Mulching Methods Research Articles

Long-term effects of different surface mulching techniques on soil water and fruit yield in an apple orchard on the Loess Plateau of China

Surface mulching has been extensively used for water conservation in dryland orchards. It is critical to choose an appropriate mulching technique for high yield and sustainable development of fruit crops. To solve the impact of water shortage on the production and growth of fruit trees on the Loess Plateau (China), the effects of different surface mulching techniques on an orchard ecosystem were monitored from 2008 to 2015. Different mulching methods, including grass cover (GC), film mulching (FM), straw mulching (SM), and gravel mulching (GM), effectively enhanced the regulatory capacity of soil water reservoir. The soil water content of SM and FM treatments was higher compared with other treatments. With the increase of planting age, the use of deep soil water increased, soil water content showed a decreasing trend, and soil desiccation was partially alleviated. Different mulching treatments improved water use efficiency and apple yield, with the best effect being achieved with GM and SM. GM resulted in lower soil water content, while it increased the proportion of short and medium branches, thus increasing the yield of apples. The water use efficiency was higher and the effect was better for the GM treatment during 2008–2012; thereafter, the benefits decreased due to a mixture of gravel and topsoil. SM produced higher soil water content and apple yield, and its regulation effect on temperature was better than other treatments. Although the soil water content of FM was relatively high, the corresponding yield and water use efficiency were low. The root growth of fruit trees was affected by high summer heat in the FM treatment. Given the high cost of labor required for GM, SM was an appropriate technique to improve the hydrological status and fruit yield of apple orchard soil in the gully region of the Loess Plateau.

Transpiration of female and male parents of seed maize in northwest China

Drip irrigation under mulch (DM) has been widely promoted and applied in arid regions. The process of crop growth and surface water and energy transfer will change significantly under the dual control of mulch and drip irrigation compared with those under the traditional border irrigation under mulch (BM) method, which will further affect the regional eco-hydrology process. The Hexi Corridor has become the largest seed maize production base in China due to its abundant solar radiation, and heat resources and large diurnal temperature difference. Unlike grain maize, seed maize can be divided into female and male parent plants. The growth conditions of the parent plants differ; male plants are planted 7–14 d later than female plants to produce preferable fertilization conditions, which distinctly influences the energy transfer process between the different parent plants and the soil and ultimately leads to significantly different plant water consumption in the maize field.To determine the difference in the transpiration rate between a BM field and a DM field and to reveal the difference in water consumption characteristics between female and male plants, eddy covariance system (EC) measurements, a thermal balance sap flow system and micro-lysimeters were applied to conduct continuous, fixed-location comparison measurements of the total evapotranspiration from 2014 to 2016. The total evapotranspiration (ET), transpiration rates of the female (Tf) and male plants (Tm) and the soil evaporation (Es) in seed maize fields were separately analysed in both the BM field and DM fields. Results indicated that Tf/ET, Tm/ET and Es/ET dynamically varied with the crop growth during the whole growth period. Transpiration rates under the DM treatment were 2–8% higher than those under the BM treatment under the local agricultural management conditions. Besides, the female plant transpiration rate exceeded the male plant transpiration rate by 9–20% in the BM treatment and by 14–32% in the DM treatment field during the whole growth stages. However, male plant transpiration produced after the pollination of female plants is useless to final seed production. It is more practical to decrease the planting ratio of male to female plants to the appropriate level and remove the male plants earlier to increase the water use efficiency in seed maize fields. Moreover, the seed maize field in this study had a smaller proportion of soil evaporation than those in other grain maize field studies conducted around the world, which was probably due to the mulching effect and higher plant density.

Effect of straw belt-mulching on soil temperature and yield of winter wheat in rain-fed semiarid region.

