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An assessment is given of the hydrogeological potential of the Terek-Kuma sands of the Western Caspian region, the strata of which contain significant reserves of underground water (artesian, ground water) of the Caspian lowland, which are located near the feeding glaciers of the Greater Caucasus. In terms of their chemical composition, they are suitable for irrigating woody and herbaceous ameliorant crops, as evidenced by the long-term scientific and experimental experience of the Achikulak Research Forestry Experimental Station of the All-Union Scientific Research Institute of Agroforestry Reclamation (now the North Caucasus Branch of the Federal Scientific Center for Agroecology, Integrated Land Reclamation, and Protective Afforestation, Russian Academy of Sciences) on the sands of the Bazhigan massif, which provides a wide potential for the use of self-pressure (artesian) and free-flow (ground) underground water in oasis irrigation of sandy lands. Compared to the capital-intensive model of preliminary reservoir accumulation of self-flowing artesian waters for irrigating pastures, the project of using ground water for irrigating fodder phytocenoses directly from wells, by pulsed sprinkling using renewable energy sources (sun, wind energy), appears to be more profitable and faster to pay for itself. According to forecast estimates, the potential of the region's underground water is sufficient for hydromelioration of more than 100 000 ha of sandy lands in an arid territory. [ABSTRACT FROM AUTHOR]

Alfalfa is a forage species widely used in Uruguay in intensive livestock and dairy farming. Supplementary irrigation makes it possible to mitigate the negative effects of climate change, increasing and stabilizing the productivity of pastures. It is necessary to evaluate its joint effect with grazing. Two irrigation thresholds were evaluated, with entry of animals. The treatments were: frequent irrigation (30% depleted), spaced irrigation (65% depleted) and rainfed. The experimental design was complete randomized blocks, and 30 months of evaluation. The average annual yield of irrigated alfalfa was 25,333 and 23,177 kg DM ha-1, first and second year of evaluation, respectively. The accumulated production (30 months) did not show a significant difference between the irrigated treatments, but it did between irrigated and rainfed. In the last summer-autumn, the yield of all treatments fell to 8660 kg DM ha-1 (irrigated) and 1756 kg DM ha-1 (rainfed). Seasonal productivity indicates the convenience of irrigating alfalfa in summer since the yield increased 43% in the second year and 4.3 times more in the last year. Furthermore, after the extreme summer drought, in the following autumn, the irrigated treatments yielded 7 times more than the rainfed. Management with spaced irrigation and irrigation depth that do not return the soil to its field capacity increases the effectiveness of precipitation, saving water and energy allocated to irrigation. The apparent density increased towards the end of the experiment as a result of grazing, however, there was no difference between the evaluated irrigation managements.

ABSTRACT Iron mining tailings have limitations for plant growth and development due to low fertility, coupled with great restriction of physical characteristics such as low water retention, high density, and lack of structure. This study aimed to evaluate whether different irrigation depths applied to Xaraés grass grown in mining tailings influence its yield and bromatological aspects. The experiment was carried out in a completely randomized design with five irrigation depths (40, 60, 80, 100, and 120% of the crop evapotranspiration), two additional treatments consisting of grass grown in tailings with soil conditioner and in natural soil, and three repetitions. Forage dry mass, plant height, leaf: stem ratio, as well as neutral detergent fibre, acid detergent fibre, crude protein, and mineral matter content, were evaluated during four cutting cycles. Xaraés grass could establish and produce forage despite cultivation limitations in iron mining tailings, which are due to their properties. Irrigation depths showed positive and linear effects on Xaraés grass dry matter yield and heights of plants grown in iron mining tailings. The soil conditioner has potential for use in pasture cultivation in iron mining tailing.

Seasonality in tropical forage production is common in tropical and subtropical regions and should be identified for decision making on the stocking rate for each period. This study aimed to evaluate the variability of dry matter production of Megathyrsus maximum cv. Mombaça ‘Guinea grass’ over two years. The experiment was carried out from February 2016 to August 2018, under a randomised block design in a 2 × 4 factorial scheme, with four replications. Treatments consisted of (i) two growing years (2016/2017 and 2017/2018) and (ii) four seasons (spring, summer, fall, and winter). The grass was fertilised with 1,000 kg N ha−1 year−1 and sprinkler irrigated, with soil moisture monitored by tensiometry. The evaluated parameters consisted of leaf dry matter, stem dry matter and total dry matter production. The results showed that the irrigated Guinea grass reached an elevated production of dry matter (DM), with the highest yields occurring in the spring/summer period, evidencing the yiel gap in the autumn/winter. The grass showed high daily forage accumulation, expressing high productive potential, demonstrating a good indicator for animal production in intensive systems with irrigated and fertilised pastures for regions of tropical climate. Thus, Guinea grass showed great potential for use in livestock.

The Conservation Reserve Program (CRP) has been a major factor in land transitions out of intensive row-crop management on marginally productive lands in the central United States. While CRP can protect these more environmentally sensitive lands against erosion and potential nutrient loss, information on how CRP affects soil quality over time is limited. Using a chronosequence with 0-40 yr of CRP conversion history, we evaluated soil quality under different land use intensities (CRP, pasture, row crop) using the SoilManagement Assessment Framework (SMAF). Effects of slope classes (higher [14-25%] and lower [2-14%]) and soil depth (0-120 cm) were also evaluated. Our results show that the soils were functioning at 84 and 78% of their theoretical capacity under CRP and row crop, respectively. Conversion to CRP enhanced overall soil quality by increasing soil biological, physical, and chemical attributes, but soil nutrient availability decreased due to the absence of fertilizer application. Increasing soil organic C (SOC) enhanced overall soil quality because of its impact on soil biological, physical, chemical, and nutrient conditions. Conversion to CRP will likely have greater benefits for more environmentally sensitive soils (i.e., higher slope) as demonstrated by structural equation modeling. Land use effects were also depth dependent, with more prominent effects within the 0-to-5-cm than the 5-to-15-cm depth increment. Overall, our methods focused on key soil quality indicators, confirmed ecological benefits of CRP conversion, and provided guidance for improved and simplified land management recommendations. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the correlation among growing degree-days (GDD), canopy height (CH), and leaf area index (LAI) for Guinea grass irrigated, considering the different combinations of the nitrogen and boron rates and cycles of regrowth. The experiment was carried out from August/2017 to August/2018 in a field experiment, and the climate of the region is classified as subtropical. A randomized block design arranged in a factorial scheme (4x3x11) with four replications was used. The treatment was (i) boron fertilization: 0, 1, and 2 kg ha-1; and (ii) nitrogen fertilization: 250, 500, 750, and 1,000 kg ha-1 distributing to 11 growth/cutting cycles. We observed the high correlation between GDD and the parameters evaluated of CH and LAI. The nitrogen results showed a low influence on canopy height and the leaf area index, and boron results did not influence these parameters.

