Effect of different soil moisture regimes and canopy wetting on ‘Baccara’ roses

The combined effect of different irrigation regimes and canopy wetting treatments on flower yield and flower quality was examined with ‘Baccara’ roses. Total yields of 390 flowers per m², of which 290 were of saleable quality for the period October–May, were obtained when the soil water tension at a depth of 15–20 cm was maintained below 4–6 centibar (cb). An increase in water tension up to 10–15 cb caused a 10 % decrease in yield. Wetting the canopy reduced the number of flowers and did not counteract the reduction in yield caused by the increase in soil water tension.Wetting the canopy slightly reduced plant surface temperature, mainly on dry and hot days. Wetting also increased the weight of flower buds obtained under irrigation treatments which maintained soil moisture tension below 5 cb (a low soil moisture treatment). The weight per unit length of flower stem increased when the canopy was wetted under all irrigation treatments. In spring, canopy wetting reduced the decrease in flower weight and in leaf area, and completely prevented the decrease in flower stem weight.     

Response of some horticultural crops to irrigation in the semi-arid region of Tunisia

Response to a limited water supply was determined for 3 horticultural crops, pepper, melon (cantaloup) and tomato, in the Nebhana Valley, Tunisia. Varying fractions of potential evapotranspiration (PET), as calculated by Penman, were used to define 4 irrigation treatments which were replicated 4 times. The study was conducted on a shallow sandy loam soil in the lower Nebhana Valley, near Monastir. For each of the crops the following production parameters were evaluated: marketable yield; average fruit weight; number of fruits per unit land area. For socio-political reasons, the cost price of the irrigation water to the farmers in the Nebhana Valley is of negligible importance, and thus the economic threshold could be drawn from the relationship between yield and total available water. The marketable yield for pepper, melon and tomato crops was not significantly affected by rationing the seasonal water application volumes to 57, 47 and 67%, respectively, of the calculated PET. To increase the water-use efficiency for the crops studied, limited irrigation is advisable.     

Effects of urea formaldehyde foam soil amendment on growth and response to transient water deficit stress of potted Flindersia schottiana saplings

Hydrocell™is a urea formaldehyde resin foam (UFRF) product used as a soil amendment. It is proposed to improve the physicochemical properties (viz. water relations and aeration) of the plant root zone. Flindersia schottiana is a tree species used in the ornamental horticulture industry. This study investigated the potential of Hydrocell™ [0–50% (v/v) incorporation rates] to promote growth of F. schottiana saplings during containerized nursery production in composted pine bark medium. The growth response of the potted saplings to transient water stress was also assessed. In addition, growth of F. schottiana saplings potted into three different soil types (sand, loam, clay) was assessed in the presence and absence of 30% (v/v) Hydrocell™. Under well-watered conditions in composted pine bark, Hydrocell™ treatments enhanced sapling leaflet numbers, with 30% (v/v) being the most beneficial treatment. However, no consistent significant differential effects of incorporation rate on either plant height or stem diameter were recorded. Extended time to wilting upon withholding irrigation was achieved, with the optimum Hydrocell™ rate being 10% (v/v). Among the three soil types compared, use of 30% (v/v) Hydrocell™ resulted in improved growth of potted F. schottiana saplings in the sand and loam soils, but not in the clay soil. These findings suggest that the UFRF, Hydrocell™, holds limited promise as a soil amendment for trees in the nursery phase. Optimum incorporation rates (v/v) would need to be determined for individual media types, specific irrigation regimes and individual taxa.     

压砂西瓜间套马铃薯油葵栽培试验

针对宁夏压砂西瓜产业发展的需要,探索压砂西瓜高效栽培模式技术(间套)。结果表明:压砂西瓜套种油葵共生期长,前期油葵与西瓜争光和肥水,西瓜坐瓜和大小受限制,影响西瓜产量;压砂西瓜套种马铃薯共生期长,马铃薯与西瓜争光、争肥水不明显,西瓜坐瓜和大小不受限制,西瓜产量不受影响,每667 m2套种马铃薯生产比对照多收入231.2元。     

