Camelina water use and seed yield response to irrigation scheduling in an arid environment

Camelina sativa (L.) Crantz is a promising, biodiesel-producing oilseed that could potentially be implemented as a low-input alternative crop for production in the arid southwestern USA. However, little is known about camelina’s water use, irrigation management, and agronomic characteristics in this arid environment. Camelina experiments were conducted for 2 years (January to May in 2008 and 2010) in Maricopa, Arizona, to evaluate the effectiveness of previously developed heat unit and remote sensing basal crop coefficient (K _cb ) methods for predicting camelina crop evapotranspiration (ET) and irrigation scheduling. Besides K _cb methods, additional treatment factors included two different irrigation scheduling soil water depletion (SWD) levels (45 and 65 %) and two levels of seasonal N applications within a randomized complete block design with 4 blocks. Soil water content measurements taken in all treatment plots and applied in soil water balance calculations were used to evaluate the predicted ET. The heat-unit K _cb method was updated and validated during the second experiment to predict ET to within 12–13 % of the ET calculated by the soil water balance. The remote sensing K _cb method predicted ET within 7–10 % of the soil water balance. Seasonal ET from the soil water balance was significantly greater for the remote sensing than heat-unit K _cb method and significantly greater for the 45 than 65 % SWD level. However, final seed yield means, which varied from 1,500 to 1,640 kg ha^?1 for treatments, were not significantly different between treatments or years. Seed oil contents averaged 45 % in both years. Seed yield was found to be linearly related to seasonal ET with maximum yield occurring at about 470–490 mm of seasonal ET. Differences in camelina seed yields due to seasonal N applications (69–144 kg N ha^?1 over the 2 years) were not significant. Further investigations are needed to characterize camelina yield response over a wider range of irrigation and N inputs.     

Deficit irrigation and nitrogen effects on seed cotton yield, water productivity and yield response factor in shallow soils of semi-arid environment

A field experiment was conducted for 2 years to investigate the effects of deficit irrigation, nitrogen and plant growth minerals on seed cotton yield, water productivity and yield response factor. The treatment comprises six levels of deficit irrigation (Etc 1.0, 0.9, 0.8, 0.7, 0.6 and 0.5) and four levels of nitrogen (80, 120, 160 and 200 kg N ha⁻¹). These were treatments superimposed with and without plant growth mineral spray. Furrow irrigation treatments were also kept. Cotton variety Ankur-651 Bt was grown during 2006 and 2007 cotton season. Drip irrigation at 1.0 Etc saved 26.9% water and produced 43.1% higher seed cotton yield over conventional furrow irrigation (1.0 Etc). Imposing irrigation deficit of 0.8 Etc caused significant reduction in seed cotton yield to the tune of 9.3% of the maximum yield. Further increase in deficit irrigation from 0.7 Etc to 0.5 Etc significantly decreased seed cotton yield over its subsequent higher irrigation level. Decline in the yield under deficit irrigation was associated with reduction in number of bolls plant⁻¹ and boll weight. Nitrogen at 200 kg ha⁻¹ significantly increased mean seed cotton yield by 36.3% over 80 kg N ha⁻¹. Seed cotton yield tended to increase linearly up to 200 kg N ha⁻¹ with drip Etc 0.8 to drip Etc 1.0. With drip Etc 0.6-0.5, N up to 160 kg ha⁻¹ provided the highest yield, thereafter it had declined. Foliar spray of plant growth mineral (PGM) brought about significant improvement in seed cotton yield by 14.1% over control. The water productivity ranged from 0.331 to 0.491 kg m⁻³ at different irrigation and N levels. On pooled basis, crop yield response factor of 0.87 was calculated at 20% irrigation deficit.     

