Root zone temperature,plant growth and yield of broccoli [Brassica oleracea (Plenck) var. italica] as affected by plastic film mulches

Plastic film mulches are often associated with increases in plant growth and yield of vegetable crops. Few studies, however, report on the effect of plastic film mulches on root zone temperature on broccoli. The objectives of this study were to determine the effects of colored plastic mulches on root zone temperature and broccoli plant growth and yield Broccoli (‘Packman’) plants were grown using plastic film mulch and drip irrigation. The treatments consisted of plastic film mulch (black, blue, gray on black, red, silver on black, and white on black mulches) and bare soil. Colored plastic film mulches affected root zone temperature and the accumulation of soil degree-days. Mean daily RZT, maximal daily RZT and degree day accumulation in the soil were highest in dark-colored mulches (blue, black, red, and gray) and lowest in light-colored mulches (silver and white), while minimal daily RZT was highest in silver mulch and lowest in white mulch. Silver mulch showed the smallest diurnal fluctuations in RZT among plastic mulches, with the highest RZT during the night and among the lowest in the afternoon. Colored plastic mulches also affected broccoli plant growth and yield, although the effect of mulches was more dramatic in the spring than in the fall seasons. Broccoli yield was linearly related to both the vegetative top dry weight and root dry weight of mature plants. Broccoli yield was little affected at mean RZT of <21 °C but increased with increasing mean RZTs above 21 °C up to 25 °C. Thus, broccoli plant growth and yield responded more favorably to dark-colored mulches than to light-colored mulches, suggesting that broccoli benefited from increased soil warming. No high RZT stress effects on broccoli plant growth or yield were observed in this study. Thus, this study suggests that plastic film mulches, particularly the dark-colored mulches, may be an option for spring broccoli production in areas with cool conditions early in the spring.     

不同覆盖物对绿地土壤和杂草的影响

利用树皮、园林有机废弃物、透水砖进行绿地土壤覆盖试验,分析了覆盖材料对绿地土壤和杂草的影响。结果表明:覆盖树皮和园林有机废弃物对绿地土壤具有一定的调温、保水、增肥的作用,随着覆盖厚度的增加,其作用也随之增加;覆盖透水砖会导致土壤pH值和容重明显增加;3种覆盖物对于绿地杂草均具有很好的抑制作用。     

Influence of soil hydrothermal environment,irrigation regime,and different mulches on the growth and fruit quality of strawberry (Fragaria × ananassa L.) plants in a sub-temperate climate

Summary

The present study was undertaken over two consecutive years under sub-temperate climatic conditions in the mid-hill region of Himachal Pradesh (30°52'N, 77°11'E; 1,175 m asl) on loamy sand Inceptisols. The aim was to investigate the effects of irrigation and mulch material on the growth, flowering, fruiting behaviour, relative leaf water content (RLWC), yield, and quality of strawberry (Fragaria × ananassa L. ‘Chandler’). The drip irrigation treatments included irrigation with 100, 80, or 60% (coded 1.0, 0.8, and 0.6 V) of the total water requirement. Both mulches increased the minimum soil temperature to a depth of 5 cm. The drip and surface irrigation treatments raised the minimum soil temperature by 3.0º – 5.4ºC, and lowered the maximum temperature by 2.2º – 5.8ºC compared to the rainfed control. Hay mulch was more effective in raising the minimum temperature and lowering the maximum soil temperature than black polyethylene mulch. Moisture conservation increased by 2.8 – 12.8% under the black polyethylene mulch compared to the no-mulch treatment. Drip and surface irrigation methods, as well as mulching, were found to be effective for enhancing the growth, irrigation water use efficiency (IWUE), fruit yield, and quality of strawberry plants. However, the number of crowns per plant, the percentage berry set, the RLWC, root length density (RLD), and fruit yield were highest under treatment M3I3 [i.e., black polyethylene mulch plus drip irrigation (1.0 V)] by 565.5%, 94.5%, 32.8%, 394.5%, and 549.6%,respectively, compared to the no mulch plus rainfed control. The maximum IWUE values for plant biomass [1.39 metric tonnes (MT) ha^–1 m^–1] and fruit yield (2.79 MT ha^–1 m^–1) were recorded under treatment M3I5 [i.e., black polyethylene mulch plus drip irrigation (0.6 V)]; whereas, the lowest values (0.39 and 0.68 MT ha^–1 m^–1, respectively) were observed using treatment M1I2 (i.e., without mulch, plus surface irrigation). Fruit size, weight, sugar content, and anthocyanin content increased significantly under treatment M2I3 [i.e., hay mulch, plus drip irrigation (1.0 V)] compared with all other treatments. Total soluble solids (TSS) contents and total acidity (TA) were highest under treatment M1I1 (i.e., no mulch, plus rainfed). A linear regression model could describe the variations in quality parameters of strawberry plants grown under sub-temperate climatic conditions. Root density was found to be the best indicator with which estimate fruit quality.     