To evaluate the effects of straw belt-covering on soil temperature and yield of winter wheat in rain-fed semiarid region in Northwest China, five mulching modes, including flat field planting without any mulching (CK), whole plastic film mulching (PM), straw mulching by 30 cm covering belt with an interval of 30 cm planting belt with three-row sowing (SM1), straw mulching by 40 cm covering belt with an interval of 40 cm planting belt with four-row sowing (SM2), and straw mulching by 50 cm covering belt with an interval of 50 cm planting belt with five-row sowing (SM3), were set by two-year fixed-site trails in 2013-2015. The results showed that soil temperature significantly varied among different growth stages and soil layers in all treatments. SM1, SM2 and SM3 significantly decreased soil temperature by 1.0-1.3 ℃, 0.7-0.9 ℃ and 0.7-1.1 ℃ in the 0-25 cm soil layer, respectively. The mulching had double effects with increasing and decreasing soil temperatures. The straw mulching significantly increased soil temperature in the duration of seedling to overwintering stage, but greatly decreased soil temperature in the duration of reviving to mature stage. The temperature-increasing effect of film mulching was stronger than that of straw mulching, which was opposite to the temperature-decreasing effect. Straw mulching significantly reduced in the effective accumulated temperature and the daily temperature variations during the whole growth stages. The effective accumulated temperature under straw mulching decreased by 3.4-33.5 ℃·d, and the soil temperature difference decreased by 0.6-2.0 ℃. During over-wintering stage, the straw mulching showed a higher average soil temperature (0.2-0.3 ℃) and negative accumulated temperature (0.4-17.0 ℃·d) than those under the CK. The straw mulching significantly increased grain yield by 11.9%-19.5%. The variations of spikes per unit area were the main factor responsible for yield difference. The findings indicated that that straw mulching method is suitable for winter wheat production in rain-fed region of Northwest China.

Constant Isothiocyanate-Release Potentials across Biofumigant Seeding Rates.

Biofumigation is an integrated pest-management method involving the mulching of a glucosinolate-containing cover crop into a field in order to generate toxic isothiocyanates (ITCs), which are effective soil-borne-pest-control compounds. Variation in biofumigation efficacy demonstrates a need to better understand the factors affecting pest-control outcomes and develop best practices for choosing biofumigants, growth conditions, and mulching methods that allow the greatest potential isothiocyanate release. We measured the glucosinolate concentrations of six different commercial varieties of three biofumigant plant species: Brassica juncea (ISCI99, Vitasso, and Scala) Raphanus sativus (Diablo and Bento), and Sinapis alba (Ida Gold). The plants were grown in the range of commercially appropriate seeding rates and sampled at three growth stages (early development, mature, and 50% flowering). Within biofumigant species, the highest ITC-release potentials were achieved with B. juncea cv. ISCI99 and R. sativus cv. Bento. The highest ITC-release potential occurred at the 50% flowering growth stage across the species. The seeding rate had a minor impact on the ITC-release potential of R. sativus but had no significant effects on the ITC-release potentials of the B. juncea or S. alba cultivars.

Developing sustainable cropping systems by integrating crop rotation with conservation tillage practices on the Loess Plateau, a long-term imperative

Loess Plateau agriculture, largely dependent on manual labor and precipitation water, exemplifies semiarid dryland agricultural systems in China, where better cropping systems and practices are essential for maintaining crop productivity and sustaining natural resources. An 11-year (2001–2011) study at the Xifeng, Gansu investigated the effects of different conservation tillage practices and straw mulching methods on yield, water productivity (WP), soil organic carbon (SOC), total nitrogen (TN), energy expenditure and economic returns of a maize (Zea mays L.)-winter wheat (Triticum aestivum L.)-summer soybean (Glycine max L.) rotation system. Treatments included conventional tillage (T) as control, conventional tillage followed by straw mulching (TS), no tillage (NT) and no tillage followed by straw mulching (NTS). On average, TS treatment had increased yield by 11, 22, and 4%; as well as WP by 13, 22, and 7% than T, NT and NTS treatments, respectively. Additionally, NTS indicated the greatest effect in increasing SOC and TN in the 0–10 cm soil layer. Our support vector machine (SVM)-based simulation modeling indicated great performance on predicting maize yield (R2 = 0.76) and wheat WP (R2 = 0.84) based on a 10-fold cross validation (10-fold CV). TS treatment provided the greatest net energy and net economic income, and NTS treatment indicated the greatest economic benefit.

