Soil water deficit and vegetation restoration in the refuse dumps of the Heidaigou open-pit coal mine,Inner Mongolia,China

The sustainability of ecosystem restoration of refuse dumps in open-pit coal mines depends on plant species selection, their configuration, and the optimal usage of water resources. This study is based on field experiments in the northern refuse dump of the Heidaigou open-pit coal mine in Inner Mongolia of China established in 1995. Eight plant configurations, including trees, shrubs, grasses, and their combinations, as well as the adjacent community of natural vegetation, were selected. The succession of the revegetated plants, soil water storage, the spatiotemporal distribution of plant water deficits degree and its compensation degree were also studied. Results indicated that the vegetation cover （shrubs and herbaceous cover）, richness, abundance, soil nutrients （soil organic matter, N and P）, and biological soil crust coverage on the soil surface are significantly influenced by the vegetation configurations. The average soil water storage values in the shrub ＋ grass and grass communities throughout the growing season are 208.69 mm and 206.55 mm, which are the closest to that of in the natural vegetation community （215.87 mm）. Plant water deficits degree in the grass and shrub ＋ grass communities were the lowest, but the degrees of water deficit compensation in these configuration were larger than those of the other vegetation configurations. Differences in plant water deficit degree and water compensation among the different config- urations were significant （P 〈0.05）. Plant water deficit degrees were predominantly minimal on the surface, increased with increasing soil depth, and remained stable at 80 cm soil depth. The soil moisture compensation in the natural vegetation, shrub ＋ grass, and grass communities changed at 10%, while that in other vegetation communities changed between 20% and 40%. Overall, we conclude that the shrub ＋ grass and grass configuration modes are the optimal vegetation restoration models in terms of ecohydrology for future ecological engineering projects.

Responses of Amygdalus pedunculata Pall.in the sandy and loamy soils to water stress

Amygdalus pedunculata Pall.is a major species that is widely planted in afforested soils with different textures in the transitional zone between Mu Us Desert and Loess Plateau,China.However,the responses of A.pedunculata to increasing intensity of water stress in different textural soils are not clear.Here,we conducted a soil column experiment to evaluate the effects of different textures(sandy and loamy)on water consumption,water use efficiency(WUE),biomass accumulation and ecological adaptability of A.pedunculata under increasing water stress,i.e.,90%(±5%)FC(field capacity),75%(±5%)FC,60%(±5%)FC,45%(±5%)FC and 30%(±5%)FC in 2018.A.pedunculata grown in the sandy soil with the lowest(30%FC)and highest(90%FC)water contents had respectively 21.3%-37.0%and 4.4%-20.4%less transpiration than those with other water treatments(45%-75%FC).In contrast,A.pedunculata transpiration in the loamy soil decreased with decreasing water content.The magnitude of decrease in transpiration increased with increasing level of water deficit(45%and 30%FC).Mean daily and cumulative transpirations of the plant were significantly lower in the sandy soil than in the loamy soil under good water condition(90%FC),but the reverse was noted under water deficit treatments(45%and 30%FC).Plant height,stem diameter and total biomass initially increased with decreasing water content from 90%to 75%FC and then declined under severe water deficit conditions(45%and 30%FC)in the sandy soil.However,these plant parameters decreased with decreasing water content in the loamy soil.WUE in the sandy soil was 7.8%-12.3%higher than that in the loamy soil,which initially increased with decreasing water content from 90%to 75%FC and then declined under water deficit conditions(45%and 30%FC).The study showed that plant transpiration,biomass production and WUE responded differentially to increasing intensity of water stress in the sandy and loamy soils.The contrasting responses of A.pedunculata to water stress in different textural soils can guide future revegetation programs in the northern region of Chinese Loess Plateau by considering plant adaptability to varying soil and water conditions.

