Effect Of Plastic Mulch Research Articles

Soil water storage and winter wheat productivity affected by soil surface management and precipitation in dryland of the Loess Plateau, China

Because of asynchrony between the winter wheat growing season and precipitation, soil water supply is the main factor constraining winter wheat production. Hence, increasing soil water conservation is a crucial approach for improving winter wheat productivity in dryland. A 5-year-long, location-fixed field experiment was conducted to determine the effects of plastic mulch, straw retention, planting legume, and straw-legume on soil water and winter wheat grain yield. In comparison to the control, average rainfall harvest during summer fallow was increased by 9% by plastic mulch and mainly occurred in wet summers, and not affected by straw retention, but respectively decreased by 22% and 17% by planting legume and straw-legume. Average soil water storage at sowing was increased by 5% in plastic mulch and occurred in most summers, as well as also increased by 3% in straw retention but only occurred in one wet summer, and decreased by 5% in both planting legume and straw-legume and occurred in most cases. Average ET was not affected by plastic mulch and straw retention, but respectively decreased by 7% and 5% by planting legume and straw-legume. As a result, plastic mulch caused a 6% increase in the average grain yield of winter wheat, but straw retention, planting legume, and straw-legume decreased it by 8%, 6%, and 5%, respectively. Overall, plastic mulch is a beneficial measure for increasing rainfall harvest during summer fallow and soil water storage at sowing, and preferable for harvesting more grain yield, but the straw retention, planting legume and straw-legume showed hardly any benefit for grain yield of winter wheat in dryland.

Colored Plastic Mulch Effects on the Yield of Lettuce (Lactuca sativa L.) and Soil Temperature

Colored Plastic Mulch Effects on the Yield of Lettuce (Lactuca sativa L.) and Soil Temperature

Effect of plastic mulching on mycotoxin occurrence and mycobiome abundance in soil samples from asparagus crops.

Plastic mulching (PM) is widely used in modern agriculture because of its advantageous effects on soil temperature and water conservation, factors which strongly influence the microbiology of the soil. The aim of this study was to assess the effect of PM on mycotoxin occurrence in relation with mycobiome abundance/diversity and soil physicochemical properties. Soil samples were collected from green (GA) and white asparagus (WA) crops, the last under PM. Both crops were cultivated in a ridge-furrow-ridge system without irrigation. Samples were analyzed for mycotoxin occurrence via liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). Total colony-forming unit was indicative of mycobiome abundance, and analysis of mycobiome diversity was performed by internal transcribed spacer (ITS) sequencing. PM avoided the drop of soil temperature in winter and allowed higher soil temperature in early spring compared to non-covered soil. Moreover, the use of PM provided controlled conditions for water content in soil. This was enough to generate a dissimilar mycotoxin occurrence and mycobiome diversity/abundance in covered and non-covered soil. Mycotoxin soil contamination was confirmed for deoxynivalenol (DON), range LOD to 32.1 ng/g (LOD = 1.1 ng/g). The DON values were higher under PM (average 16.9 ± 10.1 ng/g) than in non-covered soil (9.1 ± 7.9 ng/g); however, this difference was not statically significant (p = 0.09). Mycobiome analysis showed a fungal compartment up to fivefold higher in soil under PM compared to GA. The diversity of the mycobiome varied between crops and also along the soil column, with an important dominance of Fusarium species at the root zone in covered soils.

The effect of plastic mulch on the fate of urea-N in rain-fed maize production in a semiarid environment as assessed by 15N-labeling

A better understanding of the fate of fertilizer nitrogen (N) is critical to design appropriate N management strategies in plastic-mulched croplands. We evaluated the effects of plastic mulch on urea-N recovery by crops and loss from soil in furrow-ridge plots, with and without maize (Zea mays L.) cropping, in a semi-arid rain-fed site in China. We applied the same rate of urea-N (281kgha−1) to all treatments during the preparation of the furrow-ridges in 2011 and 2012 but 15N-labeled the urea in 2011 only. We used transparent film to cover all soil surfaces in the mulched treatments and seeded maize in furrows in treatments with crop. In 2011, plastic mulch increased the total N uptake in the aboveground biomass of maize by 53%, whereas it decreased the in-season labeled-N uptake by 19%, compared to non-mulched treatment. At harvest in 2011, in mulched treatments the total labeled-N remaining in the 0−170cm soil layer was 25% greater whereas unaccounted labeled-N was 69% less, than in non-mulched treatments, regardless of whether maize was cropped. In 2012 the effect of mulch on total maize N uptake was comparable to that in 2011, but the residual soil labeled-N uptake by maize was 63% higher in mulched compared to non-mulched treatment. At harvest in 2012, plastic mulch increased total labeled-N remaining in the 0−170cm depth in cropped soils and unaccounted labeled-N in non-cropped soils, compared with no mulch. Our results indicate that plastic mulch profoundly changes the fate of urea-N in maize production in cold and dry croplands.

