scholarly journals Precipitation alters plastic film mulching impacts on soil respiration in an arid area of northwest China

2018 ◽  
Vol 22 (5) ◽  
pp. 3075-3086 ◽  
Author(s):  
Guanghui Ming ◽  
Hongchang Hu ◽  
Fuqiang Tian ◽  
Zhenyang Peng ◽  
Pengju Yang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Drip Irrigation ◽  
Northwest China ◽  
Arid Area ◽  
Arid Areas ◽  
Plastic Film ◽  
Soil Co2 ◽  
Plastic Mulch ◽  
Film Mulching

Abstract. Plastic film mulching (PFM) has widely been used around the world to save water and improve crop yield. However, the effect of PFM on soil respiration (Rs) remains unclear and could be further confounded by irrigation and precipitation. To address these topics, controlled experiments were conducted in mulched and non-mulched fields under drip irrigation from 2014 to 2016 in an arid area of the Xinjiang Uygur Autonomous Region, northwest China. The spatio-temporal pattern of soil surface CO2 flux as an index of soil respiration under drip irrigation with PFM was investigated, and the confounded effects of PFM and irrigation/precipitation on soil respiration were explored. The main findings were as follows. (1) Furrows, planting holes, and plastic mulch are three important pathways of soil CO2 emissions in mulched fields, of which the planting hole efflux outweighs that from the furrow, with the largest values of 8.0 and 6.6 µmol m−2 s−1, respectively, and the plastic mulch itself can emit up to 3.6 µmol m−2 s−1 of CO2. (2) The frequent application of water (i.e. through irrigation and precipitation) elevates soil moisture and soil respiration and enhances their variation. The resultant higher variation of soil moisture further alleviates the sensitivity of soil respiration to soil temperature, leading to a weak correlation and lower Q10 values. (3) Soil CO2 effluxes from furrows and ridges in mulched fields outweigh the corresponding values in non-mulched fields in arid areas. However, this outweighing relation attenuates with increasing precipitation. Furthermore, by combining our results with those from the literature, we show that the difference in soil CO2 effluxes between non-mulched and mulched fields presents a linear relation with the amount of precipitation, which results in negative values in arid areas and positive values in humid areas. Therefore, whether PFM increases soil respiration or not depends on the amount of precipitation during the crop-growing season.

scholarly journals Precipitation alters plastic film mulching impacts on soil respiration in an arid area of Northwest China

2017 ◽  
Author(s):  
Guanghui Ming ◽  
Hongchang Hu ◽  
Fuqiang Tian ◽  
Zhenyang Peng ◽  
Pengju Yang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Spatial Heterogeneity ◽  
Drip Irrigation ◽  
Northwest China ◽  
Arid Area ◽  
Plastic Film ◽  
Plastic Mulch ◽  
Film Mulching

Abstract. Plastic film mulching (PFM) has been widely used for saving water and improving yield around the world, particularly in arid areas. However, the effect of PFM in agriculture on soil respiration is still unclear, and this effect may be confounded with irrigation and precipitation. To detect the effects of PFM, irrigation and precipitation on the temporal and spatial variations in soil respiration, plastic mulched and non-mulched drip irrigation contrast experiments were conducted in the arid area of the Xinjiang Uygur Autonomous Region, Northwest China. PFM generated more complicated spatial heterogeneity in the microclimate with increased albedo, improved soil temperature, soil moisture and crop growth, and led to the stronger spatial heterogeneity of the soil respiration. The soil respiration in the plant holes was larger than in the furrows, and plastic mulch itself can emit up to 2.75 μmol m−2 s−1 CO2, which indicates that furrows, plant holes and plastic mulch were the important pathways for CO2 emissions in the mulched field. Frequent irrigation and precipitation made the soil respiration much more dynamic and fluctuated. The sensitivity of the soil respiration to soil temperature was weakened by extreme variations in the soil moisture with lower correlation and Q10 values. In the wetting-drying cycle, both irrigation and precipitation restrained the soil respiration at a high soil water content (SWC) with a threshold of 60 % water-filled pore space (WFP) in the furrows and 50 % WFP in the ridges, and the restrain effect decreased gradually with the depleting of soil moisture. The accumulated soil respiration calculated from the area ratio of the different parts in the furrows and ridges in the mulched field were both larger than in the non-mulched field during the growing season. However, this magnitude decreased with increasing precipitation over three experimental years. It was speculated that the effect of drip irrigation on the soil respiration was primarily on the ridges while the effect of precipitation mostly concentrated in the furrows and ridges in the non-mulched field because of the mulch barrier. Therefore, the precipitation accelerated more respiration in the mulched than in the non-mulched field. The difference in soil respiration between the mulched and non-mulched fields was observed to have a positive correlation with precipitation per the findings of other studies. In a humid climate with much more precipitation, soil respiration in the non-mulched field can also exceed that of the mulched field and explains why certain studies concluded that plastic mulch decreased soil respiration. The above results indicate that both irrigation and precipitation alter soil respiration and this effect can be modified by plastic mulch. Therefore, whether the PFM increases soil respiration compared to a non-mulched field largely depends on precipitation in the field.

