Non-irrigated Areas Research Articles

ETHEPHON SPRAYS AS A DEFOLIANT IN ‘NIAGARA ROSADA’ VINE SUBJECTED TO TWO CROP PRODUCTION PER YEAR

ABSTRACT In climate region Cwa of the State of São Paulo the technique of double cropping the grapevine is possible, however, when it is time for the second pruning of the crop, most of the vine’s leaves are still in the plant, posing the problem that the use of ethephon as a defoliant could increase leaf senescence and improve the vine management. The objective of this study was to evaluate the effects of ethephon spray as a defoliant in the development and production of the ‘Niagara Rosada’ vine when subjected to double cropping, and the influence this bioactivator may have on carbohydrate reserves in the branch. The experiments were conducted in a commercial, non-irrigated area in agricultural years of 2011/2012 and 2012/2013. The length, diameter and total carbohydrate reserves of the branches, as well as bud break, number of clusters, crop production, length, width and mass of cluster, berry diameter, soluble solids and titratable acidity were evaluated. Ethephon treatments were applied at a concentration of 1,440 mg L-1 and 2,160 mg L-1 at 20 and 15 days before pruning. As a control, the vines were defoliated by hand at the time of pruning. A randomized block experimental design was used. Data was subjected to analysis of variance and means were compared by the Tukey test at 5% significance level. In conclusion, we propose that ethephon sprays promoted vine defoliation and improved the bud break, altered plant development and crop production. This was not due to increases in concentration of carbohydrate reserves in the branches, but due to a higher induction stimulus of bud break, which allowed the vines to express their higher yield capacity.

The influence of several irrigation water depths in the growth and productivity of coffee shrubs in the Muzambinho Region, Southern Minas Gerais, Brazil

Coffee crop, highly important worldwide, is one of the main commodities in Brazilian exports. However, due to climate changes, its cultivation is currently demanding irrigation techniques. Current assay evaluates the effect of different irrigation water levels on the development and productivity of coffee shrubs in predominant soil and climate conditions of the town of Muzambinho, in the southern region of the state of Minas Gerais, Brazil. The experiment was performed in July 2013 on a coffee plantation, planted with coffee shrubs, cultivar Red Catuai IAC/144, by drip irrigation. Experiment design consisted of randomized blocks with four replications and four treatments, or rather, different irrigation water depths: 0 (without irrigation), 50, 100 and 125% of ET0. Productivity, vegetal growth and distribution of the radicular system were evaluated after 12 months. Treatments did not affect vegetal growth. Better quantity and distribution of the radicular system were detected at 100% irrigation level, with a productionof 55 sacks.ha-1 or a 45% gain when compared to that in non-irrigated areas. Key words: Management, coffee, drip system.

Neighborhood effects and social behavior: The case of irrigated and rainfed farmers in Bohol, the Philippines

Artifactual field experiments, spatial econometrics, and household surveys are combined in a single study to investigate the neighborhood effects of social behaviors. The dictator and public goods games are conducted among rice farmers in irrigated and non-irrigated areas in the Philippines. We find the neighborhood effects but the magnitude and statistical significance of endogenous social effects vary with the irrigation availability, type of social behavior, and type of neighborhood. Altruistic and cooperative behaviors are significantly influenced by the behaviors of neighbors only in the irrigated area, where social ties are strengthened through collective irrigation management. Through this effect, irrigated farmers’ social behaviors become similar to those of one another. Neighborhood effects for cooperative behavior are stronger among farm plot neighbors than among residential neighbors, which may reflect their interactions in irrigation management. Although non-dynamic, these findings are consistent with the theory of social norm evolution through common pool resource management.

