Effects Of Plastic Film Mulching Research Articles

Biodegradable plastic film mulch increases the mineralisation of organic amendments and prevents nitrate leaching during the growing season in organic vegetable production

AbstractIntroductionOrganic vegetable production relies on inputs of organic forms of nitrogen (N). This presents a challenge as it needs to be mineralised by the soil microbial community. Difficulties matching the timing and rate of organic N amendments to crop demand could potentially lead to high rates of nitrate leaching. The use of plastic film mulch (PFM) has the potential to increase crop yield, accelerate N mineralisation, reduce rainfall infiltration and therefore N leaching. Biodegradable PFM reduces the risk of contaminating soil with plastics. Although these positive effects have been proven in major conventionally grown commodity crops, the effects of PFMs are poorly understood in organic vegetable crops, particularly in moist temperate climates prone to N losses via winter leaching.Materials & MethodsOur plot‐scale field experiment attempted to quantify the effect of biodegradable PFM on N leaching and N mineralisation in organic lettuce production in the presence and absence of biodegradable PFM. It took place in one season within a longer‐term experimental organic vegetable rotation.ResultsWe used two methods to measure the rate of carbon and N mineralisation: the buried bag method showed biodegradable PFM resulted in no additional N mineralisation; however, the ion exchange membrane method indicated an increase in N mineralisation of 30%. During heavy rainfall at the end of the growing season, nitrate leaching was observed only in the non‐PFM plots, leading to N losses equivalent to 6.3 g N m−2. This led to surplus mineral N at harvest of 18.1 g N m−2 in the PFM treatment and 8.6 g N m−2 in the corresponding unmulched plots. This did not lead to more leaching in the mulched plots in the following 6 months.ConclusionIn conclusion, our evidence supports the use of biodegradable PFMs to enhance the sustainability of organic vegetable production systems in temperate climates.

Optimum Plant Density Improved Cotton (Gossypium hirsutum L.) Root Production Capacity and Photosynthesis for High Cotton Yield under Plastic Film Mulching

Optimum Plant Density Improved Cotton (Gossypium hirsutum L.) Root Production Capacity and Photosynthesis for High Cotton Yield under Plastic Film Mulching

Optimizing the Mulching Pattern and Nitrogen Application Rate to Improve Maize Photosynthetic Capacity, Yield, and Nitrogen Fertilizer Utilization Efficiency.

Residual film pollution and excessive nitrogen fertilizer have become limiting factors for agricultural development. To investigate the feasibility of replacing conventional plastic film with biodegradable plastic film in cold and arid environments under nitrogen application conditions, field experiments were conducted from 2021 to 2022 with plastic film covering (including degradable plastic film (D) and ordinary plastic film (P)) combined with nitrogen fertilizer 0 (N0), 160 (N1), 320 (N2), and 480 (N3) kg·ha-1. The results showed no significant difference (p > 0.05) in dry matter accumulation, photosynthetic gas exchange parameters, soil enzyme activity, or yield of spring maize under degradable plastic film cover compared to ordinary plastic film cover. Nitrogen fertilizer is the main factor limiting the growth of spring maize. The above-ground and root biomass showed a trend of increasing and then decreasing with the increase in nitrogen application level. Increasing nitrogen fertilizer can also improve the photosynthetic gas exchange parameters of leaves, maintain soil enzyme activity, and reduce soil pH. Under the nitrogen application level of N2, the yield of degradable plastic film and ordinary plastic film coverage increased by 3.74~42.50% and 2.05~40.02%, respectively. At the same time, it can also improve water use efficiency and irrigation water use efficiency, but it will reduce nitrogen fertilizer partial productivity and nitrogen fertilizer agronomic use efficiency. Using multiple indicators to evaluate the effect of plastic film mulching combined with nitrogen fertilizer on the comprehensive growth of spring maize, it was found that the DN2 treatment had the best complete growth of maize, which was the best model for achieving stable yield and income increase and green development of spring maize in cold and cool irrigation areas.

