THE INFLUENCE OF MINIMAL NPK FERTILISATION ON THE QUANTITY AND QUALITY OF APPLE YIELDS

During an annual cycle, fruit trees go through developmental stages, characterised by a higher demand for some mineral elements, called critical periods, which coincide with the phenophases of bud opening and shoot initiation. Research on mineral nutrition in fruit growing has highlighted that the maximum consumption of nutrients is during the period of shoot growth, fruit development and differentiation of fruit buds. In apple, flowering is influenced more by the time of fertiliser application and the form of nitrogen than by the amount applied, as apple has high requirements for the element phosphorus in the phenophases of intense shoot growth and wood maturation. Fertilisation with NPK increased apple yield for both fertilisation treatments compared to the unfertilised control treatments. After applying 270 kg·ha⁻¹ NPK in the first year of the experiment, very significant production increases were obtained, 4.46t·ha⁻¹, with a content of 16% dry matter, 13.13°Brix soluble matter and a titratable acidity of 0.465 mg malic acid/100 g

Impact of different tillage systems and organo-mineral fertilization on soil physical and chemical characteristics in the Moldavian Plain

The investigations conducted during 1998 – 2008 followed the influence of different soil tillage systems on crop yield and soil chemical and physical characteristics. Trials were set up in split–split plots on a typical Cambic Chernozem of clayey-loam texture, mean humus content (3.2 %), weakly acid reaction and mean supply in mineral elements. After 11 years of experiences, ploughing to a depth of 20 cm has resulted in settling the soil layer at depth of 19-25 cm, causing the increase in apparent density to 1.52 g/cm3, the decrease in total porosity to 43.3 % and the increase in compaction degree until 16.2 % of the volume. In case of the tillage system with chisel and paraplow, the mean yields obtained in the last 10 years were lower by 2-5% (53-145 kg/ha) in wheat, by 4-5% (202-282 kg/ha) in maize and by 4-8% (106-206 kg/ha) in soybean, in comparison with ploughing to a depth of 20 cm. At soil tillage with chisel + disk in maize crop, the percent of hydrostable aggregates from soil, at depth of 0- 30 cm was by 15% higher, in comparison with ploughing to a depth of 20 cm. Soil tillage with chisel and paraplow determined the increase by 5.5 mg/kg (12%) and 16.0 mg/kg (7.0%), respectively, in mobile phosphorus and potassium content from soil, in comparison with ploughing to a depth of 20 cm, due to improved soil physical characteristics. At soil tillage with chisel and paraplow, the content of organic carbon from soil was higher by 0.33-0.38 g/kg, in comparison with ploughing to a depth of 20 cm

The impact of long-term fertilization and irrigation on wheat and maize yield on slope lands in the Moldavian Plain

The influence of long-term fertilization and irrigation on wheat and maize yield and soil fertility was studied at the Agricultural Research and Development Station of Podu-Iloaiei since 1980. These experiments were carried out on a 10 % slope field, on a Cambic Chernozem with clayey loam texture (423 g clay, 315 g loam and 262 g sand), a neuter to weakly acid reaction and a mean nutrient supply. The mean annual rainfall amounts, recorded in the last 28 years, were higher, with values comprised between 12.7 and 279.2 mm, compared to the multiannual mean on 80 years (542 mm) in 16 years, and lower by 25.3 - 236.7 mm in 10 years. Annual application of rates of N160 P80, in a fouryear crop rotation (soybean-wheat-sugar beet-maize) + a reserve field, cultivated with legumes and perennial grasses, determined the accumulation of a reserve of mobile phosphates of 78 mg/kg soil. Under irrigated, a good plant supply with mineral elements and the increase in the content of organic carbon from soil were done by applying the rate of N80P70+ 30 t/ha manure. Nitrogen and phosphorus fertilizers, although applied at high rates (N130 +100 P2O5), could not prevent the decrease in organic carbon content from soil