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• Néhány időjárási tényező és a hozam összefüggése száraz- és üde gyepeken

  39-42

  Gábor Török

  Márta Bajnok

  Szilárd Szentes

  Julianna Tasi

  Views:

  128

  The yield of pastures will be impaired by the climate change as a result of reduced amount of winter and vegetation precipitation and the increasing number of hot days as well as the increase in temperature. Species composition is also due to change, however, this change will be more difficult to be determined as the increasing concentration of glasshouse gases has different impacts on the various components. Grassland is a water demanding culture; droughts reduce yield significantly and these losses should be compensated by an adaptive agricultural technology. On protected and Nature 2000 pastures, comprising giving 50% of Hungarian pastures – strict regulations prevent the application of yield increasing techniques, such as irrigation, fertilization or oversowing. The impacts of the weather may only be compensated to a certain extent by the utilization technology. The effects of 3 utilization systems and some elements of weather conditions with special regard to water supply were investigated on dry and mesic grasslands in the years 2006-2010. On the bases of the results some suggestions are set up for modifying the specifications on pasture utilization in nature conservation areas, by having the first cutting earlier and increasing utilization frequency wherever possible. On dry grasslands, yield was affected most significantly by annual precipitation, the precipitation in the vegetative period showed the second strongest correlation with yield. On mesic pastures, temperature and radiation had the strongest influence on the yield. Here, the significance level in the case of total annual precipitation was lower, whereas the correlation was not significant for precipitation in the vegetative period.

• The effect of fertilization on the yield and N uptake of artificial grasslands 1.

  36-45

  Imre Kadar

  Views:

  67

  The effects of different N, P and K supply levels and their combinations on the development, yield and N-uptake of an established all-grass sward were examined in the 28th year of a long-term fertilization experiment set up 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 4Nx4Px4K=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. In 2001, however, the area had a satisfactory amount of 621 mm precipitation with a fairly good distribution. The grass was established on 21. September 2000. The main results and conclusions can be summarised as follows:
       1. Grass herbage had a very favourable wet year in 2001 with over 700 mm rainfall during the total vegetation period. The hay yield of unfertilised control plots was by the 1st cut 1.7 t/ha, by the 2nd cut 1.2 t/ha, while the N3P3K3 treatment gave 8.8 t/ha and 4.2 t/ha resp., so NPK fertilization increased the air-dried hay yield from 3 t/ha to 13 t/ha (1st+2nd cuts together).
       2. The N-requirement of the young grass was moderate while the P-response significant by the 1st cut. The optimum P-supply was at the 150 mg/kg ammonium lactate soluble AL-P2O5 in the plow layer. There were no K-responses on this soil with 135 mg/kg AL-K2O values.
       3. There were no P responses any more by the 2nd cut even on the low P-supply soil, with 66 mg/kg AL-P2O5 value, while the applied N increased the hay yield 4 times. The optimum N content in the hay, leading to maximum yield, amounted 2% by the 1st cut and 2.5-3.0% at the 2nd cut. Applied N decreased air-dried content at the 1st cut from 33% to 31%, at the 2nd cut from 27% to 21%.
       4. On the soil, well supplied with PK, the 100 kg/ha/yr N treatment gave the maximum hay surpluses: at the 1st cut 61 kg, at the 2nd cut 14 kg, that is a total of 75 kg hay/kg N applied. The 200 kg/ha/yr plots yielded 43 kg, 300 kg/ha/yr yielded 34 kg hay/kg N applied. The primary sward hay had 0.34% NO3-N in the 300 kg/ha/yr treatment, which was over the allowable 1.25% NO3-N limit for animal foodstuff. The NO3-N content in the N-control plots amounted 0.06%, in the 100 kg/ha/yr treatment 0.10%, in the 200 kg/ha/yr treatment 0.22%. At the 2nd cut the hay had generally, half as high NO3-N content as in the 1st cut hay in all treatments.
       5. The apparent recovery of applied N, using difference method, was even more than 100% on the well supplied with PK soil suggesting that in these instances grass herbage could make a good use of soil NO3-N pool accumulated in soil during the previous period and not used by the crops.

• 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%.