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1.
The effects of partial root-zone drying (PRD) as compared with deficit irrigation (DI) and full irrigation (FI) on nitrogen (N) uptake and partitioning in potato (Solanum tuberosum L.) were investigated. Potato plants were grown in split-root pots and were exposed to FI, PRD, and DI treatments at tuber bulking stage. Just before onset of the irrigation treatment, each plant received 0.6 g N (in the form of urea) with 5% of which was 15N-labeled. After 4 weeks of irrigation treatments (i.e., one drying/wetting cycles completed in the PRD treatment), the plants were harvested and plant dry mass and N content were determined. The results showed that although the plant dry mass was not affected by the irrigation treatments, due to a reduced water use by the plant, both the PRD and DI treatments significantly increased crop water use efficiency. Compared with the FI and DI plants, PRD plants had significantly higher N contents in the leaves, stems and tubers; whereas, the 15N content in the plant organs was similar for the FI, PRD, and DI plants. It is suggested that not the root N uptake efficiency but the soil N availability was enhanced by the PRD treatment.  相似文献   

2.
The aim of this study was to quantify and compare the effects of two different deficit irrigation (DI) strategies (regulated deficit irrigation, or RDI, and partial rootzone drying, PRD) on almond (Prunus dulcis (Mill.) D.A. Webb) fruit growth and quality. Five irrigation treatments, ranging from moderate to severe water restriction, were applied: (i) full irrigation (FI), irrigated to satisfy the maximum crop water requirements (ETc); (ii) regulated deficit irrigation (RDI), receiving 50% of ETc during the kernel-filling stage and at 100% ETc throughout the remaining periods; and three PRD treatments – PRD70, PRD50 and PRD30 – irrigated at 70%, 50% and 30% ETc, respectively, during the whole growth season. The DI treatments did not affect the overall fruit growth pattern compared to the FI treatment, but they had a negative impact on the final kernel dry weight for the most stressed treatments. The allocation of water to the different components of the fruit, characterized by the fresh weight ratio of kernel to fruit, appeared to be the process most clearly affected by DI. Attributes of the kernel chemical composition (lipid, protein, sugar and organic acid contents) were not negatively affected by the intensity of water deprivation. Overall, our results indicated that PRD did not present a clear advantage (or disadvantage) over RDI with regard to almond fruit growth and quality.  相似文献   

3.
Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:
•
Potatoes
°
After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.
•
Fresh tomatoes
°
From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.
•
Processing tomatoes
°
From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψsoil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψsoil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψsoil, dry side = −270 kPa).
The findings during the SAFIR project might be used as a framework for implementing water-saving deficit irrigation under different local soil and climatic conditions.  相似文献   

4.
Yield and water productivity of potatoes grown in 4.32 m2 lysimeters were measured in coarse sand, loamy sand, and sandy loam and imposed to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments received 65% of FI after tuber bulking and lasted for 6 weeks until final harvest. Analysis across the soil textures showed that fresh yields were not significant between the irrigation treatments. However, the same analysis across the irrigation treatments revealed that the effect of soil texture was significant on the fresh yield and loamy sand produced significantly higher fresh yield than the other two soils, probably because of higher leaf area index, higher photosynthesis rates, and “stay-green” effect late in the growing season. More analysis showed that there was a significant interaction between the irrigation treatments and soil textures that the highest fresh yield was obtained under FI in loamy sand. Furthermore, analysis across the soil textures showed that water productivities, WP (kg ha−1 fresh tuber yield mm−1 ET) were not significantly different between the irrigation treatments. However, across the irrigation treatments, the soil textures were significantly different. This showed that the interaction between irrigation treatments and soil textures was significant that the highest significant WP was obtained under DI in sandy loam. While PRD and DI treatments increased WP by, respectively, 11 and 5% in coarse sand and 28 and 36% in sandy loam relative to FI, they decreased WP in loamy sand by 15 and 13%. The reduced WP in loamy sand was due to nearly 28% fresh tuber yield loss in PRD and DI relative to FI even though ET was reduced by 9 and 11% in these irrigation treatments. This study showed that different soils will affect water-saving irrigation strategies that are worth knowing for suitable agricultural water management. So, under non-limited water resources conditions, loamy sand produces the highest yield under full irrigation but water-saving irrigations (PRD and DI) are not recommended due to considerable loss (28%) in yield. However, under restricted water resources, it is recommended to apply water-saving irrigations in sandy loam and coarse sand to achieve the highest water productivity.  相似文献   