土壤转换对二年生平邑甜茶根系发生与功能的影响

以2年生平邑茶为试材研究表明：土壤转换后,根系的发生与功能有所改变,由粘壤土转入沙壤土的根系吸收表面积、分泌H^ 速率和吸收NO3^-速率比由沙壤土转入粘壤土的高,但均比未处理植株低;前者新根量大,生长势强,分布广,后者的吸收根大量死亡。。     

Growth,yield and water use efficiency response of greenhouse-grown hot pepper under Time-Space deficit irrigation

Greenhouse-grown hot pepper was used to investigate the effect of Time-Space deficit irrigation (TSDI), a newly developing irrigation technique based on regulated deficit irrigation (RDI) and partial rootzone drying (PRD), by measuring plant growth, yield and irrigation water use efficiency. The treatments consisted of factorial combinations of three factors, organized following an orthogonal L₉ (3)⁴ test design with four growing stages. Three irrigation strategies (conventional furrow irrigation with full-water when soil water content was lower by 80% of field capacity (F), conventional furrow irrigation with 50% of full-water (D) and alternate furrow irrigation with 50% of full-water (P)) as the main plot factor were applied to select the optimum irrigation parameter at different stages of crop development, the treatment in which irrigation water was applied to both sides of root system when soil water content was lower by 80% of field capacity during all stages was considered as control (FFFF). Water consumption showed some significant effect of irrigation treatment during the growing period of different drought stress patterns application, and therefore decreased in these treatments to a level around 54.68–70.33% of FFFF. Total dry mass was reduced by 1.17–38.66% in TSDI treatments compared to FFFF. However, the root–shoot ratio of FFFF was lower than other treatments and the differences from FFFF and other TSDI treatments were statistically significant. The highest total fresh fruit yield (19.57 T ha⁻¹) was obtained in the FFFF treatment. All deficit irrigations increased the water use efficiency of hot pepper from a minimum of 1.33% to a maximum of 54.49%. At harvest, although there was difference recorded as single fruit weight and single fruit volume were reduced under the TSDI treatments, total soluble solids concentration of fruit harvested under the water-deficit treatments were higher compared to FFFF.     

控制灌水对梨幼树枝条生长和成花的影响

以3年生梨幼树为试材,研究了4种不同灌水处理对梨幼树枝条生长和花芽形成的影响。结果表明,在冬季一次灌水(250m~3/亩)的基础上,减少土壤供水可有效地控制新梢长度和粗度,缓和树势,增加花芽数量。减少土壤供水可使幼树总生长量轻微下降,主干生长减弱,树冠长梢比例下降,中、短梢比例增加,单位主干横截面积上的花芽数明显增加。生长季节控制灌水,可节约灌水量、扩大灌溉面积、并能促使梨幼树早期结果。     

Shade Effects on Growth and Development of Cacao Following Two Years of Continuous Dry Season Irrigation

ABSTRACT

The deployment of plantain shade and irrigation (5- and 10-day) intervals) for enhancing survival, field establishment, flowering and pod production of field-grown cacao seedlings in the dry season was investigated. The effects of dry season irrigation was profound on cacao growth, field establishment (over 90% seedling survival) and development, flowering and pod production. For the non-irrigated moderately shaded cacao, about 30% of the transplanted seedlings survived and the achievable percent survival from the various shade-irrigation combinations ranged from 47–90%. Open sun in combination with 5-day irrigation interval had best results in term of growth (root and shoot development and biomass accumulation) and establishment, flowering and pod production. Lower values of air and soil temperatures were obtained for combination of irrigation and shade regimes (dense and moderate) and higher soil moisture contents. The shade-irrigation combinations ameliorated microclimate and enhanced growth and development, seedling survival, root and shoot development, advanced flowering and promoted uniform fruiting/pod production and total bean yield. The effects of dry season irrigation at 5- or 10-day intervals was profound on cacao growth, field establishment (over 90% seedling survival), flowering and pod production. Irrigated unshaded (open sun) cacao had best results in term of growth (root and shoot development and biomass accumulation) and establishment, flowering and pod production. The achievable percent survival from the various shade-irrigation combinations ranged from 47–90%. The drip irrigation strategy adopted ameliorated dry season terminal drought (hydrothermal stresses) and promoted cacao growth, survival and flower/pod production.     