Evaluating management-induced soil salinization in golf courses in semi-arid landscapes

Abstract. Site-specific information on land management practices are often desired to make better assessments of their environmental impacts. A study was conducted in Lubbock, Texas, in the Southern High Plains of the United States, an area characterized by semi-arid climatic conditions, to (1) examine the potential management-induced alterations in soil salinity indicators in golf course facilities and (2) develop predictive relationships for a more rapid soil salinity examination within these urban landscape soils using findings from a portable X-ray fluorescence (PXRF) spectrometer. Soil samples were collected from managed (well irrigated) and non-managed (non-irrigated) areas of seven golf course facilities at 0–10, 10–20, and 20–30 cm depths and analyzed for a suite of chemical properties. Among the extractable cations, sodium (Na) was significantly (p < 0.05) higher in the managed zones of all the golf facilities. Soil electrical conductivity (EC), exchangeable sodium percentage (ESP), and sodium adsorption ratio (SAR), parameters often used in characterizing soil salinity and sodicity, were for the most part significantly (p < 0.05) higher in the managed areas. Water quality reports collected over a 22-year period (1991–2013, all years not available) indicated a gradual increase in pH, EC, SAR, total alkalinity, and extractable ions, thus supporting the former findings. Findings from the PXRF suggested possible differences in chemical species and sources that contribute to salinity between the managed and non-managed zones. PXRF-quantified Cl and S, and to a lesser extent Ca, individually and collectively explained 23–85% of the variability associated with soil salinity at these facilities.

Income Optimization of Energy Crops in Greece under Different CAP Scenarios

Abstract The present paper employs linear programming for the optimization of agricultural income generated by energy crops for the prefecture of Evros. To be more specific, we optimize agricultural income from soybean, the sunflower (proxy for energy crop), corn under different scenarios having as restrictions the value of the subsidies as a proxy for EU policy the value of inputs (costs of capital and labour) and under the irrigation conditions. Three different scenarios will be taken into consideration regarding the implementation of Common Agricultural Policy. The results of different scenarios under which the Common agricultural policy is implemented will provide us with an insight on the identification of energy crops for which the agricultural income is a potential significant motive to the farmers for their adoption related not only to other energy crops but also conventional crops. According to our findings higher income is acquired by the cultivation of the sun flower compared to that of rapeseed in non-irrigated areas while in irrigated areas highest income comes from the crop of corn compared to the crop of sunflower and rapeseed. The practical value of the present work stands on the formation of a structure of different energy crops that secure income maximization, while if we take into consideration crops with limited needs in non- cultivated areas with less fertile soils might also contribute to the formation of rural development

Mobilization of selenium from the Mancos Shale and associated soils in the lower Uncompahgre River Basin, Colorado

This study investigates processes controlling mobilization of selenium in the lower part of the Uncompahgre River Basin in western Colorado. Selenium occurs naturally in the underlying Mancos Shale and is leached to groundwater and surface water by limited natural runoff, agricultural and domestic irrigation, and leakage from irrigation canals. Soil and sediment samples from the study area were tested using sequential extractions to identify the forms of selenium present in solid phases. Selenium speciation was characterized for nonirrigated and irrigated soils from an agricultural site and sediments from a wetland formed by a leaking canal. In nonirrigated areas, selenium was present in highly soluble sodium salts and gypsum. In irrigated soils, soluble forms of selenium were depleted and most selenium was associated with organic matter that was stable under near-surface weathering conditions. Laboratory leaching experiments and geochemical modeling confirm that selenium primarily is released to groundwater and surface water by dissolution of highly soluble selenium-bearing salts and gypsum present in soils and bedrock. Rates of selenium dissolution determined from column leachate experiments indicate that selenium is released most rapidly when water is applied to previously nonirrigated soils and sediment. High concentrations of extractable nitrate also were found in nonirrigated soils and bedrock that appear to be partially derived from weathered organic matter from the shale rather than from agricultural sources. Once selenium is mobilized, dissolved nitrate derived from natural sources appears to inhibit the reduction of dissolved selenium leading to elevated concentrations of selenium in groundwater. A conceptual model of selenium weathering is presented and used to explain seasonal variations in the surface-water chemistry of Loutzenhizer Arroyo, a major tributary contributor of selenium to the lower Uncompahgre River.