Effect of Crop Root on Soil Water Retentivity and Movement

The objective of this study was to clarify the effect of crop root on soil water retentivity and movement to improve the crop growth environment and irrigation efficiency. To simulate soil water movement considering the crop root effect on the physical properties of soil, a numerical model describing the soil water and heat transfers was introduced. Cultivation experiments were conducted to clarify the effect of the crop root on soil water retentivity and verify the accuracy of the numerical model. The relationship between soil water retentivity and the root content of soil samples was clarified by soil water retention curves. The soil water content displayed a high value with increasing crop root content in the high volumetric water content zone. The experimental results indicated that the saturated water content increased with the crop root content because of the porosity formed by the crop root. The differences of the soil water retentivity became smaller when the value of the matric potential was over pF 1.5. To verify the accuracy of the numerical model, an observation using acrylic slit pot was also conduced. The temporal and spatial changes of the volumetric water content and soil temperature were measured. Soil water and heat transfers, which considered the effect of the crop root on the soil water retentivity clarified by the soil water retention curves, were simulated. Simulated volumetric water content and temperature of soil agreed with observed data. This indicated that the numerical model used to simulate the soil water and heat transfer considering the crop root effect on soil water retentivity was satisfactory. Using this model, spatial and temporal changes of soil water content were simulated. The soil water condition of the root zone was relatively high compared with the initial conditions. This indicated that the volumetric water condition of the root zone increased with the soil water extraction and high soil water conditions was maintained because the soil water retentivity of root zone increased with the root effect.

Regulations and patterns of soil moisture dynamics and their controlling factors in hilly regions of lower reaches of Yangtze River basin,China

Time-domain reflectometry was used to make continuous measurements of soil moisture to 18 sample points with depth of 2 m for 36 months in a typical artificial secondary oak forest located in a hilly area on Zijin Mountain in the suburbs of Nanjing,China.The data were then used to examine the patterns of soil moisture variations on temporal and spatial scales and predict the relationships between soil moisture and major factors of both meteorology and topography.Water in the topsoil was active,and the upper 30 cm of soil supplied about 43% of the water content variation during the whole year.This difference of water content changes among layers could be due to the distribution conditions of some soil physical properties.When initial soil moisture was in the range from 10% to 40%,the impact of a single storm event on soil moisture was extremely significant,especially on sunny slope.Both climate and slope condition were related to soil moisture change,and the impact of slope gradient on soil moisture was higher that on shady slope.Moreover,root uptake was another important path of soil water consumption.

A STUDY ON FIELD WATER CIRCULATION PATTERN IN THE DRYLAND OF NORTHERN CHINA

Based on the observed data of soil moisture from locating experiments from 1986 to 1990, the pattern of field water circulation in dryland of northern China, where the mean annual precipitation is 300 600 mm, is studied in this paper using the method of water balance. The results show that water satisfying ratio of spring seeding crops is 83.7 90.8 percent and that of winter wheat is about 70 percent in these areas; about 80 90 percent of water consumption of spring seeding crops and about 60 70 percent of water consumption of winter wheat comes from precipitation during the growing period, the rest comes from the soil water storage before the seeding period. But the available soil water is not used thoroughly, about 30 70 percent of available soil water remains unused when the crops are harvested. At the fallow period, the amount of soil water lost by evaporation is very important, which takes up 57 68 percent of precipitation in winter wheat field and 73 244 percent in field of spring seeding crops. Thus restraining soil evaporation, raising the storage ratio of natural precipitation and the soil water utilization efficiency of crops, strengthening the circulation ability of soil water by adopting efficient measures of agricultural techniques, are the main ways for exploiting and developing the potential productivity of natural precipitation in these areas.