土壤质地和砧木对苹果根际微生物功能多样性及其碳源利用的影响

以分别栽培于砂壤土、壤土和黏壤土,砧木为八棱海棠（Malus robusta Rehd.）和平邑甜茶（Malus hupehensis Rehd.）的2年生盆栽‘红富士’苹果（Malus × domestica Borkh.‘Red Fuji’）幼树根际土为试材,分析根际和未栽植果树的非根际土壤细菌16S rRNA基因拷贝数、细菌根际效应、微生物群落代谢活性、功能多样性及其碳源利用类型等。结果表明,根际和非根际土壤细菌的拷贝数、微生物群落代谢活性以及功能多样性指数均是黏壤土 > 壤土 > 砂壤土、平邑甜茶根际土 > 八棱海棠根际土、根际土 > 非根际土。两种砧木的细菌根际效应均是在砂壤土最大,黏壤土最小;砂壤土中的细菌丰度受砧木的影响最大。根际和非根际微生物群落碳源利用能力均是黏壤土 > 壤土 > 砂壤土;根际微生物群落对酚酸和羧酸类碳源的利用能力显著高于非根际;八棱海棠根际微生物群落对羧酸类碳源的利用能力在砂壤土中最高、在黏壤土中最低,平邑甜茶根际微生物群落正相反。根际微生物群落碳源利用类型因土壤质地而异,在砂壤土中主要利用氨基酸类,其次是碳水化合物和羧酸类;在壤土中主要利用碳水化合物,其次是多聚物类和氨基酸类;在黏壤土中主要利用多聚物类,其次是氨基酸类和碳水化合物。主成分分析显示土壤质地使根际微生物群落类型分离,而两种砧木的根际微生物群落在同一质地土壤下聚集在一起,即苹果根际微生物群落碳源利用类型更易受到土壤质地影响,而砧木差异所带来的影响较小。     

不同土壤条件对酿酒葡萄生理及果实品质的影响

【目的】为了探索不同土壤条件对酿酒葡萄生理及果实品质的影响,【方法】以‘蛇龙珠’酿酒葡萄为试材,研究了宁夏贺兰山东麓地区,黄河淤土、含石的沙壤土和风沙土3种土壤对葡萄糖分卸载的影响,测定了不同土壤栽培条件下葡萄果实的单果质量、可溶性固形物、可滴定酸、可溶性总糖、色素、单宁及葡萄叶片的光合速率。【结果】结果表明,在葡萄开始着色至葡萄完全成熟期间,在含石的沙壤土栽培条件下葡萄可溶性总糖含量(22.4%)比黄河淤土栽培条件下和风沙土栽培条件下分别高7%、9%;葡萄色素(5.14 mg.g-1)和叶片光合速率也最高,黄河淤土栽培条件下葡萄的含酸量(8.28 g.L-1)和单粒质量(2.32 g)较高,然而,风沙土条件下,单宁(籽单宁1.15 mg.g-1,皮单宁0.30 mg.g-1)的含量最高。【结论】土壤条件对酿酒葡萄果实品质影响较为显著,含石的沙壤土条件下葡萄品质最佳。     

Applying spent coffee grounds directly to urban agriculture soils greatly reduces plant growth

There are frequent anecdotal recommendations for the use of locally produced spent coffee grounds in urban agriculture and gardens, either through direct soil application or after composting with other urban organic wastes. This study investigates the scientific basis for direct application of spent coffee grounds (SCG) and the influence of different: (i) plant pH and nitrogen preferences, (ii) soil types, and (iii) application rates. We specifically consider impacts upon plant growth, soil hydrology and nitrogen transformation processes.We grew five horticultural plants (broccoli, leek, radish, viola and sunflower) in sandy, sandy clay loam and loam soils, with and without SCG and fertilizer amendments. The same horticultural plants were grown in the field with 0, 2.5, 5, 10 and 25% SCG amendment rates. Plant biomass growth was related to soil pH, soil moisture, nitrogen concentration and net mineralization, as was weed growth after harvesting.All horticultural plants grew poorly in response to SCG, regardless of soil type and fertiliser addition. Increasing SCG amendment significantly increased soil water holding capacity, but also decreased horticultural plant growth and subsequent weed growth. There was evidence of nitrate immobilization with SCG amendment. Growth suppression was not explained by soil pH change, or nitrogen availability, so is more likely due to phytotoxic effects.Fresh SCG should not be used as a soil amendment in ‘closed loop’ urban food production systems without consideration of potential growth suppression. Further research is required to determine the optimal composting conditions for SCG and blends with other organic wastes.     