scholarly journals Effects of mulching on soil CO2 fluxes, hay yield and nutritional yield in a forage maize field in Northwest China

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ming Fan ◽  
Qiang Li ◽  
Enhe Zhang ◽  
Qinglin Liu ◽  
Qi Wang
Keyword(s):  
Soil Moisture ◽  
Field Experiment ◽  
Water Shortage ◽  
Northwest China ◽  
Plastic Film ◽  
Agricultural Ecosystem ◽  
Forage Maize ◽  
The Sustainable Development ◽  
Heavy Carbon ◽  
Film Mulching

Abstract In arid areas of China, water shortage and heavy carbon emissions have been threatening agricultural sustainability and which has become a vital issue. A field experiment was conducted to explore how different mulching affects soil moisture and temperature, CO2 fluxes, forage-maize hay yield and nutritional value during 2 consecutive years: 2014 and 2015. The field experiment showed that mulching materials had distinct effects on soil moisture and temperature and CO2 fluxes. The soil temperature and CO2 fluxes were in order of common plastic film mulching (PFM) > bio-degradable mulch mulching (BMM) > no mulching (CK) > straw mulching (SM), while the soil moisture was in order of PFM > BMM > SM > CK over these two years. Compared with CK, hay yield respectively increased by 23.25%, 22.51% and 5.27% for PFM, BMM and SM, WUE increased by 35.60%, 32.34% and 10.88%, and the total nutrient yields increased by 17.75%, 21.35% and 6.95%, respectively. To sum up, in combination with ecology and environmental protection, bio-degradable mulch could replace common plastic film and bio-degradable mulch should be popular in future. As bio-degradable mulch is green non-pollution, it is conducive to the sustainable development of agricultural ecosystem.

scholarly journals Soil moisture modifies the response of soil respiration to temperature in a desert shrub ecosystem

2014 ◽  
Vol 11 (2) ◽  
pp. 259-268 ◽  
Author(s):  
B. Wang ◽  
T. S. Zha ◽  
X. Jia ◽  
B. Wu ◽  
Y. Q. Zhang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Seasonal Cycle ◽  
Northwest China ◽  
Interactive Effects ◽  
Co2 Efflux ◽  
Diel Variation ◽  
Desert Ecosystems ◽  
Volumetric Soil Water Content ◽  
Desert Shrub

Abstract. The current understanding of the responses of soil respiration (Rs) to soil temperature (Ts) and soil moisture is limited for desert ecosystems. Soil CO2 efflux from a desert shrub ecosystem was measured continuously with automated chambers in Ningxia, northwest China, from June to October 2012. The diurnal responses of Rs to Ts were affected by soil moisture. The diel variation in Rs was strongly related to Ts at 10 cm depth under moderate and high volumetric soil water content (VWC), unlike under low VWC. Ts typically lagged Rs by 3–4 h. However, the lag time varied in relation to VWC, showing increased lag times under low VWC. Over the seasonal cycle, daily mean Rs was correlated positively with Ts, if VWC was higher than 0.08 m3 m−3. Under lower VWC, it became decoupled from Ts. The annual temperature sensitivity of Rs (Q10) was 1.5. The short-term sensitivity of Rs to Ts varied significantly over the seasonal cycle, and correlated negatively with Ts and positively with VWC. Our results highlight the biological causes of diel hysteresis between Rs and Ts, and that the response of Rs to soil moisture may result in negative feedback to climate warming in desert ecosystems. Thus, global carbon cycle models should account the interactive effects of Ts and VWC on Rs in desert ecosystems.