Water Consumption and Maize Yield for Alternative Furrow Irrigation in Western Heilongjiang Province

Aiming at less and un-uniform distribution rainfall problems, the serious draught in spring, low crop production and water efficiency in sandy soil area of Heilongjiang Province, the experiment of alternative furrow irrigation was conducted in Dumeng County in 2009. The purpose of the experiment was to find the water consumption law and its influence on maize yield. The results showed that the highest water consumption was during the heading stage and the highest daily consumption of water was during the filling stage. The stimulation effect of alternative furrow irrigation on yield was obvious in the appropriate irrigation level. The best irrigation pattern for the highest yield was as follows： the seedling stage was 325 m3. hm^-2; the jointing stage was 400 m3-hm^-2; and the filling stage was 288 m3- hm-2. The water consumption during each growing period was that the seedling was 38.85 mm; the jointing was 108.11 mm; the heading was 124.39 ram; the filling was 88.96 ram; the milk was 60.21 ram; and the harvesting was 47.89 mm.

Reducing water and nitrogen inputs combined with plastic mulched ridge-furrow irrigation improves soil water and salt status in arid saline areas,China

Plastic mulched ridge-furrow irrigation is a useful method to improve crop productivity and decrease salt accumulation in arid saline areas.However,inappropriate irrigation and fertilizer practices may result in ecological and environmental problems.In order to improve the resource use efficiency in these areas,we investigated the effects of different irrigation amounts(400(I1),300(I2)and 200(I3)mm)and nitrogen application rates(300(F1)and 150(F2)kg N/hm^(2))on water consumption,salt variation and resource use efficiency of spring maize(Zea mays L.)in the Hetao Irrigation District(HID)of Northwest China in 2017 and 2018.Result showed that soil water contents were 0.2%-8.9%and 13.9%-18.1%lower for I2 and I3 than for I1,respectively,but that was slightly higher for F2 than for F1.Soil salt contents were 7.8%-23.5%and 48.5%-48.9%lower for I2 than for I1 and I3,but that was 1.6%-5.5%higher for F1 than for F2.Less salt leaching at the early growth stage(from sowing to six-leaf stage)and higher salt accumulation at the peak growth stage(from six-leaf to tasseling stage and from grain-filling to maturity stage)resulted in a higher soil salt content for I3 than for I1 and I2.Grain yields for I1 and I2 were significantly higher than that for I3 and irrigation water use efficiency for I2 was 14.7%-34.0%higher than that for I1.Compared with F1,F2 increased the partial factor productivity(PFP)of nitrogen fertilizer by more than 80%.PFP was not significantly different between I1F2 and I2F2,but significantly higher than those of other treatments.Considering the goal of saving water and nitrogen resources,and ensuring food security,we recommended the combination of I2F2 to ensure the sustainable development of agriculture in the HID and other similar arid saline areas.

Effects of mulches on water use in a winter wheat/summer maize rotation system in Loess Plateau, China

Limited water resources often result in reduced crop yield and low water productivity（WP）. In northwestern China, crop production is generally dependent on precipitation. Therefore, a variety of agricultural rainwater harvesting（ARH） techniques have been used for conserving soil moisture, ameliorating soil environment, increasing crop yield, and improving water use efficiency. A two-year（2013–2015） field experiment was conducted under a typical sub-humid drought-prone climate in Yangling（108°24′E, 34°20′N; 521 m a.s.l.）, Shaanxi Province, China, to explore the effects of mulching（same for summer maize and winter wheat） on soil moisture, soil temperature, crop water consumption, and crop yield with a winter wheat/summer maize rotation. Crops were planted in a ridge-furrow pattern and the treatments consisted of a transparent film mulch over the ridges（M1）, a crop straw mulch in the furrows（M2）, a transparent film mulch over the ridges and a crop straw mulch in the furrows（M3）, a black film mulch over the ridges and a crop straw mulch in the furrows（M4）, and a control with no mulch（CK）. Results showed that M4 was the best treatment for improving soil water storage and content, and decreasing crop water consumption during the summer maize and winter wheat rotation. In both maize and wheat seasons, M1 had a higher soil temperature than M2 and CK, and M3 had a higher soil temperature than M4. In the maize seasons, M4 had the highest yield, WP, and precipitation productivity（PP）, with the average values for these parameters increasing by 30.9%, 39.0%, and 31.0%, respectively, compared to those in CK. In the wheat seasons, however, M3 had the highest yield, WP, and PP, with the average values for these parameters being 23.7%, 26.7%, and 23.8% higher, respectively, than those in CK. Annual yield（maize and wheat yields combined） and WP did not differ significantly between M3 and M4. These results suggested that M3 and M4 may thus be the optimal ARH practices for the production of winter wheat and summer maize, respectively, in arid and semi-arid areas.