Salt and nitrate exports from the sprinkler-irrigated Malfarás creek watershed (Ebro river valley, Spain) during 2010

Irrigated agriculture is a clear source of non-point pollution by salts and nitrogen species. The impact of such pollution should be quantified according to specific cases. The case of the Malfaras creek basin, a sprinkler irrigation district located in the semiarid Ebro valley in northeast Spain, has been evaluated. The main crops in the district were corn, barley and alfalfa, occupying 93 % of the irrigated area. The fate of water, salts and nutrients was evaluated by a daily water balance developed at a field scale for the natural year 2010. The yearly data of the whole set of 101 irrigated fields plus the non-irrigated area compared to the measured drainage produced a basin water balance with a low degree of error. The basin consumed 90 % of the total water input of which 68 % was used for crop evapotranspiration and the rest was lost due to non-productive uses. 16 % of the incoming water left the irrigation area as drainage water. The irrigated area was responsible for 87 % of the drainage. The average volume of drained water was 152 mm year−1 for the whole basin area. The irrigated area drained 183 mm year−1. The basin exported 473 kg of salt per hectare during 2010. This value was the lowest of the sprinkler irrigation areas in the Ebro valley, mainly due to the lower soil salinity. All the crops except barley received a nitrogen surplus of 10–50 % above their needs. The extra nitrogen entered the water cycle increasing the nitrate concentration in the aquifer water (150 mg L−1) and drainage water (98 mg L−1). In 2010 the mass of nitrogen exported by drainage was 49 kg per irrigated hectare. This value is too high for this type of irrigation system and implies that 17 % of nitrogen applied as a fertilizer was lost to drainage water. The key to decreasing the nitrogen leaching and pollution that it causes could be appropriate time-controlled fertigation along with better irrigation scheduling.

New indicators for global crop monitoring in CropWatch -case study in North China Plain

CropWatch is a monitoring system developed and operated by the Institute of Remote Sensing and Digital Earth (Chinese Academy of Sciences) to provide global-scale crop information. Now in its 15th year of operation, CropWatch was modified several times to be a timely, comprehensive and independent global agricultural monitoring system using advanced remote sensing technology. Currently CropWatch is being upgraded with new indicators based on new sensors, especially those on board of China Environmental Satellite (HJ-1 CCD), the Medium Resolution Spectral Imager (MERSI) on Chinese meteorological satellite (FY-3A) and cloud classification products of FY-2. With new satellite data, CropWatch will generate new indicators such as fallow land ratio (FLR), crop condition for irrigated (CCI) and non-irrigated (CCNI) areas separately, photosynthetically active radiation (PAR), radiation use efficiency for the photosynthetically active radiation (RUEPAR) and cropping index (CI) with crop rotation information (CRI). In this paper, the methods for monitoring the new indicators are applied to the North China Plain which is one of the major grain producing areas in China. This paper shows the preliminary results of the new indicators and methods; they still need to be thoroughly validated before being incorporated into the operational CropWatch system. In the future, the new and improved indicators will help us to better understand the global situation of food security.

Geo-environmental model for the prediction of potential transmission risk of Dirofilaria in an area with dry climate and extensive irrigated crops. The case of Spain

