Short‐term effects of food waste composts on physicochemical soil quality and horticultural crop production

Abstract

AimComposts made from food waste will soon become more widespread on the market thanks to the upcoming enforcement of the legal obligation to sort biowaste. Our experiment aims at improving knowledge on the short‐term effects of these composts on soils’ physicochemical properties and vegetable crops.MethodsThree composts with contrasting characteristics were tested: a 100% v/v green waste compost (C1), and two composts composed of 50% v/v food waste and 50% v/v green waste, one prepared directly on the soil (C2) and the other from a competing producer who have the French NFU 44‐051 (AFNOR NF U 44‐051, 2006) certification for an organic amendment (C3). They were applied at a rate of 100 t ha−1 (dry matter) on two cropped soils with contrasting textures. Soil‐and‐compost mixes and compost‐free soil were planted with lettuce, radish, and potato.ResultsSeventy‐four days after planting, composts improved some soil physicochemical properties. The compost‐amended soils had better saturated hydraulic conductivity (Ks, 1 10−3–2.5 10−3 cm s−1) than the compost‐free soil (0.5 10−3 cm s−1), and water‐stable aggregates were higher than the initial value in C3 soil, equal to it in C2 soil, and lower in C1 soil. pH, total nitrogen, and organic carbon increased in all compost‐amended soils. Food waste compost stimulated crop production. The yields (dry matter) of all three crops were two to three times higher in the two soils amended with food waste compost compared to unamended soil, whereas they decreased almost two times in the soil amended with green waste compost due to nitrogen immobilization. Trace metals (particularly Pb and Cd) added by the composts, although present in edible parts of the plants, did not exceed the European rules for trace metals.ConclusionThus, food waste composts have positive effects on soils and vegetable crops, and the higher their organic matter content, the higher these positive effects.