首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 109 毫秒
1.
为了探索锡林河流域紫花苜蓿高效节水的最优灌溉制度,在田间灌溉试验基础上,研究了锡林河流域滴灌条件下紫花苜蓿的灌溉制度。利用WIN ISAREG模型对紫花苜蓿的实际灌溉制度进行了评价,在此基础上根据紫花苜蓿需水特性进行了多种灌水方案设计和模拟。研究表明:紫花苜蓿在现蕾期土壤水消耗比率最低,作物系数、产量反应系数和腾发量最大,为紫花苜蓿的需水关键期。紫花苜蓿生育期内共灌水10次,总灌水量在250 mm,产量下降率为6.0%。因此,研究结果为流域内紫花苜蓿的灌溉预报,以及当地灌溉人工草地建设提供参考。  相似文献   

2.
不同灌水方式淋洗下滨海盐土的水盐运移特征   总被引:2,自引:1,他引:1  
为了合理有效地利用水资源,快速改良滨海盐土,通过室内土柱试验探讨了不同灌水方式淋洗下滨海盐土的水盐运移特征。结果表明:咸水的入渗速率要明显高于咸淡交替和淡水入渗。在灌水淋洗后,土壤盐分含量均大幅下降,以先用咸水再用淡水灌水淋洗方式脱盐效果最好,脱盐速度最快,淡水淋洗方式脱盐速度最慢。脱盐后,3个处理土壤的pH值均上升,淡水淋洗土壤pH上升幅度最大,先咸后淡灌水淋洗土壤pH上升幅度最小。采用先咸后淡灌水方式淋洗滨海盐土的综合效果最好,为淡水资源短缺,咸水资源丰富的盐碱地区的盐土淋盐改良提供了科学的方法。  相似文献   

3.
Tomato ( Lycopersicon esculentum mill. cv. Petopride ) is the most important vegetable crop in Jordan; its production is characterized by inadequate irrigation and fertilization practices, especially under open field conditions. A field study was carried out to determine the effect of different irrigation intervals and different N-fertilizer doses on water use, tomato yields and residual soil nitrogen.
Results indicated significant differences in water use and tomato yields between irrigation treatments. Highest yield (51.4 ton ha−1) was obtained under three irrigations per week with 504 mm total water supply, whereas under irrigation once a week 35.3 ton ha−1were produced with 353 mm total water supply. There were no significant differences in yield between fertigation with ten equal time intervals and fertigations with intervals as per crop requirements, the yields were 47.1 ton ha−1 and 44.5 ton ha−1, respectively. However, yield was significantly lower with three fertigations at equal intervals and equal doses (35.8 ton ha−1) throughout the season. There were no significant differences between mineral nitrogen forms in terms of yield effects. Significant irrigation effects were observed on total soil nitrogen. Residual soil N was 0.052% in the surface layer (0–30 cm), and 0.030% in the subsurface layer (30–60 cm).  相似文献   

4.
Increasing irrigation costs and declining water availability compel producers to adapt irrigation strategies for maximum crop yield and water use efficiency. A field trial was conducted to observe the effects of various drip irrigation ratios (IR-0, IR-25, IR-50, IR-75 and IR-100) on water use efficiency (WUE), the irrigation water use efficiency (IWUE), lint yield, yield components and fibre quality at two upland cotton varieties during 2004 and 2005. WUE was found to increase from 0.62 to 0.71 kg m−3 as the irrigation water applied was reduced from 100 % to 75 % of soil water depletion. Deficit irrigation of cotton with drip irrigation at 75 % treatment level (IR-75) did not decrease seed cotton yield and yield components during 2 years, with the exception of the number of bolls in 2005. Among fibre quality parameters, no significant differences in fibre length, fineness, uniformity index and elongation were detected between the 100 % and 75 % irrigation levels in 2005. The results revealed that irrigation of cotton with a drip irrigation method at 75 % level had significant benefits in terms of saved irrigation water without reducing yield, and high WUE indicated a definitive advantage of employing deficit irrigation under limited water supply conditions.  相似文献   

