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Amelioration of mine soil is challenging because of the lack of biologically active organic matter. The study was aimed to recycle yard waste into compost and biochar and to use them to reclaim mine soil. Biochar prepared at 350 °C showed the highest stable organic matter yield index and was used for the experiments. Lady’s finger was grown on mine soil amended with biochar (1%–5%), compost (2%–10%), and biochar-compost mixtures (2%–10%). Mine soil pH increased in all treatments. Mine soil dehydrogenase activity (42%–224%), microbial biomass carbon (4%–257%), and hydrolase activity (3%–230%) increased by combined application of biochar and compost. Lady’s finger plant height, biomass, and fruit yield were superior in biochar–compost mixtures compared to biochar and compost alone treatment. Thus the use of compost along with biochar could be recommended for reclamation of mine soil.

The effects of a silver nanoparticles (AgNPs)-cow-dung combination on Abelmoschus esculentus physiology, enzyme activities, heavy metal bioaccumulation, and micronutrients were investigated. A. esculentus seedlings were nurtured with foliar application of water, 0.75 mg/L each of AgNPs, cow-dung and AgNPs-cow dung till maturity. AgNPs-cow dung inhibited root and shoot lengths by 12.9% and 24.8%, respectively as opposed to elongation recorded for individual application compared to the control. In contrast to the promotion of photosynthesis, enzyme and antioxidant activities by individual applications, AgNPs-cow dung suppressed more than 50% of these parameters. Implied toxicities of AgNPs-cow dung on A. esculentus manifested in increased malondialdehyde contents with concomitant higher bioaccumulation factor of heavy metals. Cow-dung and AgNPs each stimulated A. esculentus activities in different ways, but their combination was inhibitory, which may be ascribed to the transformed AgNPs in cow-dung and relative availability of toxic metals.

Amelioration of mine soil is challenging because of the lack of biologically active organic matter. The study was aimed to recycle yard waste into compost and biochar and to use them to reclaim mine soil. Biochar prepared at 350 °C showed the highest stable organic matter yield index and was used for the experiments. Lady's finger was grown on mine soil amended with biochar (1%-5%), compost (2%-10%), and biochar-compost mixtures (2%-10%). Mine soil pH increased in all treatments. Mine soil dehydrogenase activity (42%-224%), microbial biomass carbon (4%-257%), and hydrolase activity (3%-230%) increased by combined application of biochar and compost. Lady's finger plant height, biomass, and fruit yield were superior in biochar-compost mixtures compared to biochar and compost alone treatment. Thus the use of compost along with biochar could be recommended for reclamation of mine soil.

The ability of waxy corn, long bean and okra to remove two polycyclic aromatic hydrocarbons (PAHs) from soil containing 0.63 mg Pb kg(-1) dry soil was assessed. The presence of Pb did not reduce the ability of these plants to remove the PAHs from soil. About 49 % of anthracene and 77 % of fluoranthene were removed from Pb-spiked or non-spiked soil, respectively, after 30 days. Among the plants, okra was the most efficient at removing anthracene and fluoranthene in the presence or absence of Pb in soil after 30 days. Pb did not affect fluoranthene removal, but stimulated the removal of anthracene, by long bean, waxy corn and okra. However, growth of long bean and waxy corn was poor in Pb-spiked soil and waxy corn plants died around 22 days after transplantation. The results show some promise in using plants to remove PAHs from soil which is also co-contaminated with Pb.

A field experiment was undertaken at Indian Agricultural Research Institute, New Delhi during kharif (rainy season) in the year 2010 to evaluate the residue persistence of flubendiamide in/on okra fruits following foliar application of Belt 39.35% SC formulation at 24 (standard dose) and 48 (double dose) g a.i. ha(-1). After HPLC analysis study revealed that residues of flubendiamide in/on okra persisted till 5th and 7th day after the last spray at standard and double dose, respectively. The residues of flubendiamide were reported as parent compound, and des-iodo flubendiamide, a metabolite (photo product) of flubendiamide, was not detected in/on okra at any time during the study period. The initial deposits of 0.28 and 0.53 μg g(-1) in/on okra fruits reached below determination level of 0.01 μg g(-1) on the 7th and 10th day at standard and double dose, respectively. The half life of flubendiamide in/on okra fruits ranged from 4.7 to 5.1 days at standard and double dose, respectively. Soil sample collected from the treated field on the 15th day after the last spray revealed residues of flubendiamide or its metabolite below determination level (0.01 μg g(-1)) at single and double dose.