Distribution characteristics of residual film over a cotton field under long-term film mulching and drip irrigation in an oasis agroecosystem

Without an efficient mulch film recovery, the residual plastic film (RPF) causes pollution hazards to agronomic systems and natural environments. Here, we examined the distribution characteristics of RPF in the topsoils (0–40 cm) in an oasis agroecosystem in Northwest China. After cotton harvest in 2016, we collected 2304 soil samples from six cotton fields with different years of continuous mulching management (5, 9, 11, 13, 15 and 19 a). A total of 2471 pieces of RPF were separated and weighted. The weight of each RPF fragment was calibrated by its size measured in digital images. Our results showed that the amount of RPF ranged from 121.85 to 352.38 kg ha–1 across the six fields, remarkably exceeding the national standard of China (75 kg ha–1). The occurrence frequency of RPF fragments maximized at 5–15 cm depth. With the increase in soil depth, RPF fragments became smaller, and their total mass decreased linearly. After the constant mulching practice, RPF accumulated at an annual rate of 15.69 kg ha−1, mainly occurring at 0–30 cm depth. The accumulation of the larger RPF fragments (>25 mg per piece) primarily took place from 5 to 15 years after mulching started. It took over 15 years for the larger RPF fragments to degrade into smaller ones (<25 mg per piece), which accounted for 65% of the total number of RPF fragments in the field with 19-year of mulching. RPF fragments with a weight larger than 100 mg mostly concentrated at the surface (0–10 cm), whereas, the other smaller RPF fragments showed an evident downward migration. That said, with the constant mulching management, RPF pieces became more fragmented and distributed deeper, making mulch film recovery more challenging. To the best of our knowledge, this is the first time that the dynamics of RPF distribution in the soil profile after long-term mulching have been characterized. If the current mulching method continues, the accumulated RPF is going to cause severe soil pollution and risk the sustainability of the oasis agroecosystem.

Effects of lateral spacing for drip irrigation and mulching on the distributions of soil water and nitrate, maize yield, and water use efficiency

In this study, a two-year study in fields with and without a subsurface sand layer (identified as FSS and FNS) were conducted in the Hetao Irrigation District in Northwest China, to investigate the effects of irrigation lateral spacing and soil mulching on soil water and nitrate distribution uniformity, and the combined effects of soil water and nitrate distribution on crop yield and water use efficiency (WUE) of spring maize. The experiment followed a completely randomized block design with four treatments (S1M1, S1M2, S2M1, and S2M2) and three replicates for FSS and FNS, respectively. The four treatments resulted from the combination of two levels of lateral spacing (S1 for 1.0 m and S2 for 0.5 m) and two film-covering modes (full mulching, M1; partial mulching, M2). In each treatment, the Christiansen uniformity coefficient (CU) was used to evaluate the uniformities of soil water (CUw) and nitrate (CUn) distribution in the vertical soil profile. The results showed that the narrower lateral spacing and full mulching enhanced CUn and relative chlorophyll content of leaf, compared with the wider lateral spacing and partial mulching. However, lateral spacing and mulching methods imposed no significant effect on CUw. The correlation between CUw and CUn was not significant under mulched drip irrigation system. In soils without a subsurface sand layer, crop yield may be greater with a higher CUn in root zone. Full film-covering significantly enhanced CUn and then increased crop yields and WUE in FNS, however the combined effects of lateral spacing and mulching methods on grain yield were not significantly different. Thus, taking into account crop yields, WUE, and cost of drip laterals, the combination of wider irrigation lateral spacing and partial mulching was recommended for the FSS soil, while the combination of wider irrigation lateral spacing and full mulching for the FNS soil.

