Water Conservation Capacity Research Articles

Physiological responses of five plants in northwest China arid area under drought stress

Effects of drought stress on photosynthetic characteristics, water status, physiological and biochemical indexes were studied in five arid area plants in northwest China, including Potentilla fruticosa, Lycium ruthenicum, Caryopteris mongholica, Caragana korshinskii and Hedysarum scoparium, using pot experiments. The results showed that with the prolongation of drought stress, the water conservation capacity of leaves totally increased in above five plants, the leaf relative water content rose first and then fell, and the relative chlorophyll content and chlorophyll fluorescence parameters decreased to some extent. Overall, the photosynthetic system of H. scoparium and L. ruthenicum least affected by the stress, and P. fruticosa suffered with the most serious damage. The electric conductivity and malondialdehyde (MDA) content of P. fruticosa firstly decreased and then sharply increased, while superoxide dismutase (SOD) and peroxidase (POD) activities firstly increased and then dramatically decreased. With the decrease of soil water content, the electric conductivity rose firstly and then fell in the other four plants,the change of MDA content rose first and then fell, or fell first and then rose, and the activities of SOD and POD almost displayed upward trend. Especially, SOD activity of C. mongholica and POD activity of H. scoparium had the biggest increment among the five plants after 28 days of drought stress, increasing by 1.1 and 13.1 times respectively, compared with before processing. Additionally, there was significant variance in the accumulation of organic solutes among the five plants during the drought stress treatment. The accumulation of soluble sugar and free proline was the most in P. fruticosa, increasing by 1.1 and 22.4 times respectively, after 28 days of drought treatment. H. sco-parium accumulated the most soluble protein, increasing by 1.0 times after 28 days of drought treatment. The result of membership function method showed that the drought tolerance decreased in order of H. scoparium ＞ L. ruthenicum ＞ C. korshinskii ＞ C. mongholica ＞ P. fruticosa. The research revealed that all five plants could make positive response to drought stress through improving the activity of antioxidant enzymes and accumulating organic solutes, which could help to reduce cell damage. P. fruticos was most sensitive to water deficit in the five plants, and the degree of drought had exceeded its own regulated capacity threshold during the experiment.

Study of the Runoff Depth and Its Processes of Eucalyptus Plantations Natural Watersheds

The runoff and runoff process of <i>Eucalyptus</i> plantations natural watersheds were studied to provide guidance for scientific evaluation of water conservation capacities of <i>Eucalyptus</i> plantations, compared with the <i>Pinus massoniana</i> forest natural watersheds. The runoff volume of <i>Eucalyptus</i> plantations and <i>P. massoniana</i> forest natural watersheds were continuously monitored using the small watershed runoff monitoring method and the automatic data collection devices from August, 2013 to December, 2015, and effects of heavy rainfall and continuous rainfall on the runoff process were studied. Results show that the annual runoff coefficient of <i>Eucalyptus</i> plantations natural watershed were 0.046, and 55.8% lower than <i>P. massoniana</i> forest (0.104), with the difference being significant (P&lt;0.01). The runoff duration, time lags, maximum runoff of rainfall, and runoff depth amounts caused by a heavy rainfall process (amounting to 65.5 mm) between the two kinds of forest watershed were significant different, those of <i>Eucalyptus</i> plantations were 8.5 h, 25 min and 2.69 mm, respectively, while those of <i>P. massoniana</i> forest were 18.4 h, 55 min and 5.52 mm, respectively. <i>Eucalyptus</i> plantations natural watershed produced only 4-days runoff, and runoff depth amounted to 3.8 mm with a 7 days continuous precipitation process of rainfall with 125.0 mm, while <i>P. massoniana</i> forest produced continuously 13-days runoff, and the runoff depth was 10.1 mm. In conclusion, water conservation capacity of <i>Eucalyptus</i> plantations is obviously lower than <i>P. massoniana</i> forest.

