Effects of Organic Mulch on Soil Moisture and Nutrients in Karst Area of Southwest China

Abstract

Based on the typical engineering water shortage and soil degradation of sloping farmland in the karst area of southwest China, this experiment is to explore the suitable organic mulch materials and application rate and to provide theoretical reference for the regional soil moisture conservation and fertility enhancement. The maize monoculture was set as control (CK), five straw mulch treatments (20%, 40%, 60%, 80%, 100%, SM1-SM5) and four biochar mulch treatments (25%, 50%, 75%, 100%, BM1-BM4), which were set according to mulch application rate from low to high, and alfalfa, chicory and ryegrass intercropping in maize were set as 3 living mulches (LM1-LM3), 13 treatments in total. Observation of soil moisture, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and total potassium (TK) in the plough layer were carried out in 2018. When straw mulch application rate reached SM5, the soil moisture reached the maximum, which was significantly higher than CK and SM1-SM3 (p<0.05), but not significantly higher than SM4 (p>0.05); biochar and living mulch did not significantly improve the moisture; the overall water conservation effect of straw mulch was better than that of biochar and living mulch. Soil TOC, TN and TP with high straw and biochar mulch application rate was significantly higher than CK, however, the increase of straw and biochar mulch had no significant effect on TK; TN of LM1 was significantly higher than CK, LM2 and LM3 (p<0.05). Among the three types of organic mulches, the TOC was high under straw and biochar mulch, and the TOC, TN and TP under biochar mulch were the largest, which was significantly higher than that of LM (p<0.05). The results indicated that straw mulch played an important role in water conservation and fertility enhancement, and about 6 Mg ha -1 of straw mulch could be an appropriate reference mulch application rate for karst areas in Southwest China.

Effects of biochar on karst lime soil nutrients, soil microbial communities and physiology of Sichuan pepper plants

“…Different soil microbes have distinct functions and hereditary characters to affect soil nutrients availability and elements cycling (Cairns, Robertson, Sigmund, & Street‐Perrott, 2020; Saletnik et al, 2017; Xing et al, 2019). The carbon‐rich nature of biochar also suggests potential impacts on carbon mineralization that is driven by diverse soil microbial communities (Chen et al, 2018; Hardy, Sleutel, Dufey, & Cornelis, 2019; Li, Li, et al, 2020; Li, Wang, Chang, Jiang, & Song, 2020). However, while the positive effects of biochar on plants are widely documented (Bai et al, 2022; Kochanek et al, 2022; Mansoor et al, 2021), there is little information on the consequences of field application of biochar on woody crop (Sichuan pepper) stands and microbial communities in anti‐dip karstic soils (Gan, He, Qin, & Li, 2020b; Li, Li, et al, 2020; Li, Wang, et al, 2020; Zhou et al, 2019).…”

“…The carbon‐rich nature of biochar also suggests potential impacts on carbon mineralization that is driven by diverse soil microbial communities (Chen et al, 2018; Hardy, Sleutel, Dufey, & Cornelis, 2019; Li, Li, et al, 2020; Li, Wang, Chang, Jiang, & Song, 2020). However, while the positive effects of biochar on plants are widely documented (Bai et al, 2022; Kochanek et al, 2022; Mansoor et al, 2021), there is little information on the consequences of field application of biochar on woody crop (Sichuan pepper) stands and microbial communities in anti‐dip karstic soils (Gan, He, Qin, & Li, 2020b; Li, Li, et al, 2020; Li, Wang, et al, 2020; Zhou et al, 2019). Moreover, many studies focus on the effects of biochar on plants, soils, or microorganisms individually; however, the effect of biochar on the nexus among plants, soil, and microorganisms remains underexplored and poorly understood (Chen, Ma, et al, 2018; Kolton, Graber, Tsehansky, Elad, & Cytrya, 2017; Nash et al, 2021).…”

“…We aimed to clarify the effect of biochar application on soil water reservation capacity, soil nutrients contents, soil microbial abundances and community structure and physiology of Sichuan pepper plants. We hypothesized that biochar can positively affect Sichuan pepper plants (Bai et al, 2022) by modifying Karst lime soil microenvironment in rhizosphere (Chen, Ma, et al, 2018; Hardy et al, 2019; Kolton et al, 2017; Li, Li, et al, 2020; Li, Wang, et al, 2020; Nash et al, 2021). We also expected an increase in the photosynthetic capacity of Sichuan pepper treated with biochar.…”

Changes in Calcareous Soil Activity, Nutrient Availability, and Corn Productivity Due to The Integrated Effect of Straw Mulch and Irrigation Regimes

“…In addition to the beneficial role of mulching for enhancing activity of soil biota, helping in soil rehabilitation, and improving the nutrient availability in the soil (Jabran 2019), water conservation is another advantage of soil mulching. Li et al (2020) reported that straw mulch played an important role in water conservation and fertility enhancement. Thus, our findings proved the beneficial effect of mulching for enhancing the nutrient status of calcareous soil under moderate water supply (I80) because of raising available K (Fig.…”

Biochar and compost amendments alter the structure of the soil fungal network in a karst mountainous area

“…Karst rocky desertification leads to significant negative impacts to the local environment and socio-economic conditions (Chen et al, 2011;Jiang et al, 2014). At present, ecological restoration measures such as afforestation and soil improvement have been applied to combat karst rocky desertification (Li et al, 2020).…”