Copyright of Dyna is the property of Universidad Nacional de Colombia, Medellin, Facultad de Minas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Seasonality in tropical forage production is common in tropical and subtropical regions and should be identified for decision making on the stocking rate for each period. This study aimed to evaluate the variability of dry matter production of Megathyrsus maximum cv. Mombaça 'Guinea grass' over two years. The experiment was carried out from February 2016 to August 2018, under a randomised block design in a 2 × 4 factorial scheme, with four replications. Treatments consisted of (i) two growing years (2016/2017 and 2017/2018) and (ii) four seasons (spring, summer, fall, and winter). The grass was fertilised with 1,000 kg N ha−1 year−1 and sprinkler irrigated, with soil moisture monitored by tensiometry. The evaluated parameters consisted of leaf dry matter, stem dry matter and total dry matter production. The results showed that the irrigated Guinea grass reached an elevated production of dry matter (DM), with the highest yields occurring in the spring/summer period, evidencing the yiel gap in the autumn/winter. The grass showed high daily forage accumulation, expressing high productive potential, demonstrating a good indicator for animal production in intensive systems with irrigated and fertilised pastures for regions of tropical climate. Thus, Guinea grass showed great potential for use in livestock. [ABSTRACT FROM AUTHOR]

We sampled fish in pools located on tributaries of Cow Creek in the northern Sacramento Valley, and related fish distribution and habitat use to environmental factors across the 2003 agricultural growing season. This rangeland watershed experiences extensive livestock use, and many landowners divert stream water for pasture irrigation. Our goal was to provide landowners and managers with current baseline information about the conditions in which fish were found. Our results provide a basis for the development and comparison of irrigation best management practices that may improve conditions for native fish in rangeland streams.

Copyright of Revista IRRIGA - Brazilian Journal of Irrigation & Drainage is the property of Revista IRRIGA (Brazilian Journal of Irrigation & Drainage) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pastures are widely used due to characterizing a practical and economical way of feeding animals. In springsummer, the availability and quality of natural pastures decline due to uneven precipitation, making cultivated and irrigated pastures essential. Thus, forage sorghum is characterized as one of the best cultivation options, to cut and silage however, it needs adequate water availability to reach its production potential. The objective with this work was to evaluate the yield of forage sorghum in different irrigation depths, as well as the water use efficiency, in two agricultural years (2015/2016 and 2016/2017). The experiment was carried out in Santa Maria-RS, Brazil, with 6 treatments (0, 25, 50, 75, 100 and 125% of reference evapotranspiration) and 4 replicates, totaling 24 experimental units. The experimental desing was a randomized blocks. Seeds were harvested in November 2015 and 2016 with the cultivar AG2501. Statistically significant differences were found for productivity between the different treatments and also, among the agricultural years, as well as for water use efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Revista IRRIGA - Brazilian Journal of Irrigation & Drainage is the property of Revista IRRIGA (Brazilian Journal of Irrigation & Drainage) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study of the interaction between nitrogen, potassium and water content are important in defining the optimum doses of these factors in order to optimize the production of fodder. Thus, it had as objective in this study was to evaluate the effects of applying different water depths and nitrogen and potassium, in the production of Tanzania grass in southern state of Tocantins. To study the influence of water levels and combinations of N and K2O in the grass, the dry and wet periods of the year, it was determined during the experiment forage production. The highest yield in the same period was 8706 kg ha-1, with the dose of 576.79 kg ha-1 N: 0.8 K2O and water depth of 116% ETc, resulting in an increase of 246%. During the rainy season, the lowest yield was 6815 kg ha-1, a dose of 100 kg ha-1 yr-1 N: 0.8 K2O in the absence of irrigation. The highest yield in the same period was 11,710 kg ha-1, with the estimated dose of 672.9 kg ha-1 yr -1 N: 0.8 K2O and applied water depth of 120% of ETc, resulting in a increase of 71.8%. It was therefore concluded that work that the maximum dry matter yield estimated to the adjusted model was 20,216 kg ha-1 yr-1 obtained with the applied water depth equal to 949 mm and with the application of 630 kg ha-1 year-1 of nitrogen and potassium mixture in the ratio of a nitrogen unit for 0.8 potassium units.

The uptake of natural radioactivity by pasture-grass collected from seven different grasslands of Digor was calculated. The activities of 226Ra, 232Th and 40K in pasture-grass were in the range of 21.8 ± 6.3-49.6 ± 13.4, 51.9 ± 13.2-127.7 ± 23.8 and 309.5 ± 33.5-807.3 ± 64.4 Bq kg−1, respectively. The soil to pasture-grass transfer factors were evaluated and determined to be in the range from 0.26 ± 0.13 to 0.69 ± 0.34, 0.64 ± 0.27 to 1.99 ± 0.40 and 0.64 ± 0.014 to 1.40 ± 0.032 for 226Ra, 232Th and 40K, respectively. The distribution of 226Ra and 232Th in different parts of pasture-grass indicated a decreasing tendency in order of root > stem > leaf. 40K mainly accumulated in stem of pasture-grass and is followed by declining trend stem > leaf > root. [ABSTRACT FROM AUTHOR]

Robust information for water use on pasture-based dairy farms is critical to farmers' attempts to use water more efficiently and the improved allocation of freshwater resources to dairy farmers. To quantify the water requirements of dairy farms across regions in a practicable manner, it will be necessary to develop predictive models. The objectives of this study were to compare water use on a group of irrigated and nonirrigated farms, validate existing water use models using the data measured on the group of nonirrigated farms, and modify the model so that it can be used to predict water use on irrigated dairy farms. Water use data were collected on a group of irrigated dairy farms located in the Canterbury, New Zealand, region with the largest area under irrigation. The nonirrigated farms were located in the Manawatu region. The amount of water used for irrigation was almost 52-fold greater than the amount of all other forms of water use combined. There were large differences in measured milking parlor water use, stock drinking water, and leakage rates between the irrigated and nonirrigated farms. As expected, stock drinking water was lower on irrigated dairy farms. Irrigation lowers the dry matter percentage of pasture, ensuring that the amount of water ingested from pasture remains high throughout the year, thereby reducing the demand for drinking water. Leakage rates were different between the 2 groups of farms; 47% of stock drinking water was lost as leakage on nonirrigated farms, whereas leakage on the irrigated farms equated to only 13% of stock drinking water. These differences in leakage were thought to be related to regional differences rather than differences in irrigated versus nonirrigated farms. Existing models developed to predict milking parlor, corrected stock drinking water, and total water use on nonirrigated pasture-based dairy farms in a previous related study were tested on the data measured in the present research. As expected, these models performed well for nonirrigated dairy farms but provided poor predictive power for irrigated farms. Partial least squares regression models were developed specifically to simulate corrected stock drinking water, milking parlor water, and total water use on irrigated dairy farms. [ABSTRACT FROM AUTHOR]

