AGRONOMIJAS VĒSTIS - Latvijas Lauksaimniecības universitāte

AGRONOMIJAS VĒSTIS (Latvian Journal of Agronomy), No.10, LLU, 20080.0044+0.00062x+ 0.0000030xR = 0.87; n = 12The changesof amount of Pin the soil2g kg -10,020,010-20 -10 0 10 20 30-0,01-0,020.00053+0.00032x+ 0.000015xR = 0.86; n = 12Phosphorus balancekg ha -12soil with higher amount of Psoil with lower amount of PFigure 2. The effect of phosphorus balance on amount of mobile P in soilIn case of potassium balance the most appropriate crop fertilisation was achieved by application ofmineral potassium fertilisation rates adjusted according to the soil agrochemical properties (Table4).After fertilisation of crops with potassium rates calculated using this method, the balance insoil with higher amount of potassium was close to 0, and in soil with lower amount of this nutrient– by 22.3 kg ha -1 higher than the amount of potassium accumulated by crop yield. As a result ofsuch fertilisation, plant available potassium amount in soil with higher amount of potassium almostdid not change, in soil with lower amount of potassium it increased by 0.018 g kg -1 . When theaverage NPK rates were not adjusted according to the soil agrochemical properties, potassiumsupply was by 42.0 and 31.2 kg ha -1 higher than the amount accumulated by yield, and the amountof plant available potassium in soil increased by 0.045 and 0.042 g kg -1 .Table 4 The effect of different fertilization systems on amount of available potassium in the soilSoil with higher amount of nutrientsSoil with lower amount of nutrientsTreatthe amount of K in the soilthe amount of K in the soilment BalanceBalance2001 2005 ± 2001 2005 ±Nr. kg ha -1 g kg -1 kg ha -1 g kg -11 -76 0.093 0.089 -0.004 -65 0.090 0.076 -0.0142 38 0.130 0.168 0.038 34 0.078 0.119 0.0413 -24 0.112 0.100 -0.012 -17 0.085 0.080 -0.0054 60 0.132 0.184 0.052 42 0.089 0.125 0.0365 42 0.132 0.177 0.045 31 0.066 0.108 0.0426 8,1 0.105 0.123 0.018 9.2 0.075 0.083 0.0087 -26 0.103 0.110 0.007 -22 0.086 0.087 0.0018 1.4 0.132 0.136 0.004 22 0.081 0.099 0.0189 0,6 0.135 0.139 0.004 7.1 0.101 0.088 -0.01310 -46 0.120 0.125 0.005 -31 0.086 0.087 0.00111 -22 0.119 0.128 0.009 -26 0.072 0.087 0.01512 -6.2 0.120 0.113 -0.007 -13 0.080 0.085 0.005LSD 05 0.0196 0.016962