Reuse of Wasted Bread as Soil Amendment: Bioprocessing, Effects on Alkaline Soil and Escarole (Cichorium endivia) Production

: In an era characterized by land degradation, climate change, and a growing population, ensuring high-yield productions with limited resources is of utmost importance. In this context, the use of novel soil amendments and the exploitation of plant growth-promoting microorganisms potential are considered promising tools for developing a more sustainable primary production. This study aimed at investigating the potential of bread, which represents a large portion of the global food waste, to be used as an organic soil amendment. A bioprocessed wasted bread, obtained by an enzymatic treatment coupled with fermentation, together with unprocessed wasted bread were used as amendments in a pot trial. An integrated analytical plan aimed at assessing i) the modification of the physicochemical properties of a typical Mediterranean alkaline agricultural soil, and ii) the plant growth-promoting effect on escarole (Cichorium endivia var. Cuartana), used as indicator crop, was carried out. Compared to the unamended soils, the use of biomasses raised the soil organic content (up to 37%) and total nitrogen content (up to 40%). Moreover, the lower pH and the higher organic acid content, especially in bioprocessed wasted bread, determined a major availability of Mn, Fe, and Cu in amended soils. The escaroles from pots amended with raw and bioprocessed bread had a number of leaves, 1.7- and 1.4-fold higher than plants cultivated on unamended pots, respectively, showing no apparent phytotoxicity and thus confirming the possible re-utilization of such residual biomasses as agriculture amendments.

The Potential of Paper Industry Sludge Potency as Organic Soil Amandment

Sludge from the paper industry can affect soil fertility due to its organic content. However, sludge as waste has a contamination risk of polluting the soil. This research focused on the chemical properties content of sludge from the paper industry (pH, organic C, macro and micronutrients, heavy metals) and contaminant microbes (E. coli and Salmonella sp.) in order to evaluate to the potency of sludge to be soil amendment. Sludge sample was taken in 0-20 cm depth from Sumengko Village, Wringinanom, Gresik. The chemical properties were measured in Soil Chemistry Laboratory in Soil Science Department, and the biological properties were measured in Pest and Disease Laboratory in the Agricultural Faculty of Brawijaya University. The chemical and biological properties of sludge were compared to quality standards according to Keputusan Menteri Pertanian No. 261/2019 (Kepmentan No. 261/2019) from the Ministry of Agriculture, Indonesia. Sludge from the paper industry has the potency to be soil amendment because it meets the requirement from Kepmentan No. 261/2019. Its pH was neutral (6.9), the macro and micronutrients contents fit the requirement, and it had no microbial contaminant content. However, the organic C was under expectation, and it has over Hg content.

Stabilization of Johor Peat Soil using Sugarcane Bagasse Ash (SCBA)

Peat soil have been categorized as a problematic organic soil, because they have a high settlement rate when placed any structure on it. Therefore, the peat soil must first be stabilized using cement before it can be used. However, massive use of cement can lead to environmental pollution. Therefore, this study intends to use sugar cane bagasse ash as a substitute for cement in peat soil stabilization. The mix ratio of 5% to 20% was used to find the optimal mix ratio. Various tests were carried out on samples such as basic properties tests, Unconfined Compressive Strength (UCS) and Scanning Electron Microscope (SEM). After all the tests, the 5% replacement SCBA mix ratio gave the highest unconfined compressive strength if compared to the other mixtures ratio. Therefore, it is selected as the optimum mix ratio. The soil strength achieved by the SCBA 5% replacement ratio was found to be higher than cement stabilization alone due to the presence of secondary pozzolan reactions. The microstructure result from the SEM test had shown that the 5% replacement SCBA mix ratio filled in the hollow left by the peat soil. Hence, able to improve its soil structure and thus increasing its strength.

Spruce forest afforestation leading to increased Fe mobilization from soils

Increasing exports of Fe and DOC from soils, causing browning of freshwaters, have been reported in recent decades in many regions of the northern hemisphere. Afforestation, and in particular an increase of Norway spruce forest in certain regions, is suggested as a driver behind these trends in water chemistry. In this study, we tested the hypothesis that the gradual accumulation of organic soil layers in spruce forests, and subsequent increase in organic acid concentrations and acidity enhances mobilization of Fe. First generation Norway spruce stands of different ages (35, 61, 90 years) and adjacent arable control plots were selected to represent the effects of aging forest. Soil solutions were sampled from suction lysimeters at two depths (below organic soil layer and in mineral soil) during two years, and analyzed for Fe concentration, Fe speciation (XAS analysis), DOC, metals, major anions and cations. Solution Fe concentrations were significantly higher in shallow soils under older spruce stands (by 5- and 6-fold) than in control plots and the youngest forest. Variation in Fe concentration was best explained by variation in DOC concentration and pH. Moreover, Fe in all soil solutions was present as mononuclear Fe(III)-OM complexes, showing that this phase is dominating Fe translocation. Fe speciation in the soil was also analyzed, and found to be dominated by Fe oxides with minor differences between plots. These results confirmed that Fe mobilization, by Fe(III)-OM complexes, was higher from mature spruce stands, which supports that afforestation with spruce may contribute to rising concentrations of Fe in surface waters.