Effects of the Plastic Mulching System and Fertilizer Application on the Yield of Tartary Buckwheat (Fagopyrum tataricum) and Water Consumption Characteristics in a Semi-arid Area

Although plastic film mulching is commonly utilized to enhance crop water use efficiency (WUE) in semi-arid areas, the combined effect of plastic film mulching and fertilizer application on Tartary buckwheat yield is still unknown. To address this gap, a four-year field experiment was conducted from 2018 to 2021 to investigate the effect of plastic film mulching and fertilizers on the soil water storage, plant growth, yield, and WUE of Tartary buckwheat in semi-arid environments. The treatments comprised traditional planting without fertilizer (TNF), traditional planting with fertilizer application (N–P2O5–K2O: 40–30–20 kg ha−1) (TF), plastic film mulching with fertilizer application (N–P2O5–K2O: 40–30–20 kg ha−1) (MF), and plastic film mulching without fertilizer (MNF). The results indicated that MF treatment significantly increased leaf area index and SPAD values compared to the other treatments. The yield of Tartary buckwheat under the film mulching increased by 23.3% in comparison to no-mulching treatments, and under fertilizer application it increased by 18.2% compared to no fertilizer. WUE under film mulching exhibited an increase of 3.1% in 2018, 34.9% in 2019, 45.5% in 2020, and 34.6% in 2021, respectively, compared to no mulching. The impact of film mulching on WUE was more significant in years with lower precipitation compared to those with normal or higher precipitation levels. Overall, MF significantly enhanced both the yield and WUE of Tartary buckwheat. This approach proved to be an effective strategy for bolstering drought-resistant yield and optimizing resource efficiency in Tartary buckwheat cultivation in semi-arid regions. Moreover, the positive effects of plastic mulching and fertilizer application on grain yield and water use efficiency were more pronounced in drier years.

Acceptable Salinity Level for Saline Water Irrigation of Tall Wheatgrass in Edaphoclimatic Scenarios of the Coastal Saline–Alkaline Land around Bohai Sea

Saline water irrigation contributes significantly to forage yield. However, the acceptable salinity levels for saline water irrigation of tall wheatgrass remains unclear. In this study, field supplemental irrigations of transplanted-tall wheatgrass with saline drainage waters having salinities of electrical conductivity (ECw) = 2.45, 4.36, 4.42, and 5.42 dS m−1 were conducted to evaluate the effects of saline water irrigation on forage yield and soil salinization. In addition, the effects of plastic film mulching, fertilization, and saline water irrigation on sward establishment of seed-propagated tall wheatgrass were determined. Finally, a pot experiment was carried out to confirm the above field results. The results showed that two irrigations with ECw = 2.45 and 4.36 dS m−1 saline waters produced the highest dry matter yield, followed by one irrigation with ECw = 4.42 or 5.42 dS m−1. After rainfall leaching, the soil EC1:5 was reduced by 41.7–79.3% for the saline water irrigation treatments. In combination with saline water irrigation, plastic film mulching promoted sward establishment and enhanced the plant height and dry matter yield of seed-propagated tall wheatgrass, while fertilization played a marginal role. However, two irrigations with ECw = 7.13 and 4.36 dS m−1 saline waters resulted in rates of 3.2% and 16.0% of dead plants under the mulching and no mulching conditions, respectively. Furthermore, a pot experiment demonstrated that irrigation with ECw = 5.79 dS m−1 saline water led to the lowest reduction in forage yield and the highest crude protein content in leaves. However, the plants irrigated with ECw ≥ 6.31 dS m−1 saline water enhanced soil salinity and reduced the plant height, leaf size, and gas exchange rate. Conclusively, one irrigation with ECw ≤ 5.42 dS m−1 and SAR ≤ 36.31 saline water at the end of April or early May could be acceptable for tall wheatgrass production and minimize the soil salinization risk in the coastal saline–alkaline land around the Bohai Sea.