Berry yields of two Finnish sea buckthorn cultivars under organic farming methods

Summary

The effects of different organic farming methods on berry production by two Finnish sea buckthorn (Hippophae rhamnoides L. ssp. rhamnoides) cultivars, ‘Terhi’ and ‘Tytti’, were studied in field experiments over 4 years at Merikarvia, western Finland. Four organic fertilisers, five mulches, and two land contours were used. Two experiments were conducted. In the first, fertilisation experiment, the fully-crossed effects of four different fertilisers and two land contours were tested for both cultivars. In the second, mulch experiment, the fully-crossed effects of five different mulches and two land contours were tested for the cultivar ‘Tytti’. Some sea buckthorn bushes produced a small number of berries in the second growing season. According to the three-way interactions, the effect of fertiliser on yield depended on the land contour in ‘Terhi’, but not in ‘Tytti’. Apatite increased yields in bushes grown on flat land. Yields increased in the third and fourth growing seasons, when ‘Terhi’ produced larger berries and yields than ‘Tytti’. ‘Terhi’ had a higher yield on ridged beds than on flat land. Berry size was larger on ridged beds compared to flat land in both cultivars. The effect of mulch depended on the land contour in the second and fourth growing seasons. In the second growing season, straw mulch increased berry production on the flat land compared to the other mulches. In the fourth growing season, a plastic mulch increased yields compared to organic mulches. The results of this experiment provide information on ways to improve sea buckthorn berry yields when organic farming methods are used.     

Effects of artificial amendments in potting media on Orthosiphon aristatus growth and development

Artificial polyacrylamide gel (PAG) and urea-formaldehyde resin foam (UFRF) amendments are used for putative enhancement of soil physical properties, including increasing their water holding capacity (WHC). Effects were investigated of these two amendments alone and combined on growth and development of Orthosiphon aristatus (Cats’ Whiskers) grown in either composted pine bark or washed river sand, including under transient water deficit stress. UFRF and PAG were incorporated into these potting media substrates at recommended rates of 30% (v/v) and 0.1% (w/w), respectively. UFRF incorporation reduced bulk density and increased air-filled porosity of composted pine bark from 0.24 g cm⁻³ and 43.3% to 0.18 g cm⁻³ and 50.2%, respectively. UFRF also reduced bulk density of sand from 1.43 g cm⁻³ to 1.17 g cm⁻³ and increased its air-filled porosity from 18.5% to 25.3%. PAG slightly decreased bulk density of composted pine bark to 0.23 g cm⁻³ and also reduced sand bulk density to 1.32 g cm⁻³. Water content of composted pine bark and sand was increased by PAG addition from 47.6% and 27.7% to 51.0% and 34.2%, respectively. However, UFRF and/or PAG did not increase plant available water (PAW) in either composted pine bark or sand. PAW was 23.8% and 14.4%, 23.6% and 15.8%, 22.8% and 14.8%, and 25.2% and 17.8% for composted pine bark and sand controls, these two substrates amended with UFRF, these substrates amended with PAG, and these substrates with UFRF plus PAG, respectively. Neither shoot length nor number was increased by adding UFRF and/or PAG. Similarly, neither shoot fresh nor dry weight was increased by UFRF and/or PAG amendments. UFRF and, moreso, UFRF plus PAG slightly delayed the onset of wilting by 4–15 h in water deficit stressed O. aristatus compared to control and PAG alone in composted pine bark (experiment 1), but PAG did not. However, in experiment 2, UFRF and/or PAG did not delay wilting in either composted pine bark or sand. Thus, when incorporated at suppliers recommended rates, neither UFRF nor PAG conferred appreciable benefits for O. aristatus plant growth in either composted pine bark or sand potting media.     

