Short-term effects of compost amendments to soil on soil structure, hydraulic properties, and water regime

Abstract

Despite the increasing interest in applying composts as soil amendments worldwide, there is a lack of knowledge on short-term effects of compost amendments on soil structural and hydraulic properties. Our goal was to study the effect of compost and vermicompost-based soil amendments on soil structure, soil water retention characteristics, aggregate stability and plant water use efficiency compared to that of mineral fertilizers and food-waste digestate and examine if these effects are evident within a short time after application. We set up a pot experiment with spring wheat using a sandy and a loamy soil receiving either mineral fertilizer (MF); dewatered digestate from anaerobic digestion of food waste (DG), vermicomposted digestate (VC_DG); sewage sludge-based compost (C_SS) and sewage sludge-based vermicompost (VC_SS). We then monitored and calculated the soil water balance components (irrigation, outflow, evaporation, transpiration, and soil water content). At harvest, we measured shoot biomass, soil texture, bulk density, water retention characteristics and aggregate stability. The irrigation use efficiency (IE) and the plant water use efficiency (WUE) were calculated for each treatment by dividing the transpiration and the dry shoot biomass with the amount of water used for irrigation, respectively. For the sandy soil, we used X-Ray computed tomography to visualise the pore system after applying organic amendments and to derive metrics of the pore-network such as its fractal dimension, imaged macroporosity and critical pore diameter. X-Ray tomography indicated that composting and vermicomposting resulted in more complex and diverse porous system and increased soil macroporosity. The increased fractal dimensions also indicated that compost and vermicompost can contribute to structure formation and stabilization within a short time after their application. Despite the small application rate and short incubation time, the application of organic amendments to the two different soil types resulted in improved soil water holding capacity and water use efficiency. Composting and vermicomposting appeared to have the best effect at reducing the irrigation demand and evaporation losses and increasing the water use efficiency of the plant, likely through their effect on soil structure and the pore-size distribution.

Cattle Manure Application for 12-17 Years Enhanced Depth Distribution of X-Ray Computed Tomography-Derived Soil Pore Characteristics

“…Rivier et al also reported an increased FD with manure application which was similar to our ndings in the Brookings site, where the application of medium manure increased FD as compared to medium fertilizer treatments at 20 to 30 cm soil depth 32 . A higher FD can be due to the more complex pore structure of the soils 33 and this can contribute to the soil fertility 34 .…”

Short- and Medium-Term Effects of On-Farm Compost Addition on the Physical and Hydraulic Properties of a Clay Soil

“…Therefore, using zerokilometer compost may represent an agronomic practice to be suggested, especially when combined with other agroecological techniques [7,8]. It is well known that adding compost to soil improves the physical and hydraulic characteristics of the porous medium, including bulk density or porosity, water retention, and hydraulic conductivity (among others, e.g, [9][10][11]). For instance, Glab et al [12] reported the effects of the addition of different co-composted maize, sewage sludge, and biochar mixtures on the physical properties of a sandy soil.…”

“…Overall, the long-term effects of compost addition to soil have been extensively investigated [14], and some studies have sporadically investigated the effects on structural stability in the medium term, namely, two-three years after amendments [15,16]. Rivier et al [11], for example, pointed out that of the approximately six hundred articles published on the topic of compost use, only about 10% of them focused on evaluating the impact on soil structure and changes in hydraulic properties [17]. Furthermore, the short-or medium-term effect is largely underrepresented.…”

Compost Amendment Impact on Soil Physical Quality Estimated from Hysteretic Water Retention Curve

“…Another point that requires further investigation is the use of repacked soil samples that could be non-representative of field conditions. Many researchers hypothesized that incorporation of compost would influence soil structure and, consequently, soil hydraulic properties in the short term (among others, [1,22]). The addition of compost to sieved soil, to obtain a repacked laboratory sample, can be likened, to some extent, to the real soil shortly after compost incorporation followed by tillage.…”

“…Compared with the control soil, the physical properties of the amended soil were significantly improved with beneficial effects that were dependent on the rate of compost application and the type of feedstock. Likewise, Rivier et al [22] investigated the effect of compost and vermicompost on soil structure, water retention, aggregate stability, and plant water use efficiency, compared with that of mineral fertilizers and food-waste digestate.…”