Divergent Adaptive Strategies by Two Co-occurring Epiphytic Orchids to Water Stress: Escape or Avoidance?

Due to the fluctuating water availability in the arboreal habitat, epiphytic plants are considered vulnerable to climate change and anthropogenic disturbances. Although co-occurring taxa have been observed divergent adaptive performances in response to drought, the underlying physiological and morphological mechanisms by which epiphyte species cope with water stress remain poorly understood. In the present study, two co-occurring epiphytic orchids with different phenologies were selected to investigate their drought-resistance performances. We compared their functional traits, and monitored their physiological performances in a 25-days of drought treatment. In contrast to the deciduous species Pleione albiflora, the evergreen species Coelogyne corymbosa had different root anatomical structures and higher values for saturated water content of pseudobulbs. Moreover, plants of C. corymbosa had thicker leaves and epidermis, denser veins and stomata, and higher values for leaf mass per unit area and the time required to dry saturated leaves to 70% relative water content. However, samples from that species had lower values for net photosynthetic rate (An), stomatal length and chlorophyll content per unit dry mass. Nevertheless, due to greater capacity for water storage and conservation, C. corymbosa maintained higher An, stomatal conductance (gs), and instantaneous water-use efficiency during severe drought period, and their values for leaf water potential were higher after the water stress treatment. By Day 10 after irrigation was restarted, only C. corymbosa plants recovered their values for An and gs to levels close to those calculated prior to the imposition of water stress. Our results suggest that the different performance responding to drought and re-watering in two co-occurring epiphytic orchids is related to water-related traits and these two species have divergent adaptive mechanisms. Overall, C. corymbosa demonstrates drought avoidance by enhancing water uptake and storage, and by reducing water losses while P. albiflora employs a drought escape strategy by fixing more carbon during growing season and shedding leaves and roots at dry season, leaving a dormant pseudobulb to minimize transpiration. These findings may improve our understanding of the potential effects that climate change can have on the population dynamics of different epiphytic taxa.

Phenophysiological variation of a bee that regulates hive humidity, but not hive temperature.

Seasonal acclimatisation of thermal tolerance, evaporative water loss and metabolic rate, along with regulation of the hive environment, are key ways whereby hive-based social insects mediate climatic challenges throughout the year, but the relative importance of these traits remains poorly understood. Here, we examined seasonal variation in metabolic rate and evaporative water loss of worker bees, and seasonal variation of hive temperature and relative humidity (RH), for the stingless bee Austroplebeia essingtoni (Apidae: Meliponini) in arid tropical Australia. Both water loss and metabolic rate were lower in the cooler, dry winter than in the hot, wet summer at most ambient temperatures between 20°C and 45°C. Contrary to expectation, thermal tolerance thresholds were higher in the winter than in the summer. Hives were cooler in the cooler, dry winter than in the hot, wet summer, linked to an apparent lack of hive thermoregulation. The RH of hives was regulated at approximately 65% in both seasons, which is higher than unoccupied control hives in the dry season, but less than unoccupied control hives in the wet season. Although adaptations to promote water balance appear more important for survival of A. essingtoni than traits related to temperature regulation, their capacity for water conservation is coincident with increased thermal tolerance. For these small, eusocial stingless bees in the arid tropics, where air temperatures are relatively high and stable compared with temperate areas, regulation of hive humidity appears to be of more importance than temperature for maintaining hive health.

