Abstract
One of the main factors considered in assessing the nutritional value of feed is its chemical composition, which can be modified by fertilization. Faced with reducing P resources, alternative sources of this element are being sought. Phosphorus is an essential nutrient in soybean cultivation. The aim of the study was to use an alternative source of phosphorus fertilizer and compare its impact on the chemical composition of soybean seeds with that of a traditional fertilizer (Super FOS DAR). The study investigated a range of factors in animal nutrition as well as the basic content of macro- and microelements. A pot experiment with the Abelina soybean variety was conducted at the Experimental Station of the Wroclaw University of Environmental and Life Sciences. The experiment considered two factors against the control: phosphorus fertilizer placement (band, broadcast) and different phosphorus fertilization (Super FOS DAR, Crystal Green). Use of struvite (Crystal Green)) caused positive changes in selected amino acids content and in the nutritional value of protein in soybean seeds; this can enhance the value of soybean seeds as well as increase certain macroelements and microelements. Phosphorus fertilizer significantly increased the content of lysine, leucine, valine, phenyloalanine and tyrosine. Band fertilization with struvite caused a significant increase in amino acids (lysine, leucine, valine, phenyloalanine and tyrosine) as well as in the nutritional value of protein (as measured by the essential amino acid index, protein efficiency ratio and biological value of the protein). Favorable changes under the influence of the application of struvite were recorded in the content of calcium, as well as phosphorus, iron, and manganese. The value of the struvite in the case of its use as phosphorus fertilizer is promising; however, it needs further study.