Waterlogging is a stress of increasing importance for pastures as a consequence of global climate change. We evaluated the impact of waterlogging on four forage grasses with alleged differential tolerance, emphasising not only responses during the stress but also their reported ability to recover from it. To do this, 42-day plants of Dactylis glomerata, Bromus catharticus, Festuca arundinacea and Phalaris aquatica were subjected to 15-day waterlogging, followed by a subsequent 15-day recovery period. Shoot and root growth (i.e. RGR) during both periods, in addition to net photosynthesis and stomatal conductance rates during waterlogging were assessed. Sensitivity exhibited by D. glomerata and B. catharticus during waterlogging was related to growth arrest of roots - but not of shoots - along with a progressive fall in stomatal conductance and net photosynthesis. The injury during waterlogging preceded a negligible growth of shoots and roots, only evident during recovery in both species. By contrast, P. aquatica exhibited unaltered root RGR and promoted shoot RGR with no impact on leaf gas exchange during waterlogging; whereas F. arundinacea showed intermediate tolerance as root RGR was reduced during waterlogging, with stomatal conductance, net photosynthesis and shoot RGR remaining unaffected. These latter two species fully regained shoot and root RGR during recovery. So, P. aquatica and F. arundinacea seem more suitable for prone-to-flood lowlands, whereas to be conclusive about waterlogging tolerance, it is necessary to examine plant recovery as shown in D. glomerata and B. catharticus [ABSTRACT FROM AUTHOR]

Well-managed grazing systems can provide valuable ecosystem services, such as reducing sediment and phosphorus (P) loading to nearby waterways. However, the available long-term data to fully support this hypothesis are limited. In this article, we describe flow-weighted concentrations (FWCs) and loads for dissolved reactive P (DRP), total P (TP), iron (Fe), and aluminum (Al) over 11 years (1999-2009) from a 7.8 ha rotationally grazed pasture (W1) near Watkinsville, Georgia. The region is characterized by Fe and Al rich and acidic Ultisols. Cattle numbering 21 to 224 (mean 91) grazed W1 on 69 occasions for 1 to 71 d (mean 19.2). Of 74 runoff events, 20 occurred when the monthly rainfall was below the long-term average (deficit period) and 54 occurred during non-deficit periods. Samples were collected from 43 of 74 runoff events for nutrient analyses. Event FWC (mg L-1) ranged from 0.38 to 7.07 for DRP (mean 1.91), from 0.36 to 7.60 for TP (mean 2.43), from 0.03 to 0.55 for Fe (mean 0.23), and from 0.43 to 553 μg L-1 for Al (mean 65 μg L-1). Event load (kg ha-1) ranged from 0.00 to 0.45 for DRP (mean 0.10), from 0.00 to 0.55 for TP (mean 0.12), from 0.00 to 0.11 for Fe (mean 0.02), and from 0.00 to 0.10 for Al (mean 0.01). The total load (kg ha-1) was 4.12 for DRP, 5.12 for TP, 0.71 for Fe, and 0.25 for Al. DRP accounted for 80% of the TP FWC and load. Cattle presence increased sediment load, but the difference was not statistically significant. There was high correlation between Fe and DRP loads (r = 0.87), a likely indicator of erosion-induced losses due to cattle treading. Cattle presence increased FWCs but not loads for DRP and TP. The FWCs for DRP and TP were not different between deficit and non-deficit periods, but mean loads were 3-fold to 4-fold greater during non-deficit periods. Means from the six largest P loss events were 3-fold greater for FWC and 7-fold greater for load than the remaining 37 events. These six large events accounted for 53% of the total P load. Less than 1% of the inorganic P applied and redeposited through manure was lost in runoff. The study demonstrated that hydrologic transport processes were the dominant drivers of pollutant fluxes and highlighted the possible mitigation of pollutant fluxes through grazing management that includes maintenance of good grass cover, effective rotational grazing, and limited fertilization. [ABSTRACT FROM AUTHOR]

An experiment was carried out to assess rates and nitrogen fertilization strategies on the forage yield using irrigation to supply the water deficit during the dry season. The grasses Cynodon spp cv. tifton 85 and Brachiaria brizantha cv. Xaraés were cultivated with nitrogen (N) at levels of 200 and 400 kg/ha according to strategies: 1) half dose applied during the rainy season (RS) and half during the dry season (DS); 2) 1/3 during the RS and 2/3 during the DS; 3) 2/3 during the RS and 1/3 during the DS; 4) all doses applied during the DS. In each season the dose was divided in three applications. Eleven harvests were conducted: six in the RS and five in the DS. When 2/3 of N was applied in the DS, forage yield in this period was statistically equivalent to those obtained in the RS in three of the five harvests for both 200 and 400 kg/ha of N. With 100% of N applied in the DS, the yield of four of five cuts of forage was similar to that obtained in the RS for both rates of N. The strategy of applying more N in the DS rather than in the RS was effective, keeping the yield steadily throughout the year. The application of 100% of the dose of 200 kg/ha N and 2/3 of the dose of 400 kg/ha N both in the dry period, under irrigation, promote uniform productions per harvest throughout the year.

The objective of this study was to evaluate the effects of application of different irrigation and nitrogen (N), and potassium (K) in Xaraes grass yield in southern Tocantins. We used a mixture of fertilizer, so that combinations of N and K2O relationship of 1 N:0.8 K2O. To assess the effect of different depths of irrigation water and combinations of the concentrations of N and K2O Xaraes the grass was determined during the experiment the dry matter yield. The lowest yield in the dry season was of 4,486 kg ha-1, with the 100 kg ha-1 yr-1 N: 0.8 K2O, in the absence of irrigation, while the highest yield was of 9169 kg ha-1 at a dose of 700 kg ha-1 yr-1 N:0.8 K2O and water depth of 120% ETc, resulting in increased productivity of dry matter. The highest yield in the same period was 11,333 kg ha-1, with the application of the estimated maximum dose of 576.7 kg ha-1 N:0.8 K2O and the water depth of 120% of ETc, resulting in an increase 50 the dry period increased by 104% in the productivity of Xaraes grass with increasing rate of the mixture of N and K2O and the water depth. In the rainy season, there was a 50% increase in yield of Xaraes grass with increasing dose of N and K2O.