Assessment of Ecosystem Water Conservation Value In The Beijing Four Seasons Flower Valley

Based on the data of field investigation and multi-source data analysis, Beijing Four Seasons Flower Valley declared in 2008 towards valley economy water conservation function and value was estimated by means of rainfall storage capacity as well as ecological economy. The results showed that: Landscape structure of FSFV was forest land-cultivated land-grassland. FSFV had the highest water conservation function in Beijing valleys, with the capacity of 1101.13 m3/hm2. Annual total amount of water conservation was 31.20×106 m3, accounting for 10.07% of Beijing valleys, and the total value of water conservation was 3.61×108 Yuan. High water conservation capacity areas were mainly located in the eastern mountainous region with broadleaf forest centralized distribution. Low water conservation function areas were mainly occurred in the regions effected by human activities. Forest ecosystem had the highest capacity of water conservation of 1116 m3/hm2, while construction ecosystem had the lowest. Higher degree of human activities, lower capacity of water conservation. Shrub forest and broadleaf forest had the largest contribution on valley water conservation, with contribution rate of 36.35% and 35.62%. Ranking of water conservation capacity, broadleaf forest had the highest value of 1135 m3/hm2, followed by coniferous forest, shrub forest and mixed forest.

Differential water and soil conservation capacity and associated processes in four forest ecosystems in Dianchi Watershed, Yunnan Province, China

The soil and water conservation capacity of forest ecosystems is closely associated with precipitation, runoff, sediment delivery, and the export of the nutrients nitrogen (N) and phosphorus (P) from forest soil. Research has investigated the potential for decreasing runoff pollution from watersheds by improving the function of forest ecosystems in conserving soil and water. Four typical forest ecological systems, including Pinus armandii forest, Yunnan pine forest, mixed broadleaf-conifer forest, and broad-leaved forest, were compared for vegetation community structure and species diversity; water-holding capacity in canopy, litter and soil layers; and the relationship with surface runoff and the export of sediment, N, and P during the 2013 rainy season. The species number and species richness were in the range of 10 to 22 and 4.68 to 7.94, respectively. The Shannon-Wiener Index, Simpson Index, and Pielou Index were 0.95 to 1.67, 0.43 to 0.68, and 0.50 to 1.04, respectively. Canopy interception rate increased with decreasing precipitation. The linear correlation equation of the two parameters was described as I = −2.768x + 64.318, where I = the canopy interception rate (mm) and x = rainfall amount (mm). The broad-leaved forest had the greatest interception rate because of its dense canopy. Litter storage in the four forest ecosystems ranged from 7.31 to 11.98 t ha−1 (6,527 to 10,698 lb ac−1); the highest litter yield was found in the broad-leaved forest. In this ecosystem, both the undecomposed and semidecomposed litter had the most water retention capacity (14.02 t ha−1 [12,519 lb ac−1] and 14.71 t ha−1 [13,136 lb ac−1], respectively) and effective water interception rate (8.18 t ha−1 [7,304 lb ac−1] and 9.01 t ha−1 [8,045 lb ac−1], respectively). In the 0 to 60 cm (0 to 23.6 in) soil layer, the broad-leaved forest had the greatest soil field capacity of 188.80 t ha−1 (168,598 lb ac−1) and 18.88 mm (0.74 in) water depth equivalent. The amount of surface runoff, sediment yield, and export of N and P increased with rainfall amounts, but the four forest ecosystems differed significantly in these properties. The ranges of sediment yield and export of total N and P were 13.1 to 344.2, 0.16 to 1.55, and 0.02 to 0.10 mg m−2, respectively. The broad-leaved forest formed an extremely dense canopy and had the highest maximum water-holding capacity, porosity, and soil field capacity. These properties made this ecosystem highly suitable for decreasing surface runoff and the export of sediments, N, and P from the forest soil.

