ACTUAL SOIL FERTILITY IN VEGETABLE PLASTIC HOUSES PUBLISHEDV.LĂCĂTUŞ, Luminiţa Nicoleta CÂRSTEA
Abstract. The paper refers to a random survey, conducted in 11 Counties, important in vegetables growing in Romania, and around Bucharest, regarding to the actual fertility status of plastic house soils cultivated with vegetables. The study was conducted during the period 2002-2012, and a total of 493 of soil samples on the depth of 0-30 cm, were analysed. It was found a relatively increasing trend of fertility until 2009, after which the concentrations of nitrogen, phosphorus and potassium in water-soluble forms, have fallen. Mean values revealed a normal concentration with nitrogen (94 mg•kg-1) and medium for potassium (104 mg•kg-1), with a good content of organic matter (OM = 8.8 %). Water solubil phosphorus concentration was medium (17 mg•kg-1), on a medium textured soils. Also were calculated some significant correlations between soil pH and hydrosoluble phosphorus and nitrate nitrogen. Significated correlation coeficients were found between salt concentration and water soluble forms of N-NO3, K and Na. On the basis the plastic house soil contents of N, P and K (water-soluble forms), average fertility status of soils in our plastic houses cultivated with vegetables, crop structure in 2 cycles (early spring tomatoes and autumn cucumbers) or in one extended cycle (sweet peppers and aubergines), a total taken up of major elements and the average coefficients of fertilizers use, it was calculated an aproximative necessary of active ingredient for an area of about 7,500 hectares of plastic houses (the year 2014) namely: N 2,145 t, P2O5 1,425 t and K2O 4,425 t. This means a consumption of N, P2O5 and K2O, of 286, 190 and respectively 595 kg•ha-1•year-1.
Key words: plastic houses, actual soil fertility, agrochemical correlations, aproximative necessary of NPK.