O dejeto líquido de suíno (DLS) pode constituir-se em excelente fonte de adubação em pastagem, com aplicação por aspersão, desde que seja assegurada a proteção do meio ambiente. Apesar de seu comprovado potencial para uso em sequeiro, pouco se conhece sobre o comportamento da cultivar Tifton 85 em sistemas sob irrigação e sob aplicação de DLS. Para determinar a produção de matéria seca pré-pastejo de Tifton 85 com DLS, foi conduzido um experimento na Fazenda-Escola da Universidade de Uberaba, irrigado por aspersão em malha, com aplicação de 0; 50; 100 e 200 m³ ha-1 ano-1 de DLS. Houve efeito significativo das doses de DLS em relação à produção de matéria seca pré-pastejo, ocorrendo acréscimos de produção com o aumento das doses. O fornecimento de 200 m³ ha-1 ano-1 de DLS possibilitou produção de 5.928 kg de matéria seca (MS) da forrageira por ciclo de 28 dias.Liquid swine dejection (LSD) can constitute excellent source of fertilization in pasture, with sprinkler irrigation system, provided the conditions that assure the protection of the environment. Although with proved potential for growth without irrigation, for the Cynodon sp cultivar Tifton 85 there is little information on its behavior and production in systems under irrigation and with LSD. In order to determine the production of dry matter in irrigated and with LSD fertirrigation, an experiment was carried out in the Farm-School of the University of Uberaba - MG, Brazil, with net-sprinkler irrigation system, applying 0, 50, 100 and 200 m³ ha-1 year-1of LSD. There was significant effect among the doses of LSD in the production of dry matter, occurring additions of production with the increasing the doses. The supply of 200 m³ ha-1 year-1 of LSD made possible the production of 5,928 kg of the forage dry matter for the cycle of 28 days.

The effects of different irrigation and nitrogen (N) on morphogenetic and structural characteristics of Marandu grass (Brachiaria brizantha var. Marandu), were evaluated. The study was conducted in the experimental area of EMBRAPA Mid-North in Parnaíba, Piauí, Brazil. In design in randomized blocks, factorial 2 x 4, irrigation levels were tested (equivalent to replacement of 50% and 80% of pan evaporation Class "A") x nitrogen levels (16.7, 33.3, 50.0 and 66.7 kg N / cutting), with three replications. Sections were made every 30 days, a total of four cuts. The reduction in water depth decreases in sheet provided elongation rate, leaf appearance, final leaf length and number of green leaves, while the increased rate of senescence. Nitrogen fertilization rates increased elongation and leaf appearance, and the final leaf length, however, caused a reduction in the number of living leaves and the expansion rate of senescence. [ABSTRACT FROM AUTHOR]

Background: Production of range grasses under irrigation has been widely adopted in the arid environments of Kenya as a strategy for seasonal forage supply gap. However, their productivity has only been done under conventional methods without an evaluation of their performance at varied soil moisture conditions. This information is needed for making sustainable management of irrigation water and also increased pasture productivity at the current intensification of the production systems. Methods: Aboveground biomass of six rangeland grasses ( Chloris roxburghiana, Eragrostis superba, Enteropogon macrostachyus, Cenchrus ciliaris, Chloris gayana, and Sorghum sudanense) in pure and mixed stands at 80, 50 and 30 % soil moisture field capacity (FC), and control under rainfed as main plots. The main plots were divided into 30 subplots and randomly allocated ten grass species in three replicates. The moisture content was monitored by gypsum blocks which aided in irrigation times and levels. Seeds were sown by broadcast method in tractor ploughed and harrowed to fine tilt land. Biomass and growth morphometric characteristics were measured at phenological growth stages of 10, 12 and 14 weeks, representing vegetative stage, flowering and seed setting and mature with ripened seed stages for the studied range grasses. Results: All the irrigated treatment yielded significantly (p ≤ 0.05) higher above ground dry matter than the rainfed. S. sudanense had the highest yields at 80 % FC (13.7 t ha), though not significantly different from the 50 and 30 % FC (11.6 and 7.7 t ha), respectively. C. gayana and C. roxbhurghiana yields were not significantly affected by changes in soil moisture content with yields ranging between 10.1 and 10.8 t ha. C. ciliaris performed better at 50 % FC (9.1 t ha). Differences in tiller numbers across the watering treatments and grass species were not significant, but very low under rainfed conditions. The tiller heights in all the species were lower under rainfed than irrigated treatments. S. sudanense had the highest tiller height and biomass followed by C. gayana and E. Macrostachyus, respectively. Conclusion: Here we demonstrate that the production of range pastures under irrigation in the arid environments should consider individual species' responses to different soil moisture content for better yields and water conservation. The results show the species of importance for consideration under irrigation systems are S. sudanense and C. gayana. [ABSTRACT FROM AUTHOR]

The conversion of forest into pasture affects several properties and functions of the soil including the cycling carbon and other nutrients. Changes in selected chemical and biological properties of the soil were studied in an area of intensive irrigated pasture (PAST) and compared to soil under native vegetation (NV). The selected soil properties evaluated were: total organic carbon (TOC), total nitrogen (TN), levels of N-NH 4 + and N-NO 3 − , humic substances (fulvic and humic acids and humin), physical fractionation of the soil organic matter, water-soluble carbon (WSC), C and N microbial biomass (MB-C and MB-N), C–CO 2 evolution, and the presence of spores of arbuscular mycorrhizal fungi. The conversion of forest into pasture, and the adopted management (rotational grazing, irrigation and fertilisation) led to significant increases in soil organic matter at the surface, when compared to natural conditions. Some losses however were also seen at deeper layers, as water-soluble carbon, indicating that irrigation of soils with a sandy texture should be better planned to avoid loss of organic matter and nutrients, or contamination of the groundwater. The greater metabolic quotient in PAST than in NV is an indication of the large loss of carbon (C), which may explain the C–CO 2 emissions and may demonstrate disturbances in an area of intense productivity with elevated levels of C. Labile organic matter, such as water-soluble or related to microbial activity, were the most sensitive to the effects of land use, reflecting behaviour that can compromise the use of land as pasture under the conditions of this study. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dairy farmers in the southern Murray-Darling (M-DB) of Australia are considering subsurface drip irrigation (SDI) for pasture production in response to reduced water supply. Use of SDI in pasture production is a significant departure from previous SDI knowledge because in pasture irrigation (1) uniform moisture, nutrients and pasture growth is sought across the full paddock width, (2) the pasture is grazed by dairy cattle, and (3) is grown on duplex soils with distinctive hydraulic behaviour. A field experiment was conducted on two dairy farms with contrasting subsoil hydraulic characteristics to investigate the impact of SDI design (tape spacing) and operation (irrigation frequency) on pasture productivity and hydrology under grazed conditions. Treatments comprising of tape spacing (0.6, 1.0 and 1.4 m) and irrigation frequency (D or 4D) were imposed. SDI successfully supported contiguous perennial pasture under grazing during a period of drought. The impact of SDI design and operation on pasture accumulation and its spatial variability differed strongly between sites, reflecting soil hydraulic characteristics. Pasture composition and irrigation efficiency were insensitive to SDI design and operation at both sites. Water balance analysis indicated that deep percolation was the main pathway for water loss in SDI pasture production, though the dominance of this over surface runoff will be influenced by soil hydraulic properties. SDI can support grazed pasture production on the duplex soils of the southern M-DB; however, its performance may be insufficient to offset the high economic cost of SDI technology. [ABSTRACT FROM AUTHOR]