Response of sorghum to moisture stress using line source sprinkler irrigation I. Plant-water relations

The response of sorghum (Sorghum bicolor L.) to moisture stress during the post-rainy season was studied at ICRISAT research center on a medium deep Alfisol using a line source sprinkler irrigation system. Changes in soil moisture content, stomatal conductance, leaf-water potential and leaf temperature of sorghum as a function of distance away from the line source sprinkler system were monitored throughout the season. Use of the line source technique facilitated the imposition of a range of moisture stress levels as indicated by increased water use by sorghum closer to the line source compared with the crop farther away from the line source. Canopy response measured in terms of stomatal conductance, leaf-water potential, and leaf temperature clearly reflected the gradient in moisture stress perpendicular to the line source.     

Cotton response to non-uniformity of conventional sprinkler irrigation

Sprinkler irrigation systems are characterized by some degree of non-uniformity. The effect of non-uniformity on crop yield has been modelled in different ways but experimental studies are scarce. An experiment was conducted comparing the effects of two levels of uniformity (mean Wilkox and Swailes' uniformity coefficients of 80% and 52%) at two levels of water supply (about 400 and 260 mm for the whole irrigation season) on cotton production. Final yield was not affected either by uniformity or by the amount of water supplied. Vegetative growth was higher in the full irrigation treatments. Maximum leaf area index did not differ statistically between uniformity treatments. The lack of differences was attributed to the curvilinear shape of the yield function and to the dampening of the variations in applied water in the soil, as the coefficient of variation in applied water was more than twice the coefficient of variation of infiltrated water. These results suggest that non-uniformity of conventional sprinkler irrigation has a lower impact on cotton crop performance than expected from previous simulation studies. Received: 1 March 1996     

A regional soil survey approach for upgrading from flood to sprinkler irrigation in a semi-arid environment

Increasing pressure on water resources in Spain is forcing farmers to move from flood to pressurized water application. Initial recommendations for this upgrading require soil survey information, especially in areas prone to soil salinity. In this article a 3158 ha soil survey at a scale of 1:25,000 is presented. Soil series are split in phases based on the texture of the surface layer, slope, and salinity. Available water holding capacity (AWHC), to a depth of 1.5 m or to a lithic or paralithic contact, texture and coarse components in the surface horizons, and salinity mapped as discrete soil units are combined to develop a regional soil suitability map for irrigation upgrade. To minimize soil erosion and salt mobilization in the soils, our recommendations are: (i) maintain and improve flood irrigation on 296 ha, (ii) develop standard sprinkler irrigation on 2261 ha, and (iii) move to high frequency sprinkler irrigation on 601 ha. This research demonstrates the importance of soil survey as part of the decision making process for upgrading the regional irrigation systems.     

Predicting soil salinity in response to different irrigation practices, soil types and rainfall scenarios

A model was developed to predict rootzone salinity under different irrigation practices on different soil types, with similar rainfall but different monthly distributions. A rootzone daily water and salt balance was performed using eight scenarios: two soil types (coarse textured vs. fine textured), two multi-year series of actual rainfall data and two irrigation practices (surface with fixed number of irrigations and ET-based sprinkler irrigation). All factors influenced the mean electrical conductivity (EC) of the rootzone in the growing season (EC_eS): (i) Surface irrigation led to lower EC_eS than sprinkler irrigation; (ii) Winter-concentrated rainfall caused lower EC_eS than rainfall distributed uniformly throughout the year; and (iii) Coarser-textured soil usually resulted in lower EC_eS than the finer textured. The EC_eS was related to the total precipitation of the hydrologic year and to the annual leaching fraction (LF) but surprisingly not to the seasonal LF. In most cases, the model predicted lower EC_eS than the FAO steady-state approach. Therefore, considering these site-specific features could lead to lower leaching requirements and the safe use of higher salinity water.     