5.
The study was conducted to determine the feasibility of canopy temperature based crop water stress index (CWSI) for scheduling irrigation of Indian mustard (Brassica juncea). Field crop experiments were conducted in Hamirpur, Himachal Pradesh (India) during three consecutive cropping seasons (2015, 2016 and 2017). The experimental field was divided into five plots with different levels of irrigation treatments based on depletion of total available soil water (TASW) in the crop root zone. The maximum soil moisture depletion (SMD) of TASW at 10%, 30% and 50%, full irrigated (non-stressed) and extremely dry (full stressed) conditions were maintained in respective plots. Relationships were developed between canopy-air temperature differential (TC-TA) and vapour pressure deficit (VPD) for non-stressed and fully stressed conditions to generate non-water-stressed baseline (NWSB) and maximum water-stressed baseline (MWSB) baselines for Indian mustard crop. The CWSI was computed for different SMD of TASW by using a proven empirical approach based on the baselines. The irrigation treatment corresponding to 30% SMD with a mean CWSI of 0.4 resulted in optimal yield and maximum water use efficiency. Results of the study suggest that established CWSI value can be used to detect stress and schedule irrigations for Indian mustard.  相似文献   

6.
为研究直插式根灌条件下的土壤水分分布和根灌节水效率,在民勤荒漠区3种立地类型进行根灌和滴灌试验比较。结果表明:(1)生态林渗水性比较好,沙生植物次之,最小的是枣树试验区;(2)随着土壤深度的加深,阴阳离子浓度也不平衡,所以当土壤深度在0~60 cm时,土壤呈碱性,而当土壤深度在60~120 cm时,土壤偏酸性;(3)根灌与滴灌的土壤水分入渗率相比较,根灌更有利于提高土壤含水率;(4)试验地直插式根灌比地表滴灌节水效率高。综上所述,根灌的节水效应比滴灌高,所以在民勤干旱荒漠区可以采用根灌供水,同时也为荒漠地区的节水灌溉提供了新的思路。  相似文献   

7.
【目的】本研究旨在科学合理地利用浅层咸水资源。【方法】依托短期定位试验开展了在第3年和第4年不同咸水利用方式下(CK:造墒和蕾期灌淡水;T1:造墒和蕾期灌咸淡混配矿化度3 g·L^-1的微咸水;T2:淡水造墒蕾期灌矿化度5 g·L^-1咸水;T3:造墒和蕾期灌矿化度5 g·L^-1咸水;T4:淡水造墒蕾期不灌水)棉花长势、叶绿素荧光参数、土壤盐分累积及其运移的变化。【结果】T1和T2处理的齐苗率、株高、干物质质量、叶面积指数、叶绿素荧光参数、产量及霜前花率与CK无显著差异,土壤盐分含量较CK有所增加,但未对棉花生长产生明显抑制。T3处理的棉花长势指标、叶绿素荧光参数较CK显著降低,0~100 cm土壤盐分含量较CK明显增加。【结论】从土壤质量安全和咸水高效利用的角度考虑,连续4年用3 g·L^-1的咸淡混合水灌溉或用淡水与5 g·L^-1的咸水轮灌不仅能节约淡水,且不影响棉花产量。本研究结果为当地在棉花生产中安全利用咸水提供技术参考。  相似文献   

