Soil Quality and Crop Yields, After Utilization of Sewage Sludge on Agricultural Land, in the Moldavian Plain, Romania

Abstract

Soil Quality and Crop Yields, After Utilization of Sewage Sludge on Agricultural Land, in the Moldavian Plain, Romania Investigations conducted at the Podu-Iloaiei Agricultural Research Station, Iaşi County, have studied the influence of different sewage sludge rates on yield quality and quantity and soil agrochemical characteristics. Trials were set up in a five year-crop rotation, winter rape-wheat-maize-sunflower-wheat. Sewage sludge was applied every 2 years at rates of 20, 30, 40 and 60 t/ha, with different mineral fertilizer rates, differentiated according to the growing plant. The Cambic Chernozem used for experiments had a clayey-loam texture (410 g clay, 310 g loam and 280 g sand), a weakly acid reaction and a mean supply with mobile phosphorus and a very good one with mobile potassium. Applying rates of 30 t/ha sewage sludge has resulted in the accumulation of mobile phosphate stock in soil of 57 mg/kg and the microelement content, mobile forms from soil, was of 7.9 mg/kg at Cu, 1.4 mg/kg at B, 6.8 mg/kg at Zn and 186 mg/kg at manganese. The combined use of mean rates of mineral fertilizers (N100P80), together with 40 t/ha sewage sludge has resulted in improving soil chemical characteristics and getting yield increases in winter rape of 1854 kg/ha (108 %). After 8 years since the application of a rate of 30 t/ha sewage sludge, soil pH has increased 0.4 units, while phosphorus and potassium content from soil has increased by 30 and 52 mg/ kg soil, respectively. Sewage sludge from the Iaşi Water Treatment Station, which was applied every two years at rates of 20 and 30 t/ha, has determined the increase in the organic carbon content from soil by 2.9 g/kg (18%) and 4.4 g/kg (28%), respectively, compared to the unfertilized variant. The copper and zinc content from grains in wheat and maize crops, fertilized with 30 t/ha sewage sludge, was by two-four times higher, compared to the unfertilized control.

Assessment of flash flood susceptibility potential in Moldavian Plain (Romania)

“…Its landscape is wave‐like, with hilly areas, or shaped as low plateaus that are linked to a unitary geological surface, which is fragmented by the hydrological network. Furthermore, the landscape is covered with low plateaus or structural hills, with large, bridge‐like formations, at average altitudes of 160–180 m, and they are placed on sandy clays, covered with eluvial clays, which are representative for the entire geographical unit (Ailincăi, Jităreanu, Bucur, & Ailincăi, 2012; Ioniţă, Mărgineanu, & Hurjui, 2000; Romanescu & Constantin Stoleriu, 2017).…”

The Effect of Municipal Biosolids on the Growth, Physiology and Synthesis of Phenolic Compounds in Ocimum basilicum L.

“…Balanica et al, 2018 [ 19 ] showed that the content of heavy metals in sludge from five sewage treatment plants from South of Romania Giurgiu, Calarasi, Braila, Galati and Tulcea is below the maximum allowed limit. Ailincai et al, 2012 [ 20 ] showed that the two-year application of 30 t/ha of sludge from the sewage treatment plant in Iasi on an arable land in the Moldavian Plateau contributed to an improvement in soil properties through an increase in the organic carbon content from soil by 4.6 g/kg (28%), compared to the unfertilized variant. Utilization of sewage sludge in agriculture is of significant interest, due to nitrogen and phosphorus and microelements supply, Zn, Cu, B, and Mn.…”