This paper presents researches regarding the influence of organic (sheep manure) and NPK mineral fertilizers on the soil parameters and total crude protein content (%) of forages, harvested in the middle of May, 2008, from a permanent meadow situated near Grădinari, in Caraş-Severin district. The studied permanent meadow was organized in ten trials fertilized with different doses of NPK mineral fertilizers, organic (sheep manure) and organic-mineral fertilizers. For each trial was made five replications. The total nitrogen content (%) was determinated by Kjeldahl method, and total crude protein was calculated by multiplying total nitrogen content with 6.25. The soil pH was determinated in aqueous solution (ratio soil / water = 1/10) using potentiometric method. Mobile forms of potassium and phosphorus were determinated by Egner-Riehm-Domingo method, extracted from soil with an acetate-lactate solution buffered at pH= 4.6, at 1/5 soil-solution ratio. The statistical interpretation was performed with Multivariate Exploratory Techniques, Cluster Analysis, implemented in Statistica 6 software.
Using Cluster Analysis is possible to show the influence of organic and mineral fertilizers on the soil parameters (pH, total nitrogen content, mobile form of P, and mobile form of K) and total crude protein content of forages from the permanent meadow from Gradinari (Caraş-Severin District) by grouping all ten experimental trials in three main groups.
Researches Regarding the Influence of Organic and Mineral Fertilization on the Soil Parameters and Total Crude Protein Content of Forages from a Permanent Meadow by Cluster Analysis (Part 1)