5.
Carbon (C) sequestration through irrigation management is a potential strategy to reduce C emissions from agriculture. Two experiments (Exps. I and II) were conducted to investigate the effects of different irrigation strategies on C retention in the soil-plant system in order to evaluate their environmental impacts. Tomato plants (Lycopersicon esculentum L., var. Cedrico) were grown in split-root pots in a climate-controlled glasshouse and were subjected to full irrigation (FI), deficit irrigation (DI) and alternate partial root-zone irrigation (PRI) at early fruiting stage. In Exp. I, each plant received 2.0 g chemical nitrogen (N), while in Exp. II, 1.6 g chemical N and maize residue containing 0.4 g organic N were applied into the pot. The results showed that, in both experiments, the concentration and the amount of total C in the soil were lower in FI and PRI as compared to DI, presumably due to a greater microbial activity in the two treatments; particularly the PRI induced drying and wetting cycles of the soils may cause an increase of microbial activities and respiration rate, which could lead to more C losses from the soil. However, in both experiments the total C concentration in the PRI plants was the highest as compared with the FI and DI plants, and this was seemingly due to improved plant N nutrition under the PRI treatment. Consequently, the total amount of C retained in the soil-plant system was highest in the FI and was similar, but lower, for the PRI and DI. The different N input in the two experiments might have affected the C retention in the soil and in the plant biomass. Nevertheless, with a same degree of water saving, PRI was superior to DI in terms of enhancing C concentration in the plant biomass, which might have contributed to a better fruit quality in tomatoes as reported by [Zegbe et al., 2004] and [Zegbe et al., 2006].  相似文献   

6.
Partial rootzone drying (PRD) is a water-saving irrigation practice which involves watering only part of the rhizosphere at each irrigation with the complement left to dry to a pre-determined level. The effect of PRD, applied at different phenological stages, on yield, fruit growth, and quality of the processing tomato cv. ‘Petopride’ was studied in this experiment. The treatments were: daily full irrigation (FI) on both sides of the root system considered as the control, and PRD treatments applied at three phenological stages. These were: during the vegetative stage until the first truss was observed (PRDVS–FT), from the first truss to fruit set (PRDFT–FS), and from fruit set to harvest (PRDFS–H). In some occasions, leaf xylem water potential was lower in each PRD period than in FI. Number of fruits, total fresh and dry weight of fruit per plant, harvest index, and fruit growth were lower in PRDFT–FS and PRDFS–H plants than in FI and PRDVS–FT plants. However, irrigation water use efficiency, on a dry weight basis, was the same among the treatments. For PRDFT–FS and PRDFS–H treatments, mean fresh weight of fruit and fruit water content were reduced and dry matter concentration of cortex and total soluble solids concentration of fruit increased compared with FI and PRDVS–FT treatments. Incidence of blossom-end rot was the same among PRDVS–FT, PRDFS–FH, and FI fruit, but it was higher in PRDFT–FS fruit. Fruit skin colour was the same among treatments. Total dry weight of fruit per plant decreased by 23% for PRDFT–FS and by 20% for PRDFS–H relative to FI. Fruit quality improvement in PRDFS–H could compensate for the reduction in total dry weight of fruit where water is expensive for tomato production. But an economical analysis would be needed to substantiate this. PRD from the first truss to fruit set is not recommended because of the high incidence of blossom-end rot. An erratum to this article can be found at  相似文献   