The use of veterinary pharmaceuticals in beef cattle has led to concerns associated with the development of antibiotic resistance in bacteria and endocrine disruption in aquatic organisms. Despite the potential negative consequences, data on the transport and mitigation of pharmaceuticals in grazed watersheds with irrigated pasture are scarce. The objective of this study was to assess the transport of common beef cattle pharmaceuticals (oxytetracycline, chlortetracycline, and ivermectin) via surface runoff and leachate from manure amended to grass-vegetated soil boxes under irrigated pasture conditions. The transport of pharmaceuticals from animal manure in surface runoff and soil leachate was relatively low and appears to be limited by desorption and transport of pharmaceuticals entrained in the manure. In surface runoff, less than 4.2% of applied pharmaceuticals in manure (initial concentration: 0.2 mg kg-1 of manure) was detected after 3 wk of irrigation. Concentrations of pharmaceuticals in surface runoff and leachate never exceeded 0.5 μg L-1. The major portion of pharmaceuticals (up to 99%) was retained in the manure or in the soil directly beneath the manure application site. Based on the minimal transport of oxytetracycline, chlortetracycline, and ivermectin, the risk of significant transport for these targeted beef cattle pharmaceuticals to surface water and groundwater from manure on irrigated pasture appears to be relatively low. [ABSTRACT FROM AUTHOR]

Water-spreading banks are used in semi-arid areas such as the Cobar pediplain in western New South Wales, Australia to encourage pasture growth, often after removal of woody encroachment. We studied the arrangement of bare inter-patches and vegetated patches, and associated surface soil variables, in three pastures following installation of water-spreading banks (2, 15, 38 years ago) and in an area of woody encroachment near Cobar. The aims of the study were as follows: (i) to determine the number and percent area of inter-patches and vegetated patches, and associated surface soil variables at the three pasture sites and at the woody encroachment site and (ii) by inference, explore effects of establishing water-spreading banks and pasture following removal of woody encroachment on these factors, to understand the role of water-spreading banks as a management tool. The percent area of inter-patches in pasture with 38-year-old water-spreading banks was much lower, and the percent area of medium-vegetated patches (but not of well-vegetated patches) was substantially higher, than in the woody encroachment. Differences in soil carbon and nitrogen between the sites were related to their percent areas of inter-patches and vegetated patches. The results suggest that the mosaic of bare inter-patches and vegetated patches changes over time after clearing of woody encroachment and establishment of pasture with water-spreading banks, from many large inter-patches to a few small inter-patches, and from small to large medium-vegetated patches. Water-spreading banks are a useful management tool in these landscapes because of their benefits for landscape function, that is, bare areas become less connected, the percent area of moderately vegetated patches increases, and soil carbon builds up with time following their installation. [ABSTRACT FROM AUTHOR]

The plant cover of the natural pasture on the solonetz and saline smonitza located in the vicinity of the town of Bocar (Serbia - the Vojvodina Province - Banat) are characterized by 135 taxa (119 species, 5 subspecies, 4 varieties, 6 forms and 1 lusus). 126 taxa were listed i.e. 119 species, 5 subspecies and, because of their ecological characteristics, two varieties Aster tripolium L. var. pannonicus (Jacq.) Beck and Glyceria fluitans (L.) R. BR. var. poaeformis Fies. These varieties were put on the list because their higher taxonomic categories were not found in the studied flora. Specific features of the plant cover of the studied area are result of their ecological, phytocoenological and plant-geographic characteristics. Ecological characteristics result from 42 halophyte taxa (33.33%) with the ecological index S+. Phytocoenological elements are stands of one phytocenoses from Phragmitetea Tx. et Prsg. 1942 class (Ass. Bolboschoenetum maritimi continentale) and ten phytocenoses from Festuco-Puccinellietea Soó 1968 class (Ass. Puccinellietum limosae, Ass. Pholiuro-Plantaginetum tenuiflorae, Ass. Hordeetum histricis, Ass. Camphorosmetum annuae, Ass. Agrostio-Alopecuretum pratensis, Ass. Agrostio-Beckmannietum, Ass. Agrostio-Eleochariti-Alopecuretum geniculati, Ass. Halo-Agropyretum repentis, Ass. Artemisio-Festucetum pseudovinae i Ass. Achilleo-Festucetum pseudovinae). Plant-geographic characteristics of studied area are endemic species of Pannonian Plain Plantago schwarzenbergiana Schur and Statice gmelini subsp. hungaricum (Klokov) Soó and also subendemic species of Pannonian Plain Puccinellia limosa Holmb. and Roripa kerneri Menyh. Based on 33.33% of recorded taxa, which are characterized by S+, stands of 11 phytocenoses that are characteristic of saline sites and the presence of two Pannonian and two Subpannonian elements of flora we can conclude that natural pasture located in vicinity of the town of Bocar (Banat-Serbia) is part of halobiom of the Pannonian Plain region. [ABSTRACT FROM AUTHOR]

Subtle changes in soil pore size and shape as a consequence of changes in land use and management practices can have significant impacts on the movement of air, water, plant roots and soil biota. This paper describes a resin impregnation technique adapted for use in New Zealand pasture soils to quantify these soil pore attributes. Image analysis of the resin impregnated soil enables detailed assessment of soil pore shape and macro pore size distribution (>50 µm). [ABSTRACT FROM PUBLISHER]

