Strategy of nitrogen use at continuous stocking on the pasture for dairy cows
1996
Vidrih, T. | Kotnik, T. (Ljubljana Univ. (Slovenia). Biotechnical Fac., Agronomy Dept.)
Different patterns of N fertiliser distribution were used on continuously stocked pasture. The effects of N application on total herbage yield, herbage response and seasonal yield distribution were studied. Results of an experiment, performed over two years are presented. The changes in botanical composition and sward density were determined too. Herbage DM responses to N were satisfactory in relation to values cited in the literature. The highest total annual yield (9.7 t/ha) was obtained with the highest rate of N applied in experiment (400 kg N/ha). Similar yield was obtained also with half of fertilising intensity (200 kg N/ha). The pattern of N application had an effect on total herbage yield. Heavier spring N application gave 0.8 t DM/ha more yield. Half of the annual yield has been obtained in first cut if N was applied in spring. If spring N application was omitted first harvest presented only one third of annual herbage yield and same gave the second cut. The N response efficiency varied from 8.9 kg to 17.6 kg DM per kg N applied. The average content of white clover in sward was 18 % in spring then increased up to 30 % during mid summer and down again to 17 % in autumn on N0 treatment. Next spring there was only 1-3 % of white clover and proportionally higher content of grasses on plots where higher rates of N were applied. Measuring distances from randomly chosen points to the nearest rooted base of a plant indicate large changes in sward structure of N200 and N400 plots. Distances to the nearest plant of same group of species from chosen points were 3 - 4-fold larger than on control plot.
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