7.
Greenhouse grown tomato was used to test partial root drying (PRD), a newly developing irrigation technique to save irrigation water, in Spring- and Fall-planted fresh-market tomato (Lycopersicon esculentum L., cv. Fantastic) cultivar. The PRD practice simply requires wetting of one half of the rooting zone and leaving the other half dry, thereby utilizing reduced amount of irrigation water applied. The wetted and dry sides are interchanged in the subsequent irrigations. Six irrigation treatments were tested during the two-year work in 2000 and 2001: (1) FULL, control treatment where the full amount of irrigation water, which was measured using Class-A pan evaporation data, was applied to the roots on all sides of the plant; (2) 1PRD30, 30% deficit irrigation with PRD in which wetted and dry sides of the root zone were interchanged with every irrigation; (3) 1PRD50; (4) 2PRD50, 50% deficit irrigation with PRD in which wetted and dry sides of the root zone were interchanged every and every other irrigation, respectively; (5) DI30 and (6) DI50, 30 and 50% deficit irrigations, respectively. The defined deficit levels were all in comparison to FULL irrigation. During the first year study in 2000, only three treatments (FULL, 1PRD30 and 2PRD50) were tested. Five treatments with exception of 2PRD50 were included in 2001. The FULL irrigation treatment, in Spring-planted tomato having a 153 day growth period, yielded 110.9 t ha−1. The resulting irrigation-water-use efficiency (IWUE) was 321.8 kg (ha mm)−1. The 1PRD50 treatment gave 86.6 t ha−1, which was not statistically different (P ≤ 0.05) from the FULL irrigation (the control) and had 56% higher IWUE. Although yield differences were not statistically significant in Fall-planted tomato, the highest fruit yield was again obtained under FULL irrigation treatment (205.2 t ha−1) over a growth period of 259 days after transplanting. The PRD treatments had 7–10% additional yield over the deficit irrigation receiving the same amount of water. The PRD treatments gave 10–27% higher marketable tomato yield (>60 g per fruit), compared with the DI treatments. Abscisic acid (ABA) concentrations measured in fresh leaf tissue was the highest under PRD practice relative to FULL and DI treatments. The high ABA content of fresh-leaf tissue observed in the work supports the root signalling mechanism reported earlier in plants having undergone partial root drying cycles.  相似文献   

8.
The effects of deficit irrigation (DI) and partial rootzone drying (PRD) on apple (Malus domestica Borkh. Cv. ‘Fuji’) yield, fruit size, and quality were evaluated from 2001 to 2003 in the semi-arid climate of Washington State. PRD and DI were applied from about 40 days after full bloom until just before (2001, 2002) or after (2003) harvest and compared to a control irrigation (CI). Irrigation was applied once a week using two micro-sprinklers per tree. Soil-water content in CI was maintained above 80% of field capacity using micro-sprinklers on both sides of a tree. The DI and PRD were irrigated at about 50% (2001–2002) and 60% (2003) of the CI, but differed in placement of irrigation. For DI both micro-sprinklers were operated whereas PRD was irrigated using only one micro-sprinkler wetting half the rootzone compared to CI and DI. Wetting/drying sides of PRD trees were alternated every 2–4 weeks (2001, 2002) or when soil-water content on the drying side had reached a threshold value (2003). Seasonal (1 May–31 October) potential evapotranspiration (ET0) was 967, 1002, and 1005 mm for 2001, 2002, and 2003, and rainfall totaled 58, 39, and 21 mm, respectively. Irrigation amounts applied were 596, 839, and 685 mm in the CI; 374, 763, and 575 mm in the DI; and 337, 684, and 513 mm in the PRD for the 2001, 2002, and 2003 seasons. Higher irrigation volumes in 2002 were due to excessive (177–324 mm) irrigations after harvest. No significant differences were found in yield and fruit size among treatments in 2001 and 2003. In 2002, DI had significantly lower yield than CI, while the yield of PRD did not differ from CI and DI. Fruit from DI and PRD were firmer and had higher concentrations of soluble solids than fruit from CI, both at harvest and following short-term storage at 20°C, but differences to CI were significant in 2002 only. Treatment effects on fruit titratable acidity were inconsistent. Additional water was preserved in the soil profile under PRD compared to DI in 2001 and 2003, but no statistical differences were found between PRD and DI in 2002. Approximately 45–50% of irrigation water was saved by implementing newly developed DI and PRD irrigation strategies without any significant impact on fruit yield and size with PRD. However, apple yield was reduced by DI compared to CI in the second year.  相似文献   