Nitrogen (N) fertilizer increases pasture production in New Zealand in a near linear manner and affects pasture composition, soil below-ground communities and N losses. We monitored N fertilized plots established in long-term low-fertility pasture over different time periods to compare changes in N availability on below-ground soil communities (particularly ammonia-oxidizing archaea [AOA] and ammonia-oxidizing bacteria [AOB] as they appear to be sensitive to change). Although the most significant effects were seen in the 30 gN (300 kg/ha) treatment, there were indications that even 5 gN had effects on archaea. AOA gene copies dominated in control and 5 gN treatments but decreased in the 10 gN treatment. The ratio of AOA to AOB in 10 gN was lower and more similar to 30 gN suggesting that the AOA/AOB ratio may be a sensitive indicator of change in N status. In the 30 gN treatment, both the soil C/N ratio and the fungal phospholipid fatty acids were reduced (consistent with changes in DNA profiles) and microbes were suppressed. The number of AOB gene copies significantly increased in this treatment and corresponded to a switch from ammonium-N to nitrate-N as the dominant inorganic form of N in the 56-day incubation. This was consistent with increased soil ammonium-N and nitrate-N concentrations, leading to increased nitrate-N leaching that occurred at a threshold of between 10 gN and 30 gN, and suggesting that, with 30 gN, nitrification and nitrate leaching are influenced more by AOB than archaea. Generally there was no significant change in mesofauna, microfauna or bacterial DNA profiles with the treatments. In a high-fertility pasture, DNA profiles for bacterial, fungal and archaeal groups clustered away from low-fertility pasture suggesting that changes in soil communities, with increased soil fertility, take more time to be fully expressed. [ABSTRACT FROM PUBLISHER]

Soil invertebrates have limited defences against moisture stress but little is understood of how irrigation influences their community. This paper investigates the influence of five summer irrigation schedules on earthworms over a 15-month period in a long-term pasture irrigation study. The influence of the two extreme rates of irrigation on other soil invertebrates was also examined. The effects of frequent drought periods under dryland pasture favoured small and short-lived nematodes and oribatids. During wetter months, earthworm abundances were similar between dryland and irrigated treatments, while earthworms tended to migrate down the soil profile and aestivate in response to soil water deficits during summer. The higher abundance of earthworms in the summer months under irrigation may partly explain the lower soil carbon found under irrigation, due to enhanced rates of soil organic matter turnover, despite higher primary production and inputs of carbon. It is thus important to consider irrigation schedules not only to optimise plant growth, but also to optimise the invertebrate community and its activity. [ABSTRACT FROM AUTHOR]

Winchmore Irrigation Research Station was established in the late 1940s in the Ashburton–Lyndhurst irrigation scheme in Canterbury, New Zealand, to investigate problems associated with the introduction of border-strip irrigation to farming. Two large-scale field trials were established. The first, in 1949, aimed to investigate water requirements of permanent pasture and the second, in 1952, to examine fertiliser requirements of irrigated pasture. Initially designed to supply farmers with practical solutions, because of their longevity (61 and 58 years to date), consistent management, meticulous record keeping and archiving of regular soil and plant samples, both trials have yielded a rich source of material for many studies, some of which are reported in other papers in this issue of the journal. [ABSTRACT FROM AUTHOR]

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Abstract: The combined impact of global climate change and increasing human activities has led to the severe deterioration of grasslands in China. Using the solar irrigation systems is an effective way for sustaining pasture lands in arid regions. A solar irrigation system is the device that uses the solar cell from the sun’s radiation to generate electricity for driving the pump. And photovoltaic pump consists of an array of photovoltaic cells and pumps water from a well or reservoir for irrigation. Although ecologists and organizations constantly work and find ways to conserve grasslands through irrigation systems that use solar energy, issues on water resources are not yet thoroughly discussed. This paper takes into account the main factors in the study of water resources, including precipitation and groundwater, to analyze the feasibility of using a photovoltaic (PV) pumping irrigation. The appropriate area for such a PV pumping irrigation in Qinghai Province is also presented. The results show that the grasslands appropriate for PV pumping cover about 8.145millionha, accounting for 22.3% of the grasslands in the entire province. Finally, the problems and countermeasures of PV pumping irrigation, including the impact on regional water balance, groundwater level and highland permafrost, are also considered. [Copyright &y& Elsevier]

Irrigation of pasture forms the greatest single use of irrigation water in Australia yet there has been little monitoring of its spatial extent and water demands across southeast Australian coastal catchments where irrigated dairy farming forms an important rural livelihood. This paper provides an analysis of spatio-temporal patterns in the extent of irrigated pasture in the Bega-Bemboka catchment on the south coast of New South Wales from Landsat imagery, and establishes quantile regression relationships between metered monthly irrigation abstraction volumes, evaporation and rainfall. Over the metering period (2000-2007), annual water usage averages 4.8 ML ha year, with January being the month of highest demand with an annualised usage of 10.4 ML ha year. Analysis of Landsat imagery indicates that the spatial extent of irrigated pasture across the catchment has increased from 1266 ha in 1983 to 1842 ha by 2002, together with amalgamation of smaller holdings along less reliable streams into larger parcels along the trunk stream. Quantile regressions to estimate monthly mean and maximum abstraction volumes from monthly evaporation and rainfall data indicate that abstraction volumes are more closely correlated with evaporation. When combined with Landsat analyses of the spatial extent of irrigated areas, such relationships enable estimation of catchment-scale hydrological effects of irrigation abstractions that in turn can help guide regional-scale assessments of the ecological effects and sustainability of spatially and temporally changing irrigation abstraction volumes. [ABSTRACT FROM AUTHOR]

The article presents a study on the effectiveness of pasture water management in controlling the loss of nutrients in surface runoff in the Northern Everglades in Florida. It investigates two water management treatments on Bahia grass such as the reduced flow treatment and unobstructed flow. It notes that the reduced flow treatment was applied in the pastures by installing water control structures in drainage ditches. It indicates the effectiveness of pasture water retention in reducing runoff volume and total nitrogen loads in pastures having unobstructed and reduced flow. The phosphorus loads, on the otherhand, lowered in pastures with reduced flow compared to pastures with unobstructed flow.

