Influence of the microbiological fertilizer application on the availability of organic phosphorus in the soil

Abstract

Organski fosfor, kao oblik fosfora u tlu, sastavni je dio brojnih kemijskih spojeva, o kojima uvelike ovisi pristupačnost fosfora biljkama. Većina poljoprivrednih tala sadrže od 20 do 60 % organski vezanog fosfora, a on u tlo dospijeva nakon razgradnje biljnih ostataka ili dodatkom organskog gnojiva i podliježe procesu mineralizacije pod utjecajem mikroorganizama u tlu. Mikrobiološke transformacije fosfora obuhvaćaju procese mineralizacije organskih fosfornih spojeva (fosfomineralizacija), razlaganje anorganskih spojeva fosfora (fosfomobilizacija) te redukciju oksidiranih anorganskih oblika fosfora (defosfofikacija). Cilj ovog istraživanja bio je ispitati utjecaj mikrobiološkog pripravka za tretiranje tla na povećanje pristupačnosti organskog fosfora u tlu. Također, pretpostavlja se da na sadržaj organskog fosfora u tlu, kao i na aktivnost mikroorganizama, velik utjecaj imaju sadržaj humusa te pH reakcija tla, stoga je cilj bio utvrditi i korelacije između navedenih svojstava. Statističkom analizom podataka (ANOVA), statistički značajna razlika u sadržaju organskog fosfora bez kloroforma, prije postavljanja pokusa, utvrđena je na tretmanima KMP i pMP dok je kod sadržaja organskog fosfora s kloroformom statistički značajna razlika utvrđena između tretmana K i p. Nadalje, vrlo visoka statistički značajna korelacija utvrđena je između sadržaja organskog fosfora i sadržaja humusa prije postavljanja pokusa (r = 0,94), dok se nakon žetve ona značajno smanjila (r = 0,42). Visoka korelacija prije postavljanja pokusa utvrđena je i između supstitucijske kiselosti i sadržaja organskog fosfora (r = 0,67), koja se također smanjila nakon žetve soje (r = 0,53). Nakon žetve soje nije utvrđena statistički značajna razlika unutar tretmana kod sadržaja organskog fosfora kako bez tako i s kloroformom. Generalno možemo reći, kako je primjena mikrobiološkog pripravaka dovela do povećanja pristupačnosti organskog fosfora u tlu.Organic phosphorus, as a form of phosphorus in the soil, is a constituent of numerous chemical compounds, of which depends availability of phosphorus to plants. Most agricultural soils contain 20 to 60 % of organically bound phosphorus, and it comes into the soil after disintegration of plant residues or addition of organic fertilizer and is subject to the mineralization process under the influence of microorganisms in the soil. Microbiological transformations of phosphorus include processes of mineralization of organic phosphorous compounds (phosphomineralization), degradation of phosphorous inorganic compounds (phosphomobilization) and reduction of oxidized inorganic phosphorus forms (dephosphorylation). The aim of this study was to examine the influence of microbial fertilizer on increasing the availability of organic phosphorus in the soil. It is also assumed that the content of organic phosphorus in the soil, as well as the activity of microorganisms, are under a great influence of humus content and soil pH, so the aim was to determine the correlations between these properties. Statistical analysis of data (ANOVA) showed a statistically significant difference in the content of organic phosphorus, before trial setting without chloroform on KMP and pMP treatments while statistically significant difference in the content of organic phosphorus with chloroform was determined between the K and p treatments. A very high statistically significant correlation, also, was found between the content of organic phosphorus and humus content before trial setting (r = 0,94), which significantly decreased (r = 0,42) after the soybean harvest. High correlation was also found between exchangeable acidity and organic phosphorus content before trial setting (r = 0,67), which also decreased after soybean harvest (r = 0,53). However, after the soybean harvest, the data analysis did not show statistically significant differences in organic phosphorus content between the treatments with nor without the use of chloroform. Generally, it can be concluded that the application of microbial fertilizer have led to an increase in the availability of organic phosphorus in the soil