Sub‐soil plastic film mulch promotes the growth and yield improvement of winter wheat in coastal saline–alkali soil

AbstractCrop yields are seriously threatened in saline–alkali areas with shallow groundwater levels and high evaporation. Mulching can effectively alleviate salt stress on crops in drylands, but there is limited research on winter wheat (Triticum aestivum L.) mulching in coastal saline–alkali areas. To investigate the effect of plastic film mulching on the growth and yield of wheat in coastal saline–alkali soil, three field management measures were designed: bare ground (CK), plastic film mulch (PM), and sub‐soil plastic film mulch (PMF). Compared with CK, PM and PMF significantly increased wheat grain yield by 128.2%–313.2% and 187.8%–537.0%, respectively, over the two study stages. The movement of salt to the surface is inhibited after mulching; as a result, PMF and PM significantly decreased the electric conductivity in shallow soil (0–20 cm) by 31.1% and 23.8%, on average, compared to CK, resulting in a significant increase in dry matter accumulation (DM) for winter wheat throughout the growing season. Moreover, PMF increased the overall DM by increasing the dry matter accumulation per plant (DMP), while PM achieved a similar effect to PMF by increasing the number of tillers. Compared with PM, PMF had a better inhibitory effect on shallow soil salinity, significantly increasing the effective number of spikes, effective tillering rate, DMP, and spike weight at harvest; promoting vegetative and reproductive growth of wheat fields; and ultimately increasing yield. PMF can be used to improve winter wheat production in coastal saline–alkali soils.

A Review of Plastic Film Mulching on Water, Heat, Nitrogen Balance, and Crop Growth in Farmland in China

Plastic film mulching has been widely used to improve crop yield and water use efficiency, although the effects of plastic film mulching on water, heat, nitrogen dynamics, and crop growth are rarely presented comprehensively. This study investigated a large number of studies in film mulching fields from the past 10 years (mostly from 2019 to 2023) and summarized the impact of plastic film mulching, progress in modeling with film mulching, and future research directions. The effects of plastic film mulching were intricate and were influenced by film mulching methods, irrigation systems, crop types, crop growth stages, etc. Overall, plastic film mulching showed a positive effect on improving soil water, temperature, and nitrogen status, enhancing crop transpiration and photosynthetic rates, and promoting crop growth and yield, although film mulching may have negative effects, such as increasing rainfall interception, blocking water entering the soil, and reducing net radiation income. The crop yield and water use efficiency could increase by 39.9–84.7% and 45.3–106.4% under various film mulching methods. Coupled models of soil water and heat transport and crop growth under plastic film mulching conditions have been established by considering the effects of plastic film mulching on the upper boundary conditions of soil water and heat, energy budget and distribution processes, and the exchange of latent and sensible heat between soil and atmosphere. The models have good applicability in film mulched farmland of maize, rice, and potato for different regions of China. Further development is needed for soil water, heat, nitrogen migration, and crop growth models under different plastic film mulching methods, and the acquisition of soil and crop indicators under plastic film mulching conditions based on big data support. The study will provide reference for the subsequent development and innovation of plastic film mulching technology.

Effects of plastic film mulching and nitrogen fertilization on the emissions of greenhouse gases from vegetable field in Southwest China

This study identified the influence of plastic film mulching (FM) and nitrogen (N) fertilization on the CH4 emission, the global warming potential (GWP) and the greenhouse gas intensity (GHGI) in a summer-hot pepper and winter-radish rotation field from May 2014 to April 2017. The experiment had 8 treatments including no-mulching (NM) and plastic film mulching with four different N fertilization rates (0, 150, 300 and 450 kg N ha−1 and 0, 100, 200 and 300 kg N ha−1 in the respective hot pepper and radish growing periods). The results indicated that FM as well as N fertilization had insignificant effects on CH4 emissions in the hot pepper and radish growing periods (P > 0.05). Relative to NM, FM had little effect on GWP (P > 0.05) but lowered GHGI substantially (P < 0.05) during the hot pepper growing period. During the radish growing period, FM enhanced GWP and GHGI significantly (P < 0.05). Additionally, N fertilization significantly enhanced GWP and vegetable yields both in hot pepper and radish growing periods (P < 0.05). In hot pepper growing period, N fertilization increased GWP more significantly than yield which resulted in increased GHGI with N fertilization rate, and the promotion effect of N fertilization on hot pepper yield was strongest at 150 kg N ha−1 with a relatively low GHGI. However, in radish growing period, N fertilization increased yield more significantly than GWP which resulted in the decreasing effect of N fertilization on GHGI, and the promotion effect of N fertilization on radish yield was strongest at 300 kg N ha−1 with a relatively low GHGI. Therefore, FM with 150 kg N ha−1 and NM with 300 kg N ha−1 were respectively recommended for the hot pepper growing period and radish growing period to achieve high vegetable yields and mitigate greenhouse gas (GHG) emissions simultaneously under the present vegetable field condition in Southwest China.

