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• The effects of fertilization on a 6 years old established grassland

  19-30

  Imre Kadar

  Imre Vinczeffy

  Peter Ragalyi

  Views:

  67

  The effect of different N, P and K supply levels and their combinations were examined in the 33rd year of a long-term fertilization experiment on the yield and mineral element content of a 6 years old established all-grass sward in 2006, with seed mixture of eight grass species. The trial was established on a calcareous chernozem soil. The soil of the growing site contained around 3% humus, 5% CaCO3, 20-22% clay in the ploughed layer and was originally moderately well supplied with available K, Mg, Mn and Cu and poorly supplied with P and Zn. The trial included 4N×4P×4K=64 treatments in 2 replications, giving a total of 128 plots. The fertilizers applied were Ca-ammonium nitrate, super phosphate and potassium chloride. The groundwater table was at a depth of 13-15 m and the area was prone to drought. The 1st cut was made on 08th June, the 2nd one on 11th September. During the vegetation period of 8.5 months in 2006, the site had a total of 397 mm precipitation. The lay-out, method and main results of the trial were published earlier (Kádár, 2004, 2008; Kádár és Győri, 2004, 2005). Main conclusions of this study are as follows:

  1. The 1st cut hay yield gave the ¾ of the total yield. Highest yields were reached with the 200 kg/ha/year N-fertilization on soil well supplied with P (Ammonium-lactate soluble P2O5: 214 mg/kg). The yield of NP control plots increased from 1.5 t/ha to about 7.5 t/ha as a function of the N×P positive interaction. The rising P supply alone was not able to enhance the yield, however the N fertilization gave 3.5 t/ha hay surplus even in the P-control treatments. N and P fertilization together resulted in 6.0-6.5 t/ha yield surpluses. The effect of K fertilization also reached 1 t/ha on the NP levels where the ammonium-lactate soluble K2O content fell below 150 mg/kg.
  2. The 2nd cut hay gave 0.5 t/ha on the NP-control plots unfertilized for 33 years, and 2.5 t/ha on the 300 kg/ha/year N treatment with well P-supply. The two cuts together resulted in yield levels between 2-10 t/ha according to the extreme NPK supply. In this year, with relatively good amount of precipitation, the hay yield surpluses for 1 kg N were 47-33-23 kg for the 100-200-300 kg/ha treatments.
  3. The C/N ratio of the 1st cut was narrowed (from 52 to 24) with N-supply and the concentration of N as well as most of the cations increased with the rising N fertilization. In the low yield of the 2nd cut the elements, metals were accumulated. The P, S and Sr were enriched in hay as a result of rising P supply, as superphosphate contains these elements. Antagonistic effect of P predominated in the uptake of other elements, metals (Na, Zn, Cu, Mo, Cr, Co). K content of the hay was lifting while other elements were dropping with the increasing K fertilization partly as a result of dilution effect (N, P, S) and mainly because of cation antagonism (Ca, Mg, Na, Sr). K-B antagonism also appeared.
  4. The N×K interactions resulted in 2-fold Sr and 18-22 fold Na content changes while N×P caused 18-22 fold changes in Mo contents, especially at the 2nd cut. As it can be seen, fertilization can have drastical effects on soil and crops. The induced element deficiencies or oversupplies can lead to diseases, disturbances in the metabolism of animals, so the soil and fodder analyses are necessary.
  5. Considering the leaf diagnostical data, the satisfactory level will be at 200 kg/ha/year N supply and 150 mg/kg ammonium-lactate soluble P2O5 and K2O level or above. The S, Ca, Mg, Fe, Mn supply were satisfactory even at the control plots, while the Zn, Cu and B levels showed deficiency. The P/Zn and K/B ratios became adversely wider in some treatments, as well as the narrowing of the Cu/Mo ratio denotes Cu deficiency and Mo oversupply.
  6. The amount of elements uptaken by hay as a sum of the two cuts and as a function of the supply/yield varied between the following values in kg/ha: 17-163 N; 36-122 K; 9-48 Ca; 6-17 P; 4-15 S; 3-14 Mg; 0,3-8,0 Na; 0,2-1,4 Fe; 0,2-0,9 Al and Mn. The other elements showed the following uptake: Zn 33-194, Sr 28-141, Ba 5-46, Cu 5-39, B 5-26, Mo 3-6 g/ha.
  7. The botanical composition was drastically modified by the aging of the grass and the nutrient supply. Only three species remained out of the eight sown species and one immigrated. Coverage of the tall fescue was between 21-70% according to the N×P supply and 44% as average; coverage of cocksfoot varied between 4-24% depending on the treatment and 18% as an average; coverage of crested wheatgrass was between 0-28% and 9% as an average; the immigrant smooth brome covered 0-24% and 9% as an average; Weed cover was 3-4% as an average at the 1st cut. Weeds thrived mainly on those areas where the grass thinned away (extreme NP-deficiency or oversupply). The total plant coverage on NP-deficient soil was about 50%, while on treatments well supplied with NP it amounted 95-97%.

