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Climate change, land degradation and inadequate soil nutrients pose significant threats to food security and agricultural sustainability. This study aims to examine the effects of planting basins with farmyard manure on soil total carbon (C), nitrogen (N), isotopic C (d13C) and N (d15N) compositions within smallholder-managed farms in Makueni County, Kenya. The study involved two management practices: planting basins with manure (PM) and conventional farming practices (FP) in 12 experimental sites. Soil samples were taken at three depths (0-10, 10-20 and 20-40 cm), with three replicates for each treatment. Significant interactions were observed between land management practices and sites as well as land management practices and soil depth on soil total C and N. At each of the 12 sites, soil total C was higher under PM (ranging from 0.44% to 1.86%, p < .05) than FP management (ranging from 0.35% to 1.37%), across all soil depths. Soil total N concentrations ranged from 0.027% to 0.100% under FP and (0.060% to 0.190%, p < .05) under PM management. Across soil depths, higher (less negative) soil d13C values were observed under conventional farmer practice (range - 22.5? to -17.1?) compared with PM management range (-24.3? to -18.1?). Soil d15N was significantly enriched under PM management (range: 7.4? to 12.6?, p < .05) compared with the conventional farmer practices (range: 6.1? to 9.8?, p < .05). The findings show that planting basins with farmyard manure offers both climate mitigation and adaptation benefits by increasing soil C contents and improving soil fertility. The study provides insights into the real-world implications of these practices, emphasizing the potential of planting basins with manure in enhancing soil quality and climate resilience. [ABSTRACT FROM AUTHOR]

Converting alfalfa (Medicago sativa L.) into annual cropland (rotated cropland, RC) is commonly done to reuse degraded alfalfa pasture. However, it is a big challenge for RC to achieve high productivity and maintain high soil organic carbon (SOC) to the levels achieved by previous alfalfa pasture. We converted a long‐term alfalfa pasture into RC in 2010, and studied the effects of fertilization on soil moisture, crop productivity, and SOC in the RC and in continuous cropland (CC), both under plastic film mulching, from 2010 to 2018. Before the conversion, alfalfa pasture had a higher SOC (12.3%) and total N (7.7%) than CC. However, not only severe soil desiccation occurred, but the available P and inorganic‐N were only about 39.4 and 25.1% of levels for CC. After the conversion, soil moisture in RC (measured at 0–0.6 m depth) was up to CC levels only after 1 year, and was restored to 95.3 and 69.2% of CC levels at 0.6–2 and 2–5 m depths only after 9 years. Crop yield and biomass in RCF (RC with fertilization) were comparable to those for CCF (CC with fertilization) after two years from conversion due to the increased available P and inorganic‐N, and sufficient soil moisture restoration at 0–0.6 m depath. SOC in RC decreased by 8.1% over the 9 years, while RCF consistently kept SOC levels up to those of pre‐conversion alfalfa pasture. These findings help to eliminate concerns about the continuously low production and rapid decline of SOC in croplands converted from alfalfa and suggest ways to support sustainable high‐productivity and high SOC sequestration in dryland farming. [ABSTRACT FROM AUTHOR]

A comparative study of the efficiency of contaminant removal between five emergent plant species and between vegetated and unvegetated wetlands was conducted in small-scale (2.0 m × 1.0 m × 0.7 m, length × width × depth) constructed wetlands for domestic wastewater treatment in order to evaluate the decontaminated effects of different wetland plants. There was generally a significant difference in the removal of total nitrogen (TN) and total phosphorus (TP), but no significant difference in the removal of organic matter between vegetated and unvegetated wetlands. Wetlands planted with Canna indica Linn., Pennisetum purpureum Schum., and Phragmites communis Trin. had generally higher removal rates for TN and TP than wetlands planted with other species. Plant growth and fine root (root diameter ⩽ 3 mm) biomass were related to removal efficiency. Fine root biomass rather than the mass of the entire root system played an important role in wastewater treatment. Removal efficiency varied with season and plant growth. Wetlands vegetated by P. purpureum significantly outperformed wetlands with other plants in May and June, whereas wetlands vegetated by P. communis and C. indica demonstrated higher removal efficiency from August to December. These findings suggest that abundance of fine roots is an important factor to consider in selecting for highly effective wetland plants. It also suggested that a plant community consisting of multiple plant species with different seasonal growth patterns and root characteristics may be able to enhance wetland performance. [ABSTRACT FROM AUTHOR]

Creating a soil habitat is the first step to manage soil health for long‐term soil quality and output. This means using soil management methods that lessen the soil uproar. An experiment was established in 2016 and 2017 on a middle term (7 years) consistent tillage method in typical Latosolic red soil of Southern China to access the effects of four treatments: subsoiling (SS), two passes of rotary tillage (2RT), two passes of rotary tillage + subsoiling (2RTSS), and zero tillage (ZT), on soil organic carbon, soil total nitrogen, soil biological activities (bacteria, fungi, actinomycetes, urease, catalase, and phosphatase), and maize grain yield. The results showed that mean SOC, total N, biological activities, and maize grain yields were affected significantly (p < 0.05) by tillage methods. Compared with SS, 2RT, and 2RTSS, ZT had higher SOC, total N, soil bacteria, and soil actinomycetes in the 0–40 cm soil depth. The highest levels of fungi, urease, catalase, and phosphatase were recorded under SS in the 0–40 cm soil depth. Average maize grain yield of 7.37 ton/ha (9.81%) was recorded under SS compared to under ZT. Overall, we conclude that SS could be adopted as a promising soil management method for soil health, quality, and productivity resulting in a sustainable agricultural system. [ABSTRACT FROM AUTHOR]