Effects of plastic film mulching and legume rotation on soil nutrients and microbial communities in the Loess Plateau of China

BackgroundPotato (Solanum tuberosum L.) continuous cropping causes the decrease of tuber yield, deterioration of quality and soil degradation in the semi-arid area. These negative effects can generally be mitigated by legume rotation and mulching. However, little is known about how can mulching and legume rotation alleviate the above damage through altering soil environment.MethodsA field experiment was conducted to investigate changes in soil properties and microbial community in response to legume rotation and mulching under six planting patterns: potato continuous cropping without film mulching (PC), potato continuous cropping with film mulching (PCF), potato–broad bean rotation without film mulching (R1), potato–broad bean rotation with film mulching (R1F), potato–pea rotation without film mulching (R2) and potato–pea rotation with film mulching (R2F).ResultsCompared with the PC, the R1F and R2F had significantly enhanced the contents of alkaline nitrogen (AN), available phosphorus (AP), available potassium (AK), total carbon (TC) and total nitrogen (TN), but reduced soil pH and electrical conductivity (EC). The Shannon index of fungi in R1F and R2 was significantly higher than other treatments. The dominant bacterial and fungal phyla of each treatment was Proteobacteria and Ascomycota. R1, R1F, R2 and R2F enhanced the relative abundance of metabolic fungi and altered key differential microbial species. Soil EC, AN and AK were major factors influencing the soil bacterial and fungal communities.ConclusionOverall, the study demonstrated that potato-broad bean/pea rotation with mulching can be adopted as the preferred cropping systems to alleviate potato continuous cropping obstacles through enhancing soil fertility and regulating soil microbial communities in the semi-arid of Loess Plateau, China.Graphical

Is adding biochar be better than crop straw for improving soil aggregates stability and organic carbon contents in film mulched fields in semiarid regions? –Evidence of 5-year field experiment

Plastic film mulching is used widely to increase crop yields in semiarid areas, but improving the soil fertility in film mulched fields is also important for achieving sustainable high yields in northwest of China. In this study, a completely randomized two–factor field design experiment was conducted in Pengyang, Ningxia, China during 2017–2021. In order to investigate the effects of plastic film mulching with straw/biochar addition on the soil aggregate characteristics, organic carbon content, and maize yield. Six treatments were established as follows: control (C), straw (S), biochar (B), plastic film mulching (F), plastic film mulching with added straw (FS) or biochar (FB). After 5 years of continuous production, each straw and biochar addition treatments significantly improved the soil aggregate distribution and stability, and the average aggregate content >0.25 mm increased significantly by 47.32%. Compared with the treatments without plastic film mulching, the mean weight diameter and geometric mean diameter of the soil particles increased by 9.19% and 4.15%, respectively, under the plastic film mulching treatments. The organic carbon content of the 0–60 cm soil layer increased significantly under each straw and biochar addition treatment compared with the without straw. The aggregate organic carbon contents under each treatment increased as the aggregate particle size increased, where the straw and biochar addition treatments significantly increased the organic carbon content of the aggregates, whereas the contents decreased under the plastic film mulching treatments. The contributions of the soil aggregates >0.25 mm to the organic carbon contents of the 0–60 cm soil layer were significantly higher under FS (37.63%) and FB (56.45%) than F. Structural equation modeling showed that straw/biochar added, plastic film mulching, and a greater soil organic carbon content could significantly promote yield increases, where the straw and biochar addition treatments significantly increased the average maize by 14.6% on average. In conclusion, carbon input as straw, especially biochar, had a positive effect on improving the soil organic carbon content and maize yield under plastic film mulching farmland in a semiarid region.