谈谈喷灌工程的管理与发展

通过对现有喷灌工程的管理进行分析，探讨喷灌工程如何适应当前我国农村经济体制改革与发展的管理问题及新建喷灌工程需要解决的问题，促进喷灌事业的发展。     

喷灌工程管理模式探讨

1　喷灌的发展概况喷灌是当今世界上最主要的节水灌溉技术之一。这种灌溉方法起始于 190 0年 ,第一个农业喷灌系统是用于城市草坪的幼苗灌溉 ,192 0年以前喷灌仅限于蔬菜、苗圃和果园。195 0年以来 ,由于发展了高效喷洒器、轻型铝管、更高效率的水泵 ,加上廉价的电能和内燃机燃料的广泛应用 ,使喷灌设备增加得很快。喷灌已经使用于各种类型的土壤、不同地形和坡耕地 ,以及多种作物。 1993年世界各国喷灌面积为 10 0万ｈｍ2 ,196 0年为 2 5 0万ｈｍ2 ,1980年达到 5 0 0 0万ｈｍ2 ,90年代初为 1 3亿ｈｍ2 。从 70年代初到 80年代是喷灌发展速…     

Drought response of rice at different nitrogen levels using line source sprinkler system

Summary In rainfed rice, the nitrogen status of soil and plant is closely related to the moisture regime in the soil. The lower the soil moisture content, the lower the nitrogen use efficiency in the plants.In this study, the yield and growth responses of four rice cultivars to seven irrigation and three nitrogen levels were evaluated using the line source sprinkler system. Visual observations on the degree of drought reaction and measurement of leaf water potential (LWP) were also made.The effect of drought was least on the traditional variety Kinandang Patong and most on the modern variety IR 20. Increasing nitrogen levels from 0 (no nitrogen fertilizer) to 60 and 120 Kg N/ha increased the degree of water stress. This also resulted in decreased LWP especially when the total water applied was minimal. At all levels of nitrogen, Kinandang Patong had significantly higher LWP than IR 20. There was a curvilinear decrease in the number of days to heading and a linear increase in plant height and dry matter production with increase in total water applied.The yield-water-fertilizer relationships of the four cultivars revealed different production surfaces. The early-maturing IR 52 rice gave the highest grain yield at 120 kg N/ha and with maximum water application of 850 mm. Without nitrogen fertilizer application, Kinandang Patong gave the highest predicted yield with 550 mm of water applied. At 120 kg N/ha and 550 mm of water, IR 36 was superior in yield to other rices tested.Results suggest that in areas of uncertain moisture supply, nitrogen application rate should be reduced from that normally used for irrigated rice.     

Influence of vertical sand column and supplemental irrigation on barley yield in arid soils affected by surface crust

A field experiment was conducted during the 1996/1997 season at the University of Jordan Research Station near Al-Muwaqqar village to investigate the effects of sand columns, sand column spacing, soil ridges, and supplemental irrigation on soil water storage, redistribution, and barley yields. The experimental site represents a typical Jordanian arid environmental soil suffering from surface crust formation overlaying impermeable material. In the 600-mm-depth soil profile, soil water storage was improved significantly by 59%, 45%, and 38% in the 1-m, 2-m, and 3-m sand column spacing treatments, respectively, compared with soil water storage in the control treatment (no sand columns). Sand columns increased the moisture stored in all four soil layers (0–150, 150–300, 300–450, and 450–600 mm). Moisture stored in the 450–600 mm soil layer increased significantly by about 188%, 147%, 88%, and 29% in the 1-m, 2-m, 3-m, and 4-m sand column spacing treatments, respectively, compared with moisture stored in the same soil layer of the control treatment. Increasing soil water storage also increased barley consumptive use significantly from 130 mm in the control treatment to an average of about 185 mm in sand column treatments. Without supplemental irrigation, barley grain and straw yields were negligible and almost zero. Barley yields in the control treatment, with 167 mm supplemental irrigation were low, being 0.19 ton/ha and 1.09 ton/ha of barley grain and straw, respectively. Sand columns increased barley grain and straw yields significantly compared with the control treatment to a maximum of 0.68 ton/ha and 3.97 ton/ha, respectively, with the 1-m sand column spacing. Soil ridges perpendicular to the land slope had no significant effect on increasing soil water storage due to lateral runoff and loss along the ridge. In general, sand columns minimize surface runoff and evaporation by allowing water to infiltration through the strong surface crust. Sand columns act as a sink for surface water, enhance subsurface lateral water movement, and reduce the possibility of surface crust formation in the vicinity of the sand column opening by preventing surface ponding. Received: 3 October 1997     