Increasing rainfed wheat yield by optimizing agronomic practices to consume more subsoil water in the Loess Plateau

Erratic rainfall and misalignment between the rainy season and the growing season of winter wheat greatly limit rainfed winter wheat yield in the Loess Plateau of China. To increase the grain yield of winter wheat in this region, the effects of different agronomic practices, including adjusting planting pattern(NR, narrow row spacing), increasing seeding rate(high seeding rate, HS), decreasing basal nitrogen rate and increasing top-dressed nitrogen rate(DBN), and replacing an old cultivar with a new cultivar(NC) on wheat yield were investigated for two consecutive years. The results showed that the current grain yield of rainfed winter wheat in the Loess Plateau could be increased to 5879–7093 kg ha^(-1) by HS, DBN and NC practices relative to the practice of high-yielding farmers(PF). The increased yield due to HS, DBN and NC was attributed to the higher number of spikes ha^(-1), 1000-grain weight, and kernels spike^(-1). Before the flowering stage, HS increased soil water consumption(SWC) in 1–3 m subsoil due to the higher plant population compared with that of PF, whereas DBN decreased SWC in the 0–2 m soil layer compared with that of PF. After the flowering stage, HS, DBN, and NC increased SWC by 8–16 mm in 2–3 m subsoil compared to PF. The water use efficiency(WUE) was increased under DBN and NC in comparison with PF.However, the WUE did not increase under HS as it had the highest evapotranspiration among the five treatments. Increasing the use of subsoil water during the late growth stage by optimizing agronomic practices or applying new cultivars with expansive roots should be the primary approach to increase rainfed winter wheat yield in this region.

Stem sap flow of Haloxylon ammodendron at different ages and its response to physical factors in the Minqin oasis-desert transition zone, China

Haloxylon ammodendron, with its tolerance of drought, high temperature, and salt alkali conditions, is one of the main sand-fixing plant species in the oasis-desert transition zone in China. This study used the TDP30(where TDP is the thermal dissipation probe) to measure hourly and daily variations in the stem sap flow velocity of H. ammodendron at three age-classes(10, 15, and 20 years old,which were denoted as H10, H15, and H20, respectively) in the Minqin oasis-desert transition zone,China, from May through October 2020. By simultaneously monitoring temperature, relative humidity,photosynthetically active radiation, wind speed, net radiation, rainfall, and soil moisture in this region, we comprehensively investigated the stem sap flow velocity of different-aged H. ammodendron plants(H10,H15, and H20) and revealed its response to physical factors. The results showed that, on sunny days, the hourly variation curves of the stem sap flow velocity of H. ammodendron plants at the three age-classes were mainly unimodal. In addition, the stem sap flow velocity of H. ammodendron plants decreased significantly from September to October, which also delayed its peak time of hourly variation. On rainy days, the stem sap flow velocity of H. ammodendron plants was multimodal and significantly lower than that on sunny days.Average daily water consumption of H. ammodendron plants at H10, H15, and H20 was 1.98, 2.82, and 1.91kg/d, respectively. Temperature was the key factor affecting the stem sap flow velocity of H. ammodendron at all age-classes. Net radiation was the critical factor influencing the stem sap flow velocity of H.ammodendron at H10 and H15;however, for that at H20, it was vapor pressure deficit. The stem sap flow velocity of H. ammodendron was highly significantly correlated with soil moisture at the soil depths of 50and 100 cm, and the correlation was strengthened with increasing stand age. Altogether, our results revealed the dynamic changes of the stem sap flow velocity in different-aged H. ammodendron forest stands and its response mechanism to local physical factors, which provided a theoretical basis for the construction of new protective forests as well as the restoration and protection of existing ones in this region and other similar arid regions in the world.