Effects of Plastic Film Mulching on Soil Nematodes and Soil Quality at Different Growth Stages of Maize Planted in Semiarid Areas of China

Plastic mulching is considered as a simple, yet effective land management measure to modify microclimate in semi-arid areas. However, the influence of plastic mulching on local soil nematodes and soil quality needs to be investigated more deeply. To fill the knowledge gap, we compared the characteristics of soil nematode communities (density, trophic structure), soil enzyme activities, soil physicochemical properties, and their relationships between maize fields cultivated with use of plastic film mulching and no film mulching, under the same land conditions in Chifeng region, Inner Mongolia. The results showed that the total number of nematodes in most of the film mulched (FM) fields was lower than in no film mulched (nFM) fields. Most of soil chemical properties showed no significant difference between nFM samples and FM samples. Only 0–10 cm soil layer in nFM samples had significantly higher urease activity than in FM samples in June. Plastic film mulching may have an adverse effect on soil quality. Thus, the correct and effective use of plastic film mulch is one of the important measures for future agricultural development in semiarid areas.

Integrated Effects of Water Stress and Plastic Film Mulch on Yield and Water Use Efficiency of Grain Maize Crop under Conventional and Alternate Furrow Irrigation Method

Water scarcity in arid regions increases the need for technologies to improve water productivity. The integrated effects of plastic film mulching and water stress on grain maize under conventional and alternate furrow irrigation methods are still poorly understood in Sindh’s climate. Therefore, field trials were conducted at Malir farm, Sindh Agriculture University Tandojam, Pakistan, during the cropping season 2020–2021 to investigate whether mulching is practicable for grain maize production under the different furrow irrigation methods. The experiments involved two types of furrow irrigation, two water stress levels (sufficient and severe water stress), and plastic film mulching. Treatments were laid out in a randomized block design and three replications. The conventional and alternate furrow irrigation method was assigned to the main plot, while the water stress and plastic film mulching were in sub-plots. The results showed that different furrow irrigation methods significantly affected plant growth, grain yield parameters, and crop harvest index. Significant highest plant growth and grain yield of maize crop were observed with the conventional furrow irrigation (CFI) compared with the alternate furrow irrigation (AFI) method. However, grain yield and irrigation water productivity (IWP) were increased significantly by the plastic film mulching. The results revealed that sufficient water stress was more effective in sustaining grain yield and IWP than crop irrigating at several water stresses. The interaction effect of furrow irrigation and water stress, furrow irrigation, and plastic film mulching significantly impacted the IWP of grain maize. The IWP of the maize crop was significantly higher under the AFI than the CFI method if it was mulched with plastic film and irrigated at sufficient water stress level.

Plastic film mulching significantly boosts crop production and water use efficiency but not evapotranspiration in China

It is a huge challenge for China to produce enough food on its own croplands to feed a population of over 1.4 billion. Plastic film mulching technology has been applied widely in the past decades and China represents a major player in terms of plastic film use in the world. So far, a series of field experiments have been conducted across the croplands to investigate the effects of plastic film mulching on crop productivity. This offers an opportunity to comprehensively identify the crop yield and water use improvement potential and their key drivers based on local environmental conditions. Here, a synthetic analysis was conducted to illustrate the overall effects of plastic film mulching on relative changes in crop yield, water use efficiency (WUE), and evapotranspiration (ET), as well as the key impacting factors behind the changes. The results showed that plastic film mulching significantly increased crop yield by 39.5% and WUE by 37.9%, whereas the increase of ET under plastic film mulching (1.9%) was insignificant. The crop yield improvement under traditional film was significantly higher than that under degradable film, whereas the difference of crop yield improvement between film colours was not significant. Furthermore, crop yield and WUE improvements varied among different cropping regions and crop species, and were influenced by mean annual precipitation (MAP), mean annual temperature (MAT), elevation, and soil organic carbon (SOC) concentration. Generally, the performance of plastic film mulching in sustaining crop production was better in regions with poor environmental conditions, including low temperature and precipitation, high elevation, and poor SOC content. Unlike the significant increases of yield and WUE in most cases, the changes in ET varied among groups, ranging from significant decline to insignificant change to significant increase. The results of this study illustrate that plastic film mulching plays a critical role in terms of promoting crop production, improving water use, increasing farmers’ income and securing food security. The successful application of plastic film mulching in China may have important implications for other developing regions in the world to overcome the severe problems of food shortage. However, the adverse effects on environment must be properly addressed by upgrading mulching film materials in the future.

Effects of plastic film mulching on the spatiotemporal distribution of soil water, temperature, and photosynthetic active radiation in a cotton field.