PENINGKATAN KEKUATAN TANAH ORGANIK DENGAN PENCAMPURAN EMPAT JENIS LIMBAH RAMAH LINGKUNGAN

Waste is one of the problems in Indonesia. Based on the Ministry of the Environment, each person produces an average of 0.8 kg of waste per day. The average waste per person will increase in line with the increase in people's welfare and lifestyle. Assuming 220 million Indonesians, waste reaches 176,000 tons per day. Accompanied by increasing population growth, the need for infrastructure development on land is increasing. Soils that is often used for construction land is organic soil. It has low soil bearing capacity values and soil improvement methods are commonly used. The general method usually is to mix the soil with better bearing capacity. To minimize costs, a physical stabilization system is carried out that can use soil improvement methods with waste. This can deal with 2 problems at once, where there is the use of certain types of waste and also the planning of organic soil stabilization with small carrying capacity. By doing a triaxial test on organic soil by mixing 4 different types of waste, it shows that the best waste mixture that can affect the bearing capacity of the soil in sequence is coconut husk, tile fragments, construction demolition debris, and chicken egg shells. ABSTRAKLimbah merupakan salah satu permasalahan di Indonesia, Berdasarkan informasi Kementerian lingkungan Hidup, setiap orang menghasilkan rata-rata 0,8 kg sampah per hari. Rata-rata limbah per orang akan meningkat sejalan dengan meningkatnya kesejahteraan dan gaya hidup masyarakat. Dengan asumsi 220 juta penduduk Indonesia, limbah mencapai 176.000 ton per hari. Diiringi dengan peningkatan pertumbuhan penduduk, maka kebutuhan pembangunan infrastruktur di lahan tanah semakin bertambah. Salah satu tanah yang sering dipakai untuk lahan konstruksi adalah tanah organik. Tanah organik memiliki nilai daya dukung tanah yang rendah dan biasa dilakukan metode perbaikan tanah. Metode umum yang biasa dilakukan adalah dengan melakukan pencampuran tanah dengan daya dukung yang lebih baik. Untuk memperkecil biaya maka dilakukannya sistem stabilisasi fisik yang bisa menggunakan metode perbaikan tanah dengan limbah. Hal ini bisa menangani 2 masalah sekaligus, dimana adanya pemanfaatan dari jenis limbah tertentu dan juga perencanaan stabilisasi tanah organik dengan daya dukung kecil. Dengan melakukin uji triaksial pada tanah organik dengan mencampurkan 4 jenis limbah berbeda menunjukan bahwa campuran limbah terbaik yang bisa mempengaruhi daya dukung tanah secara berurutan adalah sabut kelapa, pecahan genteng, puing pembongkaran konstruksi, dan cangkang telur ayam.

Effect of Biochar and PGPR on the Growth and Nutrients Content of Einkorn Wheat (Triticum monococcum L.) and Post-Harvest Soil Properties

Limited availability of nutrients to crops is a major agricultural concern. Deteriorated soil health and poor fertility status decrease the bioavailability of essential nutrients to the plants. Consequently, organic soil amendment biochar is gaining attention due to its potential benefits. Rhizobacterial inoculation, are also documented as an effective technology for mobilization of immobile nutrients in soil. However, limited literature is available on combined use of rhizobacteria and biochar. Therefore, this study was carried out to examine the changes in the nutrient content of einkorn wheat and the change in some soil properties during the application of plant growth-promoting rhizobacteria (PGPR) with biochar. Four doses of biochar (0, 2.5, 5, and 10%) were applied with and without PGPR in the study. Biochar increased the growth criteria such as plant fresh weight (PFW), plant dry weight (PDW), root fresh weight (RFW), root dry weight (RDW), number of tillers, germination rate (GR) and potassium (K), calcium (Ca), sodium (Na), iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), and nickel (Ni) elements. While PGPR application increased soil pH, dry and fresh weight of root, R/S, K, Ca, Mg, Fe, and Ni contents, and it caused a decrease in PH, PFW, tillers, GR, P, Cu, and Zn values. Combined biochar applications and PGPR had a significant effect on the pH, RFW, R/S, P, Na, and Cu. In conclusion, the combination of biochar and PGPR applications has shown a positive effect in terms of soil properties, plant growth, and element contents of einkorn wheat.

Evidence of Mid-Holocene (Northgrippian Age) Dry Climate Recorded in Organic Soil Profiles in the Central Appalachian Mountains of the Eastern United States

Peatlands in Canaan Valley National Wildlife Refuge hold a pedomemory of Pleistocene and Holocene climatic fluctuations in the central Appalachian Mountains of the eastern United States. A field investigation profiling 88 organic soil profiles, coupled with 52 radiocarbon dates and peat accumulation rates, revealed a distinct sequence of organic soil horizons throughout five study areas. The dominantly anaerobic lower portions of the organic soil profiles consist of varied thicknesses of hemic and sapric soil materials, typically layered as an upper hemic horizon, underlain by a sapric horizon, underlain by another hemic horizon. Peat deposition began after the Last Glacial Maximum with relatively high Heinrich Stadial 1 accumulation rates to form the lowest hemic horizon. Peat accumulated at significantly slower rates as the climate continued to warm in the early Holocene Greenlandian Age. However, between 10,000 and 4200 cal yr BP peat accumulation decreased further and the decomposition of previously deposited peat prevailed, forming the sapric horizon. This interval of greater decomposition indicates a drier climatic with dates spanning the late Greenlandian Age through the Northgrippian Age. The upper hemic horizon within the anaerobic portion of the soil profile formed from high peat accumulation rates during the wetter late Holocene Meghalayan Age.