Ảnh hưởng của gốc ghép và biện pháp phủ liếp đến bệnh héo xanh vi khuẩn (Ralstonia solanacearum) và năng suất của ớt hiểm lai, tại Cù Lao Tây, huyện Thanh Bình, tỉnh Đồng Tháp

The aim of this research was to determine mulching methods and rootstocks affecting on tolerance ability of hot pepper to bacterial wilt caused by Ralstonia solanacearum and yield in field condition at Tan Hoa and Tan Hue communes of Thanh Binh district, Dong Thap province. The experiments were designed as four-replication split-plots of two factors. The main factor (in sub-plots) includes five cultivars used as rootstocks (local, TN557, Hiem 27, and self-grafted and non-grafted as two controls). The secondary factor (in main plots) is mulching methods including silvery-gray plastic and rice straw as control. The results of rootstock in Tan Hoa, chilli grafted on TN557 had a lower disease incidence (18.8%) than non-grafted control (36.3%) at the end of harvest, fruit yield 10.3 t/ha, higher than 25.0% compared to the non-grafted control and 32.1% compared to the control grafted on itself. In Tan Hue, chilli grafted on TN557 also had a lower incidence of bacterial wilt (20.0%) than non-grafted control (38.8%) at the end of harvest, fruit yield 5.44 t/ha, higher than 18.0% compared to the non-grafted control and 23.4% compared to the control self-grafted. Mulching materials did not affect bacterial wilt disease, the yield of chilli using silvery gray mulch was 9.63 t/ha, equivalent to 33.0% higher than that of ricestraw mulch in Tan Hoa commune and 5.17 tons/ha, equivalent to 30.5% higher than that of rice straw mulch in Tan Hue commune.

Yield and water use efficiency of dryland potato in response to plastic film mulching on the Loess Plateau

ABSTRACTWater shortage is a key factor limiting potato yield in dryland farming regions, and the practice of soil mulching with plastic film has proven to be effective for increasing crop yield and improving soil and water conservation. This study investigated the effects of plastic mulching on potato yield and water use efficiency (WUE) on the Loess Plateau of China based on a synthesis of 44 publications (1987–2016) from 17 sites. Our results indicated that relative to no mulching, plastic mulching significantly increased the yield and WUE by 29.2% and 31.7%, respectively. The effects on yield under different mulching methods were ranked as follows: ridge-furrow mulching (RFM) > flat mulching (FM), and the effects on yield with different mulching extents were ranked full-area mulching (FAM) > partial-area mulching (PAM). The effects of plastic mulching on the yield using different colors of film were ranked as white plastic mulching (WPM) > black plastic mulching (BPM) and under different rainfall levels as (precipitation < 400 mm) > (precipitation > 400 mm). The rankings of the effects of plastic mulching on WUE were the same as for potato yield. The yield-evapotranspiration (ET) relationship could be described using a quadratic polynomial, and the yield response curve to ET under plastic mulching fell above the no-mulching curve, indicating that plastic mulching can result in higher yields than no mulching when ET is equal. The yield-ET relationship indicated that potatoes required an ET of 334 and 360 mm to achieve the highest yield under plastic mulching and no mulching, respectively, and potato WUE increased linearly with yield under both plastic mulching and no mulching. This study indicated that RFM, FAM and WPM are better potato management measures and that there is potential to improve the yield and WUE on the Loess Plateau.

Plastic-Film Mulching for Enhanced Water-Use Efficiency and Economic Returns from Maize Fields in Semiarid China.

