Jerzy Barszczewski

"Kształtowanie się obiegu składników nawozowych
w produkcyjnym gospodarstwie mlecznym
w warunkach dochodzenia do zrównoawżonego systemu gospodarowania"

Abstract

Agricultural production requires the delivery of much nutrients in a form of both fertilisers and fodders. Only part of nitrogen, phosphorus and potassium input to a farm is utilised for plant and animal production, the rest is being dispersed. Many conventional farms of the largest milk production seek more sustainable ways of farming which would consider both environmental requirements and farming efficiency.

This study was aimed at working out scientific bases for sustainable management of nitrogen, phosphorus and potassium. Working hypothesis assumed a possibility of decreasing the surplus of nutrients with parallel increase of production. The study lasted thirteen years. Management of nitrogen, phosphorus and potassium was evaluated with the balance method "at the farm's gate" in first stage of the study. Results were used to plan changes in the way of farming which were gradually implemented in second stage of the study. Nutrient balance (after every-year analysis of the effects achieved in the previous year) was the rationale to implement changes in fertilisation, crop structure, harvesting, preservation and preparation of fodder and in animal nutrition in the next year. At this stage, using large resources of manure to fertilise arable fields and meadows, mineral fertilisation was markedly reduced and the share of maize and alfalfa was enlarged in the crop structure. Contribution of hay-silage to preserved fodder was systematically increasing and its quality was being improved. Changes in fodder preparation and animal nutrition consisted mainly in the implementation of the so-called Partially Mixed Ration and in improved balance of fodder doses.

Effects of implemented changes were evaluated from the amount of plant and animal production and from nutrient balance in the field and in animal production. Moreover, environmental threat in the farm caused by nutrient dispersal near the paddock, in manure storage places, along cattle passages and near watering places in pasture was estimated. Environmental effects of changes in the land use structure were also evaluated.

Long term study of dairy farm transformation from insufficient utilisation of natural fertilisers to sustainable nutrient management demonstrated that it was a long but feasible process that required complex actions concerning fertilisation but also plant and animal production and the reduction of nutrient dispersal.