Soil refinement accelerates in-field degradation rates of soil-biodegradable mulch films

Soil-biodegradable mulch films are a promising solution to replace conventional polyethylene-based mulch films, the use of which has led to negative environmental impacts. Soil-biodegradable mulch films are specifically designed to be incorporated into the soil at the end of the cropping cycle, and are expected to be biodegraded by soil microorganisms. The biodegradability of such products must be tested under laboratory-controlled conditions following international standards, although these can fail to represent real environmental conditions where mulch films are used. The objective of this study was to evaluate the effects of soil refinement on the degradation rates of three different commercial soil-biodegradable mulch films after their incorporation into the soil. The hypotheses were that: (i) soil refinement (i.e., ploughing followed by grubbing) creates more favourable conditions for film biodegradation compared to ploughing alone; and (ii) different mulch films show different degradation rates. An open-field completely randomised design was applied to test the effects of soil refinement by ploughing to 0.35 m depth without and with subsequent grubbing to 0.15 m depth twice. Three commercially available soil-biodegradable mulch films were sampled in 2020 (i.e., two Mater-bi-based, one Ecovio-based) at the end of a zucchini growing season (~3 months) when films were still lying above ground, and were later buried at 0.2 m depth inside mesh bags. Biodegradation rates of the sampled films were assessed with the indirect indicators of film weight loss and surface area loss at ~2-month intervals over 314 days. The results showed that soil refinement significantly accelerated degradation of the three tested mulch films by 14% and 17% according to the loss of weight and surface area indicators, respectively. One Mater-bi-based film showed higher degradation rates compared to the other two films. Future studies are needed to quantify the time needed for these different mulch films to be completely biodegraded. Such studies should be carried out following standards for laboratory incubation and/or in-field quantification of residual polymers in the soil over time. Highlights- Degradation rates of three biodegradable mulch films were evaluated in the open-field.- Soil refinement accelerates the degradation of film weight (14%) and surface (17%).- Highest degradation rates were observed for one Mater-bi-based film.- Fastest degradation rates were observed in spring for all the tested films.- Weight and surface area loss indicators showed positive relationship

Effect of contrasting crop rotation systems on soil chemical and biochemical properties and plant root growth in organic farming: First results

Organic farming is claimed to improve soil fertility. Nonetheless, among organic practices, net C-inputs may largely vary in amount and composition and produce different soil conditions for microbial activity and plant-root system adaptation and development. In this study, we hypothesised that, in the regime of organic agriculture, soil chemical and biochemical properties can substantially differ under contrasting crop rotation systems and produce conditions of soil fertility to which the plant responds through diverse growth and production. The impact of 13 years of Alfalfa-Crop rotation (P-C) and Annual Crop rotation (A-C) was evaluated on the build up of soil organic carbon (SOC), active (light fraction organic matter, LFOM; water soluble organic carbon, WSOC) and humic fraction (fulvic acids carbon, FAC; humic acids carbon, HAC), soil biochemical properties (microbial biomass carbon, MBC; basal respiration, dBR; alkaline phosphatase AmP; arylsulfatase ArS; orto-diphenoloxidase, o-DPO) and the amount of available macro-nutrients (N, P, and S) at two different soil depths (0-10 cm and 10-30 cm) before and after cultivation of wheat. We also studied the response of root morphology, physiology and yield of the plant-root system of wheat. Results showed that the level of soil fertility and plant-root system behaviour substantially differed under the two crop rotation systems investigated here. We observed high efficiency of the P-C soil in the build up of soil organic carbon, as it was 2.9 times higher than that measured in the A-C soil. With the exception of o-DPO, P-C soil always showed a higher level of AmP and ArS activity and an initial lower amount of available P and S. The P-C soil showed higher rootability and promoted thinner roots and higher root density. In the P-C soil conditions, the photosynthesis and yield of durum wheat were also favoured. Finally, cultivation of wheat caused an overall depletion of the accrued fertility of soil, mainly evident in the P-C soil, which maintained a residual higher level of all the chemical and biochemical properties tested

Chemical composition and nutritive value of alpine pasture's species in North-eastern Italy

none3noneZILIOTTO U.; SCOTTON M.; D'OTTAVIO P.Ziliotto, Umberto; Scotton, Michele; D'Ottavio, P

Effect of NPK fertilisation on seasonal growth rate, production and nutritive value of alpine grasslands

none3noneZILIOTTO U.; D'OTTAVIO P.; SCOTTON M.Ziliotto, Umberto; D'Ottavio, P.; Scotton, Michel