Comparison of the water consumption levels of four shelterbelt tree species in a typical arid oasis in Northwest China

The shelterbelt is an indispensable barrier to the ecological and economic development of an oasis.Soil moisture,groundwater and irrigation greatly affect the shelterbelt water consumption and development.In this study,the transpiration rate of shelterbelt trees,soil moisture and meteorological data were collected to determine the effects of soil moisture and meteorological factors on the water consumption of different shelterbelt tree species via multivariate statistical methods.The results showed that the water consumption rate was positively correlated with solar radiation,air temperature and precipitation.Moreover,the leaf transpiration rate exhibited the trend of P.Russkii Jabl.˃P.alba˃P.simonii Carr.>P.nigracv,while the average daily water consumption decreased in the order of P.alba>P.Russkii Jabl.>P.simonii Carr.>P.nigracv.The average daily water consumption levels of P.alba,P.Russkii Jabl.,P.simonii Carr.and P.nigracv were(9.15±0.92)kg/(tree∙d),(6.95±1.41)kg/(tree∙d),(4.43±1.32)kg/(tree∙d),and(1.58±0.18)kg/(tree∙d),respectively.Over the growing season,the soil water consumption levels of P.alba,P.Russkii Jabl.,P.simonii Carr.,and P.nigracv in each shelterbelt tree stand reached 674.8,336.9,358.1 and 161.7 kg,respectively.More than 96%of the soil moisture lost was provided by the upper 120-cm soil layer.Understanding the influence and contribution of soil water and meteorological factors to shelterbelt water consumption is beneficial for shelterbelt management and protection.

Study on consumption efficiency of soil water resources in the Yellow River Basin based on regional ET structure

Based on the regional water resources character, the concept of soil water resources is first redefined, and then associated with their transfer relationship in the hydrological cycle, Evapotranspiration (ET)-based consumption structure and consumption efficiency of soil water resources are analyzed. According to ET 's function in productivity, the consumption efficiency of soil water resources is di- vided into three classes: high efficient consumption from vegetation transpiration, low efficient con- sumption from soil evaporation among plants with high vegetation coverage and inefficient consump- tion from soil evaporation among plants with low vegetation coverage and bare soil evaporation. The high efficient and low efficient consumption were further classified as productive consumption. The ineffi- cient consumption is considered non-productive consumption because it is significant in the whole hydrological cycle process. Finally, according to these categories, and employing a WEP-L dis- tributed hydrological model, this paper analyzes the consumption efficiency of soil water resources in the Yel- low River Basin. The results show that there are 2078.89×108 m3 soil water resources in the whole basin. From the viewpoint of consumption structure, the soil water resources are comprised of 381.89×108 m3 transpiration consumption from vegetation and 1697.09×108 m3 evaporation consumption from soil among plants and bare soil. From the viewpoint of consumption efficiency, soil water re- sources are composed of 920.11×108 m3 efficient consumption and 1158.86×108 m3 of inefficient con- sumption. High efficient consumption accounts for 41.5 percent of the total efficient consumption of the whole basin, low efficient for 58.5 percent. Furthermore, consumption efficiency varies by region. Compared with ET from different land use conditions, the whole basin appears to follow the trend of having the greatest proportion of consumption as inefficient consumption, followed by low efficient consumption, and then the least proportion as high efficient consumption. The amount of inefficient consumption in some regions with vegetation is less than in other regions without vegetation. The amount of inefficient consumption in grasslands is much greater than in forestlands. However, the proportion of low efficient consumption is the greatest in crop fields. The amount of high efficient con- sumption in grasslands and forelands is similar to the corresponding low efficient consumption. However, the low efficient consumption in grasslands is larger than in the forelands. Therefore, when adjusting the utilization efficiency of soil water resources, vegetation coverage and plant structure should be modulated in terms of the principle of decreasing inefficient consumption, improving low efficiency ET and increasing high efficiency ET according to area character.

