Sewage Sludge Amendment Combined with Green Manuring to a Coastal Mudflat Salt-Soil in Eastern China: Effects on Soil Physicochemical Properties and Maize Yield

Abstract

Sewage sludge and green manure have become widely used organic amendments to croplands in many regions of the world. However, the amending effect of the combination of sewage sludge with green manuring in reclaimed coastal mudflat salt-soil has been unclear yet. This paper was one of earlier studies to investigate and evaluate the effects of sewage sludge amendment combined with green manuring on selected soil physicochemical properties of the mudflat soil in a rain-fed agroecosystem. The mudflat salt-soil was amended by one-time input of sewage sludge at the rates of 0, 30, 75, 150, and 300 t ha −1 . After green manuring for three consecutive seasons, maize (Zea mays L.) was planted in 2013 and 2014. The results showed that SSA combined with green manuring decreased bulk density, pH, salinity, and exchangeable sodium percentage of the topsoil (0-20 cm soil layer) and increased aggregate stability, cation exchange capacity, and N and P concentration of the topsoil. As a result, the maize yield increased with the increase of SSA rates. Sewage sludge combined with green manuring can be applied in coastal mudflat salt-soil amendment, which provides an innovative way to create arable land resources and safe disposal of sewage sludge.

Effects of brewery sludge on soil chemical properties, trace metal availability in soil and uptake by wheat crop, and bioaccumulation factor

“…The findings of the current study are in line with previous reports. For example, Bai et al. (2017) observed that a combined application of sewage sludge and green manuring significantly elevated organic carbon content by 97.5–122.2%, 167.9–205.7%, 320.2–345.2%, and 352.8–427.8% at the rate of 30, 75, 150, and 300 t ha −1 in 2013 and 2014 seasons, respectively as compared to the control plots.…”

Structural and Predicted Functional Diversities of Bacterial Microbiome in Response to Sewage Sludge Amendment in Coastal Mudflat Soil

“…This was consistent with our previous studies that found sewage sludge has significant effects on soil alkalinity, salinity, and nutrient retention [ 14 , 23 , 24 , 48 ]. Specifically, soil pH was significantly lower in sewage sludge-amended soils as compared to CK treatment ( Table 1 ), which might be partially attributed to neutralization caused by lower-pH sewage sludge (6.32, Table S1 ) and organic acids (i.e., humic and fulvic acids) generated during the degradation of organic matters in sewage sludge [ 6 , 49 ]. Additionally, cumulative H+ secreted by plants roots and increased CO 2 , NO 3 − , and NO 2 − levels [ 50 , 51 , 52 , 53 ] might also be responsible for the decline in mudflat soil pH.…”

“…Unsurprisingly, considerably increased soil organic carbon content and decreased soil salinity were observed in sewage sludge-amended treatments as compared to unamended soil ( Table 1 ). The reason lies in the fact that applying sewage sludge with abundant organic matter into mudflat salt-affected soil can not only rapidly elevate soil organic carbon stocks [ 54 ], but also significantly facilitate water-stable aggregate formation, which efficiently prevents saline water from moving upward through soil capillaries, and finally reduced salt in the plough layer [ 6 ]. Apart from the soil organic carbon, sewage sludge application also promoted nitrogen and phosphorus contents in mudflat soil, which increased with the application rate of sewage sludge ( Table 1 ).…”

“…The coastal mudflat, which is widely distributed worldwide, has been considered a promising alternative reserve for cultivated land resources to mitigate the issue described above [ 3 , 4 , 5 ]. Especially in China, approximately 13,000 km 2 of coastal mudflats, more than half of the national total, have been reclaimed in the recent decades to meet the ever-growing land resource demands for industrial and agricultural development [ 6 , 7 ]. However, due to long-term seawater immersion and intensive evapotranspiration, coastal mudflat soils are characterized by high salinity, sodicity, and nutrition deficiency, which seriously influence the newly reclaimed soil’s health and subsequent cultivation performance [ 8 , 9 , 10 , 11 ].…”

Mitigating the impact of soil salinity: recent developments and future strategies

“…Saline soils are diverse in nature and require specific strategies, such as the application of sulfurcontaining compounds to aid the management and reclamation for long-term productivity (Bello et al, 2021, Tomaz et al, 2020. Other related amendments such as sewage sludge, biochar, compost of municipal solid wastes and zeolite have also been used to reclaim sodic soils (Bai et al, 2017, Mukhopadhyay et al, 2021.…”