A comparative study of young ‘Thompson Seedless’ grapevines (Vitis vinifera L.) under drip and furrow irrigation. II. Growth, water use efficiency and nitrogen partitioning

The response of 3-year-old grapevines (Vitis vinifera L. cultivar ‘Thompson Seedless’) to furrow and drip irrigation was quantified in terms of water status, growth, and water use efficiency (WUE). Drip irrigation was applied daily according to best estimates of vineyard evapotranspiration while furrow irrigations were applied when 50% of the plant available soilwater content had been depleted. Drip and furrow irrigated vines showed similar water status (midday leaf water potential, Ψ₁) and shoot growth patterns throughout the season. Dry weight partitioning was not significantly different between treatments but root mass was somewhat larger for the furrow than drip irrigated vines. Nitrogen concentrations of the fruit and roots were significantly (P < 0.05) less for the drip irrigated vines when compared with the furrow treatment. Similar WUE (kg water kg⁻¹ fresh fruit wt.) were obtained for both treatments indicating that furrow irrigation was as efficient as drip irrigation under the conditions of this study. The data indicate that drip irrigation may increase the potential for control of vine growth by making vines more dependent on irrigation and N fertilization than furrow irrigation.     

Effect of saline irrigation water on agronomical and phytochemical characters of chamomile (Matricaria recutita L.)

In arid and semi-arid regions, where water availability is a major limitation in crop production, using alternative water resources, such as saline water is one way to utilize lands. Chamomile (Matricaria recutita L.) as an annual medicinal herb may be considered as an economic substitute for field crops irrigated with fresh water since it has adaptability to wide range of climate and soil. A field examination was conducted during 2004–2005 using complete randomized block design with four replications in order to evaluate the effects of saline irrigation water on morphological characters, mineral content, oil quantity (content, yield), oil composition and apigenin content of chamomile. In each plot, 0.6 g/m² of seeds were grown in 4 rows. The irrigation water had five different salinity levels (0, 4, 8, 12 and 16 dS m⁻¹). The investigated characters through cultivation were fresh weight of flower (g), dry weight of flower (g), dry weight of aerial stems (g), dry weight of root (g), oil yield (kg/h), oil content (%), oil quality and apigenin content (%). After harvesting, the content of minerals (Na⁺, Cl⁻, K⁺, Ca²⁺, Mg²⁺) were evaluated in aerial parts and roots of each plot. Mean comparisons for fresh flower weight in different treatments showed that fresh flower yield decreased with increasing salinity and it was higher in control compared to others. Analysis of variance showed that saline irrigation water had no significant effect on oil quantity (yield and content), oil quality (chemical composition) or apigenin content. Our results showed that chamomile is able to maintain all its medical properties, under saline condition and could be cultivated economically in such conditions.     

Application of secondary-treated effluents for cultivation of sunflower (Helianthus annuus L.) and celosia (Celosia argentea L.) as cut flowers

In this study we have examined the effects of irrigation with municipal secondary-treated effluents on growth of sunflower (Helianthus annuus L.) and celosia (Celosia argentea var cristata L.) plants for cut flower production. The applied treated effluents contained higher levels of Na (∼X6), Cl (∼X4.5), N–NH₄ (30–50 mg/l), B, HCO₃, P, K, and Fe than the potable water. The effect of the two types of irrigation water on the chemical composition of soil and leaves, flower yield and postharvest performance was examined. Our results demonstrate higher accumulation of Cl, Na, B, and NO₃ in soils irrigated with effluents as compared to potable water only in the 40–60 cm soil layer. Phosphorus accumulated to higher levels in the upper soil layer (0–20 below ground), as well as in the lower soil layer, irrigated with effluents. SAR levels as well, were higher under irrigation with the treated effluents in the soil until 40 cm below ground indicating higher Na absorption in comparison to Ca and Mg. In both sunflower and celosia, boron accumulated to higher levels in leaves of plants irrigated with effluents. In addition, under irrigation with effluents, celosia accumulated higher levels of N and Mn and sunflower higher levels of P and lower levels of Fe. Despite these differences in mineral contents, the quality of the irrigation water did not affect cut flower yield. In both species spike length, receptacle size, number of flowers and flower weight were not affected. However, flowers’ quality, examined during vase life, was compromised by irrigation with the effluents. Celosia leaves appeared more yellow and sunflower petal edges became browner. Nevertheless, leaf yellowing in celosia occurred mainly on the lower leaves of the stem, which can be removed to maintain high commercial value. The reduction in sunflower quality as well, will most likely not pose any commercial problem since these negative symptoms appeared at a late stage of vase life. Overall, our results demonstrate that secondary-treated municipal effluents can be used for production of sunflower and celosia for cut flowers, in the northern-eastern part of the ‘Negev’ desert in Israel. Due to the high SAR values of the water, and in order to avoid damage to the soil structure, dilution of this water should be considered for commercial growth.     