This study evaluated the behavior of spontaneous vegetation in seedbed conditions, under different soil mulches and irrigation depths. The plant residues used as soil mulches were Gliricidia (Gliricidia sepium), Pigeon pea (Cajanus cajan), Cameroon grass (Pennisetum purpureum), and Bamboo (Bambusa vulgaris "vitata"), besides seedbed without mulches. The irrigation depths were characterized as T5, T4, T3, T2 and T1, corresponding to approximately 117%, 100%, 72%, 59% and 38% of reference evapotranspiration (ETo). Samplings were made 26, 64, 92, 124 and 152 days after the disposal of the plant residues. The main species identified were Cyperus rotundus, Commelina benghalensis, Digitaria horizontalis, Panicum maximum and shoots of previous crops. Plant residues led gravimetric moist urelevels in soil layers of 0.10 and 0.20 m on average 2% over the exposed soil. After the 92nd day, the dead mulching with legumes residues showed levels of soil moisture inferior to the one observed for grass residues. All studied dead mulches were able to reduce the total number of weeds emerged, but the relative frequencies and densities were similar. Cyperus rotundus presented in all treatments relative frequency above 50% and relative density above 70%, given that the residues of legumes had higher population densities and dry mass. The irrigation depth did not influence weeds relative frequencies, densities and dry mass, with the exception of Cyperus rotundus, both in time and the different mulches with plant residue. [ABSTRACT FROM AUTHOR]

Abstract: Border-check irrigation is the predominant method of applying water to dairy pastures in Australia. Dairy pastures consume 40% of total irrigation water in Australia and, with irrigation water security in Australia under threat from climate variability/change and rising demands from other users, socio-economic pressure for water savings in the dairying sector are increasing. Currently, there are no simulation tools that successfully link factors controlling irrigation efficiency at the within-bay scale to management factors that drive economic water productivity (principally pasture growth, pasture consumption and animal production). A simulation framework was developed to connect a biophysical research model of weather–soil–plant animal interaction in dairy systems (‘DairyMod’) to a surface irrigation hydraulic model, SRFR (Simulation of basin, border and furrow irrigations). The connection enabled simulation of the effects of border-check irrigation scheduling and event management on irrigated pasture production systems. Modifications were made to DairyMod, in which the paddock surface was represented as a point, so that it could accommodate infiltration data in a one-dimensional form, from the surface irrigation model SRFR. Multiple simulations of DairyMod were run each representing different discrete spatial zones within an irrigation bay, and the SRFR routines connect each discrete spatial zone with information on the advance front water depth. Model integration and the workings of the integrated model are described, and the process used to verify the integrity of the data transferred between the two models is presented. Comparisons of data input and output parameters from the stand-alone models and the integrated model confirmed that the data transfer between the models within the integrated framework did not introduce new sources of errors. Preliminary output for a scenario involving three irrigation durations is also presented. The scenario represented a perennial ryegrass based pasture on a texture contrast clay loam soil over a period of 10 years using measured climate data. Model predictions agreed well with data reported in the literature for annual irrigation amounts and pasture growth. It was demonstrated that the integrated model could be used effectively to determine how pasture production varied with changes in irrigation management such as irrigation duration. A limitation of the integrated model was its dependence on two sets of infiltration models that were difficult to relate to each other. [Copyright &y& Elsevier]

Tree clearing is a topical issue the world over. In Queensland, the high rates of clearing in the past were mainly to increase pasture production. The present research evaluates the impact of clearing on some soil biological properties, i.e. total soil respiration, root respiration, microbial respiration, and microbial biomass (C and N), and the response of soil respiration to change in temperature. In-field and laboratory (polyhouse) experiments were undertaken. For in-field studies, paired cleared and uncleared pasture plots were selected to represent three major tree communities of the region, i.e. Eucalyptus populnea, E. melanophloia, and Acacia harpophylla. The cleared sites were chosen to represent three different time-since-clearing durations (5, 11-13, and 33 years; n=18 for cleared and uncleared plots) to determine the temporal impact of clearing on soil biological properties. Experiments were conducted in the polyhouse to study in detail the response of soil respiration to changes in soil temperature and soil moisture, and to complement in-field studies for estimating root respiration. The average rate of CO2 emission was 964 g CO2/m2/yr, with no significant difference (P<0.05) among cleared and uncleared sites. Microbial respiration and microbial biomass were greater at uncleared compared with those at cleared sites. The Q 10-value of 1.42 (measured for different seasons in a year) for in-field measurements suggested a small response of soil respiration to soil temperature, possibly due to the limited availability of soil moisture and/or organic matter. However, results from the polyhouse experiment suggested greater sensitivity of root respiration to temperature change than for total soil respiration. Since root biomass (herbaceous roots) was greater at the cleared than at uncleared sites, and root respiration increased with an increase in temperature, we speculate that with rising ambient temperature and consequently soil temperature, total soil respiration in cleared pastures will increase at a faster rate than that in uncleared pastures. [ABSTRACT FROM AUTHOR]

The main goal of this research was soil-loss determination and comparison of the plot measurement results with simulation model (universal soil loss equation (USLE)) results in different land use and slope classes. The research took place in three different land-use types (Scotch pine forest, pasture land, and agricultural land) and in two different slope classes (15–20%, 35–40%). Within six measurement stations (for each land-use type and slope class-one station), totally 18 measurement plots have been constituted, and soil-loss amount measurements have been investigated during the research period (3 years along). USLE simulation model is used in these measurement plots for calculation the soil-loss amounts. The results pointed out that measured (in plots) and simulated (with USLE) soil-loss amounts differ significantly in each land-use type and slope class. [ABSTRACT FROM AUTHOR]

Cadmium (Cd), a naturally occurring element, is a potentially biotoxic metal in terrestrial and aquatic ecosystems. Whether it is biotoxic or not will depend upon the concentration in the soil, its bioavailability and its potential transfer through the ecosystem. However, little data are available for losses to waterways, especially via surface runoff. A study was conducted on two long-term trials under pasture to determine how the concentration of Cd in the soil was affected by different irrigation and fertiliser regimes and in turn how this affected the potential for transfer in surface runoff and outwash of flood irrigation. Concentrations of total Cd in the soil varied from 0.06 to 0.58 mg kg−1 and reflected different rates of P fertiliser applied (from 0 to 376 kg superphosphate ha−1 year−1), but was also less (20–25% compared to dryland) in treatments receiving more frequent irrigation when the same rate of P was applied. This indicated that there was potential for transfer. An experiment using simulated rainfall to generate surface runoff indicated that the major form of Cd lost was dissolved (on average 65% <0.45 μm) and could be predicted by water extraction of the soil. Loads of Cd in outwash were significant (0.17 to 0.92 g ha−1 year−1) and at least as great as the measured leaching losses in other studies. Loads confirmed the loss of Cd from each trial was largely dissolved, and related to soil water-extractable Cd and the frequency of irrigation. While Cd concentrations in sediment from ditches receiving outwash were enriched, indicating potential transfer to waterways, the effect will likely be small due to dilution and sorption by sediment and thereby localised to areas closer to the farm. However, to minimise any potential impact, management should be directed to minimising the occurrence of outwash (e.g. by better irrigation timing) or Cd transfer by using less Cd-rich P fertiliser or minimising P fertiliser use in areas susceptible to surface runoff. [ABSTRACT FROM AUTHOR]

