WATER SOLUBLE PHOSPHORUS SOIL INSURANCE IN PLASTIC HOUSES CULTIVATED WITH VEGETABLE CROPS AND ACTIVE SUBSTANCE REQUIREMENT

摘要

The paper refers to a random survey, conducted in 11 Counties, important in vegetables growing in Romania, and around Bucharest, regarding to the actual phosphorus insurances of plastic house soils cultivated with vegetables. The study was conducted during the period 2002-2012, and a total of 497 of soil samples on the depth of 0-30 cm, were analyzed. It was found a relatively increasing trend of fertility until 2009, after which the concentrations of phosphorus in water-soluble forms, have fallen. Concentration of water soluble phosphorus has a mean value (17 mg·kg^-1), on a mean textured soils. On the basis the plastic house soil contents P (water-soluble forms), average fertility status of soils in our plastic houses cultivated with vegetables, crop structure, mainly, in 2 cycles (early spring tomatoes and autumn cucumbers) or in one extended cycle (sweet peppers and eggplants), a total taken up of phosphorus and the average coefficients of fertilizers use, it was calculated an approximate necessary of active ingredient (P₂O₅) for an area of about 7,500 hectares of plastic houses (the year 2014) namely, P2O5 1,425 t. This means a consumption of P2O5 of 190 kg·ha^-1·year^-1.