Rose flower production as related to plant architecture and carbohydrate content: Effect of harvesting method and plant type

Summary

The dependence between flowering cycles and woody stem parts of a rose crop was studied, with respect to plant architecture and carbohydrate content. Two harvesting methods (“control” versus “flush”) and two plant types (“control” versus “one stemmed”) were compared. Crop growth and partitioning of dry matter were studied as influenced by crop management during 18 months of culture. For a full-productive year, flush harvesting generally promoted bud break as compared with continuous harvesting but at the same time, also due to lower light interception, blind-shoot formation was enhanced and the individual flower weight reduced. Numbers of basal shoots were hardly related to flower production over a full cropping year. Flower production was much more sensitive to the number and diameter of branches at the height of cutting the flowers. The treatments did not affect carbohydrate allocation in the plant. Total carbohydrate storage was much too low to argue a clear role for the possible use of movement of carbohydrate reserves towards new growth. Maximum starch concentration was found at the beginning of summer and gradually dropped to a minimum in December and then increased again to a spring maximum. A cold treatment did increase the total non-structural carbohydrate (TNC) concentration but no positive influence on new basal-shoot formation was observed. No starch gradient was found in basal stem parts.     

Potassium Mineral Nutrition Combined with Sustained Deficit Irrigation to Improve Yield and Quality of a Late Season Peach Cultivar (Prunus persica L. cv ‘Chatos’)

ABSTRACT

Fruit quality traits are directly related to agronomic practices such as irrigation and fertilization, especially potassium supply since its effects on quality and water drought resistance. The objective of this study was to evaluate the effect of different combinations of potassium rate and application mode (in soil: 200S and 100S, foliar spray: 100F) with two irrigation regimes (FI: irrigation with 100%ETc and DI: irrigation with 66%ETc) on peach yield and quality parameters. The experiment was performed during two consecutive years. At harvest, only in the second year significant differences between treatments were observed in yield. In fact, potassium foliar spray, even in DI regime, improved yield. The fruit diameter was slightly affected by treatments in the first year. However, in the following season foliar potassium spray even in DI water regime increased fruit size. Concerning the firmness, no significant differences were observed in the first year except for the second year it decreased with DI strategy independently of potassium treatment. The soluble solids content was strongly affected by the treatments. The highest values were observed in 100F+DI treatment with no significant effect on acidity. Vegetative growth was affected only by water regime which DI reduced shoot length.     

The Effect of Wet or Dry Soil Conditions at Different Growth Stages on the Components of Yield of a Pea Crop

An experiment is described in which the effect of irrigation, at four different growth stages, on the growth and yield of peas, variety Dark-Skinned Perfection, was determined. The sandy loam soil was brought to field capacity immediately after sowing the seed and subsequently ten different combinations of wet or dry soil conditions were imposed on the plants. No increase in yield of peas resulted from irrigating before flowering but irrigating at the start of flowering increased the yield per plant by increasing the number of marketable pods and the number of peas per pod. Irrigating at petal-fall had no effect on yield but yields were appreciably increased by irrigating when the pods were swelling. This increase followed from an increase in the number of pods per plant and in the mean weight per pea. A combination of irrigation at the start of flowering and at pod-swelling gave the highest yield per plant.     