Zoonotic filarioses caused by Dirofilaria immitis and Dirofilaria repens are transmitted by culicid mosquitoes. Therefore Dirofilaria transmission depends on climatic factors like temperature and humidity. In spite of the dry climate of most of the Spanish territory, there are extensive irrigated crops areas providing moist habitats favourable for mosquito breeding. A GIS model to predict the risk of Dirofilaria transmission in Spain, based on temperatures and rainfall data as well as in the distribution of irrigated crops areas, is constructed. The model predicts that potential risk of Dirofilaria transmission exists in all the Spanish territory. Highest transmission risk exists in several areas of Andalucía, Extremadura, Castilla-La Mancha, Murcia, Valencia, Aragón and Cataluña, where moderate/high temperatures coincide with extensive irrigated crops. High risk in Balearic Islands and in some points of Canary Islands, is also predicted. The lowest risk is predicted in Northern cold and scarcely or non-irrigated dry Southeastern areas. The existence of irrigations locally increases transmission risk in low rainfall areas of the Spanish territory. The model can contribute to implement rational preventive therapy guidelines in accordance with the transmission characteristics of each local area. Moreover, the use of humidity-related factors could be of interest in future predictions to be performed in countries with similar environmental characteristics.

An Assessment of Irrigation Water Quality and Selected Soil Parameters at Mutema Irrigation Scheme, Zimbabwe

Soil salinity and sodicity are major factors limiting agricultural productivity in irrigation schemes located in semi-arid areas. A study was conducted to assess the quality of irrigation water used in Mutema Irrigation Scheme located in south-east Zimbabwe to understand how irrigation water quality is related to the chemical quality of soils in the scheme. Irrigation water samples were collected from groundwater and surface sources in 2012 and their hydrochemistry determined while soil samples were collected from irrigated and non-irrigated parts of the scheme in 2006 and 2012 and analysed for selected chemical properties. The results indicated that the groundwater had high concentrations of Na+ (4.35 mg/l), Mg2+ (4.75 mg/l), Cl- (3.6 mg/l) and Electrical Conductivity (EC) (1729 Msm/cm) compared to the surface irrigation water source which had 0.72 mg/l Na+, 2.25 mg/l Mg2+, 0.78 mg/l Cl- and 594 Msm/cm EC. The soils in the scheme had higher levels of pH, Sodium Adsorption Ratio (SAR), Exchangeable Sodium Percentage (ESP) and EC which in some blocks exceeded the threshold requirements for cropping. It was found that pH, SAR and ESP were significantly higher (p ) in irrigated blocks compared to non-irrigated areas of the scheme, indicating an influence of irrigation water on soils characteristics in irrigated plots. Mg2+ and Ca2+ in the soils positively correlated with Na+ (r2 = 0.67 and r2 = 0.57 respectively). The results indicated that the groundwater presents a chloride hazard to the soils in the scheme which are becoming saline and therefore require proper management and choice of crops to sustain crop production.

Modelling the effect of irrigation on the hydrological output from a small prairie watershed

In a typical irrigation practice the soil water content is maintained at or near field capacity, which can affect hydrological processes such as deep percolation and runoff in different ways. The aim of this study was to evaluate these effects for a partially irrigated, small watershed in the Canadian prairie using the Soil Water Assessment Tool (SWAT). The watershed was defined by upstream (inlet) and downstream (outlet) monitoring stations located along a short reach of a river. SWAT was calibrated and validated using the net flow between the upstream (inlet) and downstream (outlet) locations because the watershed was defined by this reach. Runoff contribution to the incremental streamflow was minimal, as indicated by the reduced values of the calibrated initial curve number (CNII) (CNII range 49–59). Irrigation activity increased runoff depth but the differences between irrigated and non-irrigated areas were not statistically (α ≤ 0.05) significant. The low runoff contribution was also corroborated by the streamflow record that demonstrated the low potential for runoff generation in the watershed. The only apparent runoff occurred after a major rainfall event of a cumulative depth of more than 200 mm. The modelling also showed that the shallow aquifer discharge was the main streamflow constituent. Precipitation during May to July was responsible for 70–90% of the seasonal deep percolation. By the end of the season the deep percolation from the irrigated areas exceeded that of the non-irrigated areas by up to 70%. Thus, the irrigation activity in the watershed did not change the water partitioning among the existing hydrological pathways but had temporal effects on the magnitudes of runoff and, more importantly, deep percolation and the subsequent groundwater discharge in the main reach.