Effect of plastic mulching on the photosynthetic capacity, endogenous hormones and root yield of summer-sown sweet potato (Ipomoea batatas (L). Lam.) in Northern China

A field experiment was conducted to examine the effects of plastic mulching (PM) on the photosynthetic rate, endogenous hormones and root yield of summer sweet potato [I. batatas L. cv. Jishu18 and Ayamuraski (Aya.)]. The results showed that the PM treatments decreased soil bulk density, increased soil porosity and soil available nutrient content, and retained soil water content at a relatively stable level, but no significant difference in soil temperature was observed compared with the control. The leaf chlorophyll content, photosynthetic rate, ribulose 1,5-bisphosphate carboxylase activity, leaf area index, soluble sugar content, and adenosine triphosphate content was higher in the PM treatments compared with the control. In addition, root gibberellic acid, zeatin riboside and abscisic acid content increased under PM treatment. The PM treatment improved the soil micro-environment of sweet potato, resulting in a higher storage root yield and top/root ratio (T/R). According to these results, it is concluded that mulching summer-sown sweet potato is an effective way to increase root yield in northern China, most likely through the modification of the soil micro-environment, photosynthetic capacity and endogenous hormones.

Effects of Cultivation Strategies on Hybrid Pennisetum Yield in Saline Soil

ABSTRACTHybrid pennisetum (Pennisetum americanum × P. purpureum) is a popular energy grass with great potential for biofuel production. The objective of this research was to understand the effects of various cultivation strategies on the yield of hybrid pennisetum when growing in saline soil. The effects of plastic mulching, planting density, organic amendment, and additional fertilizer application on the yield and other characteristics of hybrid pennisetum were investigated in a 2‐yr field study conducted on the saline land of the Yellow River Delta, China. The results showed that mulching markedly increased the growth by reducing soil salinity and increasing soil moisture and soil temperature. Yield increased with plant density, and the highest yield (151.4 tons ha−1) was obtained with 27,778 plants ha−1. Plant growth also increased as organic amendment level increased from 0 to 1500 kg ha−1 and with addition of urea (applied when plant height was 80 cm and 150 cm). The abundance of culturable soil microorganisms was increased by the above cultivation measures. It can be concluded that suitable cultivation measures such as mulching, plant density, and application of organic and inorganic fertilizers, which were examined independently, greatly increased the biomass of hybrid pennisetum growing in a saline soil on the Yellow River Delta. The highest yield of hybrid pennisetum obtained was 175.3 tons ha−1.

Effects of plastic mulch and crop rotation on soil physical properties in rain-fed vegetable production in the mid-Yunnan plateau, China

Plastic mulch is widely used for vegetable cropping in the mid-Yunnan plateau, southwestern China. However, the effects of plastic mulch on soil physical properties are poorly understood. A field experiment was conducted to evaluate the effects of different plastic mulch patterns (narrow and wide plastic mulch) and rotations (broccoli–zucchini–winter wheat and broccoli–zucchini–fallow) on soil physical properties and soil organic carbon content in a vegetable production system at a research station in the region. The experiment comprised four treatments and laid out in the field using randomized complete block design replicated nine times. The soil (0–20cm) under wide plastic mulch retained more water than the soil narrow plastic mulch under the vegetable growing season over 3 consecutive severe drought years. Significant decline (11%) of surface soil (0–5cm) organic carbon was observed in 2012 compared with in 2010, but soil organic carbon and physical properties did not differ significantly between the two different plastic mulch patterns. The higher macro-porosity, aggregate stability, Ksat and lower bulk density in the plastic mulched ridges imply that the conversion from narrow-plastic-mulch to wide-plastic-mulch increases mulched area thereby conserving larger area soil structure in the croplands. Although increased catch crop stubble retention in the furrows apparently improved surface soil macro-porosity and saturated hydraulic conductivity, the autumn rotary cultivation in broccoli–zucchini–winter wheat rotation system has significantly decreased (5%) surface soil organic carbon. The results suggested that continued use of vegetable–cereal crop rotation system, even with stubble retention, may result in loss soil organic carbon. Further research that covers wetter years should be taken to assess effects of vegetable–cereal crop rotation pattern on soil physical properties in this region.