English

Soil erosion is one of the biggest environmental problems. It is urgently needed to understand soil and water conservation capacity of different plantation types so that the best plantation type can be determined. In Qinjiagou watershed of Simian Mountain, Chongqing City, 18 indices were selected from canopy layer, litter layer, soil layer and topography to evaluate the soil and water conservation capacities of four common plantation types by ideal point method. Results indicated that the broadleaf plantation of robur (Lithocrpus glabra) and Chinese gugertree (Schima superba) (LS) has the biggest soil and water conservation capacity. The rank of three other plantation types from big to small is the mixed broadleaf plantation of sweetgum (Liguidambar formosana), Chinese gugertree and camphor tree (Cinnamomum camphora) (LSC), the mixed broadleaf-conifer plantation of Chinese fir (Cunninghamia lanceolata), Masson pine (Pinus massoniana) and Chinese gugertree (CPS), and the mixed Pine plantation of Chinese fir and Masson pine (CP). Under the same climate and topographical condition, the broadleaf plantation has better soil and water conservation capacity than the conifer plantation. Sensitivity analysis showed that the three most sensitive indices are soil non-capillary porosity, soil aggregation, and soil initial infiltration rate. The litter amount and soil properties are the most important indicators of soil and water conservation capacity of plantations. Therefore, suitable measurements such as deep tillage should be taken to improve the properties of soil under different plantations. &nbsp; Key words: Ideal point method, soil erosion, soil and water conservation, soil properties, sensitivity analysis.

Water-holding capacity of different forestlands 20 years after converted from farmland in loess region,western Shanxi Province.

To compare the water conservation capacity of four typical forest stands converted from farmland 20 years ago in loess region,western Shanxi Province,the maximum water-holding capacity( WCm) and effective water-holding capacity( WCe) of litter and soil layers in secondary forest( SF),Pinus tabuliformis plantation( P),Robinia pseudoacacia plantation( R) and P. tabuliformis × R. pseudoacacia plantation( P × R) were examined based on field investigations and laboratory analyses in July 2013,with the farmland as a control( CK). The results were as follows: 1) WCmand WCe of litter layer in secondary forest were 201. 20 and 154. 32 t / ha,respectively,which were 1. 35- 2. 14 times and 1. 33-2. 06 times of those in the plantations. Both WCmand WCeshowed the trend as P × R R P. 2)The WCeof the soil layer in four forest stands ranged between 5 102- 5 563 t / ha,and the WCewas 1 007-1 251 t / ha,which were significantly higher than 4 695 and 812 t / ha of the farmland( CK),respectively.The WCeshowed the trend as SF P × R P R,while WCmas SF P × R R P. 3) The WCeof the forestlands increased about 32. 9%-73. 1% and much higher than the WCmincrement about10. 7%-22. 8%,which was consistent with the changes of non-capillary porosity. This implied more significant effects of the conversion of farmland to forest( CFF) on WCethan WCm. 4) The water-holding capacity of the converted forestlands showed the trend as SF P × R R P with significantly higher WCmand WCethan the farmland. This was mainly resulted from the improvement of soil characteristics and then the increase of water-holding capacity in the soil,and also certain water-holding effect of litter layers. In general,the water-holding ability has been significantly improved through the CFF in loess area of western Shanxi Province. The water-holding capacity of the secondary forest was better than the other three plantations,indicating that the secondary forest should be the main type of vegetation restoration in CFF program in the loess region.

Assessment on 2000-2010 Ecosystem Function Changes of Yiwulvshan National Nature Scenic Area

Based on the remote-sensing data and ground data, this study is conducted on the ecosystem function of Yiwulvshan National Nature Scenic Area (hereinafter as “Yiwulvshan Scenic Area”) from 2000 to 2010 with the GIS (geographic information system) and RS (remote sensing) technology, so as to provide reference for better environmental protection of the scenic area. It is shown from the results that there is no obvious change of land use in Yiwulvshan Scenic Area; while the capacity for soil and water conservation is slightly improved mainly due to increase of vegetation coverage; the vegetation net primary productivity declines somewhat about 5.27% in past 10 years; and biodiversity is slightly increased. As a whole, the ecosystem function of Yiwulvshan Scenic Area basically kept stable in the past 10 years, which indicated that the existing regulations can effectively protect the ecological function of the Scenic Area.