9.
World water supplies are limited and water-saving irrigation practices, such as partial rootzone drying (PRD), should be explored. We studied the effects of PRD, applied through furrow and drip irrigation, on plant water relations, yield, and the fruit quality of processing tomato (Lycopersicon esculentum Mill. cv. ‘Petopride’). There were four treatments. The first two were: full irrigation by hand on both sides of the root system which mimicked furrow irrigation (FuI), and half of irrigation water in FuI given alternately only to one side of the root system with each irrigation (PRDFuI). The next two treatments were: full drip irrigation (DrI) to both sides of the root system, and half of irrigation water in DrI given alternately only to one side of the root system with each irrigation (PRDDrI). Leaf water potential was the same among the treatments except for the PRDFuI plants, which had the lowest midday values only in one sampling out of four. Photosynthetic rate was the same among the treatments except for the drip-irrigated plants having the lowest value in one sampling out of four. Number of fruit, mean fruit mass of fruit, total fresh and dry mass of fruit, and harvest index were the same among treatments, but PRD plants had increased irrigation use efficiency compared to fully irrigated plants. There was no incidence of blossom-end rot in any of the treatments. PRDDrI fruit had redder colour and higher total soluble solids concentration. Advancement in fruit maturity and enhancement of quality could be achieved without detrimental effect on fresh and dry mass of fruit by application of PRD. Independent of the irrigation method, PRD treatments improved irrigation use efficiency by ca. 70%. PRD has the potential for use in processing tomato especially in environments with limited water.  相似文献   

10.
Gas exchange was measured in potatoes (cv. Folva) grown in lysimeters (4.32 m2) in coarse sand, loamy sand, and sandy loam and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments received 65% of FI and started after tuber bulking and lasted for six weeks until final harvest. Midday photosynthesis rate (An) and stomatal conductance (gs) of fully irrigated (FI) plants were lowest in coarse sand and mean An of diurnal measurements in FI, PRD and DI tended to be lower in this soil as compared with the loamy sand and sandy loam. The results revealed that diurnal values of An and gs in PRD and DI were consistently lower than FI without reaching significant differences in accordance with findings that xylem [ABA] in PRD was significantly higher than FI, and tended to be higher than in DI. Diurnal measurements showed that An reached peak values during mid-morning and midday, while gs were highest during the morning. Intrinsic water use efficiency (An/gs) correlated linearly well with the leaf to air vapor pressure deficit (VPD) and the slope of the line revealed the rate of An/gs increase per each kPa increase in VPD, i.e. approximately 10 μmol mol−1. Transpiration efficiency (An/T) of PRD was higher than DI, which shows slightly better efficient water use than DI. The slope of the linear relationship between transpiration efficiency and VPD decreased from −2.03 to −1.04 during the time course of the growing season, indicating the negative effect of leaf ageing on photosynthesis and thus on plant water use efficiency. This fact shows the possibility to save water during last growth stages through applying water-saving irrigations without much effect on transpiration efficiency.  相似文献   