Film mulch has gradually been popularized to increase water availability to crops for improving and stabilizing agricultural production in the semiarid areas of Northwest China. To find more sustainable and economic film mulch methods for alleviating drought stress in semiarid region, it is necessary to test optimum planting methods in same cultivation conditions. A field experiment was conducted during 2013 and 2014 to evaluate the effects of different plastic film mulch methods on soil water, soil temperature, water use efficiency (WUE), yield and revenue. The treatments included: (i) the control, conventional flat planting without plastic film mulch (CK); (ii) flat planting with maize rows (60 cm spacing) on plastic film mulch (70 cm wide); (iii) furrow planting of maize (60 cm spacing), separated by consecutive plastic film-mulched ridges (each 50 cm wide and 15 cm tall); (iv) furrow planting of maize (60 cm spacing), separated by alternating large and small plastic film-mulched ridges (large ridges: 70 cm wide and 15 cm tall, small ridges 50 cm wide and 10 cm tall); and (v) furrow-flat planting of maize (60 cm spacing) with a large plastic film-mulched ridge (60 cm wide and 15 cm tall) alternating with a flat without plastic film-mulched space (60 cm wide). Topsoil temperature (5–25 cm) was significantly (p < 0.05) higher in field plots with plastic film mulch than the control (CK), and resulted in greater soil water storage (0–200 cm) up to 40 days after planting. Maize grain yield and WUE were significantly (p < 0.05) higher with the furrow planting methods (consecutive film-mulched ridges and alternating film-mulched ridges) than the check in both years. Maize yield was, on average, 29% (p < 0.05) greater and 28% (p < 0.05) greater with these furrow planting methods, while the average WUE increased by 22.8% (p < 0.05) with consecutive film-mulched ridges and 21.1% (p < 0.05) with alternating film-mulched ridges. The 2-year average net income increased by 1559, 528, and 350 Chinese Yuan (CNY) ha−1 with the consecutive film-mulched ridges, furrow-flat planting and alternating film-mulched ridges, respectively, compared with the control (CK). We conclude that the consecutive film-mulched ridge method was the most productive and profitable for maize in this semi-arid area with limited and erratic precipitation.

Cultivars and cultivation systems for organic strawberry production in Norway

ABSTRACTCultivars and cultivating methods for organic strawberry production were studied in experiments in open fields and high plastic tunnels during four cropping seasons in southern Norway. In open fields, flowers and fruits were attacked by grey mould when the flowering and harvest seasons were wet, and marketable yield was reduced by up to 20%. Production in high tunnels showed a potential of high yields of fruits of good quality when strawberry powdery mildew was controlled. Berry size varied significantly among the cultivars. ‘Frida’ had the largest fruits followed by ‘Sonata’ and ‘Florence’, while ‘Polka’, ‘Korona’ and ‘Iris’ had the smallest fruits. All cultivars yielded well, but due to fruit decay caused by grey mould the marketable yield was significantly reduced, especially in open field. Grey mould was the most important factor influencing marketable yields. Fruits from matted rows were largest, while the highest yield was obtained on woven polyethylene. There were no effects of mulching methods on marketable yield or the amount of fruits with grey mould. High tunnels with good control of pests and diseases showed a potential of high and stable yields of good quality.

Effects of different types of mulches and legumes for the restoration of urban abandoned land in semi-arid northern China

Abandoned land is a type of resource wasteland that significantly damages the ecological environment and affects city construction. The northwestern Chinese ecological environment of the semi-arid field is fragile and susceptible to temperature variability. It is difficult to transform such abandoned land into sustainable urban land. However, vegetation restoration on urban abandoned land can ameliorate the soil conditions but received less attention. In the ecological restoration of such abandoned land, the use of certain types of mulch and legume is efficient and effective. In this research, three mulching methods, including a straw blanket (SB), bark plot (BP) and wood shavings (WS), and a control plot (CP) were evaluated over separate growing seasons to determine their effects on the vegetation biomass and the soil physicochemical properties, including soil temperature and soil moisture. The results indicated that mulching had multiple benefits, including improved vegetation growth by decreasing soil evaporation and regulating the soil temperature. SB and BP were the preferred materials because they were more effective. The wood shavings method did not favor the establishment of vegetation and resulted in vegetation similar to that of the control plot. In addition, the legumes Amorpha fruticosa, Lespedeza bicolor and Medicago sativa significantly enhanced the soil physicochemical properties. Thus, the straw blanket, bark plot mulch are recommended for a beneficial water retention effect on topsoil and vegetation growth of abandoned land. This ecological restoration technology for urban abandoned land also exhibits environmental friendliness and sustainability.