Growth, grain yield, and water use efficiency of rain-fed spring hybrid millet (Setaria italica) in plastic-mulched and unmulched fields

In order to analyze the effect of plastic mulching on water use efficiency of spring hybrid millet (Setaria italica), field experiments were conducted during the 2012 growing season, at an experimental station located in a semi-arid region of North China. Four treatments were applied: (i) plastic mulching of ridges and furrow sowing (T1), (ii) ridges and furrows without plastic mulch (T0), (iii) flat soil with plastic mulch (A1), and (iv) flat soil with no plastic mulch (A0) (control). Dynamics of soil moisture and soil temperature, together with crop growth, were monitored continuously in both mulched and unmulched fields. Changes in water consumption, soil temperature, and plant growth and development were analyzed. Results indicated that plastic mulching produced a 2–5-day advance in emergence of each growth stage. Soil temperature at 0–15cm depth increased by 1.25°C and 0.84°C under mulched treatments A1 and T1, respectively, while soil water content at a depth of 0–10cm increased by 1.42% and 1.29% in the same treatments. Leaf area index and plant height were also significantly higher in plastic-mulched treatments, except in later growth stages. Because plastic mulching improved tiller and ear numbers significantly, grain yield increased by 13.25% and 6.64%, in Al and T1 treatments, respectively. Water use efficiency at yield levels of plastic-mulched A1 and T1 plots was 24.44% and 3.6% higher than in unmulched flat and furrowed plots, respectively. Plastic mulching significantly reduced water consumption, retained soil water content, and increased soil temperature, to promote spring hybrid millet germination, and increased tiller numbers, and consequently, aboveground dry matter; it eventually significantly improved grain yield and water use efficiency. Plastic film mulching produced greater grain yield, water use efficiency, and benefits when used in flat planting patterns.

Sweet Corn Weed Control and Yields in Response to Sowing Date and Cropping Systems

The high vulnerability of sweet corn (Zea mays L. var. saccharata) to weed competition and the urgent reduction of the dependence on chemical herbicides are major challenges facing the agricultural community. To investigate the effects of plastic mulches on weed control and yields in sweet corn under different sowing dates, a 2-year experiment was conducted at Varamin, Iran, in 2010 and 2011. The mulch treatments included black plastic mulch, semitransparent biodegradable mulch, an unmulched weeded control, and an unmulched unweeded control. The sowing dates were 5 June, 20 June, and 6 July. Results revealed that delayed sowing (6 July) reduced weed dry weight by 51% and 41% compared with the 5 June sowing date in 2010 and 2011, respectively, without reducing crop yield. The black plastic mulch treatment had the lowest weed biomass. The sowing date × mulch interactions on kernel number per ear, length of ear, percentage of unfilled ear tip, and yield of sweet corn were statistically significant (P < 0.01) in both years. The maximum kernel number per ear (535) and the highest fresh ear yield (24,684 kg·ha−1) in 2010 were obtained on the 6 July sowing date under biodegradable mulch. The plants sown on 6 July produced the highest fresh kernel yield with the black plastic mulch (12,893 kg·ha−1) and unmulched weeded control (11,777 kg·ha−1) in 2010 and 2011, respectively. The highest percentage of unfilled ear tips in both years was observed in the unmulched unweeded plots sown on 5 June. According to our findings, to suppress the weeds and avoid the sweet corn yield loss in such a hot summer that we had, using the black plastic mulch and delayed sowing are recommended.

Influence of Drip Irrigation and Plastic Mulch on Yield of Sapota (Achraszapota) and Soil Nutrients