Mulching type-induced soil moisture and temperature regimes and water use efficiency of soybean under rain-fed condition in central Japan

Soybean(Glycine max)is a high water-demand crop and grown under moderate temperature in Japan.To protect the crop from hot summer and to utilize rainfall for its cultivation,selection of appropriate mulching material(s)is crucial.For optimum production of the crop,soil moisture and temperature regimes as well as water use efficiency(WUE)of the crop were investigated under straw,grass,paper,plastic and bare soil(control)mulching under rain-fed condition at Gifu university farm in Japan.The mulching treatments,compared to the control,lowered soil temperature by 2°C at 5 cm depth and 0.5°C at 15 and 25 cm depths.The plastic and straw mulching stored the highest quantity of soil moisture at 5 and 15 cm depths;the bare soil stored the lowest quantity.At 25 cm depth,soil-moisture content was the highest under paper mulch but invariable under the other mulches.Plastic mulching reduced evaporation rate from the soil surface and,consequently,the reduced soil-water consumption(SWC)from the root zone augmented WUE of soybean.The paper mulching,by conserving soil-moisture and reducing soil temperature,provided better crop growth attributes,while the plastic mulching improved WUE of green soybean.Therefore,the plastic mulch performed best in reducing soil-water consumption and increasing WUE,while the paper mulch was good for soil-moisture conservation and temperature modification that increased soybean yield.

Study on Intermittent Irrigation for Paddy Rice: I. Water Use Efficiency

A field experiment was conducted in a well-puddled paddy field developed on the Tama River alluvial soil in the Farm of Tokyo University of Agriculture and Technology, Japan, to study the effect of intermittent irrigation on water use efficiency of paddy rice. Four treatments were arranged with 2 replicates: continuous flooding irrigation treatments (CFI), and three intermittent irrigation treatments Ⅱ-0, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Water consumption was lower in treatment Ⅱ-0 than in treatment CFI because the percolation rate was reduced by the reduction in the hydraulic head of ponded water. Intermittent irrigation led to soil repeated shrinking and swelling in Ⅱ-1 and Ⅱ-2 plots and, therefore, soil cracks developed rapidly. Since they became the major routes of water percolation, the soil cracks increased water consumption in treatments Ⅱ-1 and Ⅱ-2. There were no significant differences in dry matter production and grain yields between treatment Ⅱ-0 and treatment CFI, but the dry matter production and grain yields in treatments Ⅱ-0 and CFI were significantly higher than those in treatments Ⅱ-1 and Ⅱ-2. Therefore, the water use efficiency in the treatments was in the order of Ⅱ-0 > CFI > Ⅱ- 2 > Ⅱ- 1.

Effects of water and salt coordinated regulation at the different growth stages on water consumption and yield of tomato

The objective of this study was to explore the effects of different degrees of water and salt stress on the actual water consumption and soil salt accumulation of tomatoes and the salt tolerance characteristics of tomatoes under brackish water combined with regulated deficit irrigation mode.The greenhouse pot experiment was used to set three influencing factors,the irrigation water salinity S1 was 1.1 g/L(local shallow groundwater),S2 was 2.0 g/L,and S3 was 4.0 g/L,respectively,and different degrees of water deficit(W1 ranged from 65%-75%Field Capacity(FC),W2 ranged from 55%-65%FC,W3 ranged from 45%-55%FC)and seedling stage(T1),blossoming and bearing fruits stage(T2)and mature picking stage(T3).The response of fresh fruit weight,stems and leaves weight,yield and water use efficiency of tomato under water and salt stress were monitored and analyzed.The results showed the coordinated regulation of water and salt can significantly reduce the electrical conductivity of the 0-30 cm soil of the tomato root system.The higher the salinity of irrigation water,the better the salt control effects of the coordinated regulation of water and salt;the coordinated regulation of water and salt at different growth stages had significant effects on the weight of fresh tomato fruits,the weight of stems and leaves and the yield.The salinity of irrigation water was in inverse proportion to the yield of tomatoes;In S1 treatment irrigation(irrigation water salinity was 1.1 g/L)under the mildly regulated deficit in the seedling stage(irrigation water was 55%-65%of the field water capacity)can effectively reduce the irrigation water volume during the whole growth stage while ensuring that there was no significant reduction in yield.The research results provided a scientific and reliable theoretical basis for the increase of local tomato production,the improvement of water use efficiency and the formulation of suitable irrigation patterns.

