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• Investigation of the Effect of P-Supply on Maize (Zea mays L.) Development

  171-173

  Klára Pokovai

  János Géza Kovács

  János Nagy

  Views:

  77

  Quantification of plant development is important in areas where the actual dates of certain phonological stages should be identified. The influences of different ecological factors are put into algorithms by crop modellers. In this process the effect of plant nutrients are not yet well quantified. This paper gives data on the effect of phosphorus on maize development prior to flowering stage. The main conclusions are as follows: 1. In lack of phosphorus more degree days are needed for flowering then in case of well P-supply. 2. The effect of P is seen not on leaf initialisation (i.e. final eaf number is the same) but rather on the phyllochron interval. 3. P effect on phyllochron interval can be observed at the younger stage (prior to leaf number 10) but not later.

• Nutritive value of Timothy (Phleum pratense L.) during primary growth in 2005

  61-67

  Péter Kovács

  János Lazányi

  Géza Nagy

  Views:

  94

  In this paper we analysed the change of the chemical composition and nutritive value of Timothy observed during the spring of 2005. The nutritive value of Timothy was observed between the end of April and the beginning of June relating to the following parameters: crude protein, crude fibre, crude fat, ash, N-free extract, net-energy growth, net-energy lactation, net-energy maintenance, Metabolizable Protein Energy dependent, Metabolizable Protein N-dependent. We also analysed whether a relationship between the environmental factors that affect the
  growing period of grasses and the chemical composition can be detected or not. While testing for correlation, the number of days from 1st January, the amount of heat accumulation, solar radiation and rainfall were considered as independent coefficients.
  For the estimation of weather conditions we calculated the climate index. The observed year can be described as a year with a rainfall above the average and abundant solar radiation. A correlation can be detected between the change of parameters of nutritive value and the quality of the current year. In 2005 the result of the analysis of nutritive value was showed a significance difference with respect to each chemical composition at the rate of P<0.001 depending on the time when the samples were taken.
  According to the outlined data it can be stated that the change of the value of crude protein and ash show decreasing tendency agreeing the research literature. In parallel with the change of nutritive value, the amount of crude fibre and N-free extract increased. However, the value of Net-Energy maintenance showed an alteration only in the first half of the observed period. The same alteration tendency can be detected in the Net-Energy growth and the Net-Energy lactation. 

• Changes of chemical composition and nutritive values of Reed Canary Grass (Phalaroides arundinacea) in first growth

  37-42

  Péter Kovács

  János Lazányi

  Géza Nagy

  Views:

  94

  Change in chemical composition and nutritive value of Reed Canary Grass (Phalaroides arundinacea) were investigated in springtime in 2004-2006. The nutritive value of Reed Canary Grass was observed between the end of April and the middle of June relating to the following parameters: crude protein, crude fibre, crude fat, ash, N-free extract, net-energy growth, net-energy maintenance, Metabolizable Protein Energy dependent,
  Metabolizable Protein N-dependent.
  It was also analysed whether a relationship between the climatic factors affecting the growing period as well the chemical composition of grasses and the annual weather were looked for. For the estimation of weather conditions the climate index was calculated. A correlation can be detected between the change of parameters of nutritive value and the quality of the current year. Between 2004 and 2006, the result of the analysis of nutritive value indicated a significant difference with respect to each chemical composition at the rate of P<0.01 depending on the time when the samples were taken. According to the outlined data it can be stated that the change of the value of crude protein and ash show decreasing  endency agreeing the research literature. In parallel with the change of nutritive value, the amount of crude fibre and N-free extract increased. However, the value of Net-Energy maintenance revealed an alteration only in the first half of the observed period. The same alteration tendency can be detected
  in the Net-Energy growth.