Capability of the ‘Ball-Berry’ model for predicting stomatal conductance and water use efficiency of potato leaves under different irrigation regimes

The capability of the ‘Ball-Berry’ model (BB-model) in predicting stomatal conductance (g_s) and water use efficiency (WUE) of potato (Solanum tuberosum L.) leaves under different irrigation regimes was tested using data from two independent pot experiments in 2004 and 2007. Data obtained from 2004 was used for model parameterization, where measurements of midday leaf gas exchange of potted potatoes were done during progressive soil drying for 2 weeks at tuber initiation and earlier bulking stages. The measured photosynthetic rate (A_n) was used as an input for the model. To account for the effects of soil water deficits on g_s, a simple equation modifying the slope (m) based on the mean soil water potential (Ψ_s) in the soil columns was incorporated into the original BB-model. Compared with the original BB-model, the modified BB-model showed better predictability for both g_s and WUE of potato leaves on the parameterization data set. The models were then tested using the data from 2007 where plants were subjected to four irrigation regimes: non-irrigation (NI), full irrigation (FI), partial root-zone drying (PRD), and deficit irrigation (DI) for 3 weeks during tuber initiation and earlier bulking stages. The simulation results showed that the modified BB-model better simulated g_s for the NI and DI treatments than the original BB-model, whilst the two models performed equally well for predicting g_s of the FI and PRD treatments. Although both models had poor predictability for WUE (0.47 < r² < 0.71) of potato leaves, the modified BB-model was able to distinguish the effects of the irrigation regimes on WUE being that the WUE was generally greater for PRD than for FI and DI plants. Conclusively, the modified BB-model is capable of predicting g_s and of accounting for the differential effects of irrigation regimes on WUE of potato leaves. This information is valuable for further simulating potato water use thereby optimizing WUE under field conditions.     

Substrate temperature fluctuation and dry-weight partitioning of Lantana grown in four green roof growing media

Summary

Four potential green roof substrates were evaluated in a field study for their thermal characteristics and their impact on Lantana camara dry-weight accumulation. The substrates were a) a sandy loam soil (S), b) the sandy loam soil amended with urea formaldehyde resin foam (S:F) at a proportion of 60:40 v/v, c) the sandy loam soil mixed with peat and perlite (S:P:Per) at a proportion of 50:30:20 v/v, respectively and, d) peat amended with urea-formaldehyde resin foam (P:F) at a proportion of 60:40 v/v. Measurements included the monitoring of the substrate temperature and the determination of the dry-weight accumulation rhythm of shoots, leaves and roots. In addition, the lateral spreading of the roots was recorded and the shoot/root ratio determined. Temperature fluctuation within the substrates was found to depend on the type of the substrate, plant growth, and season. Temperature fluctuation was high in S, moderate in S:F and S:P:Per and low in P:F. Shoot and root dry-weight accumulation was reduced in P:F, while root growth was promoted in S substrate. Differences in dry-weight accumulation and the lateral spreading of the roots were affected more by the water holding capacity of the substrate than by the substrate temperature.     

Drying half of the root-zone from mid fruit growth to maturity in ‘Hass’ avocado (Persea americana Mill.) trees for one season reduced fruit production in two years

We tested the effect of extended drying of half the root system on fruit yield and fruit Ca concentration, an indirect measure of fruit quality, in avocado (Persea americana Mill. cv Hass). In a field experiment on a sandy soil, withholding irrigation and plastic sheeting was used to dry the root-zone beneath the whole canopy (DD) or half the canopy (WD), compared with well-watered trees (WW). The irrigation water contained added nutrients and was slightly saline. Yield, shoot growth, leaf conductance, leaf and fruit water status and mineral concentrations of leaves and fruit were studied. The responses of treated trees were assessed in the following season during which normal irrigation practices were restored. With respect to yield, the WD treatment behaved the same as the DD treatment. It reduced yield by more than half and proportionately more than the reduction in water supply thus reducing irrigation efficiency. Re-watering did not restore yield of WD or DD-trees in the next season. The WD and DD treatments had no effect on the concentration of Ca in the fruit mesocarp and so are unlikely to affect fruit quality. The main impact of reduced water supply on the trees was fruit abscission and this was linked to dry soil around the roots rather than the water status of the leaves or fruits. We conclude that extended drying of half of the root-zone in one season reduced irrigation efficiency for two seasons by promoting the abscission of developing fruit to the same extent as occurred when the whole root system was exposed to extended drying.