• The effects of fertilization on 2 year old established swards. Mineral uptake 7.

  107-118

  Imre Kádár

  Views:

  52

  The effects of different N, P and K supply levels and their combinations were examined on the mineral element uptake of an established 2 year old all-grass sward in the 29th year of a long-term fertilization field experiment set up on a calcareous chernozem soil. The soil of the growing site contained around 3% humus, 3-5% CaCO3, 20-22% clay in the ploughed layer and was originally moderately well supplied with available N, K, Mg, Mn and Cu and poorly supplied with P and Zn. The trial included 4N×4P×4K=64 treatments in 2 replications, giving a total of 128 plots. The fertilizers applied were Ca-ammonium nitrate, superphosphate and potassium chloride. The groundwater table was at a depth of 13-15 m and the area was prone to drought. In 2002 the area had 401 mm precipitation and gave 2 cuts of grass. The lay-out and method of the trial as well as the fertilizer responses on the hay yield and element content were published earlier (Kádár 2006). The main conclusions drawn as follows:
  1. While the hay yield was basically determined by N-fertilization which lifted the hay mass 5 times compared to the N-control, the uptake of elements was drastically modified through the N×K and N×P synergistic and antagonistic interactions.
  2. As a function of N×K treatments the uptake K changed for example at the 1st cut between 23-198 kg/ha, at the 2nd cut between 9-80 kg/ha. At the same time the uptake of Na fluctuated between 0.05-7.15 kg and 0.4-4.4 kg/ha, that of Mo 0.4-3.2 g/ha and 0.2-2.3 g/ha resp. As a function of N×P treatments the uptake of P changed at the 1st cut between 3-14 kg/ha, Sr between 12-388 g/ha, Mo between 0.5-4.5 g/ha. The nutrient accumulation at the 2nd cut showed an analogical picture.
  3. The K-fertilization stimulated accumulation of K and Ba, while inhibited the antagonistic metal cations’ uptake of Ca, Mg and Na. The increased P-supply rose the absorption of P, S, Sr and Ba while diminished the extracted amount of Mo, which dropped down by 1/3rd compared with the control. The liberal N-supply stimulated the incorporation of N, K, Mn, Sr and Cu resulting an increase of an order of magnitude.
  4. Between the two extreme supply levels (N0P0K0 and N3P3K3) there were found extreme differences in element uptake in 2002 as follows: 34-302 kg/ha K, 15-168 kg/ha N, 8-35 kg/ha Ca, 5-22 kg/ha S, 4-22 kg/ha P (9-51 kg/ha P2O5) and 3-14 kg/ha Mg. The incorporated Mn, Sr, Zn and Cu enhanced an order of magnitude on N3P3K3 plots compared to the N0P0K0 absolute control. Uptake of As, Cd, Co, Cr, Hg, Pb and Se left behind the detection limit of 1 g/ha.
  5. To have 1 t air-dry hay it was used by grasses 17-35 kg K, 9-19 kg N, 3-5 kg Ca, 2.0-2.5 kg S, 1.3-2.5 kg P (3.0-5.7 kg P2O5), 1.4-1.9 kg Mg, 170-980 g Na, 90-170 g Fe, 60-120 g Mn and Al, 10-50 g Sr, 7-25 g Zn, 3-6 g Ba, B and Cu, 0.3-1.3 g Mo and 0.4-0.9 g Ni. Data illustrate the nutrient turnover of a grassland and may be used for assessing the nutrient demand of all-grass sward.