11.
A four-year study was conducted on young Olea europaea L. trees to investigate the effect of deficit irrigation starting from the onset of fruit production. Subsurface drip irrigation was used to supply 100% (FI), 46–52% (DI), or 2–6% (SI) of tree water needs. Tree growth was reduced by deficit irrigation, whereas, return bloom was not. Per tree fruit yield of DI trees was 68% that of FI, but fruit yield efficiency based on tree size was similar between treatments. Fruit set and the number of fruits of FI trees were similar to those of DI trees and significantly higher than in SI trees. No significant differences in fruit fresh weight were found between FI and DI. The oil yield and oil yield efficiency of the DI treatment were 82 and 110% that of FI trees, respectively. A level of about 50% deficit proved sustainable to irrigate trees for oil production.  相似文献   

12.
不同灌水方式下春玉米的根系生长分布   总被引：2，自引：0，他引：2  
为了研究不同灌水方式对春玉米根系分布的影响,在大田条件下对玉米进行垄植沟灌,设计常规沟灌（CI）、交替隔沟灌溉（AI）和固定隔沟灌溉（FI）3种灌水方式.结果表明,（0,40]cm土层中,根长密度以AI较大,FI较小;（60,100]cm土层中,CI下根长密度较小;FI下的植株两侧根长密度差异明显,CI和AI与之相反.（0,100]cm土层中,监测时期内,AI下的玉米总根长和总根干质量都较大.相较FI,AI下的籽粒产量、生物产量和灌溉水利用率分别提高17.37%,18.42%和17.45%.CI表现介于AI与FI之间.抽雄期、植株两侧和（0,40]cm土层根系生长分布受土壤含水率影响较大.可见,局部灌溉对深层根系生长有利,抽雄期植株两侧（0,40]cm土层根系生长分布受灌水方式影响最大;CI与AI下的根系分布相对均匀;与FI和CI相比,AI方式既能促进根系生长,也有利于产量和灌溉水利用率的提高.  相似文献   

13.
不同灌溉处理对玉米生长及水分利用效率的影响   总被引：5，自引：1，他引：4  
通过温室试验,研究了不同灌溉处理对玉米的生长状况,生理特性及产量和水分利用率的影响。结果表明,充分灌溉处理(FI)的植株株高、茎粗与叶面积长势优于其它处理,而地上部分及根系的干物质累积量低于其它处理。相同的灌溉量条件下,分根交替灌溉处理(PRD)的植株产生的脯氨酸含量高于调亏灌溉处理(DI),说明PRD处理能够使植株提高渗透调节能力。在产量构成中,FI处理的植株产量最高,PRD 75%(灌水量为充分灌溉的75%)处理的植株产量略低于FI处理,二者差异不显著,其次为D I75%处理(灌水量为充分灌溉的75%)。尽管FI处理的植株绝对产量最高,但是以牺牲水分利用率为代价的,而其它处理尽管绝对产量较FI处理略低,但由于其耗水量也低,水分利用率反而高于FI处理。特别是PRD 75%处理的植株绝对产量和水分利用率都有较好的表现。  相似文献   

14.
The reduction in agricultural water use in areas of scarce supplies can release significant amounts of water for other uses. As improvements in irrigation systems and management have been widely adopted by fruit tree growers already, there is a need to explore the potential for reducing irrigation requirements via deficit irrigation (DI). It is also important to quantify to what extent the reduction in applied water through DI is translated into net water savings via tree evapotranspiration (ET) reduction. An experiment was conducted in a commercial pistachio orchard in Madera, CA, where a regulated deficit irrigation (RDI) program was applied to a 32.3-ha block, while another block of the same size was fully irrigated (FI). Four trees were instrumented with six neutron probe access tubes each, in the two treatments and the soil water balance method was used to determine tree ET. Seasonal irrigation water in FI, applied through a full-coverage microsprinkler system, amounted to 842 mm, while only 669 mm were applied in RDI. Seasonal ET in FI was 1024 mm, of which 308 mm were computed as evaporation from soil (Es). In RDI, seasonal ET was reduced to 784 mm with 288 mm as Es. The reduction in applied water during the deficit period amounted to 147 mm. The ET of RDI during the deficit period was also reduced relative to that of FI by 133 mm, which represented 33% of the ET of FI during the deficit irrigation period. There was an additional ET reduction in RDI of about 100 mm that occurred in the post-deficit period.  相似文献   