Drip irrigation lateral spacing and mulching affects the wetting pattern, shoot-root regulation, and yield of maize in a sand-layered soil

Soil with a 20–60cm thick subsoil (60–90cm below the surface) sand layer has been recently reclaimed to exploit its grain production potential in an arid region in northwest China. A 2-year field study was conducted in the Hetao irrigation district to investigate the effects of lateral spacing and soil mulching methods under drip irrigation on the soil moisture, NO3−, shoot-root regulation, and water use efficiency (WUE) of spring maize. The Christiansen uniformity coefficient (Cus) was adopted to evaluate soil moisture and NO3− distribution, which was calculated with soil water content and NO3− concentration. The four studied treatments consisted of two irrigation lateral-spacings (A1: 1.0m, A2: 0.5m) and two film-covering modes (M1: fully mulched, M2: partially mulched) were arranged.Soil moisture was most affected by mulch coverage (full or half surface coverage) under low frequency irrigation lateral spacing (adjacent to or between crop rows) under high frequency irrigation. Lateral spacing exerted a notable influence on soil moisture at a 20cm depth, while the mulching method influenced soil moisture mainly at 40cm. Irrigation frequency and close lateral spacing can effectively enhance Cus. Based on our observations, a decrease in the Cus of soil NO3− may occur under frequent fertigation, particularly when irrigation laterals are between crop rows. The mulching method can play an important role in improving the concentration and Cus of soil NO3−, while the A2 treatments can slow the decrease of the Cus of soil NO3− under frequent fertigation. Root length density (RLD) under A1 treatments were lower close to lateral while higher away from lateral than A2 treatments. Close lateral spacing can result in high hundred gain weight (HGW) and high harvest index (HI) while exerting a more conspicuous effect than the mulching method by extending the grain filling stage.Frequent fertigation (i.e. once every three days) after jointing is preferentially recommended in a sand-layered field. A1M2 should be chosen for higher HI and low cost. If frequent fertigation is infeasible, A2M1 can be a good choice under low frequency fertigation.

Effect of Soil Solarization on Soil Borne Fungi, the Growth and Yield of Tomato Grown In Clay Loam Soil at Alexandria Governorate, Egypt

Mulching by 100 µ thickness transparent plastic sheets compared with specific fungicides for controlling soil borne fungi were carried out at Al-Sabahia, Horticulture Research Station, Alexandria Governorate, Egypt. Solar heating resulted from mulching gradually reduced the tested soil borne-fungi to very low levels, comparable with non-mulched treatment. Soil Temperature, fungal frequency and tomato yield were recorded during the experimental seasons. The results indicated that there were no significant differences between the three months mulching and specific fungicides treatments effect against soil borne fungi. So, it could be concluded that possibility of using mulching method to control soil-borne diseases pathogens in the clay loam soil by planting the crop in solarized fields. The results also proved significant effect of the soil solarization on the vegetative growth of tomato plants and enhanced the yield and its components compared with the control. The results for the total yield per feddan proved that there were no significant differences between the treated root with fungicide and the three month soil solarization treatments in both seasons. The percentages increase in the estimated total yield per feddan were 21.40, 18.95, 12.40 and 3.11% for treated root with fungicide, three, two and one month treatments over the control, respectively in 2014 season, whereas, they were 25.65, 22.51, 16.40 and 9.52% for the same treatments, respectively in the 2015 season.

An experimental study of the surface and subsurface irrigation methods with respect to soil moisture on grape yard

AbstractIn this study, field experiment has been carried out on the grape yard during the summer, Rainy, and winter seasons using different irrigation methods and measuring its impact on moisture retention. Six different irrigation methods such as drip irrigation (DI), drip irrigation with plastic mulching (DIPM), drip irrigation with organic mulching (DIOM), subsurface irrigation with stone column (SISC), subsurface irrigation with mud pot (SIMP), and subsurface irrigation with plastic bottles (SIPB) are used during experimental work. CROPWAT-8.0 model (FAO) is used to find out crop water requirements. Soil moisture is measured using soil moisture sensors fixed in the depth of 30 and 60 cm at the same location. Climatic parameters are obtained from the automatic weather station which is located near the experimental field. Multifactorial statistical analysis has been carried out using recorded soil moisture and climatic data. As per experimental results and analysis, it is observed that drip irrigation with the plastic mulching method is found to be the best method of irrigation for soil moisture retention among all other methods due to its highest soil moisture retention value as 25–30%. Whereas subsurface irrigation with the plastic bottle method is found to be suitable as it retained 15–20% soil moisture and material used in this irrigation method is waste material and the cheapest one.