极端干旱区降解膜对滴灌棉花土壤水热及产量的影响

为了探明降解膜在哈密盆地滴灌棉花种植的应用效果,选取降解膜M1,M2,M3,M4及普通塑料地膜PE(CK)开展对照试验,研究降解膜的降解性能及其对滴灌棉花土壤水热变化与产量的影响.结果表明:M2在覆膜80 d左右最早出现降解、180 d左右进入残存期,生育期末仍有小块地膜残片存在;而降解膜M1与M3于生育期末才进入崩解...     

入渗模型对垂直线源灌线源长度的适用性

为了分析垂直线源灌下土壤水分的入渗规律,探明不同线源长度的入渗率和累积入渗量,通过室内土箱模拟试验,研究了3种常规入渗模型对垂直线源灌下不同线源长度入渗规律的适用性.结果表明,随着线源长度的增加,入渗率和累积入渗量均增大;3种模型均能模拟不同线源长度下的入渗规律,其中Kostiakov入渗公式最精确,Philip入渗模...     

Effects of applied water and sprinkler irrigation uniformity on alfalfa growth and hay yield

This study was conducted to investigate the effects of applied water and sprinkler irrigation uniformity on alfalfa (Medicago sativa L.) growth and hay yield in a semi-arid region. Field experiments were carried out in 2006 in Varamin, Iran, on three plots of 25 m × 30 m. Each plot was subdivided into 25 subplots of 5 m × 6 m. Different irrigation depths and sprinkler water uniformities were obtained by various scenarios of sprinkler nozzle pressure. In each plot, applied water was measured at 250 points (125 points above and 125 points below canopy) and the soil water content of 40 cm deep below soil surface was monitored at 25 points, each in the center of a subplot, throughout the irrigation season. The results showed that sprinkler water and soil water content uniformity varied between 66-78 and 88-91%, respectively. The findings revealed that soil water content uniformity was around 20% higher than sprinkler water uniformity. The irrigation uniformity below the canopy was estimated to be 2.5% greater than above the canopy, and canopy-intercepted water could account for 11-15% of the total seasonal applied water. Evaluation showed that alfalfa leaf area index relies more heavily on farm water application uniformity than hay yield and crop height. The experimental results illustrated that water distribution in sprinkler irrigation systems has a direct effect on alfalfa growth, hay yield and water productivity such that the applied water reduction and the increased sprinkler water uniformity led to an increased alfalfa water productivity of 2.41 kg m⁻³.     

An alternative water source and combined agronomic practices for cotton irrigation in coastal saline soils

The field experiment for cotton crop (Gossypium hirsutum L.) was conducted at the Zhongjie Farm, Huanghua city of Hebei province in the coastal salinity-affected areas in North China Plain, to determine the effects of an alternative of irrigation water sources/methods and agronomic practices on seedling emergence and yields of cotton, soil water–salt distributions, and soil pH changes during cotton growth stages. The experiment was setup using split-plot design with two water sources as main treatments (well water/desalinized sea-ice water); two irrigation methods (+PAM (Polyacrylamide)/−PAM); and four fertilization modes: check (CK), mineral fertilizer (F), mineral + organic fertilizer (FM), and mineral fertilizer + gypsum (FG). Using desalinized sea-ice water irrigation showed the same effects on top-soil salt leaching and desalinization as using well water did. There was no significant difference in seedling emergence and cotton yields between two irrigation water sources for cotton irrigation. Using PAM-treated irrigation, the 10-cm top-soil salinity significantly decreased to about 2.3–3.9 g kg⁻¹ from 4.6 to 8.6 g kg⁻¹ (PAM untreated). The PAM-treated irrigation increased seedling emergence by about 13, 29 and 36% and yields by about 50, 49, and 70%, with F, FM, and FG, respectively, as compared with CK. PAM-treated irrigation, either using well water or desalinized sea ice, especially in combination with gypsum-fertilization, shows the best practice for both seedling emergence and cotton yields. In conclusion, the desalinized sea-ice water used as an alternative water source, integrated with better agronomic practices of soil water-salt management could be acceptable for cotton irrigation in the coastal saline areas.     