PENDAPATAN DAN RISIKO PENDAPATAN USAHA TANI PADI DAERAH IRIGASI DAN NON IRIGASI DI KABUPATEN BANJAR KALIMANTAN SELATAN

This study aims to determine the income and revenue risk from rice farming inirrigated and non irrigated land are also factors that influence it. The hypothesisadvanced is that (1) factors that affect revenue and revenue risk rice farming inpaddy fields are irrigated and non irrigated land area, the price of seed, fertilizerprices, wage labor, the price of seeds, irrigation areas and varieties, (2 ) rice farmincome risk in irrigated land is lower than non-irrigated land. Data obtainedthrough interviews with 80 randomly simple rice farmers. The method used ismultiple linear regression analysis model with Ordinary Least Square (OLS) andthe analytical coefficient of variation (CV). The results showed that the area ofland, the price of urea, ponska price, the price of pesticides, and irrigation areadummy effect on income. While the risk is influenced by the land revenue, theprice of seed, the price of urea fertilizer, fertilizer prices ponska, pesticide pricingand superior varieties of variables. Income risk in the area of irrigated ricefarming was smaller than non-irrigated areas with kofisien variation of 0.83 and0.89.Key words: revenue, risk, rice, irrigated and non irrigated area.

Nitrate and Salt Water Contamination Associated with the Transition of an Agrarian Basin into an Irrigated Area

The introduction of irrigation to agrarian areas involves several environmental changes that can be aggravated by physical and agronomic factors. The aim of this study is to analyze the spatiotemporal dynamics of the environmental impact on water resources that result from the transition of an agrarian basin into an irrigated area. During five hydrological years, a spatiotemporal comparison was carried out on the quantity and quality of drainage from the four zones in which the study area was subdivided. Introduction of irrigation activities incorporated flows that lowered salinity and increased nitrate concentration in the basin. The zones/years with most irrigation showed the greatest exports of salts and nitrates, with temporal variations related to rainfall patterns and spatial variations related to soil salinity and nitrogenous fertilization. The agro-environmental impacts of the gradual introduction of irrigation into a previously non-irrigated area were congruent to that of established irrigation areas with similar characteristics.

Did irrigation impact 20th century air temperature in the High Plains aquifer region?

This study investigates potential impacts of widespread adoption of irrigation on long-term temperatures over the High Plains aquifer (HPA) region of the Great Plains. It is well known that availability of soil moisture can modify near surface energy partitioning (latent vs. sensible) and temperature. This study provides an assessment of the changes in the historical near surface temperature records in the HPA region due to adoption of irrigation. Long-term growing season mean monthly maximum and minimum air temperature data from 24 irrigated and 26 non-irrigated sites were analyzed. These stations are part of the US Historical Climate Network (USHCN). This study reports that growing season mean maximum temperature (GTmax) at irrigated areas is predominantly cooler than non-irrigated areas with up to 1.01 °C cooling at some locations. A geographical variation in magnitude of this cooling is also observed. The majority of irrigated locations report warming in GTmin with up to 1.00 °C increases. The results are largely statistically significant. This paper suggests more focus on regional- and local-scale studies is needed to better understand impacts of land use changes on climate change and variability.

Changes in the yield components of durum wheat (Triticum durum Desf.) during irrigation controlled by soil sensors

The effect of irrigation water on the yield and on individual yield components was examined for 19 durum wheat varieties by continually recording weather data and carrying out measurements on the moisture content, temperature, electrical conductivity and tension of the soil. Dry (rain-fed) and irrigated treatments were included in the experiment, which was carried out in the framework of the EU FP7-244374 DROPS project.During the rainless spring of 2011 the soil moisture content of the non-irrigated area dropped to 21–22 vol% and the effect of drought stress was still felt at harvest. The quantity of irrigation water applied during the growing season ensured normal conditions for generative development and a significant difference could be detected between the yield components in the two treatments. The thousand-kernel weight of the varieties was identical in the dry and irrigated plots, but in response to irrigation there was an increase in the number of grains per ear and the grain weight, and an improvement in fertilisation, resulting in higher yields.