Plastic film mulching (PFM) affects the spatiotemporal distribution of soil moisture and temperature, which in turn affects cotton growth and the spatiotemporal distribution of canopy photosynthetically active radiation (PAR). Due to the spatial heterogeneity of soil moisture, temperature and limited monitoring methods, the issues such as relatively few sampling points and long sampling intervals in most existing studies prevent the accurate quantification of spatiotemporal changes in moisture and temperature along soil profile. To investigate the effects of PFM on spatiotemporal changes in soil moisture, temperature, and canopy PAR in cotton fields, two field trials of plastic film-mulched (M) and nonmulched (NM) cultivations were performed in 2018 and 2019. The grid method was used for the soil information continuous monitoring and multiple-time fixed-site canopy PAR monitoring during the duration of cotton growth. Two-year field trial data showed that, M cultivation increased soil moisture by approximately 13.6%–25% and increased temperature by 2–4 °C in the 0–50 cm soil layer before the first irrigation (June 20) and by 1–2 °C in the 70–110 cm soil layer, compared with NM cultivation. In addition, the temperature difference between the two treatments gradually decreased with the increase in irrigation and air temperature. The M treatment reached the peak PAR interception rate 10 days earlier than the NM treatment. In 2018 and 2019, the PAR peak value under the M treatment was 4.62% and 1.8% higher than that under the NM treatment, respectively, but the PAR interception rate was decreased rapidly in the late growth stage. Overall, PFM had an effect on soil moisture retention during the whole growth period and greatly increased the soil temperature before budding stage, thus promoted the early growth of cotton. Considering this, we suggest that the irrigation quota and frequency could be appropriately decreased in the case of plastic film mulching cultivation. For nonmulching cultivation, the irrigation quota and frequency should be increased, and it is necessary to take measures to improve the soil temperature before middle July.

Is biodegradable film an alternative to polyethylene plastic film for improving maize productivity in rainfed agricultural areas? — Evidence from field experiments

Due to increasing concerns regarding plastic pollution throughout the world, biodegradable mulch is considered a promising alternative to polyethylene film and its suitability has been verified in some crops. However, it is unclear whether the long-term continuous use of biodegradable mulch as a substitute for polyethylene film is sustainable in rainfed agricultural areas, and whether its effect is consistent under different climatic conditions. Therefore, we conducted 7-year (2013–2019) and 4-year (2015–2018) field experiments in two regions with different precipitation levels (semiarid and semi-humid regions) on the Loess Plateau in China. We compared the effects of polyethylene film mulching (PM), biodegradable film mulching (BM), and traditional flat planting without film mulching (TF) on the soil temperature, soil moisture, grain yield, crop water productivity (WPc), and economic benefit (EB). The results showed that compared with TF, the grain yields under BM and PM increased by 2.1–93.3% and 7.6–34.6%, respectively, WPc increased by 2.1–93.3% and 7.6–34.6%, and EB increased by –16.6–131.5% and –7.8–27.0%. The differences in these indexes under the two mulching methods mainly occurred in the dry years with less precipitation in the semiarid region, whereas there were no significant differences in the grain yield, WPc, and EB under BM and PM in the semi-humid region. Therefore, the decision regarding whether BM can replace PM to improve maize productivity is significantly affected by the annual precipitation in rainfed areas. Furthermore, the univariate quadratic equation model was used to simulate that BM can obtain a higher crop yield and EB than PM when the precipitation is more than 600 mm and less than 800 mm, so as to achieve a win–win situation with continuous yield and income increases, and environmental friendliness in the Loess Plateau of China. However, the yield increase effect of plastic film mulching is also related to crop types, mulch types and farming practices except for climate. In addition, reducing the production cost will still be important for encouraging farmers to use biodegradable film instead of polyethylene film.