scholarly journals Significance of soil respiration from biological activity in the degradation processes of different types of organic matter

2020 ◽  
Vol 1 (2) ◽  
pp. 171-179
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Total Soil

Soil respiration is a major component of global carbon cycle. Therefore, it is crucial to understand the environmental controls on soil respiration for evaluating potential response of ecosystems to climate change. In a temperate deciduous forest (located in Northern-Hungary) we added or removed aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture, and soil temperature. Soil CO2 efflux was measured at each plot using soda-lime method. Temperature sensitivity of soil respiration (Q10) was monitored via measuring soil temperature on an hourly basis, while soil moisture was determined monthly. Soil respiration increased in control plots from the second year after implementing the treatment, but results showed fluctuations from one year to another. The effect of doubled litter was less significant than the effect of removal. Removed litter and root inputs caused substantial decrease in soil respiration. We found that temperature was more influential in the control of soil respiration than soil moisture. In plots with no litter Q10 varied in the largest interval. For treatment with doubled litter layer, temperature sensitivity of CO2 efflux did not change considerably. The effect of increasing soil temperature is more conspicuous to soil respiration in litter removal treatments since lack of litter causes greater irradiation. When exclusively leaf litter was considered, the effect of temperature on soil respiration was lower in treatments with added litter than with removed litter. Our results reveal that soil life is impacted by the absence of organic matter, rather than by an excess of organic matter. Results of CO2 emission from soils with different organic matter content can contribute to sustainable land use, considering the changed climatic factors caused by global climate change.

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

scholarly journals Response and Modeling of Hybrid Maize Seed Vigor to Water Deficit at Different Growth Stages

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3289
Author(s):  
Rongchao Shi ◽  
Ling Tong ◽  
Taisheng Du ◽  
Manoj K. Shukla
Keyword(s):  
Water Deficit ◽  
Drip Irrigation ◽  
Field Experiments ◽  
Seed Vigor ◽  
Growth Stages ◽  
Arid Areas ◽  
Flowering Stage ◽  
Maize Production ◽  
Film Mulching ◽  
Hybrid Maize

Research is imperative to predict seed vigor of hybrid maize production under water deficit in arid areas. Field experiments were conducted in 2018 and 2019 in arid areas of northwestern China to investigate the effects of different irrigation strategies at various growth stages with drip irrigation under film mulching on grain yield, kernel weight, seed protein content, and seed vigor of hybrid maize (Zea mays L.). Water deficit at vegetative, flowering, and grain-filling stages was considered and a total of 16 irrigation treatments was applied. A total of 12 indices of germination percentage, germination index (GI), shoot length (SL), and root length (RL) under different germination conditions (standard germination and accelerated aging); electrical conductivity (EC) of the leachate; and activities of peroxidase, catalase, and superoxide dismutase in seeds were measured and analyzed using the combinational evaluation method (CEM). Furthermore, five water production functions (Blank, Stewart, Rao, Jensen, and Minhas) were used to predict seed vigor evaluated by CEM under water deficit. The results showed that leachate EC was higher under water deficit than that under sufficient irrigation. The SL, RL, and GI of different germination conditions increased under water deficit at the flowering stage. The Rao model was considered the best fitted model to predict the vigor of hybrid maize seeds under water deficit, and an appropriate water deficit at the flowering stage is recommended to ensure high seed vigor of hybrid maize production with drip irrigation under film mulching. Our findings would be useful for reducing crop water use while ensuring seed vigor for hybrid maize production in arid areas.

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