SWCF of Forest in Three-Gorges of Yangtze River

In Qinjiagou watershed of Three-Gorge of Yangtze River, 18 indices were selected from canopy layer, litter layer, soil layer and topography to evaluate the soil and water conservation capacities of four common plantation types by ideal point method. Results indicated that the broadleaf plantation of robur (Lithocrpus glabra) and Chinese gugertree (Schima superba) (LS) has the biggest soil and water conservation capacity. The rank of three other plantation types from big to small is the mixed broadleaf plantation of sweetgum (Liguidambar formosana), Chinese gugertree and camphor tree (Cinnamomum camphora) (LSC), the mixed broadleaf-conifer plantation of Chinese fir (Cunninghamia lanceolata), Masson pine (Pinus massoniana) and Chinese gugertree (CPS), and the mixed Pine plantation of Chinese fir and Masson pine (CP). Under the same climate and topographical condition, the broadleaf plantation has better soil and water conservation capacity than the conifer plantation. Sensitivity analysis showed that the three most sensitive indices are soil non-capillary porosity, soil aggregation, and soil initial infiltration rate. The litter amount and soil properties are the most important indicators of soil and water conservation capacity of plantations. Therefore, suitable measurements such as deep tillage should be taken to improve the properties of soil under different plantations.

The Water Conservation Capacity of the Ecotone of the Forest and Grassland in HulunBuir

Based on the remote sensing data and meteorological data of MODIS, this paper studied the water conservation capacity of different land use type of the ecotone of the forest and grassland in Hulun Buir with the help of the ArcGIS software. The results shows that the average of the water conservation capacity of 11 years of the whole ecotone of the forest and grassland in Hulun Buir is 62.78×108m3/yr. Among of these, the forest land accounts for 69.37% of the total water conservation capacity, and the grassland, the cultivated land and the unused land account for 23.36%, 3.67% and 3.60%. And the water conservation capacity of the four land use types presented a fluctuated improving trend. The average water conservation capacity in each year of the unit area of the ecotone achieved its maximum value, 498.43m3/hm2 ,in 2003, and achieved its minimum value,193.03m3/ hm2,in the year of 2007.

Evaluation of soil and water conservation capacities for plantations on the Simian Mountains of China

Eighteen indices were selected to evaluate soil and water conservation capacities of four different mixtures of plantations using the Ideal Point Method. Results indicate that a broadleaf plantation of robur (Lithocarpus glabra) and Chinese guger tree (Schima superba) had the best conservation capacity, a mixed broadleaf plantation of sweetgum (Liquidambar formosana), Chinese gugertree and camphor tree (Cinnamomum camphora) was ranked second. A mixed broadleaf–conifer plantation of Chinese fir (Cunninghamia lanceolata), Masson pine (Pinus massoniana) and Chinese gugertree ranked third with a mixed coniferous plantation (Chinese fir and Masson pine) fourth. Under similar climates and topographical conditions, broadleaf plantations have better soil and water conservation capacities than conifer plantations. Sensitivity analysis showed that litter amounts and soil properties are the most important indicators of soil and water conservation capacities of plantations. Suitable measures such as deep tillage should be used to improve soil aggregation in different plantations.