The experiment was carried out to study the response of Sapota (Achraszapota) crop under drip irrigation and plastic mulch. Three levels of irrigation water applied through drip, ring basin irrigation method in combination with plastic mulch were experimented with five replications on Sapota plants. Reference evapotranspiration was estimated using FAO-56 Penman Monteith approach. The Sapota crop water requirement was estimated using reference evapotranspiration data and crop co-efficient for different crop growth stages. The irrigation water was applied at 60%, 80% and 100% of the crop water requirement. Irrigation intervals were at 2 and 5 days respectively in drip and ring basin irrigation treatments. The water requirement of Sapota crop varies between 2.14 mm (10.71 L) per day per plant in winter season and 6.89 mm (34.44 L) per day per plant in summer season for 100% water requirement treatment at peak growth stage. To investigate the effect of plastic mulch on soil, the physico-chemical analysis of soil was performed for the soil samples collected from three different depths (0-30, 30-60, 60-90 cm). The soil chemical analysis indicated increase in organic carbon, organic matter, humic acid, microbial count, available potassium, available phosphorus, total nitrogen content and C:N ratio for the soil covered with the plastic mulch treatment. The pH and available nitrogen was found to decrease in the soil covered with plastic mulch. The biometric observations (canopy, height, girth, no. of branches) of Sapota plants showed positive influence of the irrigation and plastic mulch treatments on growth of Sapota crop. Due to mulch alone the increase in Sapota yield varied from 7.62% to 41% in different treatments. Yield of Sapota crop was found to increase by 21.05% due to drip in comparison to ring basin irrigation.

SURFACE ENERGY BALANCE PARTITIONING OVER A CHILI BELL CROP UNDER TWO TYPES OF PLASTIC MULCH

Previous studies have been conducted to evaluate the effect of plastic mulch on the temperature of the upper soil profile and its relations to the growth and yield of crops. However, the presence of plastic mulch on the soil surface also affects all components of the energy balance (net radiation, Rn; sensible heat flux, H; latent heat flux, LE and soil heat flux, G). In this study, the energy balance components through the different growth stages of the chili crop were measured and the daily and seasonal partitioning of the surface energy balance was evaluated. The results showed that net radiation was the major term of the energy balance. At the early stage of the crop growth most of the net radiation was dissipated in sensible heat flux (H), because the crop only covered a small part of the bed. Once the crop reached full foliage growth, Rn was dissipated mainly in LE. During crop senescence, most of the Rn was dissipated in H in a lower rate in G, and small proportion on LE.

밭토양에서 퇴비시용과 비닐멀칭이 토양탄소 축적에 미치는 영향

Abstract BACKGROUND: In most studies, soil carbon sequestration has been evaluated simply with change of soil organic carbon content. So far, information regarding stability of soil organic carbon is limited. METHODS AND RESULTS: This study was conducted to determine changes in soil organic carbon (SOC) content and stability of carbon in response to compost application rates and plastic mulching treatment during the hot pepper growing season. Under the pot experiment condition, compost was mixed with an arable soil at rates corresponding to 0, 10, 20, and 40 Mg/ha. To determine effects of plastic mulching on soil carbon sequestration, plastic mulching and no mulching treatments were set up in soils amended with the application rate of 20 Mg/ha. The SOC content did not significantly increase with application of compost and plastic mulching at harvest time. No significant changes in bulk density with compost application and plastic mulching was found. These might result from short duration of experiment. While hot water extractable organic carbon content significantly decreased with compost application and plastic mulching, humic substances increased. Belowground biomass of hot pepper was biggest at the recommended application rate (20 Mg/ha) of compost.

Plastic mulch effects on ground beetle communities (Coleóptera: Carabidae) in an organic blueberry field

A study was conducted to determine the effect of synthetic mulch on the diversity and abundance of carabid beetles in an organic blueberry crop. The treatments consisted of plastic mulch, plastic mulch combined with pine needles, pine needles only and bare soil as control. Beetles were captured using pitfall traps. The number of individuals collected was greater in the treatment consisting of mesh and pine needles and in bare soil, whereas the mesh treatment alone presented the lowest values. Species richness showed no differences between treatments. Although there were density differences among the treatments, further studies are needed in order to establish the preference of these insects for any particular groundcover more clearly. Nevertheless, the results suggest that the incorporation of vegetal material as mulch in the holes left open in the mesh for the plant may improve the capacity of synthetic covers to harbor carabid beetles and hence improve the biological control of pests, particularly in organic crops

Effect of plastic mulch and winter catch crop on water availability and vegetable yield in a rain-fed vegetable cropping system at mid-Yunnan plateau, China

The fluctuation of rainfall is the primary limiting factor for sustainability of rain-fed vegetable cropping systems in mid-Yunnan plateau. Our objectives were to evaluate effects of an alternative plastic mulching practice (narrow vs. wide plastic mulch) and an additional catch crop (broccoli–zucchini–winter wheat vs. broccoli–zucchini–fallow) on the soil moisture status, crop yield and water use efficiency (WUE) in the rain-fed vegetable cropping systems. Rainfall was much low and erratic during the entire experiment period compared with the long-term average (1971–2000). The 0–60cm soil water storage (113mm) of growing season was significantly higher under wide plastic mulch plots than narrow plastic mulch plots (99mm). Fruit yield and water use efficiency of broccoli and zucchini were enhanced with wide plastic mulch during growing season in the three years experiment. Compared with the broccoli–zucchini–fallow plots, the broccoli–zucchini–winter wheat rotation treatment did not significantly decrease available soil water at broccoli transplanting stage. This implicated that the addition of winter wheat in the vegetable cropping system would not pose serious consequences for water storage. The results obtained in this study have practical implications for sustainability of the rain-fed vegetable culture.