Effects of different mulches and irrigation methods on root growth,nutrient uptake,water-use efficiency and yield of strawberry

Field studies were conducted for two consecutive years under sub-temperate climatic conditions at Nauni in district Solan of Himachal Pradesh (30°52′N, 77°11′E 1175 asl) on loamy sand Inceptisols to investigate the effect of different mulches (hay: HM, black polyethylene: BP) on root growth, nutrient uptake, water-use efficiency (WUE) and yield of strawberry cv. Chandler under drip (DI) and surface irrigation (SI) systems. Unmulch (UM) and rainfed treatments were kept as control. Higher soil moisture content was registered under both the mulch materials during entire crop growth period. However, it was greater under BP mulch as compare to HM. The moisture conservation increased by 2.80–12.80% under BP mulch as compared to UM. HM treatment, irrespective of irrigation method increased the minimum soil temperature (2.8–5.2 °C) and reduced the maximum soil temperature (2.7–5.8 °C) as compared to UM. BP mulch increased the minimum soil temperature from 0.4 to 2.5 °C. Application of irrigation moderated the soil (minimum 2.6 and maximum 1.4 °C) temperature. Both the mulch materials were effective in enhancing root growth, nutrient uptake, WUE and yield. Application of mulch enhanced the root growth (63%), nutrient uptake (179.20%), WUE (84.40%) and yield (343%) under DI. However, respective increase under SI was 23.60, 83.80, 109.40 and 219.20%. Under DI, 51% of irrigation water was saved and about 19% higher fruit yield was obtained as compared with SI treatment. Linear regression model could significantly describe the variations in nutrient uptake (N, P and K) and WUE of strawberry under sub-temperate climatic conditions, root mass density was better indicator for estimating nutrient uptake of strawberry.     

Effects of Mulching on Soil Temperature,Scion Rooting,and Soil Moisture of Mounded Grapevines

Soil-hilling around grapevines is required in the eastern United States for winter protection of grafted and cold sensitive grape cultivars (Vitis vinifera). The effects of simazine-treated mulches (STM) on soil temperature, scion rooting, and soil water conservation were measured. Neither simazine nor interactions between simazine and mulches affected any variables measured in this study. Wood and straw mulches increased the minimum temperature of media around the graft union as effectively as hilled soil, reduced scion rooting by a factor of 2 to 75 compared with soil-hilling, and increased soil moisture content 45 to 75% at Wooster and 8 to 23% at Kingsville. These results indicate that mulches have positive attributes and should be considered as an alternative to traditional soil-hilling in vineyards for temperature mitigation around graft union.     

Microclimates in a desert city were related to land use and vegetation index

A heterogeneous patchwork mosaic of soil, vegetation, and built surfaces that result from a variety of urban land uses cause urban microclimates within cities. We studied the seasonal relationships of land use, urban plant cover and microclimate in Phoenix, Arizona, USA, metropolitan. Early morning (0500 HR) and afternoon (1500 HR) near-surface temperatures and humidities were measured along multiple transects in this desert city and outlying areas during June and December 1999. A Landsat thematic mapper normalized differential vegetation index (NDVI) image was used to quantify spatial patterns of plant density. Land use had the most pronounced effect on microclimate during the early morning hours of summer. Agricultural and residential land uses had the highest relative humidities, dew point temperatures, and NDVI, and the lowest air temperatures. Commercial and industrial land uses had highest temperatures and lowest NDVI. Temperatures were generally negatively correlated to NDVI, while humidity and dew point temperatures were generally positively correlated to NDVI. Distance from the urban core did not affect NDVI but had a significant negative effect on adjusted air temperature. In addition, a historical comparison of land use, NDVI and microclimate data collected during 1976 and again during 1999 along two transects revealed overall decreases in NDVI and relative increases in air temperature indicative of urban expansion. These findings show that microclimates in this desert city are caused by more than just variations in plant cover, and are likely an interactive effect of vegetation density and other non-vegetative urban surfaces.     