Reestablishment of Perennial Ryegrass in Lawns Damaged by Diesel and Hydraulic Fluid Spills

Petroleum-based spills on turfgrass often occur during lawn care maintenance. Damage caused by diesel and hydraulic fluid is particularly difficult to correct. The objective of this study was to compare the effectiveness of combining mulching with remediation for reseeding spilled areas in lawns. Diesel and hydraulic fluid were applied to plots at a rate of 15 L·m−2. Immediately after the spill treatments, two liquid humic amendments and an activated flowable charcoal were applied at a volume rate of 8 L·m−2, respectively, with tap water/dishwashing detergent used as a control. Nitrate nitrogen was added to each remediation treatment to facilitate remediation. The spilled areas were reseeded with perennial ryegrass (Lolium perenne) and then mulched with biochar, peat pellets, and paper pellets, respectively. At 6 weeks after seeding, humic amendment 1 and activated charcoal showed better turf quality than humic amendment 2. Peat pellet mulching presented better turf quality than other mulching methods. Reseeding perennial ryegrass and mulching with peat pellets after remediation with either humic amendment 1 or activated charcoal resulted in acceptable turf quality 6 weeks after diesel and hydraulic fluid spills. Therefore, this reestablishment method is recommended as a practical way to deal with diesel or hydraulic fluid spills in cool-season turfgrasses.

Impact of mulches and growing season on indicator bacteria survival during lettuce cultivation

In fresh produce production, the use of mulches as ground cover to retain moisture and control weeds is a common agricultural practice, but the influence that various mulches have on enteric pathogen survival and dispersal is unknown. The goal of this study was to assess the impact of different mulching methods on the survival of soil and epiphytic fecal indicator bacteria on organically grown lettuce during different growing seasons. Organically managed lettuce, cultivated with various ground covers — polyethylene plastic, corn-based biodegradable plastic, paper and straw mulch — and bare ground as a no-mulch control, was overhead inoculated with manure-contaminated water containing known levels of generic Escherichia coli and Enterococcus spp. Leaves and soil samples were collected at intervals over a two week period on days 0, 1, 3, 5, 7, 10 and 14, and quantitatively assessed for E. coli, fecal coliforms and Enterococcus spp. Data were analyzed using mixed models with repeated measures and an exponential decline with asymptote survival model. Indicator bacterial concentrations in the lettuce phyllosphere decreased over time under all treatments, with more rapid E. coli declines in the fall than in the spring (p<0.01). Persistence of E. coli in spring was correlated with higher maximum and minimum temperatures in this season, and more regular rainfall. The survival model gave very good fits for the progression of E. coli concentrations in the phyllosphere over time (R2=0.88±0.12). In the spring season, decline rates of E. coli counts were faster (2013 p=0.18; 2014 p<0.005) for the bare ground-cultivated lettuce compared to mulches. In fall 2014, the E. coli decline rate on paper mulch-grown lettuce was higher (p<0.005). Bacteria fluctuated more, and persisted longer, in soil compared to lettuce phyllosphere, and mulch type was a factor for fecal coliform levels (p<0.05), with higher counts retrieved under plastic mulches in all trials, and higher enterococci levels under straw in fall 2014 (p<0.05). This study demonstrates that mulches used in lettuce production may impact the fate of enteric bacteria in soil or on lettuce, most likely in relation to soil moisture retention, and other weather-related factors, such as temperature and rainfall. The data suggest that the time between exposure to a source of enteric bacteria and harvesting of the crop is season dependent, which has implications for determining best harvest times.