Numerical Simulation of Soil Water Dynamics in a Drip Irrigated Cotton Field Under Plastic Mulch

Drip irrigation under plastic mulch has been widely applied in arid Northwest China as a water-saving irrigation technology. A comprehensive knowledge of the distribution and movement of soil water in root zone is essential for the design and management of irrigation regimes. Simulation models have been proved to be efficient methods for this purpose. In this study, the numerical model Hydrus-2D was used to simulate the temporal variations of soil water content in a drip irrigated cotton field under mulching. A concept of partitioning coefficient, calibrated to be 0.07, was introduced to describe the effect of plastic mulch on prevention of evaporation. The soil hydraulic parameters were optimized by inverse solution using the field data. At the optimized conditions, the model was used to predict soil water content for four field treatments. The agreements between the predictions and observations were evaluated using coefficient of determination (R2) and root mean square error (RMSE). The results suggested that the model fairly reproduced the variations in soil water content at all locations in four treatments, with R2 ranging from 0.582 to 0.826 and RMSE from 0.029 to 0.050 cm3 cm−3, indicating that the simulations agreed well with the observations.

New methods of crop production and farmland birds: effects of plastic mulches on species richness and abundance

Summary Modern methods of crop production are regarded as one of the major factors moderating ecosystem processes in agricultural landscapes and may negatively affect farmland biodiversity. One method which is on the increase is mulching: the use of plastic foil to cover crops at sowing in order to promote early growth by reducing the negative effects of variable temperatures and to limit pesticide use. However, almost nothing is known of the role of mulching on farmland biodiversity. In this study, carried out in southern Poland in 2011, we investigated the impact of mulching with plastic foil on the number of species and abundance of farmland birds at two spatial scales. At the local scale, bird species number and abundance were lower in areas where foil was used than those in the control areas, both during the period when the foil was used and after it was removed from the crops. At the landscape scale, we found a significant negative relationship between the proportion of crops covered by foil and bird species richness and abundance. Farmland specialists, nonfarmland birds, ground nesters and above‐ground nesting species were all negatively affected by foil mulching. Foil had a negative effect on potential resources for birds including adult butterflies and their larvae and weed species. Synthesis and applications. Our results provide the first evidence that the use of foil for mulching has negative effects on farmland bird populations, probably through the trophic cascade and habitat disturbance. Therefore, foil mulches must be considered as another factor contributing to the decline of farmland biodiversity. We suggest limiting the use of this method of vegetable production at the farm level. Decreasing the field size and converting some arable fields into grassland patches are proposed as mitigation measures in landscapes with high foil cover.

Cucumber (Cucumis sativus, L.) water use efficiency (WUE) under plastic mulch and drip irrigation

To study the effect of two types of plastic mulch (transparent and black) with drip irrigation on water requirement and Cucumber (Cucumis sativus, L.) yield, in addition to their effect on Maturity time. Trials were carried out at Teezen Research Station, Hama Agricultural Research Center, GCSAR, Syria, during 2009–2010 growing seasons using complete randomized block design with three replicates. Soil characteristics were followed too because they reflect the effects of plastic mulch. Treatments were transparent mulched drip irrigation (DI+TM), black mulched drip irrigation (DI+BM), drip irrigation without mulching (DI) and surface furrow irrigation (SI). The results of the study indicated that (DI+TM) treatment excelled all other treatments at yield and water use efficiency (WUE), where its yield was 63.9tha−1, and (WUE) was 0.262tha−1mm−1, while (DI+BM) treatment produced 57.9tha−1, with a (WUE) of 0.238tha−1mm−1. However cucumber yield and WUE declined in the remaining treatments of no mulch (DI) and (SI) to reach 44.1tha−1 with 0.153tha−1mm−1 and 37.7tha−1 with 0.056tha−1mm−1, respectively. The results showed that (DI+TM) treatment gave the highest soil temperature and moisture during both of the seasons in comparison to (DI+BM). This enhanced its vegetative growth and almost doubled its productivity compared to the SI treatment.

