Nitrogen and phosphorus availability effect on activity of cellulolytic microorganisms in meadows

Abstract

Meadows occupy more than 23 % of agricultural land in the Czech Republic and also represent the largest pool of carbon in soil organic matter. The organic material is an essential component of healthy soil. Decomposition of organic matter is a biological process, affected by high amount of N and P fertilizer applied in the second half of the twentieth century. This work presents the analysis of the effect of available nutrients nitrogen and phosphorus on the activity of cellulolytic microorganisms in permanent grassland of Sanguisorba-Festucetum comutatae association in the soil surface in the Protected Landscape Area of ádárská Hills. Contents of available nutrients established by the Mehlich III method were measured ex situ. Data referring cellulose decomposition rates were obtained in situ using the standard mesh-bag method. In the feld experiment, the highest loss of cellulose was recorded in variants with the addition of nutrients (PK, 90N + PK and 180N + PK) with result 90.38 % on average. The difference was statistically signifcant, compared with the control variant without added nutrients 27.87 % (P < 0.05). The added amount of nitrogen in the variant 90 kg of N + PK per ha had no signifcant effect on loss of cellulose compared to PK variant, as well as variant 180 kg of N + PK per ha. From the results obtained, it is evident that the highest decomposition of cellulose was observed at variant with added phosphorus, compared to variant with nitrogen. Moreover, the effect of different intensity of grassland utilization was found: the amount of decomposed cellulose was higher in two variants (control and 90N + PK) of two cut system in comparison with the same variant in three cut system.