Effects of plastic mulches on root zone temperature and on the manifestation of tomato spotted wilt symptoms and yield of tomato

Tomato spotted wilt (TSW) disease is a serious constraint to tomato production in various regions of the world. The effect of TSW on tomato yield is largely influenced by time of infection. Early infection usually results in severe stunting of the seedling and even death of the plant. Plastic film mulches affect both the incidence of TSW, and plant growth and yield of tomato. The objective of the present study was to determine the effect of root zone temperature (RZT) as affected by plastic film mulch on the manifestation of symptoms of TSW, and growth and yield of tomato plants either artificially inoculated with tomato spotted wilt virus (TSWV) or under natural TSW infection. In artificially inoculated plants as well as in plants under natural TSW infection, vegetative top fresh weight (FW) and fruit FW both increased with the length of time after transplanting that the plants remained free from TSW symptoms. The root zone temperature was highest under black mulch (seasonal mean = 27.5 °C), followed by gray (27.0 °C), silver (25.8 °C), and white (24.8 °C) mulches. The plants grown on black mulch showed the earliest appearance of TSW symptoms, and had significantly reduced vegetative growth and fruit yields compared to plants on the other mulches. In conclusion, utilization of plastic mulches that created conditions of high RZT stress resulted in reduced plant growth and yield and predisposed the plants to earlier expression of TSW symptoms compared to plants grown at RZTs more favorable to tomato plant growth (optimal RZT = 26.1 °C [Díaz-Pérez, J.C., Batal, K.D., Granberry, D., Bertrand, D., Giddings, D., Pappu, H., 2003. Vegetative top growth and yield of tomato grown on plastic film mulches as affected by the appearance of symptoms of Tomato spotted wilt virus. HortScience 38, 395–399]). Since these plant responses to TSW under heat stress occurred in artificially inoculated plants as well as in plants under natural TSW infection, high RZTs probably affected the plants directly, independently of any possible effects on the thrips vectors.     

Distribution of Ilex and Juniperus roots in three container-media

Ilex crenata Thunb. cultivar ‘Green Luster’ and Juniperus horizontalis Moench. cultivar ‘Plumosa’ were grown in 3 container-media for 13 months. The container-media were dissected by 2 horizontal cuts to yield 3 depth zones, 3 equal concentric areas were outlined on the lower surface of each depth zone and root distribution determined. A greater number of Ilex roots were in the 2 inside concentric areas of the bottom two-thirds of the peat:perlite medium than in the same divisions of soil:peat:sand and pine bark:sand media. Juniperus roots were more evenly distributed through the depth zones of pine bark: sand than soil:peat:sand or peat:perlite media.     

Effect of different biodegradable and polyethylene mulches on soil properties and production in a tomato crop

The use of plastic materials for mulching is a very common practice for vegetable crops. Black polyethylene is the most widely used due to its excellent properties and low cost. However, the massive use of these materials supposes an environmental risk. In the last few years, the use of starch-based biodegradable films has been introduced as an alternative to conventional mulches. These materials can be incorporated into the soil at the end of the crop season and undergo biodegradation by soil microorganisms. A 2-year study was conducted to determine the response of a tomato crop to seven mulch materials (polyethylene and biodegradable) in open fields in Central Spain. Biodegradable films underwent early decomposition, but in general remained functional during use and did not affect yield and the fruit quality attributes (total soluble solids, firmness, dry weight, juice content and shape). The temperatures reached under polyethylene films were always higher than under biodegradable films, which could be a disadvantage in certain circumstances, especially in hot climates, although may be advantageous in cool conditions. The use of polyethylene films resulted in the lowest values of soil microbial biomass C and soil organic matter mineralization, probably due to the increase of temperature registered under mulches. The analysis of the marketable yield components indicates that the variability in yield mainly depended on the number of fruits, with mean fruit weight being practically constant in the different treatments and seasons, which suggests the strong varietal character of this parameter.     

