Compost can successfully replace mineral fertilizers in the nutrient management of commercial peach orchard

The objective of this experiment was to evaluate in the long‐term (9 years), the suitability of compost as a fertilizer in commercial peach orchard. The experiment was carried out on nectarine trees ( Prunus persica var . nectarina ), Stark RedGold grafted on GF677 peach × almond ( P. amygdalus L.) hybrid. The treatments were: (1) unfertilized control; (2) mineral fertilization including phosphorus (P at 100 kg/ha) and potassium (K at 200 kg/ha) applied at planting and nitrogen (N at 70–130 kg/ha/yr) split in two applications at 40 days after full bloom (60%) and in September (40%); (3) cow manure supplied at planting [10 t dry weight (dw)/ha] and then, from the forth year at the rate of 5 t dw/ha/yr in spring; (4) compost supplied at planting (10 t dw/ha) and then, from the forth year at the rate of 5 t dw/ha/yr in spring; (5) compost supply at a rate of 5 t dw/ha/yr, and (6) 10 t dw/ha/yr, both treatment 5 and 6 split as described for treatment 2. Nitrate‐N soil concentration was usually not affected by treatments. Soil microbial carbon, organic matter, total N, P, K were increased by application of organic fertilizers. SOM and total N were positively correlated to soil microbial biomass. Aggregate stability, humic and fulvic acid concentration were not affected by fertilization treatment. Only the application of compost at 10 t dw/ha/yr (6) increased fruit production.