Plastic film mulch combined with adding biochar improved soil carbon budget, carbon footprint, and maize yield in a rainfed region

Plastic film mulch is used widely in rainfed areas to increase crop yields, and the addition of biochar to soil has been proposed as an effective measure for reducing greenhouse gas emissions. Comprehensive analysis is required to assess the effects of plastic film mulching combined with adding biochar on the net ecosystem carbon budget (NECB), greenhouse gas emissions, and water use efficiency (WUE) in farmland ecosystems. Therefore, we tested the following six treatments in a three-year (2018–2020) field trial: no mulching or added biochar (NM); biochar applied at 4.5 t ha–1 without mulching; biochar applied at 9.0 t ha–1 without mulching; plastic film mulch without biochar application (PM); biochar applied at 4.5 t ha–1 with plastic film mulching; and biochar applied at 9.0 t ha–1 with plastic film mulching (PMH). The results showed that plastic film mulching improved the maize yield (20.22%), greenhouse gas emissions (CO2: 22.57%; N2O: 17.58%), NGWP (net global warming potential; 15.19%), and CF (carbon footprint; 13.97%), but the effect on NECB did not differ significantly from that under NM (P > 0.05). Compared with PM, PMH reduced the CO2 (3.24%) and N2O (26.44%) emissions, increased the absorption of CH4 by 65.55%, and significantly increased NECB. Under PMH, the maize yield, WUEg (water use efficiency of grain), and PUEg (precipitation use efficiency of grain), increased by 6.40%, 10.14%, and 6.92%, respectively, whereas the NGWP, GHGI (greenhouse gas intensity), and yield-scaled CF decreased. Therefore, PMH simultaneously improved the productivity, production efficiency (WUE, PUE, and yield-scaled CF) and soil carbon budget in rainfed farmland, as well as reducing greenhouse gas emissions into the atmosphere, and thus it is a possible sustainable management method for farmland in rainfed areas.

Effects of Plastic Film Mulching on Soil Enzyme Activities and Stoichiometry in Dryland Agroecosystems.

Soil extracellular enzymes are pivotal for microbial nutrient cycling in the ecosystem. In order to study the effects of different nitrogen application rates under plastic film mulching on soil extracellular enzyme activities and stoichiometry, five nitrogen application levels (i.e., 0, 90, 150, 225 and 300 kg·hm−2) were set based on two treatments: plastic film mulching (PM) and no film mulching (LD). We measured the soil extracellular enzyme activities (EEAs) and stoichiometry (EES) of four enzymes (i.e., β-1,4-glucosidase (βG), leucine aminopeptidase (LAP), β-1,4-N-acetylaminoglucosidase (NAG) and alkaline phosphatase (AP)) involved in the C, N and P cycles of soil microorganisms in surface soil at five maize growth stages (seedling stage, jointing stage, trumpet stage, grout stage and harvest stage). The results showed that there were significant differences in soil EEA at different maize growth stages. The soil nutrient content and soil EEA were significantly improved under PM, and the stoichiometric ratio of extracellular enzymes (EC:N:P) was closer to 1:1:1, which indicated that PM was beneficial to the balance of soil nutrients and the activity of microorganisms. At each stage, with the increase in nitrogen application levels, the soil EEA showed a trend of increasing first and then decreasing (or remained unchanged), and both LD and PM treatments reached their highest activity at the 225 kg·hm−2 nitrogen application rate. When the nitrogen application level was less than 225 kg·hm−2, the soil enzyme activity was mainly limited by the N nutrient, and when the nitrogen application level reached 300 kg·hm−2, it was mainly limited by the P nutrient. RDA and correlation analysis showed that the soil C:P, C:N, N:P and pH had significant effects on soil βG, NAG + LAP and AP activities as well as EC:N, EC:P and EN:P.

Water regimes on soil covered with plastic film mulch and relationships with soil water availability, yield, and water use efficiency of papaya trees

Plastic film mulches have the potential to be used in papaya production, mainly aiming to reduce water application in semi-arid regions. However, there is a lack of technical information and the need to introduce mulching practices in papaya orchards. The objective of this work was to evaluate the effects of plastic film mulch and irrigation depths on soil water availability (SWA), stomatal conductance, leaf temperature, and agronomic traits of papaya trees. The study was carried out during 2018 and 2019 in Jaíba city, located northern Minas Gerais state, in the Brazilian semi-arid region. The experiment was a split plot design, with soil cover conditions assigned to the plots (bare soil and mulched soil) and water replenishment levels to subplots (25%, 50%, 75%, 100% and 125% of crop evapotranspiration [ETc]). Plants were drip irrigated with water replenishments based on climate data. Soil moisture was measured along time and agronomic and physiological characteristics of papaya trees, as well. Water tensions were higher in treatments with lower water replenishments. Results showed that the increase in irrigation depth favors leaf-area growth rate, stomatal conductance, yield, and water footprint of papaya. The use of mulch together with the increase in water replenishment levels contributes for maintenance of the soil water content between the upper limit of SWA and 75%SWA. The use black plastic mulching with drip irrigation in medium-textured soil saves up to 152 L of water per Kg of fruit, and increase productivity up to 34% by replenishing the crop evapotranspiration every irrigation event. The use of black plastic as ground cover is technically feasible for keeping soil water availability above 75% by irrigation supply of at least 75% of ETc on sand-clay-loam soil.