遂昌县主要森林类型水源涵养与保育土壤功能及其价值评估

对浙江省遂昌县的6种主要森林类型的水源涵养量与固土保肥量及其价值进行研究。结果表明：1) 年水源涵养能力最强的是阔叶林(32930.46万m3)，产生价值270052.85万元；年保育土壤能力最强的同为阔叶林(251.79万t)，产生总价值28028.89万元，因此，该地阔叶林涵养水源与保育土壤所产生的经济价值最高；2) 单位面积年水源涵养量最大的森林类型是毛竹(0.51万m3ohm-2)，其产生的经济效益4.15万元ohm-2；年保育土壤最优的森林类型是阔叶林(38.06 tohm-2)，其直接产生经济价值0.42万元ohm-2；对于水源涵养与保育土壤功能最强的森林类型是阔叶林，年产生价值4.51万元ohm-2。由于水源涵养与保育土壤功能是森林生态服务功能中最为重要的两个功能，本研究中得出阔叶林与毛竹在遂昌县研究森林生态系统服务功能总体性评价上，有着重要的影响力。因此，在遂昌县的生态林业建设决策中，建议增加阔叶林的比例，加快“针改阔工程”步伐，大力发展毛竹，以产生更大的森林生态效益。 This paper is an investigation on soil and water conservation capacity and its value of 6 forest types in Suichang, Zhejiang province. The results showed that: 1) The maximum water-capacity was broad-leaved forest, the annual total amount and value of water conservation was respectively 329.3046 million stere and 2700.5285 million yuan; the maximum soil-capacity was broad-leaved forest, the annual total amount and value of soil and fertilizer con- servation was respectively 2.5179 million t and 280.2889 million yuan. Therefore the broad-leaved forest occupied dominant economic status in six forest types of Suichang County. 2) The maximum water-capacity was bamboo forest (Phyllostachys pubescens) in unit area scale, the annual amount and value of water conservation was respectively 5100 stere and 41,500 yuan per hectare; the maximum soil-capacity was broad-leaved forest, the annual total amount and value of soil and fertilizer conservation was respectively 38.06 t and 4200 yuan per hectare. Therefore the broad-leaved forest occupied dominant status in water and soil conservation capacity, and the annual total value of broad-leaved for- est was 45,100 yuan per hectare. For water conservation and soil conservation are the most important functions of forest ecosystem services, the search holds that broad-leaved forest and bamboo forest (Phyllostachys pubescens) have sig- nificant influence in studying the general assessment of forest ecosystem services in Suichang County. Consequently, the research suggests increasing the broad-leaved forest proportion; speeding up transforming the coniferous forest into the broad-leaved forest project, and developing bamboo forest (Phyllostachys pubescens) to produce more forest eco- logical benefits.

Rotational Tillage Improves Photosynthesis of Winter Wheat during Reproductive Growth Stages in a Semiarid Region

Tillage is important for soil water conservation and it affects crop growth, photosynthesis, and yield by adjusting soil water status in semiarid areas. A field study was conducted between 2007 and 2010 in the semiarid area of southern Ningxia, China, to determine the effects of rotational tillage practices on soil water status, flag leaves photosynthetic characteristics of late growth stage winter wheat (Triticum aestivum L.), and grain yield. Three tillage treatments were tested: no‐tillage in Year 1, subsoiling in Year 2, and no‐tillage in Year 3 (NT/ST/NT, respectively); subsoiling in Year 1, no‐tillage in Year 2, and subsoiling in Year 3 (ST/NT/ST, respectively); and conventional tillage over Years 1 to 3 (CT). Compared with CT, the mean soil water storage during the wheat growing season was significantly (p = 0.0305) higher at 0‐ to 2.0‐m depth with NT/ST/NT (+9.1%) and ST/NT/ST (+9.8%). The rotational tillage treatments significantly increased the net photosynthetic rate (PN), and transpiration rate (E) during the late growth stage. Greater intrinsic water use efficiency (WUEi) was achieved with NT/ST/NT (+13.4%) and ST/NT/ST (+19.2%) at the filling stage when compared with CT. Meanwhile, rotational tillage treatments produced higher levels of maximal photochemical efficiency of photosystem II (PSII) (Fv/Fm) in darkness, actual photochemical efficiency of photosystem II (φPSII) in light, and photosynthetic electron transport rate (ETR). Compared with CT, rotational tillage significantly increased wheat yields by 9.6% (NT/ST/NT) and 10.7% (ST/NT/ST). Overall, the results indicated that rotational tillage enhanced water conservation capacity, significantly improved crop photosynthetic characteristics and yield.