Water use and yield response of wheat to irrigation and nitrogen on an alluvial soil in North India

Field studies were conducted for four years on alluvial soils of North India to determine the water use, water use efficiency and yield performance of a semi-dwarf high-yielding wheat variety (Triticum aestivum L.) in response to irrigation schedule and nitrogen fertilization. Irrigation scheduling was based on different ratios between irrigation water and cumulative pan evaporation (IW/CPE). Irrigations of 6-cm depth were applied on the basis of IW/CPE ratio of 0.45, 0.60, 0.75 and 0.90. Pan evaporation data were recorded daily using standard USWB-Class A Open pan (as prescribed by India Meterological Department) located at Research Farm, Selakui, Dehradun where the experiment was conducted. The CPE values were computed for each year individually. The crop was fertilized with nitrogen at the rate of 0, 60 and 120 kg/ha.The yield and yield attributes were highest and irrigation efficiency was maximum when irrigation was applied at an IW/CPE ratio of 0.75 in a normal-rainfall year and at 0.90 in a low-rainfall year. Water use efficiency decreased with increase in irrigation frequency. Nitrogen fertilization increased the yield of wheat linearly and was maximum at 120 kg nitrogen per hectare.     

Comparing soil moisture under trickle irrigation modeled as a point and line source

The validity of the assumption that an irrigation event from point sources can be approximated as an infinite line source is investigated in this article. This is accomplished by comparing soil water dynamics under line and point sources. Two existing mathematical models which simulate point and line drip irrigation were used. The models consider root water uptake, evaporation of soil water from the soil surface and incorporate hysteresis in the soil water characteristic curve. The comparison was made for two soil types (loamy sand and silt).The results showed that the treatment of a point source as a line source underestimates the water content values for both the soil types. This difference decreases when the depth of comparison increases. For soil depths greater than 30 cm and for time greater than irrigation duration the two models gave very close results. For the same emitter spacing and for the horizontal direction perpendicular to the drip line on the emitter spot, when the distance from the point and the line sources increases the difference of water content values increases. On the contrary, in the direction parallel to the drip line when the distance from the emitter increases (the distance from the line source remains the same) the difference of water content decreases. Lastly, differences are greater in the case of coarse grained soil than in fine grained soil.     

喷灌发展与土地经营模式的思考

发展喷灌要因地制宜，采用与土地经营模式相适应的喷灌形式是保证喷灌生命力的一个重要前提。通过对国内外发展喷灌中采用的主要形式及其土地经营模式的分析，总结了国内外喷灌发展中的经验。针对我国现行的农村生产体制，对我国喷灌发展的提出了个人的见解；改进现有机型，发展适合我国农村土地经营模式的喷灌设备，从而促进我国喷灌的健康发展。     

Effect of irrigation methods,management and salinity of irrigation water on tomato yield,soil moisture and salinity distribution