Effects of Plastic Film Mulching and Biochar Application on N2O Emission from a Vegetable Field

The aim of this research was to examine the effects of biochar addition (B0:0 t·hm-2, B20:20 t·hm-2, and B40:40 t·hm-2) and mulching (FM:film and NM:no film) on vegetables. The impact of N2O emissions in the field was based on the pepper-radish rotation vegetable field system on the farm of Southwest University, using static dark box/gas chromatography to conduct in-situ observations in the field for one year. In this experiment, a total of six treatments were set up, namely NMB0 (CK) and FMB0, NMB20 and FMB20, and NMB40 and FMB40. The results showed that FM significantly increased the content of ammonium and nitrate nitrogen in the pepper season soil (P<0.05) but had no significant effect on soil environmental factors in the radish season. Compared with that of NM, the pepper season FM increased the N2O emissions of the B0, B20, and B40 treatments by 52.87%, 52.97%, and 52.49% (P<0.05), respectively, but the radish season FM had no significant effect on N2O emissions. Biochar had no significant effect on soil environmental factors in the pepper and radish seasons. The addition of biochar in the radish season reduced N2O emissions by 28.76%-67.88% (P<0.01), and the addition of biochar in the pepper season had no significant effect on N2O emissions. Compared with that of NM, under different biochar levels, FM increased the yield of pepper by 15.85%-161.32% and increased the yield of radish by 43.97%-75.80%. Biochar significantly increased the yield of peppers and had no significant effect on the yield of radishes. Regardless of whether the film was covered or not, when the amount of biochar added was 20 t·hm-2, the yields of pepper and radish were the highest. The analysis of N2O emission intensity revealed that FM in the pepper season significantly reduced N2O emission intensity, whereas in the radish season FM and biochar significantly reduced N2O emission intensity, and both planting seasons reached the lowest N2O emission intensity under the FMB20 treatment. Therefore, mulching and applying 20 t·hm-2 biochar were the best farmland management measures for the pepper season and radish season, which could achieve high yields and the lowest N2O emissions, accomplishing a win-win for economic and environmental benefits.

Response of soil microbial community parameters to plastic film mulch: A meta-analysis

Plastic film mulch alters the soil environment and improves crop production. Although the response of aboveground parts of agroecosystems to plastic film mulch has been extensively studied, no studies have investigated the response of the soil microbiome to plastic film mulch and its effect on crop yield. Here, we performed a meta-analysis of 536 observations to elucidate the response of the soil microbial community to plastic film mulch. Plastic film mulch significantly increased soil microbial alpha-diversity (Shannon: +0.043, 95% CI: +0.022 to + 0.064; richness: +0.037, 95% CI: +0.007 to + 0.067), abundance (+0.104, 95% CI: +0.070 to + 0.139), and eco-functionality (+0.129, 95% CI: +0.087 to + 0.170). In neutral pH soil and field combined plastic film mulch with ridge–furrow tillage, plastic film mulch had a significant impact on microbial richness. Microbial abundance increased significantly when chemical fertilizer was used, but not when organic fertilizer was used. The effect of low-level nitrogen on N acquisition enzyme actives is greater than that of medium and high nitrogen input. Thick film mulch produced a larger positive response in microbial abundance, C acquisition, and oxidative enzyme activities than thin film mulch. Changes in microbial functionality were decoupled with diversity, while in tandem with its abundance and community structure. The increases in microbial C acquisition, N acquisition, and oxidative enzyme activities were significantly linked to yield. Our findings highlight the beneficial effects of plastic film mulch on the soil microbial community and have further implications for the development of soil health-friendly agricultural management.