Development of Variable Threshold Models for detection of irrigated paddy rice fields and irrigation timing in heterogeneous land cover

Accurate monitoring of irrigated paddy field area and irrigation timing are of a great concern in agricultural water management due to the substantial consumption of fresh water when irrigating paddy fields. Spectral threshold methods (Xiao et al., 2005) have been widely applied to detect irrigated paddy fields and irrigation timing using Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI). These methods applied constant additive threshold values (T) to LSWI and compared it to EVI to detect the irrigated paddy fields. In this study, we developed Variable Threshold Models that utilized different pixel-based threshold values depending on sub-pixel land cover heterogeneity and hence, improve detection performance on distributed small-scale paddy fields. Non-irrigated sub-pixels were quantified with irrigation maps produced by Synthetic Aperture Radar (SAR) microwave images. Significant positive correlation between EVI and the sub-pixel numbers of non-irrigated area were found (r=0.87), which resulted in higher T for MODIS pixels with more non-irrigated sub-pixels. Accordingly, a Variable Threshold Model, i.e. a regression model between T and EVI, was developed. With the Variable Threshold Model, agreement rates between MODIS and SAR-based irrigated small-scale paddy field classification doubled compared with that from a fixed threshold value. In comparison with field observations, the Variable Threshold Models showed a mean error of +0.9 days, an improvement over the mean error of +2.8 days from a fixed threshold model. Combined utilization of SAR and MODIS images provides a useful tool for developing a Variable Threshold Model that can enhance accurate monitoring of irrigation dates across heterogeneous paddy field regions.

Estimation of malaria transmission intensity in Sennar state, central Sudan

Understanding the behaviour of malaria vectors is crucial for planning mosquito control programmes. The aim of this study was to estimate the malaria transmission intensity in 2 different ecological zones in a highly endemic malaria area of Sennar state in central Sudan over the main transmission period. Species confirmation by PCR indicated that Anopheles arabiensis was the only malaria vector in the study area, with high anthropophilic behaviour (84.9% human-feeding). ELISA studies showed Plasmodium falciparum sporozoite rates rose from 1.8% to 4.5% and the average entomological inoculation rates rose from 2.4 to 4.2 infectious bites per person per night in September (the beginning) to November (the end) of the 3-month transmission season. The proportion of malaria-positive slides ranged from 50.1% to 57.0%. The proportion of human-blood positive mosquitoes was significantly higher in the irrigated area (El Booster) compared with the non-irrigated area (Rahal).

Land Application of Treated Industrial Wastewater on a Chihuahuan Desert Shrubland: Implications for Water Quality and Mineral Deposition

Land application of wastewater conserves fresh water and recycles nutrients, but little is known of its impacts on arid and semiarid landscapes. Lagoon treated saline−sodic industrial effluent was applied from 2002–2005 to a 0.4-ha Chihuahuan Desert shrubland to assess the deposition and recovery of effluent components and changes in soil quality vis-à-vis a non-irrigated area. Effluent irrigation supplied 26% of the average annual nonstressed evapotranspiration (ET) of the native shrubs [Larrea tridentata (DC.) Coville and Prosopis glandulosa Torr. var. glandulosa], and increased both soil stress factors (sodicity, salinity, and pH) and soil fertility (N, P, and K). After 3 yr, the soil saturation extract electrical conductivity (ECe) reached as high as 6.1 dS m−1 and Cl− 76 molc m−3 at 105 cm depth under irrigated L. tridentata. After 4 yr, saturation extract sodium adsorption ratio (SARe) reached 25–35 at 7.5 cm under the irrigated shrubs and intershrub spaces. There were 27 Mg ha−1 of cumulative ionic deposits to the site comprised mostly of Na+, Cl−, and CaCO3 equivalent alkalinity, with soil analysis recovering most of the deposits (>57%) except for K+ and Na+ (8% to 13%). Subsurface leaching of and P was detected within the upper 1 m soil depth after 4 yr, and a high downward mobility of Cl− revealed the potential for deeper leaching at higher N loading rates. While long-term effects on the natural vegetation are unknown, results contribute to a limited scientific database for sustainable wastewater land application in semiarid regions.

