Assessing the efficiency of nitrogen application is a valuable first step in establishing an optimum N fertilizer management plan. The aim of this study was to elaborate a sustainable N management system for sown grassland installed in temperate regions, through manipulation of nitrogen use efficiency and nitrogen response efficiency (NRE) indicators. Research was performed in western Romania. The biological material consists in two forage species of major importance for the forage base worldwide, namely Trifolium pratense L. and Lolium multiflorum Lam., in pure stands and in mixture. Both forage species were sown at two different spacings between rows (12.5 and 25.0 cm) and were fertilized with nitrogen (N) in three doses (N0-control, N50-fertilized with 50 kg N ha⁻¹ and N100-fertilized with 100 kg N ha⁻¹). The studies were made in 2016 and 2017, years very different from each other in matter of rainfalls. The results revealed a different behavior of the three sward types analyzed: while in Trifolium pratense monoculture and in the mixture of the two species studied, less N was removed than was applied; on the other hand Lolium multiflorum monoculture used a high proportion of the N applied, being at the limit to access N from the organic pool or residual N from fertilizer applications to a preceding crop.

Over time, studies of the vegetation of natural grasslands have evolved from simple observations to rigorous research. Feed obtained from natural meadows without major technological imputations is mediocre in quality, and pastures in a rather advanced state of degradation. The main purpose of this paper is the ecological and fodder evaluation of the Festuca rubra type of grasslands in the Apuseni Mountains based on the floristic composition and the productivity of these grasslands. The experience was carried out in Ghetari village, Apuseni Mountains, which was located in 2001, following the method of randomized blocks with 4 experimental variants in 4 rehearsals. Each variant were fertilized with organic inputs using the same quantities each year. In the paper we use the results obtained after 15 years of experience. The application of organic fertilizers caused significant changes in the canopy causing changes in the dominance of the type of grassland. The livestock manure applied on the studied grassland has increases significant yield production at all variants of fertilization.In this paper it was shown on which species the productivity of the grassland increased from the control variant to the fertilized variant with the maximum dose. Regarding the analysis of the phytodiversity, this tells us if the number of species is reduced in all the treatments, 10 t/ha of manure leads to an increase in phytocoenosis equivalence and implicitly to the Shannon index.

The present study was carried out to isolate and to investigate biochemical characteristics of twenty rhizobacteria strains from red clover (Rhizobium trifolii) and alfalfa (Sinorhizobium meliloti). The result of the study showed a low diversity in morphological, physiological and symbiotic properties among the rhizobial strains. Phenotypically all isolated strains had the same colony morphology conical with a smooth margin, the color and texture was watery to translucent. The isolates were fast-growing and failed to absorb Congo red. API 20NE and API 20E showed a negative reaction for the reduction of nitrate in RtS1, RtR2, and positive for SmM1, SmM2. The reaction was positive for β-galactosidase, β- glucosidase and negative for urease, arginine dihydrolase, for all rhizobial isolates. Carbon sources: glucose, arabinose, mannose,mannitol, maltose, were also positive for all strains. Rhizobial strains utilized a wider range of carbohydrates and this may be a helpful tool for the characterization of the isolates.

Important areas of semi-natural grasslands are affected by abandonment in Apuseni Mountains, situation that leads to a series of specific negative aspects. Semi-natural grasslands pass through certain successional stages, materialized by different types of grasslands. The aim of our study was to follow the successional stages of Agrostis capillaris L. – Festuca rubra L. grassland type, as a result of abandonment. The study included 27 grasslands with similar site conditions. There were three different categories of abandoned grasslands: abandoned up to 5 years, abandoned between 6 and 10 years, abandoned more than 10 years. The categories of abandonment caused changes at the level of phytocoenoses, registering a degradation of the vegetation from both, agronomic and ecologic point of view. The semi-natural grasslands, situated on sites with different disadvantages (defectuous orography, reduced trophicity, pronounced acidity, etc.) which are on the threshold to be abandoned, or are already abandoned, need to be mowed at least once at four or five years, to preserve their specific floristic structure.

The pastoral area of Romania, covering of over 4.8 million ha, has been influenced, over the last decades, by natural and human factors, which affect the normal functioning of the grassland ecosystem. The aim of this paper is to point out the dynamics of phytocoenotic biodiversity, as a result of applying grassland technical measures, in order to improve the yield and quality of grassland ecosystems with minimum effects on the environment. Therefore, the main aim of our study is to establish a positive relationship between biodiversity and the optimum quantity of organic fertilizers, which would improve the quality and quantity of the yield, without diminishing the floristic biodiversity. In the case of the studied grasslands, the phytocenotic biodiversity is influenced by the type of fertilization, the used rates and by the soil and climatic conditions. These grasslands may be improved by manure fertilization and reasonable usage, if proper management is applied. In Gradinari, Caras-Severin county, the dominant species are Festuca rupicola and Calamagrostis epigeios, in Magurele, Brasov county, Agrostis capillaris, Festuca pratensis, Poa pratensis and Trifolium repens, and in Pojorata, Suceava county, Agrostis capillaris, Trisetum flavescens, Trifolium repens and T. pratense species. The highest number of identified species (43) has been recorded by the meadow made up of Agrostis capillaris and Festuca rubra, from Pojorata, Suceava county.