The increasing demand for irrigation water to secure food for growing populations with limited water supply suggests re-thinking the use of non-conventional water resources. The latter includes saline drainage water, brackish groundwater and treated waste water. The effects of using saline drainage water (electrical conductivity of 4.2–4.8 dS m⁻¹) to irrigate field-grown tomato (Lycopersicon esculentum Mill cv Floradade) using drip and furrow irrigation systems were evaluated, together with the distribution of soil moisture and salt. The saline water was either diluted to different salinity levels using fresh water (blended) or used cyclically with fresh water. The results of two seasons of study (2001 and 2002) showed that increasing salinity resulted in decreased leaf area index, plant dry weight, fruit total yield and individual fruit weight. In all cases, the growth parameters and yield as well as the water use efficiency were greater for drip irrigated tomato plants than furrow-irrigated plants. However, furrow irrigation produced higher individual fruit weight. The electrical conductivity of the soil solution (extracted 48 h after irrigation) showed greater fluctuations when cyclic water management was used compared to those plots irrigated with blended water. In both drip and furrow irrigation, measurements of soil moisture one day after irrigation, showed that soil moisture was higher at the top 20 cm layer and at the location of the irrigation water source; soil moisture was at a minimum in the root zone (20–40 cm layer), but showed a gradual increase at 40–60 and 60–90 cm and was stable at 90–120 cm depth. Soil water content decreased gradually as the distance from the irrigation water source increased. In addition, a few days after irrigation, the soil moisture content decreased, but the deficit was most pronounced in the surface layer. Soil salinity at the irrigation source was lower at a depth of 15 cm (surface layer) than that at 30 and 60 cm, and was minimal in deeper layers (i.e. 90 cm). Salinity increased as the distance from the irrigation source increased particularly in the surface layer. The results indicated that the salinity followed the water front. We concluded that the careful and efficient management of irrigation with saline water can leave the groundwater salinity levels unaffected and recommended the use of drip irrigation as the fruit yield per unit of water used was on average one-third higher than when using furrow irrigation.     

不同喷灌水氮组合对马铃薯耗水、产量和品质的影响

为了探讨黑龙江省克山县圆形喷灌机条件下不同水氮组合对马铃薯的耗水规律、产量和品质的影响,同时确定节水、节肥、高产目标下适宜的水氮组合方式,试验设置了2个灌水水平:灌水总量W1(80 mm)和W2(100 mm);4个追氮量水平:F1(45 kg/hm²),F2(56.6 kg/hm²),F3(70 kg/hm²)和F4(86.6 kg/hm²);2个施氮频次:C1为块茎膨大期1次施入,C2为块茎膨大期分2次施入,并选择雨养区作为对照.结果表明:马铃薯全生育期耗水量为313~332 mm,块茎膨大期耗水量最大,占全生育期耗水总量63.4%~66.0%,幼苗期和块茎形成期是需水关键期,应结合马铃薯生长状况和当地雨水情况,适当进行补充灌溉;相比于其余处理,W2F4C2处理产量最高,达到46 525 kg/hm²;不同水氮组合间马铃薯的淀粉、维生素C、粗蛋白含量及商品薯率无显著差异,粗蛋白含量随着施氮量的增加呈现先降低后升高的趋势.综合比较,建议在黑龙江半湿润地区,可采用高水(100 mm)高肥(86.6 kg/hm²)高频次(块茎膨大期分2次施入)的方案.     

Simulation of furrow irrigation practices (SOFIP): a field-scale modelling of water management and crop yield for furrow irrigation

Because of the spatial and temporal variabilities of the advance infiltration process, furrow irrigation investigations should not be limited to a single furrow irrigation event when using a modelling approach. The paper deals with the development and application of simulation of furrow irrigation practices (SOFIP), a model used to analyse furrow irrigation practices that take into account spatial and temporal variabilities of the advance infiltration process. SOFIP can be used to compare alternative furrow irrigation management strategies and find options that mitigate local deep-percolation risks while ensuring a crop yield level that is acceptable to the farmer. The model is comprised of three distinct modelling elements. The first element is RAIEOPT, a hydraulic model that predicts the advance infiltration process. Infiltration prediction in RAIEOPT depends on a soil moisture deficit parameter. PILOTE, a crop model, which is designed to simulate soil water balance and predict yield values, updates the soil moisture parameter. This parameter is an input of a parameter generator (PG), the third model component, which in turn provides RAIEOPT with the data required to simulate irrigation at the scale of an N-furrow set. The study of sources of variability and their impact on irrigation advance, based on field observations, allowed us to build a robust PG. Model applications show that irrigation practices must account for inter-furrow advance variability when optimising furrow irrigation systems. The impact of advance variability on deep percolation and crop yield losses depends on both climatic conditions and irrigation practices.