fertilised soil: digestion 17 and 19.3 %, refined sugar 12.7 and 1 6.7 %, molasses 2.3 and 4.2 %, toxic N 3.0 and 9.0, K 4.3 and 7.4, Na 0.8 a nd 2.0 mgeq/100 g. The crude sugar yield ranged from 7.0 to 10.4 t/ha and t he refined sugar yield from 6.3 to 9.0 t/ha. 3. Depending on the nutrient supplies of the soil, differences of 2-3 times were observed in the clement concentrations of the sugar beet organs, the quality-reducing effect of luxury uptake being manifest in the composition of the young leaf-blades and leaf-stalks and in that of the foliage and bee ts at harvest. All the organs examined could be used for the diagnosis of t he nutrient status. 4. The element uptake of sugar beet was influenced to the greatest extent b y the N supplies, which stimulated the uptake of all the elements. The beet s accumulated 2/3 of the N, P and Fe and 3/5 of the K, while the foliage ac cumulated 56 % of the Mg and 75-76 % of the Na and Ca. The quantity of N ab sorbed by the foliage + beet ranged from 100 to 508 kg for N, 160 to 355 kg for K (192 to 426 kg K2O) and 8 to 38 kg for P (18 to 87 kg P2O5) The upta ke of Na, Mg, Ca, Cu and Zn also increased several times. 5. The specific element content of 10 t beet + the relevant foliage yield e xhibited the following minimum and maximum values depending on the treatmen ts: 24-88 kg N, 40-58 kg K (48-70 kg K2O), 6-42 kg Na, 7-24 kg Mg, 8-21 kg Ca, 2-6 kg P (5-14 kg P2O5), 2-7 kg Fe, 300-400 g Mn, 15-80 g Zn and 22-52 g Cu. The lower specific element requirements could be used as a guideline for the Hungarian extension service. 6. Scanning electron microscopic (SEM) and transmission electron microscopi c (TEM) analyses indicated that the cell-waits of beets over-fertilised wit h N and weighing over I kg were almost a tenth thinner than those of small N-deficient beets (Figure I). Such beets are more easily damaged and less r esistant to microorganisms causing rotting, so they not only have poorer in dustrial quality, but are also difficult to store.