01756naa a2200253 a 450000100080000000500110000800800410001910000260006024500680008626000090015430000190016349000080018252010390019065000110122965000090124065300110124965300280126065300250128865300120131370000250132570000200135070000170137077301150138714536592004-10-27       1989    bl uuuu     u00u1 u    #d1 aMASCARENHAS, H. A. A.  aGreen stem and foliar retention caused by potassium deficiency.  c1989  ap.728-733. t.2  vt.2  aPotassium deficiency in areas traditionally cultivated with soybeans for the past 13 to 20 years was due to utilization on inadequate fertilizer formulas, which have not catered to the needs of the soybean cultivars planted throught the years. The low potassium concentration in the soil caused symptoms like green stem at harvest, foliar retention, pod drop at pod filling stage, and the formation of  parthernocarpic fruits similar to those found in male sterile soybean plants. The (Ca+Mg)/K ratio of the soil as well as that of the leves seem to be a good indicator of the nutritional imbalance that caused the above mentioned symptioms. With the increase in yield, the quantity of potassium extracted by the crop (without taking into consideration potassium fixa-tion and leaching, etc.) was greater than applied by the fertilizers using the traditional formulas: 350 kg/ha of the 0-18-6 formula and 200 kg/ha of the 4-30-10 formula applied annually. Consequantly, along the years, potassium deficiency appeared in soybean crops.  aBrazil  aSoja  aBrasil  aDeficiencia de potassio  aPotassium deficiency  aSoybean1 aMIRANDA, M. A. C. de1 aBULISANI, E. A.1 aBRAGA, N. R.  tIn: CONFERENCIA MUNDIAL DE INVESTIGACION EN SOJA, 4., 1989, Buenos Aires. Actas... Buenos Aires: AASOJA, 1989.