IMPACTS OF AGRICULTURAL DRAINAGE WELL CLOSURE ON CROP PRODUCTION: A WATERSHED CASE STUDY1

ABSTRACT: Much of north-central Iowa is characterized by flat topography, shallow depressions, and poor natural surface drainage. Land drainage systems comprising of tile drains and agricultural drainage wells (ADWs) are used as outlets for subsurface drainage of cropland under corn and soybean production. Studies have shown that these drainage systems, mainly the ADWs, are potential routes for agricultural chemicals to underground aquifers. To protect the region's vital groundwater resource, researchers are evaluating alternative outlets ranging from complete closure of existing ADWs (and creation of wetlands) to continued use of ADWs and chemical management in a comprehensive policy framework. This paper presents the results of a study designed to provide government jurisdictions, farmers, and land managers information for assessing the impact of closing ADWs on crop production. The study couples a geographic information systems database for a 471-hectare watershed in Humboldt County, Iowa, with a groundwater flow model (MODFLOW) and an empirical crop yield loss model to predict long-term effects of complete closure of ADWs on crop production. The cropland areas inundated and the relative crop yield loss due to ADW closure are determined as a function of long-term climatic data. The results indicate that elimination of drainage outlets in the watershed could result in ponding of low-lying areas and poorly drained soils, making them unsuitable for crop production. Such wetness also decreases the efficiency of production in the no-ponding areas by isolating fields, and the crop yield loss can be reduced by an annual average of about 18 percent.     

Biodegradable Blends from Corn Gluten Meal and Poly(butylene adipate-co-terephthalate) (PBAT): Studies on the Influence of Plasticization and Destructurization on Rheology,Tensile Properties and Interfacial Interactions

Melt extrusion was used to obtain thermoplastic corn gluten meal (tCGM) blends from plasticized corn gluten meal (pCGM) and poly(butylene adipate-co-terephthalate) (PBAT). Dynamic rheological tests, morphology and spectroscopy were employed to understand the effect of the plasticization and destructurization of corn gluten meal (CGM) on tCGM blends. Rheological data showed a plateau in the low frequencies for tCGM blends demonstrating network formation which responds elastically over long timescales. Also, complex viscosity data showed the existing of shear thinning for PBAT and PBAT–CGM blend. Furthermore, rheology and morphology showed the synergistic influence of plasticization and destructuralization of CGM on the phase structure development of the blends. In addition, it was found for unmodified CGM–PBAT blend there was significant frequency dependence for G′ indicating it just acted as filler for PBAT matrix. FTIR studies showed that the urea has helped in unfolding the corn protein and facilitated hydrogen bonding interactions with PBAT. Tensile properties showed an improvement in tCGM blends when compared unmodified CGM blend. Tensile strength of tCGM blends was almost same as that of the neat PBAT matrix. Percent elongation, a strong reflection of the state of interface in the blends has showed higher values, indicating strong interactions between the PBAT and pCGM in the blend system.     

Effects of silver nanoparticles on stress biomarkers of Channa striatus: immuno-protective or toxic?

Environmental Science and Pollution Research - Nanotechnology is a novel arena with promising applications in the field of medicine, industry, and agriculture including fisheries....     

Evolving remanufacturing strategies in China: an evolutionary game theory perspective

Environment, Development and Sustainability - Rapid pace of natural resource depletion and environment deterioration is a cause of concern worldwide. Remanufacturing offers a promising option for...     

Phosphorus speciation in the marine sediment of Kalpakkam coast,southeast coast of India

A study was carried out at Kalpakkam coast to find out the distribution of various fractions of phosphorus (P) in the marine sediment during pre-northeast monsoon period. Samples were collected from ten locations covering ~80 km² of the inner-shelf region. Sedimentary parameters such as sand, silt, clay, and organic carbon percentage were analyzed in order to find out their relation with various P fractions. The sediment was found to be predominantly sandy in nature with low silt and clay content. Among all the fractions (loosely bound (LoP), calcium bound (CaP), iron bound (FeP), aluminum bound (AlP), and organic (OP)), CaP fraction constituted the largest portion (68.7 %) followed by organic fraction (16.3 %). The bioavailable P fractions ranged from 5 to 44 % of the total P (TP) content. Relatively high LoP content was observed at the offshore locations with comparatively high mud percentage as compared with the near-shore locations. As FeP and AlP concentrations were directly proportional to the amount of fine-grain sediment, the low levels of these fractions found in this coastal area were therefore attributed to the sandy nature of the sediments. The order of abundance of the major forms of P in the surface sediments of Kalpakkam coast was as follows: CaP?>?OP?>?LoP?>?AlP?>?FeP.     