Capacity for water conservation in invasive ( Gerbillus nigeriae) and declining rodents ( Taterillus pygargus and Taterillus gracilis) that exhibit climate-induced distribution changes in Senegal

Following the southward shift of rainfall isolines in the Sahel at the end of the 1960s, Gerbillus nigeriae appeared in northern Senegal in the mid-1990s, and two resident Gerbillidae ( Taterillus pygargus and Taterillus gracilis) subsequently declined. We investigated the causal role of the capacity to conserve water in such climate-related shifts in the distribution of these Gerbillidae by comparing the effects of a water-poor diet on the water-efflux rate (W −out) of freshly trapped adults pre-acclimatized to a water-rich diet. During the 12-day period of water restriction in all species, 30–50% of individuals became hyperactive and showed greater weight loss and higher W −out than the remaining inactive individuals. Such emergence of migratory strategists within populations could accelerate the expansion of G. nigeriae. On a water-poor diet, T. gracilis showed a lower capacity to conserve water (higher W −out) than T. pygargus and G. nigeriae, in both inactive (W −out = 44.5 ± 1.8 vs 29.6 ± 0.8 vs 27.4 ± 0.7 ml kg −0.82.day −1, respectively) and hyperactive individuals (W −out = 60.4 ± 1 vs 45.4 ± 0.7 vs 44 ± 0.8 ml kg −0.82.day −1, respectively). We propose that the capacity to conserve water accounted for both expansion of G. nigeriae and decline of T. gracilis, whereas competition between T. pygargus and G. nigeriae could account for the decline of T. pygargus.

Regional differences of water conservation in Beijing’s forest ecosystem

The water conservation capacities of main forests in Beijing, China were estimated through the quantitative analysis. Various methods developed in published papers on forest hydrology were employed. The forests in Huairou, Yanqing, Miyun, Mentougou and Fangshan districts are the main contributors to water conservation (the cumulative ratio reaches 65%), and the forests in Tongzhou, Chaoyang, Shunyi and Daxing districts have the highest water conservation capacity (3000 m3/ha). Altitude and slope are the key factors to affect the water conservation capacity. The forests located in Plain Area, Hilly Area, Low Mountain, and Middle Mountain contributes 27%, 28%, 24% and 21% of the conserved water, respectively. The water conservation capacity of forests in Plain Area (2 948 m3/ha), is superior to the forests in other regions. And the forests situated on Flat Slope, Moderate Slope and Gentle Slope constitute the largest proportion (nearly 93%) of water conservation, while the forests on Flat Slope has the highest water conservation capacity (2 797 m3/ha), and the forest on Steep slope has the lowest water conservation capacity (948 m3/ha).

Implementing Landscape Water Conservation in Public School Institutional Settings: A Case for Situational Problem Solving1

Kilgren, Douglas C., Joanna Endter‐Wada, Roger K. Kjelgren, and Paul G. Johnson, 2010. Implementing Landscape Water Conservation in Public School Institutional Settings: A Case for Situational Problem Solving. Journal of the American Water Resources Association (JAWRA) 46(6):1205–1220. DOI: 10.1111/j.1752‐1688.2010.00486.xAbstract: Urban water conservation programs and research generally focus on residential and commercial use while paying less attention to institutional settings. We studied irrigated landscape water conservation at public schools, controlling for type of irrigation system (manual vs. automated control) and water conservation interventions (control, directive, prescriptive, and educational). We monitored landscape water use to compare changes among interventions and irrigation systems to measured plant water needs and historical use. Interviews and diaries allowed the study of behavior among custodians managing landscape irrigation. Large irrigation system effects overshadowed impact of the interventions. Schools using automated systems had high landscape water use and substantial capacity for water conservation but actual savings varied among schools. Schools using manual systems were the opposite yet many still managed further reductions in response to interventions. Effectiveness of water conservation interventions depended upon the contexts in which they were applied. Interventions were more effective when they led to situational problem solving that integrated generalized scientific and technical knowledge with experiential knowledge. Our findings suggest ways for school districts to decide where, when, and how to intervene in promoting water conservation but caution school districts investing in automated‐irrigation systems, particularly if they will be operated remotely.