15.
This study assesses the long-term suitability of regulated (RDI) and sustained deficit irrigation (SDI) implemented over the first six growing seasons of an almond [Prunus dulcis (Mill.) D.A. Webb] orchard grown in a semiarid area in SE Spain. Four irrigation treatments were assessed: (i) full irrigation (FI), irrigated to satisfy maximum crop evapotranspiration (100% ETc); (ii) RDI, as FI but receiving 40% ETc during kernel-filling; (iii) mild-to-moderate SDI (SDImm), irrigated at 75–60% ETc over the entire growing season; and (iv) moderate-to-severe SDI (SDIms), irrigated at 60–30% ETc over the whole season. Application of water stress from orchard establishment did not amplify the negative effects of deficit irrigation on almond yield. Irrigation water productivity (IWP) increased proportionally to the mean relative water shortage. SDIms increased IWP by 92.5%, reduced yield by 29% and applied 63% less irrigation water. RDI and SDImm showed similar productive performances, but RDI was more efficient than SDImm to increase fruiting density and production efficiency (PE). We conclude that SDIms appears to be a promising DI option for arid regions with severe water scarcity, whereas for less water-scarce areas RDI and SDImm behaved similarly, except for the ability of RDI to more severely restrict vegetative development while increasing PE.  相似文献   

16.
Root distribution of field grown potatoes (cv. Folva) was studied in 4.32 m2 lysimeters and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. Drip irrigation was applied for all irrigations. Irrigations were run in three different soils: coarse sand, loamy sand, and sandy loam. Irrigation treatments started after tuber bulking and lasted until final harvest with PRD and DI receiving 65% of FI. Potatoes irrigated with water-saving irrigation techniques (PRD and DI) did not show statistically different dry root mass and root length density (RLD, cm root per cm3 soil) compared with root development in fully irrigated (FI) potatoes. Highest RLD existed in the top 30-40 cm of the ridge below which it decreased sharply. The RLD was distributed homogenously along the ridge and furrow but heterogeneously across the ridge and furrow with highest root density in the furrow. Most roots accumulated in the surface layers of coarse sand as compared to the other soil types. In the deep soil profile (30-70 cm) a higher root density was found in loamy sand compared with the sandy loam and coarse sand. Approximately twice the amounts of roots were found below the furrows compared with the corresponding layers below the ridges. The RLD values in the soil profile of the ridges and the furrows followed the Gerwitz and Page model: RLD = α × exp(−β × z). The highest value of surface root density (α) and rate of change in density (β) was found in coarse sand while the lowest values of α and β were found in the sandy loam and loamy sand. The model estimated the effective rooting depth in coarse sand and sandy loam quite well but did slightly overestimate it in the loamy sand. Statistical analysis showed that one α and β value can be used for each soil irrespective of the irrigation treatment. Thus, the effective rooting depths corresponding to root length densities of 0.1 and 0.25 cm cm−3 for sandy loam, loamy sand, and coarse sand soils were 99, 141, and 94 cm, and 80, 115, and 78 cm, respectively, calculated from top of the ridge. The findings of this study can be used in practice for efficient use of water and nutrients in the field.  相似文献   

