The change of physical and chemical characteristics in cambic chernozem, as influenced by soil erosion, in the Moldavian Plain

The analyses carried out on soil profiles, at the beginning of testing period and after 36 years, on a 16% slope, with length of 310 m, have shown that on the entire slope length, soils had a very different fertility. Soils were influenced by erosion and silting processes. On weakly eroded land, the percentage of hydrostable aggregates was comprised, according to rates and type of applied fertilizers, between 38.9 and 53.6 %; on highly eroded land, the ratio of hydrostable aggregates has increased from 34.4 in unfertilized control to 52.0% at the fertilized variant with 40 t/ha manure. On eroded slope lands, poor in organic matter and nutritive elements, applying rates of 40 t/ha manure has determined yield increases in maize of 1835-2340 kg/ha, respectively, 45.9 – 58.5 kg grains/ t of manure, compared to unfertilized control. The combined use of mean rates (N70P70) of mineral fertilizers, together with 40 t/ha manure, has improved soil physical and chemical characteristics. Yield increases were of 3150 kg/ha in wheat and 3771 kg/ha in maize, compared to unfertilized variant

Effects of long-term fertilization on the fertility of erosion-affected soils from the Moldavian Plateau

The paper presented the results of investigations concerning the influence of long-term fertilization (43 years) on some chemical characteristics of Cambic Chernozem from the Moldavian Plain and on the maize yield. On slope lands, the high rate fertilization of maize crop (N140P100) has determined, in the latest ten years, an average yield increase of 103% (3373 kg/ha), against the control, and applying a rate of N70P70+40 t/ha manure resulted in getting a very close yield increase (99%, 3258 kg/ha). The minimum supply level of mobile phosphorus in soil (37-72 ppm) in pea-wheat-maize rotation (37 ppm) was maintained in case of annual application of a rate of N100P80. The total carbon content in Cambic Chernozem from the Moldavian Plain has registered significant increases at higher rates than N140P100 and in case of organo-mineral fertilization. The annual fertilization of wheat and maize, at the rate of 70 kg N + 70 kg P2O5/ha + 6 t/ha stalks of wheat, has determined, compared to the unfertilized variant, the increase in the content of organic carbon from soil by 14.5% (2.4 g organic C/kg) on weakly eroded soils, and by 29.5% (4.2 g organic C/kg) on highly eroded soils. During the long-term fertilizing of wheat and maize with high rates of mineral fertilizers (N140P100), on highly eroded lands, the total content of carbon has increased by 16.9% (2.4 g organic C/kg soil), against the unfertilized control. Applying moderate rates of mineral fertilizers (N70P70), together with 60 t/ha manure, has determined, after 43 years of testing, the increase by 32% (5.3 g organic C/kg) in the content of organic carbon from soil, on weakly eroded soils, and by 42.3% (6.0 g organic C/kg soil) on highly eroded soils, compared to the unfertilized control. On 16% slope arable lands from the Moldavian Plateau, the mean annual soil losses by erosion, registered during 1986-2007, were of 1.640 t/ha in winter wheat, 4.618 t/ha in beans, 1.89 t/ha in the field cultivated with perennial grasses and legumes on the second year of vegetation, 9.176 t/ha in maize and 9.6 t/ha in sunflower

Effects of Hybrid Polymeric Material Based on Polycaprolactone on the Environment

Polymers are of great interest in areas such as agriculture, medicine and pharmacy, the food and cosmetic industries, and the chemical and construction industries. However, many polymers are nonbiodegradable and are not environmentally friendly. They are highly resistant to degradation and therefore can lead to waste disposal problems. In recent years, the interest in the microbial degradation of polymeric materials has grown due to the desire for less waste pollution in the environment. In this study, the biodegradable polymer that was obtained by the ring-opening polymerization of ε-caprolactone (CL) using an aminopropyl-polydimethylsiloxane (APDMS) oligomer and the effects of the polymer towards the growth and development of tomato plants (Lypercosium esculentum) were investigated. The obtained product was characterized using FTIR spectroscopy, NMR spectroscopy, and energy dispersion spectroscopy (EDX) analysis, and the effects of this compound on the evolution of tomato plants (Lypercosium esculentum) were studied. We also studied the biological stability of the product by identifying some of the microorganisms that developed on the surface, given its susceptibility to biodegradation

Comparison Adsorption of Cd (II) onto Lignin and Polysaccharide-Based Polymers

Given the predominantly negative impact of heavy metals on living organisms, the present study proposed to evaluate the adsorption performances under static conditions of Cd (II) from aqueous solutions on unmodified Sarkanda grass lignin compared to the adsorption performances of polysaccharide polymers chemically functionalized, obtained by synthesis and in their native state, but which, although effective, have a cost price that does not allow for large-scale expansion. To improve the retention of Cd (II) on this aromatic component of the biomass resulting from the processing of lignocellulosic materials, different experimental conditions (pH, concentration, dose and contact time) were followed. The Freundlich and Langmuir isotherms were used to describe the equilibrium conditions. Adsorption kinetics were assessed using the Lagergren I and Ho and McKay II kinetic models, furnishing informative insights into the process mechanism. Lignin adsorption capacity was also analyzed by performing biological tests on tomato seeds (Lypercosium esculentum), since heavy metals are known to be a stress factor for seeds by disturbing the osmotic equilibrium. Through the prism of the investigated parameters and under precisely established experimental conditions, unmodified Sarkanda grass lignin—an aromatic biopolymer—can be recommended as a promising adsorbent for the retention of Cd (II) from aqueous solutions, successfully replacing polysaccharide, especially cellulose-based polymers