Influence of no-tillage and organic mulching on tomato (Solanum Lycopersicum L.) production and nitrogen use in the mediterranean environment of central Italy

In conservation tillage systems based on legume mulches it is important to optimize N management strategies. The present study evaluated the effect of some winter legume cover crops converted into mulches on the following no-tillage tomato (Solanum Lycopersicum L.) yield, tomato nitrogen uptake, tomato use efficiency (NUE), soil nitrate and the apparent N remaining in the soil (ARNS) in a Mediterranean environment. Field experiments were carried out from 2002 to 2004 in a tomato crop transplanted into: four different types of mulches coming from winter cover crops [hairy vetch (Vicia villosa Roth.), subclover (Trifolium subterranem L.), snail medic (Medicago scutellata L. Miller), and Italian ryegrass (Lolium multiflorum Lam.)]; a conventional tilled soil (CT); and a no-tilled bare soil (NT). All treatments were fertilized with three different levels of nitrogen (N) fertilizer (0, 75, and 150 kg N ha⁻¹). Cover crop above-ground biomass at cover crop suppression ranged from 4.0 to 6.7 t ha⁻¹ of DM and accumulated from 54 to 189 kg N ha⁻¹, hairy vetch showed the highest values followed by subclover, snail medic and ryegrass. The marketable tomato yield was higher in no-tilled legume mulched soil compared to no-tilled ryegrass mulched soil, CT, and NT (on average 84.8 vs 68.7 t ha⁻¹ of FM, respectively) and it tended to rise with the increase of the N fertilization level. A similar trend was observed on tomato N uptake. Hairy vetch mulch released the highest amount of N during tomato cultivation followed by subclover, snail medic, and ryegrass (on average 141, 96, 90 and 33 kg N ha⁻¹). The tomato NUE tended to decrease with the increase of the N fertilization rates, it ranged from 39 to 60% in no-tilled legume mulched soil and from −59 to 30% in no-tilled ryegrass mulched soil when compared to the CT. The soil NO₃-N content and the ARNS was always higher in the soil mulched with legumes compared to the soil mulched with ryegrass and in NT and CT. This study shows that direct transplanting into mulches coming from winter legume cover crops could be useful for improving the yield and the N-uptake in a no-tillage tomato crop. Furthermore, considering the high N content in the upper soil layer and the remaining N content in the organic mulch residues after tomato harvesting, there is a large amount of N potentially available which could be immediately used by an autumn–winter cash crop.     

The assessment of mulch sheets to inhibit competitive vegetation in tree plantations in urban and natural environment

Weed control is often crucial for successful tree establishment. Removal or suppression of competitive vegetation has most often been done by either mowing or the use of herbicides. The Institute of Forestry and Game Management in Flanders (Belgium) has been conducting a three-year experiment (as part of a five-year programme) to assess 18 treatments for newly planted deciduous trees established on ex-agricultural sites. On grass-covered sites mortality of English oak(Quercus roburL.) decreased significantly when mulch sheets were applied. Mulch sheets increased growth of all species in a pasture. An unequivocal relation was found between the diameter of the weed-free area around the tree and the Relative Growth Rate of Common alder (Alnus glutinosa (L.) Gaertn.). Rigid sheets, such as those made of polypropylene could severely damage the trunk of the trees. Bark mulch decreased growth of English oak in the first year, but increased it significantly after 3 years. The application of bark mulch was time-consuming compared to the other treatments. Usage of herbicides on a clay soil was nefarious to both survival and growth of the treated trees. Mowing, often used by the Flemish Forestry Service, had no significant effect on the growth of the trees.     