Assessment of metal accumulation in calcareous soil and forage crops subjected to long-term irrigation using treated wastewater: Case of El Hajeb-Sfax, Tunisia

In Sfax (Tunisia), waters deriving from the treatment of a mix of industrial and domestic effluents have been used for the purpose of forage crop irrigation for 17 years. The aim of this study is to evaluate the impact of this wastewater irrigation on the metal contents in soil and to assess the risk of metal uptake by plants over the long term. The bioavailability and phytoabsorption of metals by alfalfa (Medicago sativa) and sorghum (Sorghum bicolor) forage crops have been evaluated through an approach based on spatially distributed topsoil (0–7cm) and plant samples. This approach uses direct measurements of the metal uptake by the roots and shoot tissues of the plants, in addition to the total metal content of the soil and the available fraction for uptake by plants (i.e. the bioavailable fraction), as extracted by ethylenediaminetetra-acetic acid (EDTA) mixed with ammonium acetate (NH4OAc). Two sites were selected from within the same calcisol field so as to focus on various agricultural practices.It was found that only total Zn content was accumulated in soil irrigated with treated wastewater, compared to the nearby non-irrigated control area, though these contents remained within the critical limits for normal plant growth. However, total metal contents in the soil and in the bioavailable fraction of soil were higher in the topsoil layer of the permanent 3-year alfalfa plot than the contents of the summer sorghum plot. A lack of correlation between metal content in the bioavailable fraction of soil and metal content in plants (either the tissues of aerial parts or roots) suggests that NH4OAc–EDTA serves as a partial extractant. When only the mineral fraction, for both soil and plants, is considered in the calculation of enrichment and transfer factors, a linear relationship appears in a log scale representation. This approach has refined results obtained by the classical calculations of TF (Transfer Factors) and the BCF (BioConcentration Factor) and moreover has provided complementary information about the specific selectivity of each plant with respect to the five studied metal elements. In addition, this approach has enabled identifying similarities in the metal behaviour for both forage plants. Lastly, this treatment has highlighted specific behaviour associated with the two studied plants as regards metal uptake.

Farmer's perception and adaptation practices to cope with drought: Perspectives from Northwestern Bangladesh

This study was conducted with 718 farmers of owner, owner-cum-tenant and tenant farmers of irrigated and non-irrigated villages at 14 upazila (sub-district) in two severe drought-prone districts of northwestern Bangladesh through a semi-structured questionnaire. It assessed farmer's perception and awareness, impacts and adaptation measures of farmers towards drought. The results revealed that farmers in both areas perceived a changed climate in recent years. They not only identified that drought is the most prevalent disaster in the study area because of rainfall and temperature variation, but also groundwater depletion, lack of canal and river dragging, increased population, deforestation, etc. accelerate drought in this area. As a consequence of drought, agriculture as well as farmers' social life and health are threatened the most. To cope with drought, farmers have been adapting various practices mainly through agronomic management, crop intensification, water resource exploitation, etc. Among different farmer groups in both irrigated and non-irrigated areas, it has been seen that owner farmers have more capacity to adopt new technology than owner-cum-tenant and tenant farmer. In conclusion, this study recommended that interrelationship among different stakeholders, effective early warning system and improved water conservation systems are essential to sustain farmers livelihood in the event of drought.