• The effects of fertilization on 2 year old established swards. Yield and mineral content 6.

  94-106

  Imre Kadar

  Views:

  58

  The effects of different N, P and K supply levels and their combinations were examined on the hay yield and mineral element content of an established 2 year old all-grass sward in the 29th year of a long-term fertilization field experiment set up on a calcareous chernozem soil. The soil of the growing site contained around 3% humus, 3-5% CaCO3, 20-22% clay in the ploughed layer and was originally moderately well supplied with available N, K, Mg, Mn and Cu and poorly supplied with P and Zn. The trial included 4N×4P×4K=64 treatments in 2 replications, giving a total of 128 plots. The fertilizers applied were Ca-ammonium nitrate, superphosphate and potassium chloride. The groundwater table was at a depth of 13-15 m and the area was prone to drought. In 2002, the area had 401 mm precipitation and gave 2 cuts of grass. The 1st year results of the trial were published earlier (Kádár, 2005a, b). The main conclusions can be summarised as follows:
  1. As a function of N×P fertilization the two cuts of the hay yield made up 1.4-8.0 t/ha while the green herbage 5.0-24.0 t/ha. The N-fertilization was of vital importance, which increased the hay mass 5 times. The P-response was moderate in the 1st, cut while there were no K-responses at all on this soil with 135 mg/kg ammoniumlactate (AL) soluble K2O values in plough layer.
  2. On those plots well supplied with PK the 100 kg/ha/yr N-treatment gave a total of 48 kg surplus hay/kg N applied. The 200 kg/ha/yr N-treatment yielded 11 kg, while the 300 kg/ha/yr N-treatment yielded 4 kg surplus hay/kg N applied. The NO3-N content of the 1st cut hay increased over permitted 0.25% level when using the maximum N-rate and made up this NO3-N form 26% of the total-N pool. The optimum PK-supplies in this site seems to be about 130-150 mg/kg AL-P2O5 and AL-K2O in plow layer with 200 kg/ha/yr N applied.
  3. N-fertilization enhanced the content of N, K, Mg, Na, Mn, Cu and NO3-N, while the concentration of S, P, Al, Fe, B and Mo dropped in the primary hay. The increasing P-supply stimulated the uptake of P, Ca, Mn, Sr and Ba, while hinderned the uptake of S and Mo. The K-fertilization rose the content of K and Ba and diminished the concentration of Mo and the antagonistic metal cations like Ca, Mg and Na.
  4. The NPK fertilization-induced Mo-deficiency can first of all jeopardized the fodder quality in this site. On the unfertilized plots the hay showed around 1.0 mg Mo /kg D.M., while on the N3P3K3 plots 0.1-0.2 mg/kg D.M. The P/Mo ratio lifted from 2-4 thousand up to 20 thousand. In the 2nd cut this phenomena partly disappeared, while developed the P-Zn antagonism. On P-control plots measured 15 mg/kg Zn
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  GYEPGAZDÁLKODÁSI KÖZLEMÉNYEK, 2006/4.
  dropped to 10 mg/kg while the P/Zn ratio rose from 167 up to 364.
  5. The 2nd cut hay had a little yield, yet was rich in minerals having 30-50% higher average element content compared with the primary hay. However the N, Al, Fe and Mo showed 2-times higher concentrations in the 2nd cut hay. There were found extra large, 25-fold differences in hay Na content as a function of N×K supply levels under synergetic effect of N and antagonistic effect of K treatment.
  6. Summarizing the above we can state that the long-term fertilization may drastically change the content and ratios of elements built in hay through synergetic or antagonistic effects. In the air-dried 1st cut hay for example, the minima-maxima concentrations of measured elements varied as follows: N 0.7-3.0%, K 1.3-3.0%, Ca 0.3-0.5%, Mg 0.13-0.21%, S 0.15-0.32%, P 0.10-0.32%; Na 50-1400, Mn 60-120, Al 50-120, Fe 70-140, Sr 8-170, Zn 6-40, Ba and B 3-6, Cu 2.5-5.5, Ni 0.4-1.4, Mo 0.1-1.0 mg/kg.