Abstract: The irrigated dairy pasture system in Australia is a high input–high output production system associated with intensive irrigation and nitrogen (N) fertilizer applications. The environmental impacts of such systems are attracting increasing attention in terms of greenhouse gas emissions, such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). In this study, the daily and total chamber-measured N2O emissions from an intensively-irrigated pasture grown on a clay loam-textured soil for non-fertilized (CK), urea and urine treated plots at Kyabram in Southeastern Australia were measured over a period of 20 months and compared with the predictions by a process-based agroecosystems model, water and nitrogen management model (WNMM). WNMM was capable of estimating daily and annual N2O emissions but with different levels of success during different seasons and at different temporal scales. The simulations and statistical analysis indicated that the performance of WNMM in predicting the daily and monthly N2O emissions for the three treatments is in the order: CK

Agricultural reuse of treated sewage effluent (TSE) is an environmental and economic practice; however, little is known about its effects on the characteristics and microbial function in tropical soils. The effect of surplus irrigation of a pasture with TSE, in a period of 18 months, was investigated, considering the effect of 0% surplus irrigation with TSE as a control. In addition, the experiment consisted of three surplus treatments (25%, 50%, and 100% excess) and a nonirrigated pasture area (SE) to compare the soil microbial community level physiological profiles, using the Biolog method. The TSE application increased the average substrate consumption of the soil microbial community, based on the kinetic parameters of the average well color development curve fitting. There were no significant differences between the levels of surplus irrigation treatments. Surplus TSE pasture irrigation caused minor increases in the physiological status of the soil microbial community but no detectable damage to the pasture or soil. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the growth and physiological quality of seeds of rice cultivars grown in alternative systems for pasture renewal. The study was conducted in the municipality of Alta Floresta-MT in the 2006/07 growing season. The experimental design was in randomized blocks with 4 replications in a 2×8 factorial scheme, consisting of the combination of two rice cultivars (BRS Primavera and BEST 2000) and eight options for renewal, and four low concentrations of the cyhalofop butil herbicide (180 g L-1) (0, 0.40, 0.80 and 1.2 L ha-1) and brachiaria sown by hand and incorporated 10 and 20 days after rice emergence. In treatments in which brachiaria received low herbicide concentrations, the grass was sown together with the rice. The following plant characteristics were evaluated: plant height, length and diameter of between node and leaf area index. The tests on physiological quality of seed, germination, first count, speed of germination index, electrical conductivity and accelerated aging were carried out. The BRS Primavera cultivar produced seed of better quality, all the alternatives were shown to be viable for seed and the region of Alta Floresta was shown to be suitable for rice seed production. [ABSTRACT FROM AUTHOR]

Abstract: Water use was monitored during rehabilitation of flood-irrigated farms in the lower Murray River of South Australia. Ten irrigation offtakes at six farms were monitored over a period of two years during the rehabilitation process. Full rehabilitation consisted of improved inlet structures, flow metering, elimination of water leaks, laser levelling of paddocks, and construction of re-use systems to recycle excess surface irrigation runoff. Partial rehabilitation consisted of the same improvements with the exception of the re-use system. The mean water use per watering of 0.61±0.08Ml/ha for the fully rehabilitated farm was approximately one third of that for non-rehabilitated farms (1.89±0.15Ml/ha) and two thirds of that for partially rehabilitated farms (0.99±0.07Ml/ha). These differences were statistically significant at the 95% confidence level. A large improvement in efficiency of water use was achieved by upgraded water delivery infrastructure and laser levelling of paddocks. Considerable improvement in water use efficiency was also gained, however, only by installation of re-use systems. It is expected that the overall rehabilitation of irrigation infrastructure will result in a significant reduction of water extracted from the river for flood irrigation in this region. Further longer term monitoring is required to confirm this. [Copyright &y& Elsevier]

Copyright of Agro Sur is the property of Universidad Austral de Chile, Facultad de Ciencias Agrarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In southern New Zealand, grazing of forage crops is common practice to satisfy feed requirements of animals in winter when pasture growth is limited. This practice has been shown to cause soil physical damage and increased loss of surface water contaminants sediment and phosphorus (P) to water bodies. Strategies to mitigate the loss of sediment and P were trialled on a Pallic soil type (Aeric Fragiaquept) in the North Otago Rolling Downlands of New Zealand. All sites were irrigated and measurements were made of losses in overland and sub-surface flow from intensive cattle or sheep grazed, winter forage crops, and sheep grazed pasture. Two mitigations (restricted grazing of crop to three hours and the application of aluminium sulphate) were assessed for their potential to decrease contaminant loss from cropland. Volumes of surface runoff and loss of total P, filterable reactive P and sediment showed significant differences ( P < 0.05) between the control treatments (i.e. no mitigation) with cattle crop (88 mm surface runoff) > sheep crop (67 mm) > sheep pasture (33 mm). The contribution of irrigation water to overland flow water, as a result of saturation-excess conditions, varied between treatments with more loss under cattle crop (20% of total) compared with sheep crop (15%) and sheep pasture (11%). These differences are probably an effect of soil physical condition and highlight the importance of accurate irrigation scheduling to keep soil moisture below field capacity. Restricted winter grazing and alum application after grazing significantly ( P < 0.05) decreased P losses in surface runoff under cattle (from 1.4 to 0.9 kg P/ha) and sheep (from 1.0 to 0.7 kg/P/ha) grazed crop plots by about 30%. In cattle grazed plots, restricted grazing also decreased suspended sediments (SS) by 60%. The use of restricted grazing is suggested as a means of decreasing P and SS loss from grazed winter forage crops. The use of alum shows some promise for decreasing P losses, but requires further work to determine its long-term effectiveness and use in other soils and management regimes. [ABSTRACT FROM AUTHOR]

Wetlands are a very important universal heritage; in the Moroccan High Atlas mountains the geomorphology and the slopes evolution determine the existence of the numerous projecting ledges of pozzines on plateaus and oozing. This is particularly the case in Oukaimeden site located at 75 km south of Marrakesh. These wet grasslands have been developed on small surface areas supported by soils water accumulation; and close to the sources and on some banks constitute wetlands of high floristic richness, which makes them very coveted pastures by local populations. These wet pastures are highly sensitive to climatic factors. Recent climatic changes, the anthropic and pastoral pressures and the global environmental changes, affect these zones at the level of their structure (areas, soil characteristics¿) and their ecological functions. In the Oukaimeden plateau, the use of aerial photography made it possible to carry out a detailed follow up of the hydraulic adjustments (dam construction in the 1970s) as well as the setting up of new adjustments (tracks, paths, drain channel) on the structure and functioning of these grasslands. [ABSTRACT FROM AUTHOR]