Tree crown traits and planting context contribute to reducing urban heat

Urban warming affects many millions of city dwellers worldwide. The current study evaluated the extent to which trees reduce air and surface temperatures in urban settings across Greater Sydney, Australia. Summertime air and surface temperatures were measured directly in the shade of 470 individual trees planted in three contrasting contexts (parks, nature strips, asphalt) and compared with temperatures in paired adjacent areas receiving full sunlight. Differences between shade and sunlit temperatures were evaluated against measured morphological traits (leaf area index [LAI], clear stem height, crown depth, height and diameter at breast height) for all trees. On average, tree shade reduced mean and maximum air temperatures by 1.1 °C and 3.7 °C, respectively. Temperatures of standardised reference surfaces (black and white tiles and artificial grass) in tree shade were up to 45 °C lower compared to full-sun exposure, and were also lower in parks and nature strips compared to asphalt settings. The surface temperature of shaded natural grass was cooler compared to sunlit natural grass, although this difference did not vary between nature strip and park settings. The magnitude of air and surface temperature reductions due to tree shade was significantly, positively related to tree-level LAI and these relationships were stronger in asphalt and park contexts compared to nature strips. These findings can inform decisions made by urban managers and planners around the selection of tree characteristics to enhance cooling benefits in different contexts, as an important step towards more liveable and resilient cities.     

覆沙对旱地果园土壤的水热效应研究

以4、7、10 a生“红富士”苹果为试材,研究不同覆沙年限对土壤含水量、土壤温度及苹果产量的影响.结果表明:果园覆沙主要在苹果开花期之前有增温效应,可明显提高0～20 cm土壤地温2℃左右;覆沙4～7 a保墒效应明显,10 a后逐渐减弱,需要换沙.     

Response of Dendranthema grandiflora (Ramat) to three plant growth regulators in container paint mix applications

The effectiveness of plant growth regulators (PGRs) when applied in a paint mix to the inside of containers was evaluated. Two kinds of paint (regular flat latex and SpinOut^®) were evaluated for their respective effectiveness with three separate plant growth regulators (paclobutrazol, uniconazole, and ancymidol) on the growth of Dendranthema grandiflora (Ramat) (cv. Fina and Pelee) plants. Chrysanthemums grown in containers were subjected to three different application methods: interior surfaces covered by a mixture of paint and plant growth regulator (PGR) and soil drench or spray treatments according to label recommendations. The effect of composted pine bark on the effectiveness of two methods of application (paint and drench) was also compared. Paint alone had no effect on growth and development. None of the plants given treatments with paint with or without PGR, showed any sign of phytotoxicity. Plants exposed to PGRs appeared greener and were shorter than control plants. Both the regular flat latex and SpinOut paints were effective carriers of PGRs, although plants grown in containers coated with PGR/SpinOut paint were taller than plants grown with latex/PGR-coated containers. Composted pine bark slightly reduced the effectiveness of ancymidol on plant growth. This reduction in effectiveness was smaller when ancymidol was carried by latex paint but was greater when carried by SpinOut paint. These results indicate that the paint/PGR method may not represent any real advantage over the drench method to overcome the effect of composted pine bark in the growing mixes on the effectiveness of ancymidol. Chemical names used: β-((4-chlorophenyl)methyl)--(1,1-dimethyl)-1H-1,2,4,-triazole-1-ethanol (paclobutrazol); (E)-(+)-(S)-1-(4chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3ol (uniconazole-P); -cyclopropyl-(p-methoxyphenyl)-5 pyrimidinemethanol (ancymidol).     