农林保水剂效果评价及其环境风险探讨

从我国“七五”计划旱农科研项目以来,农林保水剂作为抗旱保水产品受到关注。《农林保水剂》(NY 886)农业行业标准2004年颁布,2010、2016和2022年3次修改,但至今缺乏相关配套的田间试验效果评价体系,极大影响其推广应用。本文结合国内外30多年来的相关研发与应用文献分析,针对农林保水剂应用对土壤保水、作物用水、作物产量及其环境影响等效果进行综述研究,结果表明:(1)保水剂适用于改善土壤蓄水保水性能,对旱作地区作物抗旱保苗、节水增产和水分利用效率(WUE)提高有积极影响,尤其是在砂质土壤上。(2)提出农林保水剂效果评价指标,主要包括土壤贮水量、作物耗水量、作物产量及其WUE等指标,以适用于农林保水剂产品的田间试验效果评价。(3)根据农林保水剂对作物产量增减不一和增产与收益不统一等现象,提出农林保水剂应用需要制定相应的技术规程,明确作物适宜的保水剂类型及其施用方式和用量。(4)农林保水剂产品(以聚丙烯酰胺(PAM)和聚丙烯酸(PAA)型材料为主)的环境安全性主要涉及残留单体(丙烯酰胺(AM)和丙烯酸(AA))的生物毒性,以及材料的降解性等。市场上部分PAM和PAA相关产品分别存在残留AM和AA单体含量超标风险,超标率约占22%—100%。研究指出生物质类等天然聚合物类材料是农林保水剂发展方向。研究结果对农林保水剂效果评价标准的制定提供参考。建议相关部门对于PAM和PAA型农林保水剂产品加强残留单体检测及其残留单体的环境安全阈值的研究,并对产品的生物降解性指标与土壤生态环境的安全性的关联性进行探讨,以期为农林保水剂产品的环境安全性提供保障。

不同种植方式对高寒旱区地膜小麦耗水特征和产量的影响

于2019—2022年在陇中高寒旱区以裸地条播为对照(CK),设置全膜覆土穴播(FM)和膜侧沟播(FS)两种覆盖方式,研究不同覆盖种植方式对冬小麦耗水特性、生长发育及产量的影响。结果表明:与CK相比,FM和FS处理播种期~拔节期0~20 cm土层土壤温度分别平均提高3.1℃和2.1℃,灌浆期分别降低0.6℃和1.0℃。覆盖能不同程度提高冬小麦各生育期0~200 cm土层土壤含水量,其中出苗期、返青期、拔节期和灌浆期提高幅度均高于20%。与CK相比,FM处理返青后冬小麦耗水量平均显著提高29.2%,返青前显著降低42.4%;FS处理返青期~灌浆期耗水量提高12.6%,返青前降低25.7%。各处理冬小麦基本苗、分蘖数、公顷穗数、穗粒数、千粒重和产量均表现为FM>FS>CK,处理间差异显著,其中FM和FS处理产量分别较CK平均提高74.7%和45.4%;处理间耗水量差异不显著;FM处理水分利用效率最大,较CK平均提高67.3%,FS次之,较CK平均提高46.1%。综上,地膜覆盖可调节土壤水分状况,改善冬小麦生长发育和成穗情况,显著提高产量和水分利用效率,其中全膜覆土穴播调节效应优于膜侧沟播,是适宜在高寒旱区地膜小麦生产中推广应用的种植方式。