Residual behavior and risk assessment of flubendiamide on tomato at different agro-climatic conditions in India

Supervised field trials were conducted at four different agro-climatic zones in India to evaluate the dissipation pattern and risk assessment of flubendiamide on tomato. Flubendiamide 480 SC was sprayed on tomato at 48 and 96 g active ingredient (a.i.) ha^?1. Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10, 15, and 20 days after treatment. Quantification of residues was done on a high-performance liquid chromatography (HPLC) device with a photo diode array detector. The limit of quantification (LOQ) of this method was found to be 0.01 mg kg^?1 while limit of detection (LOD) being 0.003 mg kg^?1. Residues of flubendiamide were found below the determination limit of 0.01 mg kg^?1 in 20 days at both the dosages in all the locations. The half-life of flubendiamide at an application rate of 48 g a.i.?ha^?1 varied from 0.33 to 3.28 days and at 48-g a.i. ranged from 1.21 to 3.00 days. On the basis of data generated under the All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 1 day has been recommended, and the flubendiamide 480 SC has been registered for its use on tomato by the Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on tomato has been fixed by the Ministry of Health and Family Welfare, Government of India under Food Safety Standard Authority of India, as 0.07 μg g^?1 after its risk assessment.     

Dissipation pattern of flubendiamide in/on brinjal (Solanum melongena L.)

Residues of flubendiamide and desiodo flubendiamide were studied following three applications of flubendiamide 480 SC at 7 days interval at 90 and 180 g a.i. ha(-1) in/on brinjal fruits. An average initial deposit of 0.33 and 0.61 mg kg(-1) of flubendiamide was observed respectively after application at single and double dosages. The residues of flubendiamide dissipated quickly at both the dosages, and after 3 days, the extent of dissipation was found to be about 76% and 79% at the single and double dosages, respectively. Brinjal fruit samples analysed at different time intervals did not show the presence of desiodo flubendiamide. The half-life of flubendiamide was observed to be 0.62 and 0.54 days at single and double dosages, respectively. The limit of determination of flubendiamide and desiodo flubendiamide was observed to be 0.05 mg kg(-1). Soil samples analysed after 15 days of the last application did not reveal the presence of flubendiamide and desiodo flubendiamide at their determination limit of 0.05 mg kg(-1). An assessment of the total intake of flubendiamide resulting through the consumption of brinjal fruits and its comparison with acceptable daily intake seems to be quite safe from consumer point of view.     

Dynamics and quantification of dissolved heavy metals in the Mahanadi river estuarine system,India

Dynamics of heavy metals such as Fe, Mn, Zn, Cr, Cu, Co, Ni, Pb, and Cd in surface water of Mahanadi River estuarine systems were studied taking 31 different stations and three different seasons. This study demonstrates that the elemental concentrations are extremely variable and most of them are higher than the World river average. Among the heavy metals, iron is present at highest concentration while cadmium is at the least. The spatial pattern of heavy metals suggests that their anthropogenic sources are possibly from two major fertilizer plants and municipal sewage from three major towns as well as agricultural runoff. The temporal variations for metals like Fe, Cu, and Pb exhibit higher values during the monsoon season, which are related to agricultural runoff. Concentrations of Ni, Pb, and Cd exceed the maximum permissible limits of surface water quality in some polluted stations and pose health risks. Dissolved heavy metals like Fe, Mn, Cr, Ni, and Pb exhibit a non-conservative behavior during estuarine mixing, while Zn, Cu, and Co distribution is conservative. Distribution of cadmium in the estuarine region indicates some mobilization which may be due to desorption. The enrichment ratio data suggest that various industrial wastes and municipal wastes contribute most of the dissolved metals in the Mahanadi River. The Mahanadi River transports 18.216 × 10³ t of total heavy metals into the Bay of Bengal and the calculated rate of erosion in the basin is 128.645 kg km^− 2 year^− 1.