Title: The effect of potassium fertilizers on soil and plant, as established by a 35-year field experiment. Personal Authors: Hofmann, E., Büchner, A., SCHULZ-SCHOMBURGK, E. Author Affiliation: Tech. Hochsch., Weihenstephan. Editors: No editors Document Title: Z. PflBau. PflSch. Abstract: The effects are compared of various K fertilizers on cereals and some legume and root crops on loessial sandy loam rich in K (0.31% K2O). The fertilizers were applied at annual average rates of 94.2 and 103.3 kg./ha. on plots receiving an annual average of 52 kg./ha. of N and 60.5 kg./ha. of P and occasional lime or manure. Responses varied, from practically nil with winter rye to 115% increase in field beans. No striking difference in the effect of kainit, 40% or 50% KCl or K2SO4 were established, but KCl was slightly superior, particularly on turnips and most cereals, and increased leaf and straw production; potatoes, oats, beans and rapeseed apparently preferred K2SO4. The K requirement and uptake of soil K varied considerably with crops, but the applied amounts of K fertilizers were insufficient to make up for the removal during harvests. Lime status, soil reaction and base saturation were not significantly affected, and humus content was uniformly increased by fertilizer treatments. Low K levels slightly decreased the percentage of humic acid whereas a dressing of 300 dz./ha. of farmyard manure increased humus content by 0.5% without exerting any effect on yields at high K levels. Analytical values obtained by the methods of Neubauer, Niklas or Egnér agreed with the results of field experiments.
Posted on: Thu, 20 Mar 2014 21:17:45 +0000
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