8.
A combination of appropriate crop rotation(s) and management interventions has the potential to transform saline‐sodic soil and water resources from an environmental burden into an economic asset. We carried out 2‐year field studies in the Indus Basin of Pakistan to evaluate different irrigation and soil management options of using saline‐sodic waters (SSW) and soils for reclamation and for growing salt‐tolerant cultivars of rice (SSRI‐8) and wheat (SIS‐32). These soils have variable levels of salinity and sodicity (ECe 9–44 dS m?1 and SAR 83–319). The treatments on both the sites were the same and consisted of: (1) Irrigation with SSW, (2) Irrigation with freshwater (FW), (3) Soil application of gypsum at 100 % gypsum requirement of soil + SSW (G + SSW), (4) G + one irrigation with SSW and one with FW (G + 1SSW + 1FW), (5) G + two irrigations with SSW and one with FW (G + 2SSW + 1FW), (6) Farm manure at 25 Mg ha?1 each year before rice + one irrigation with SSW and one with FW (FM + 1SSW + 1FW) and (7) FM + two irrigations with SSW and one with FW (FM + 2SSW + 1FW). Rice was grown as the first crop. After harvesting final wheat crop (fourth in sequence), maximum decrease in bulk density and increase in infiltration rate was observed with G + 1SSW + 1FW while FM + 1SSW + 1FW treatment showed higher decrease in pHs and ECe. Significantly the highest decrease in SAR occurred at both sites with G + 1SSW + 1FW. Maximum yields of rice and wheat were generally observed with G + 1SSW + 1FW. The crop yield and economic benefits with treatments showed a positive correlation with that of improvement in soil physical and chemical properties. Overall, the greatest net benefit was obtained from G + 1SSW + 1FW treatment. We also found that the farmers’ management skills were crucial in the overall success in improving crop yields during reclamation of saline‐sodic soils. Based on the results of this study, we propose that SSW could be used to reclaim saline‐sodic soils by using a rice–wheat rotation and a site‐specific combination of soil amendments and water application strategies.  相似文献   

9.
Latest published information is limited on agronomic responses of winter wheat to irrigation quantity and the necessity of irrigation at the anthesis stage. This study was conducted to (1) evaluate winter wheat yield, water use, assimilate redistribution and economic benefit with respect to water input and (2) quantify relationship between water input and yield to develop a standard for withholding irrigation at anthesis. A 4-year long field experiment was conducted to evaluate winter wheat water use, yield formation pathway and farmers' income under three irrigation regimes: rainfed, irrigation at sowing and jointing (SJ-W) and irrigation at sowing, jointing and anthesis (SJA-W). The yield formation pathway was correlated with the water-induced variation in assimilate redistribution and accumulation. Throughout the experimental period, wheat yield was 19–38% lower in rainfed than that under other irrigation treatments. Moreover, SJ-W treatment substantially increased biomass accumulation at anthesis, accelerated assimilate redistribution in vegetative organs and eventually resulted in a similar wheat yield to that of SJA-W. Simultaneously, the SJ-W treatment had lower irrigation water, reduced additional irrigation cost, suppressed yield loss and obtained a similar farmer's net income to the SJA-W treatment. Water-induced variations in yield were determined by irrigation, rainfall and soil water storage. SJ-W plots receiving 204–331 mm water input (rainfall + irrigation) before anthesis and holding 549–587 mm soil water during anthesis stage achieved higher irrigation water use efficiency and yield relative to the rainfed and SJA-W plots. In contrast, water input under rainfed plots exceeded 200 mm before anthesis, limiting yield substantially even when seasonal soil water consumption exceeded 160 mm. Developing a standard for withholding irrigation at the anthesis stage should incorporate 204–331 mm of water input (rainfall + irrigation) before anthesis and 549–587 mm soil water storage at anthesis, which could achieve a high wheat yield and save water resources.  相似文献   

10.
为了合理利用水资源,探索实现低定额均匀灌溉的适宜方法和技术路线,设计作物高效用水的有限灌溉制度,在陕西省杨凌区中壤土玉米地开展了不同畦田规格和灌水定额对土壤水分及玉米产量影响的田间试验。结果表明:对于田面坡度一定的试验田块,入畦单宽流量在3~6l/m/s范围内,畦田宽度在4m以内时,各处理小区的土壤平均含水量无显著性差异,但畦田内土壤水分分布却有不同差异,当畦宽2~3m,畦长50 m时可达到较高灌水效率(Ea>80%)和灌水均匀度(DU>80%);玉米拔节-抽雄期的灌水定额处理对玉米的生长存在明显影响;不同灌水定额对作物产量、水分利用效率影响显著。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号