The effect of fertilizer best management practices on nitrate leaching in a plastic mulched ridge cultivation system

Groundwater pollution by fertilizer NO3− is a major problem recognized in many parts of the world. The excessive use of mineral fertilizers to assure high yields in agricultural production intensifies the leaching problem especially in regions affected by a monsoon climate as in South Korea. The extent that leaching occurs depends on several factors such as climatic conditions, agricultural management practices, soil properties and the sorption characteristics of fertilizers and agrochemicals. In the South Korean monsoon season 2010, NO3− concentrations under varying nitrogen fertilizer rates were monitored in a plastic mulched ridge cultivation (RTpm) with radish crops (Raphanus sativus L.). Based on these findings we calibrated a three-dimensional water flow and solute transport model using the numerical code HydroGeoSphere in combination with the parameter estimation software ParallelPEST. Subsequently, we used the calibrated model to investigate the effect of plastic mulch as well as different fertilizer best management practices (FBMPs) on NO3− leaching. We found that cumulative NO3− leaching under RTpm was 26% lower compared to ridge tillage without coverage (RT). Fertilizer placement confined to the ridges resulted in 36% lower cumulative NO3−-leaching rates compared to broadcast applied fertilizer. Splitting the total amount of 150kgNO3−ha−1 per growing season into three fertilizer applications (1–4–2.5 ratio) led to a reduction of NO3− leaching of 59% compared to the one-top dressing at the beginning of the growing season. However, the combination of a fertilizer rate of 150kgNO3−ha−1, plastic mulched ridges, fertilizer placement only in the ridges and split applications of fertilizer resulted in the lowest cumulative NO3− leaching rate (8.14kgha−1) during the simulation period, which is equivalent to 5.4% of the total NO3− fertilizer input. Compared to RT with conventional one-top dressing fertilization in ridges and furrows, the NO3− leaching was reduced by 82%. Consequently, the combination of all FBMPs is highly recommendable to decrease economical costs for fertilizer inputs as well as to minimize nitrate leaching and its impact on groundwater quality.

Modelling the effects of plastic mulch on water, heat and CO2 fluxes over cropland in an arid region

Plastic mulches are often used to improve agricultural production by suppressing soil evaporation in the vast arid and semi-arid regions. As a special surface cover, plastic mulch evidently affects the surface albedo and prevents vapour exchange between the land surface and the atmosphere, but these physical processes were not contained in the present land surface models. Therefore, simulations remarkably deviate from observations when land surface models are applied to areas with underlying plastic mulch covering. Investigating the effects of various plastic mulches assists in better understanding the atmosphere-land interaction. In this study, a detailed plastic mulch layer model, which considers the effect of plastic mulch on the radiation and heat transfer is constructed and incorporated into a land surface model Two-Big-Leaf-SHAW (TBLSHAW) to simulate the water (H2O), heat and CO2 (carbon dioxide) fluxes in an agro-ecosystem covered by plastic mulch. Data collected by Gulang Heterogeneous Underlying Surface Layer Experiment (GHUSLE) at a plastic mulch-covered cropland site in an arid region were employed to verify the model; simultaneously, the TBLSHAW model was run with the same atmospheric forcing as a comparison to investigate the effect of the plastic mulch. Results suggest that the model can appropriately simulate the water, heat and CO2 fluxes over an arid cropland. The model efficiency is high, and the mean bias error and root mean bias error between the simulated and the observed values are minor. Compared to TBLSHAW simulations, the plastic mulch with special optical properties obviously influenced the surface albedo and radiation balance. By limiting the underside soil evaporation, plastic mulch changes the energy and water transfer between the atmosphere and the land surface. The soil temperature and soil moisture are improved by the transparent plastic mulch, and the plastic mulch not only suppresses the CO2 generated by soil respiration but also affects CO2 budget as a result of the net assimilation controlled by the soil water and heat conditions.

Planting Sweet Sorghum in Yellow River Delta: The Cultivation Measure, Yield and Effect on Soil Microflora

Field experiment was conducted in the saline soil of Yellow River Delta between May to Oct. Sweet sorghum was planted with different cultivation measures to test the effect of plastic mulch, plant density, organic manure application and additional fertilizer application on the yield, stalk juice Brix and extraction rate. The soil bacteria and actinomycetes quantities were also determined after harvesting to test the amelioration effects of different measures on soil.