AGRONOMIJAS VĒSTIS - Latvijas Lauksaimniecības universitāte

AGRONOMIJAS VĒSTIS (Latvian Journal of Agronomy), No.10, LLU, 2008thermostat in the temperature of 105 °C, exposure of hay was calculated with 15 % humidity,chemical composition of perennial herbage was determined with a computer infrared ray analyser.Investigation was carried out in four repetitions. The total area of a test site was 48 m 2(4×12), area of the calculated site was – 15 m 2 (3×5). Data of investigation was mathematicallyassessed by method of dispearse analysis with a programme ANOVA.ResultsThe biggest part of the harvest of the first year’s perennial herbage was obtained byfertilizing the sward with a K 90 S 51 Mg 30 rate of potassium magnesia. Essential increase in theamount of hay was achieved 0.73 – 1.30 t ha -1 or 16.5 – 33.8 per cent when compared to perennialherbage with no fertilizers applied or the ones fertilized with K 30 S 17 Mg 10 . The rate being increasedfrom K 60 S 34 Mg 20 to K 120 S 68 Mg 40 , no significant increase in the amount of hay was observed. Mostgreen proteins and fats accumulated when a rate of K 90 S 51 Mg 30 was applied. Essential increase ingreen proteins (0.71 – 1.16 per cent) and fats (0.31 – 0.43 per cent) was obtained compared tounfertilized herbage and the one fertilized with K 30 S 17 Mg 10 . Fertilization with potassium magnesiacaused a slight decrease in green fibre and increase in green ashes. Fertilization with potassiummagnesia slightly increased the amount of grasses and decreased the amount of legumes in abotanical composition of the sward (see Table 1 and 2).Table 1. Effect of potassium magnesia rates on the harvest and chemical composition of perrenialherbageNo. Index K 0 S 0 Mg 0 K 30 S 17 Mg 10 K 60 S 34 Mg 20 K 90 S 51 Mg 30 K 120 S 68 Mg 40 LSD 051. Harvest of hay, 3.85 4.42 4.71 5.15 5.12 0.64t ha -12. Green proteins, % 11.73 12.18 12.54 12.89 12.43 0.593. Green fats, % 0.82 0.94 1.17 1.25 1.19 0.244. Green fibre, % 30.04 29.77 29.34 29.97 29.96 1.255. Green ashes, % 2.05 2.23 2.32 2.28 2.31 0.39Table 2. Effect of potassium magnesia rates on botanical composition of perennial herbageNo. Index K 0 S 0 Mg 0 K 30 S 17 Mg 10 K 60 S 34 Mg 20 K 90 S 51 Mg 30 K 120 S 68 Mg 40 LSD 051. Clover, % 85.08 86.14 85.25 84.36 83.83 5.202. Grasses, % 13.81 12.61 13.32 14.46 14.82 2.413. Other herbage,%1.11 1.25 1.43 1.18 1.35 0.53The greatest harvest of the first year’s perennial herbage was obtained by fertilization witha rate of potassium sulfate K 90 S 32.4. Essential increase of the harvest was achieved 0,98 - 1,27 t ha -1or 23,7 – 32.9 per cent. When the rate was increased from K 60 S 21.6 to K 120 S 43.2 , no significantincrease in the amount of harvest was observed. Most green proteins accumulated with afertilization rate of K 60 S 21.6 , and the greatest amount of green fats accumulated when the rate ofK 90 S 32.4 was applied. Increasing the rate of potassium sulphate even further caused a decrease inthese indexes of perennial herbage. When rates of K 30 S 10.8 – K 90 S 32.4 were applied, the amount ofgreen proteins increased comparing to K 120 S 43.2 , the greatest rate of potassium sulphate and theherbage with no fertilizers applied. The amount of green fats essentially increased only comparedto herbage with no fertilization applied, and there were no significant differences between separatetreatments. Fertilization with potassium sulphate caused a slight decrease in the amount of greenfibre and an increase in the amount of green ashes. Fertilization also had an effect on the botanicalcomposition of the sward, causing an increase in the amount of grasses and a decrease in legumes(see Table 3 and 4).153