Diversity of weed communities in soybean [Glycine max (L.)] crop growing under direct sowing depending on cover crops and different herbicide doses

Despite being harmful for agricultural production, weeds are an essential component of biodiversity in agricultural landscapes. A field study was conducted during the period 2007–2009 on grey-brown podzolic soil (sandy), designated as PWsp, with the granulometric composition of silt and classified Class 2 in agricultural land suitability. The study evaluated the structure of weed communities based on selected indicators of diversity of a soybean crop grown under no-tillage with mulch from winter rye, winter oilseed rape, and white mustard as well as using herbicide rates reduced by 25% and 50% in relation to the standard rate (2 L ha&lt;sup&gt;−1&lt;/sup&gt;). The studied factors were as follows: (i) mulch plant species and mulch management method; (ii) rates of the foliar herbicide Basagran 600 SL (a.i. bentazon; 600 g L&lt;sup&gt;−1&lt;/sup&gt;). The results of this study confirm that no-tillage with mulch significantly changes the diversity of weed flora in a soybean crop. Among the mulches used, the mowed rye and winter oilseed rape in particular increased the values of the general diversity (&lt;em&gt;H&lt;/em&gt;'), species richness (&lt;em&gt;d&lt;/em&gt;), and evenness (&lt;em&gt;J&lt;/em&gt;') indices relative to the control treatment. On the other hand, the study found a strong decrease in the value of the dominance index (&lt;em&gt;c&lt;/em&gt;). Reduced herbicide rates modified only the species richness index, in the case of which the 75% rate resulted in its significantly higher values compared to the full rate.

고속도로 갓길 외측 성토상단의 잡초침입 억제를 위한 시험 연구

From January 2013 to October 2015, weed invasion control techniques was tested in the test road of Jungbunaeryuk expressway so as to collect preliminary data for the management methods of the upper exterior banking of expressway shoulders. Then, monitoring was conducted and its results are as follows. Mat (sheet), solidifying agent, and mulching (wood chips) were applied for the test and their initial effects of preventing weed invasion were all excellent. It was found that the homogeneity of the wood chip mulching method needs to improve. In the mat method and the mulching method were found to have the most excellent economic feasibility and aesthetics, respectively. The covering degree was found to be the highest at 80% in the control site, followed by the wood chip site at 20% and the solidifying agent site and the non-woven fabric site at 5% each. As for species diversity, the control had the largest variety of species. Two years after the construction, many different species of plants invaded and were growing. Plants including weed didn't tend to invade the slopes applied with non-woven fabric. In addition, weed didn't invade the solidifying agent site and the aesthetics of the upper exterior banking of expressway shoulders was found to be excellent. The wood chip site was found to require consistent management for preventing weed invasion. The mat (sheet) site, the solidifying agent site, and the wood chip mulching site were found to have excellent weed prevention effects. As time passed, the mat (sheet) site and the solidifying agent site showed better weed prevention effects. However, they need consistent monitoring for further application.

Temperatura do solo afetada pela irrigação e por diferentes coberturas

RESUMO A irrigação suplementar e a cobertura do solo ("mulching") são práticas de manejo comumente usadas na agricultura. O objetivo deste trabalho foi quantificar a temperatura do solo desnudo com e sem irrigação, e sob diferentes coberturas do solo. Um ensaio de campo foi conduzido em Santa Maria-RS (29o 43' S latitude, 53º 42' W longitude e 95 m de altitude), com seis diferentes áreas: solo desnudo sem e com irrigação, solo com "mulching" de plástico transparente (espessura 100 µm), "mulching" de plástico opaco preto (espessura 110 µm), "mulching" de plástico opaco branco (espessura 150 µm) e cobertura vegetal com palha na dose de 5 t ha-1. A temperatura do solo foi medida a 0,05 m de profundidade, diariamente, às 15h (18 UTC), no período de 10-10-2011 a 31-05-2012. Foram também realizadas medidas horárias de temperatura do solo em quatro dias sem nebulosidade, em outubro e novembro de 2011, e janeiro e março de 2012. A temperatura do solo diurna seguiu a sequência: plástico transparente (42,4 oC) &gt; plástico opaco preto (37,8 oC) &gt; solo desnudo sem irrigação (33,4 oC) &gt; solo desnudo com irrigação (29,2oC) &gt; palha (27,0 oC) &gt; plástico opaco branco (24,6 oC). A região de Santa Maria-RS, tem potencial físico de aquecimento do solo com a técnica da solarização.