小麦滴灌技术研究进展与发展趋势

小麦滴灌技术是华北地区高标准农田的主要建设内容,也是应对该区域水资源不足和保障国家粮食安全的重要技术手段。结合国内外小麦滴灌技术研究的最新进展和课题组多年的科学研究实践,总结阐述了滴灌诸要素如滴头流量、滴水元件间距、滴灌带铺设距离对土壤水分分布的影响;滴灌灌溉制度的制定;滴灌对小麦耗水特性、干物质积累和产量构成等方面调控作用研究成果提出未来小麦滴灌技术的发展方向即融合气象、土壤和作物多要素的智慧灌溉决策和水肥一体化技术,以期为加快我国在小麦主产区滴灌技术的应用推广提供理论与技术支撑。

地下膜调控润灌对冬小麦土壤水分及生长的影响

【目的】探索地下膜调控润灌下冬小麦适宜灌溉制度。【方法】针对地下膜调控润灌,设定300 m^(3)/hm^(2)(W1)、450 m^(3)/hm^(2)(W2)和600 m^(3)/hm^(2)(W3)3种灌水定额,采取连续灌溉(S1)、间歇灌溉(S2)和传统畦灌(CK)3种灌水模式,通过灌水定额与灌水模式田间小区组合试验,研究土壤水分分布和冬小麦的生长性状、耗水规律、产量构成和水分利用效率。【结果】①W3S1处理和W3S2处理较CK灌溉水更集中分布于作物根系层,下渗量减少,提高了株高、籽粒产量和水分利用效率(WUE);②地下膜调控润灌下,随着灌水定额的增加,20~60 cm土层土壤含水率增加;S2处理较S1处理可降低灌溉水向80~100 cm土层下渗;③冬小麦各生育阶段株高、叶面积指数(LAI)和全生育期耗水量均和灌水定额呈正相关;灌水模式对株高和LAI的影响不显著,但可显著提高全生育期耗水量;④随着灌水定额增加,S2处理较S1处理分别增产6.52%、13.11%和3.46%,籽粒产量和WUE呈现先增加后减少的趋势。【结论】相较于CK,地下膜调控润灌可实现节约灌溉用水并提高产量,综合考虑灌后土壤水分分布、作物生长性状、耗水规律、产量和WUE,W2S2处理是最优的灌溉制度,可以在获得更高籽粒产量的同时,提高WUE。

淮北平原干旱胁迫对夏大豆土壤耗水量及产量的影响

为探究不同干旱水平在各生育期对夏大豆在砂姜黑土与黄潮土中的影响及差异,基于2022年五道沟实验站桶栽受旱试验,在夏大豆分枝期、花荚期、鼓粒成熟期通过水分控制,设置轻旱、中旱、重旱3个干旱水平与全生育期无旱对照(CK),分析各生育期不同干旱水平胁迫对夏大豆在两种土壤中耗水量、产量、水分利用效率(WUE)的影响及差异。结果表明:(1)两种土壤中夏大豆各生育阶段随干旱加重耗水量呈减小趋势,重旱减小最显著;砂姜黑土中耗水量各受旱组小于对照组,黄潮土除分枝期轻旱外耗水量均低于对照组,且耗水量减少水平除鼓粒成熟期轻旱均小于砂姜黑土。(2)两种土壤重旱对产量影响最强烈,鼓粒成熟期重旱减产最严重;黄潮土花荚期不同受旱水平减产率均低于砂姜黑土,分枝期各受旱组砂姜黑土减产率低于黄潮土。(3)两种土壤花荚期、鼓粒成熟期WUE随干旱程度加剧呈明显递减趋势,重旱影响下WUE减小明显,鼓粒成熟期重旱对WUE影响最严重;受旱减产水平在不同生育阶段存在差异,使得花荚期黄潮土各处理组WUE均高于砂姜黑土,分枝期黄潮土WUE均低于砂姜黑土。