17.
为了揭示棉花生长发育对咸水灌溉的响应特征,采用小区对比试验,研究了不同矿化度咸水灌溉对棉花出苗、株高、叶面积、果枝数、地上部干质量等形态指标以及产量构成、耗水量和水分利用率的影响.结果表明,棉花出苗率和成苗率随着灌溉水矿化度的增大而减小,但3 g/L灌水处理与对照间的差异不具有统计学意义,而5,7 g/L处理与对照间差异极具统计学意义.在移栽补全苗情况下,咸水灌溉对棉花形态生长指标产生了一定的抑制效应,灌溉水矿化度愈大,抑制作用愈大;对株高、叶面积和地上部干质量的影响在蕾期最明显,花铃期之后开始逐渐减弱;对果枝数和棉铃生长的影响程度随着棉花生育进程的推进而降低.处理间棉花的耗水量差异不具有统计学意义,籽棉产量和水分利用率的大小顺序,按灌水处理依次为3,1,5,7 g/L,其中7 g/L处理与对照间的差异具有统计学意义.与灌水前初始值相比,试验结束后1,3 g/L灌水处理的0~40 cm土层盐分未增加,5,7 g/L灌水处理则形成了积盐.研究结果可为咸水安全利用提供重要参考.  相似文献   

18.
灌水方式与施钙水平对盆栽番茄产量和品质的影响   总被引：1，自引：0，他引：1  
分别在喷施氯化钙溶液质量分数为0%、0.3%、0.5%、0.8%、1.0%条件下进行3种不同灌水方式即常规全根灌溉(CI)、分根区固定灌溉(PRD)和分根区交替灌溉(APRI)的盆栽试验,测定番茄产量和品质.结果表明,分根区交替灌溉(APRI)番茄植株长势、果实产量和品质均显著优于分根区固定灌溉(PRD)和常规全根灌溉...  相似文献   

19.
The objective of this study was to investigate the comparative effects of alternative partial root-zone irrigation (PRI) and deficit irrigation (DI) on fertilizer-N use efficiency in tomato plants under mineral N and organic N fertilizations. The plants were grown in split-root pots in a climate-controlled glasshouse and were subjected to PRI and DI treatments during early fruiting stage. When analyzed across the N fertilizer treatments, PRI treatment led to significantly higher N yield, agronomic N use efficiency (ANUE), and apparent N recovery efficiency (ANRE) as compared with the DI treatment, indicating significantly higher fertilizer-N use efficiency and soil N availability as well as enhanced plant’s N acquisition ability in the PRI treatment. Analysis across the irrigation treatments showed that the mineral N fertilizer treatment (MinN) significantly increased N yield, ANUE and ANRE relative to the organic N fertilizer treatment (OrgN). Compared with DI, the rhizosphere and bulk soil mineral N content in the soil were significantly lowered in the PRI treatment, indicating the enhanced root N uptake efficiency. It is suggested that PRI-enhanced soil water dynamics may have increased soil nitrate mass/diffusive flow to the root surfaces and root N uptake efficiency in the wetting soil and stimulated soil N mineralization and plant N demand, contributing to the improved fertilizer-N use efficiency in the PRI relative to the DI treatment.  相似文献   

20.
不同灌水水平对温室番茄地土壤CO_2排放影响   总被引：1，自引：0，他引：1  
为分析不同灌水水平对温室番茄地土壤CO_2排放的影响,采用静态箱气相色谱法对2014年秋冬季和2015年春夏季番茄地土壤CO_2排放进行原位观测。试验设置2个灌水水平分别为:充分灌溉(FI)和亏缺灌溉(DI)。结果表明:番茄两个生长季中,不同灌水处理下土壤CO_2排放通量均呈波动性变化。2015年春夏季试验各处理土壤CO_2平均排放通量和排放量高于2014年秋冬季试验对应的各处理土壤CO_2平均排放通量和排放量,且两个生育期内高灌水处理的土壤CO_2排放在番茄生育期绝大多数时间内均高于低灌水处理。以2015年FI处理土壤CO_2累积排放量最大(5 641.57kg/hm~2),分别较2014年FI处理、2014年DI处理和2015年DI处理增加了3.9%、54.2%和16.7%。此外,研究还发现春夏茬试验中不同灌水处理下,土壤CO_2排放通量与土壤水分呈显著负相关关系。这为评估设施菜地温室气体减排提供一定的科学依据。  相似文献   

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