Advance regeneration and seed banking of woody plants in Ohio pine plantations: Implications for landscape change

Silviculturally-managed pine plantations within southern Ohio are chronically disturbed patches of introduced vegetation distinct from the surrounding matrix of hardwood forest. To determine the successional pathways by which such pine stands might blend back into the hardwood forest matrix under different types of silvicultural management, we determined the current status of hardwood regeneration under 24 pine stands. Stands of Pinus virginiana (Virginia pine) had the highest density of hardwood seedlings and saplings (20,560 stems ha^-1) whereas P. strobus (white pine) stands averaged only 7090 hardwood stems ha^-1; P. resinosa (red pine) stands were intermediate. The most abundant hardwood seedling and sapling species under pine canopies were Acer rubrum and Cornus florida. DCA ordination of the seedling + sapling assemblages clustered most of the P. resinosa and P. strobus stands in the center of the ordination along with a group of species which are common in second-growth forests of the area. P. virginiana stands, in contrast, were scattered throughout the ordination space. Most of the woody species common in second-growth forests of the region were also common in the pine understory. Multiple regression indicated that large plantations with deeper litter, higher soil pH and lower total hardwood density had the greatest abundance of mesic-site species in the understory. This relationship did not hold for P. resinosa stands, however, due to more frequent and intense silvicultural intervention. The seed bank was not an important source of woody seedlings to the understory assemblage under intact pine plantations. The vegetation of 1–4 yr old clear-cut sites was dominated by wind and bird dispersed species which were generally absent from the understory of intact plantations. We conclude these chronically disturbed planted patches will revert to matrix vegetation faster if the disturbance is allowed to end in a gradual manner through stand senescence than if it is abruptly ended by clear-cutting.     

Screening of AM fungi and Azotobacter chroococcum under natural,solarization, chemical sterilization and moisture conservation practices for commercial mango nursery production in north-west Himalayas

The present study investigates the performance of mango seedlings screened with indigenous arbuscular mycorrhizal (AM) fungi and Azotobacter chroococcum strains under solarized, chemical sterilized and natural soil conditions. Two isolates each of AM fungi namely, Glomus fasciculatum (Thaxter sensu Gerdemann) and Glomus mosseae (Nicol. & Gerd.), and two strains of A. chroococcum viz., A. chroococcum strain-I (AZ1) and A. chroococcum strain-II (AZ2) were inoculated at nursery stage under four different moisture conservation practices viz., black polyethylene mulch and organic mulches (grass mulch, cover crops, green manure) and clean cultivation. The observations on microbial population, root colonization, growth parameters and leaf nutrient content of the seedlings were recorded. Mango seedling's inoculated with G. fasciculatum and AZ1 had increased seedling's height, diameter, leaf area and total root length, microbial consortium of the rhizosphere soil and leaf N, P, K and Zn content in plots where solarization and black polyethylene mulching was used. The study revealed that the inoculation of mango stones and the saplings with G. fasciculatum and AZ1 under solarized black polyethylene mulched practice may be considered the best practice for raising mango nursery and maintaining soil health under rain-fed conditions of mid-hills of north-west Himalayas.     

花境下垫面对北京园林小气候影响因子分析

通过对北京林业大学校园内花境下垫面、水泥地下垫面、湿裸地3种不同下垫面太阳辐射、气温、地温、风速、气压5个小气候因子的测定,结果显示花境下垫面小气候舒适度更高,间接证明花境作为园林植物景观的重要组成部分,能够充分改善园林小气候,创造舒适人居环境。     

The Behaviour of Certain Pears on Various Quince Rootstocks.

Summary

A model for describing the modification of soil and air temperature by nonwoven polypropylene has been developed. Such a model takes into account the first two harmonics of the Fourier series determined from the normalized data of soil and surface temperature. The numerical model predicts with accuracy the soil thermal regime for hourly and daily intervals throughout the crop production cycles of Chinese cabbage (Brassica campestris ssp. pekinensis), lettuce (Lactuca sativa), table beet (Beta vulgaris) and spinach (Spinacia oleracea). Furthermore, the model proposed by Parton (1984) has been modified to estimate the surface temperature based on data of temperature measured at 2.m height, biomass and global solar radiation flux density incident on the crop grown under nonwoven polypropylene conditions.