Biogeochemical effects of forest vegetation on acid precipitation-related water chemistry: A case study in southwest China

The elemental composition of rainwater, throughfall, and soil solutions of a forest ecosystem in the acid rain control region of southwest China was investigated during 2007-2008 to assess the acid buffering capacity of different forest covers. A possible seasonal distribution of wet deposition was identified. Sulfur was determined as the dominant acidification precursor in this region. The chemical composition of rainfall intercepted by the forest canopy was modified substantially; generally the ion concentrations were increased by dry deposition and foliar leaching. As an exception, the concentration of NH(4)(+) and NO(3)(-) decreased in throughfall, which was probably due to the absorption of nitrogen by the leaves. Elemental concentrations in soil solutions decreased with depth. The water conservation capacity of different forests was also evaluated. The most appropriate forest vegetation for water conservation and remediation of acid precipitation in this region was explored for the sake of ecosystem management, ecological restoration and economic development.

Aging and Disturbances of Thirst and Fluid Balance

Fluid and electrolyte homeostasis depend on a balance between the intake and output of water. Aging is characterized by reduced homeostatic capacity. Changes in the control of both water intake and excretion accompany aging and may predispose the elderly to disturbances in sodium and water balance. Reduced thirst and water intake in response to water deprivation and thermal dehydration have been observed in healthy elderly persons. This reduction, combined with reduced renal water-conservation capacity, may predispose the elderly to dangerous dehydration when illness increases water losses or physical incapacity prevents access to water. The reasons for the thirst deficit are not clear. The elderly have a reduced capacity to excrete a water load, which means they are predisposed to water overload and hyponatremia. Furthermore, various neuroendocrine changes in the elderly affect fluid and electrolyte homeostasis. More studies are needed to understand the etiology of the disturbances of fluid intake and output so that they can be better prevented and treated.

Vertical characteristics of the Hani terrace paddyfield ecosystem in Yunnan, China

The Hani terrace paddyfield in Yunnan Province, China is categorized as a ‘constructed wetland’ under the Lamsar Convention classification. The Hani terrace paddyfield ranges from an altitude of 144 to 2000 m above sea level (ASL) in the southern slopes of the Ailao Mountains, angling down at a range of 15° to 75°. In this study, we investigated the ecosystem of the terrace paddyfields in the Mengpin and Quanfuzhuang administrative villages located at the center of the cultural heritage conservation district in the Hani terrace paddyfield. The Hani terrace paddyfield ecosystem structure is “forest-village-terrace paddyfield-river” in the order of descending altitude. Soil and water samples were sequentially taken from forests, villages and the terrace paddyfields to be able to study the vertical characteristics of Hani's terrace paddyfields. PO4-P and NH3-N in water were measured to test for water contamination. Seven soil nutrient factors were tested, including organic material (OM), char and nitrogen ratio (C/N), pH, total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), and available potassium (AK). Soil quality was also evaluated using the characteristics of the soil nutrient factors. Vertical changes in the landscape, wetland types, wetland plants, hydrology and soil nutrients were characterized. Results showed that: (1) Hani's terrace paddyfield can be divided into five types of wetlands; the rice varieties and cultivation patterns vary in each type of wetland. (2) Hani's terrace paddyfield has a great capacity for water conservation and a strong ability to purify contaminants. The impoundage of Hani's terrace paddyfield is about 5050 m3/hm2. Contaminants in the terrace paddyfield soils decrease exponentially with the decline in altitude. (3) Comparison of soil quality in five different land use types indicates decreasing soil quality from forest to terrace land to terrace paddyfield to water source. Except for headwater soil, single factors such as OM, TN and TP, and the comprehensive soil quality in individual sampling zones tend to increase with altitude elevation. Comprehensive soil quality in the Quanfuzhuang sampling zone is better than in the Mengpin sampling zone. Finally, a comparison of Hani's terrace paddyfield with plain paddyfields and natural wetlands highlighted the vertical characteristics of Hani's terrace paddyfield.