Residue levels of chlorpyriphos were determined in unprocessed and processed okra fruits to evaluate the effect of different processes (washing and washing followed by boiling/cooking) on reduction of residues of this pesticide in okra. The study was carried out on okra crop (Variety, Varsha Uphar) in research farm of Chaudhary Charan Singh, Haryana Agricultural University, Hisar with application of chlorpyriphos (Radar 20 EC) at 200 g a.i./ha and 400g a.i./ha (Single Dose, T(1)) and 400 g a.i./ha (Double Dose, T(2)). Samples of okra fruits were collected on 0, 1, 3, 5, 7, 10, 15 days and at harvest after treatment. Residues were estimated by GC-ECD system and reached BDL of 0.010 mg kg(-1) on 7th and 15th day in case of single and double dose, respectively. The residues dissipated with half-life period of 3.15 days at lower dose and 3.46 days at higher dose following biphasic first order kinetics. Processing was found very effective in reducing the levels of chlorpyriphos residues in okra fruits. Maximum reduction (64-77%) was observed by washing + boiling followed by washing (13-35%).

Fenazaquin (4-[[4 (1,1-dimethylethyl) phenyl] ethoxy]quinazoline) is a new acaricide of the quinazoline class. Residue levels of fenazaquin were determined in unprocessed and processed okra fruits to evaluate the effect of different processes (washing, boiling and washing followed by boiling) in reduction of residues of this pesticide in okra. The study was carried out on okra crop (Variety, Varsha Uphar) in research farm of Chaudhary Charan Singh Haryana Agricultural University, Hisar with application of fenazaquin (Magister 10 EC) @ 125 ga.i./ha (Single Dose, T(1)) and 250 g a.i./ha (Double Dose, T(2)). Samples of okra fruits were collected on 0, 3, 7, 15 days after treatment and at harvest (30 days). Residues were estimated by gas chromatograph equipped with capillary column and nitrogen phosphorus detector. Residues reached below maximum residue limit of 0.01 mg/kg at harvest. The residues dissipated with half-life period of 3.13 days at lower dose and 4.43 days at higher dose. Processing is shown to be very effective in reducing the levels of fenazaquin residues in okra fruits. Maximum reduction (60-61%) was observed by washing + boiling followed by boiling/cooking (38-40%) and then by washing (31-32%).

Experimental investigations were conducted to evaluate the toxic effects of different arsenic (As) species such as arsenite (As(III)), arsenate (As(V)) and dimethylarsinic acid (DMA) on the growth of okra (Abelmoschus esculentus). The present study describes the changes in the growth, yield and accumulation characteristics of okra plants spiked with 20 and 50 mg kg(-1) of As(III), As(V) and DMA. As species negatively affected the yield and growth of the plant.The availability of arsenic compounds in the aerial parts decreased in the order As(V) > As(III) > DMA and in the roots observed as As(III) > As(V) > DMA. The results showed that except As(V), okra accumulated As(III) and DMA mainly in its roots with limited transport to shoots. Thus the plant has the capacity to tolerate As stress and can be considered as a resistive variety. The study also reveals that removal of As by boiling the vegetables with excess of water is not possible.

Pot-culture experiments showed that organically grown Vicia faba, influenced by atmospheric deposition, accumulated (μg g(-1)) 0.088-3.246 Cadmium, 0.19-42.48 Chromium, 0.0124-30.43 Copper, 0.075-4.28 Lead and 0.63-67.68 Zinc. Similar trends appeared for Abelmoschus esculentus. At high deposition sites, Cadmium, Lead and Zinc exceeded the safe limits of Prevention of Food Adulteration standards. Health risk index for Cadmium, Copper and Lead exceeded the safe limits of United States Environmental Protection Agency. The study suggests that atmospheric deposition could substantially elevate metal levels in organically grown vegetables in 2011.

In an effort to compare the persistence of imidacloprid and beta-cyfluthrin, when applied through a ready mix formulation, Solomon 300 OD @ 200 and 400 mL ha(-1) in the fruits of brinjal, tomato and okra, the present study has been made. The study indicated that the dissipation of these insecticides irrespective of fruits followed concentration dependent first order kinetics. The degradation constant and half live value of beta-cyfluthrin varies between -0.287 and -0.642 day(-1) and 1.07 and 2.41 days while that of imidacloprid between -0.21 and -0.34 day(-1) and 1.98 and 3.30 days respectively suggesting that the persistence of beta-cyfluthrin is lower than that of imidacloprid in fruits of these vegetables. Moreover, the persistence of these insecticides when compared between different fruits, it is highest in brinjal followed by tomato and least in okra, a probable clue of which has been proposed based on the non-enzymatic antioxidant content of the fruits.

Residues of propargite were estimated in okra fruits by high performance liquid chromatography following single application of Omite 57 EC @570 and 1,140 g a.i./ha. Residues of propargite were confirmed by high performance thin layer chromatography. The average initial deposits of propargite were observed to be 1.36 and 3.32 mg/kg, respectively, which were below its maximum residue limit of 2 mg/kg. The residue levels of propargite dissipated below its limit of quantification of 0.02 mg/kg after 7 days at single dose and after 10 days at double dose. The half-life values (T 1/2) of propargite were worked out to be 0.79 and 0.73 days, respectively, at recommended and double the recommended dosages.

Cadmium contamination of the soil is a common cause of environmental concern in the suburban areas of developing cities in India The present research paper describes the changes in physiological, biochemical, growth and yield characteristics, and bioaccumulation potential of lady's finger (Abelmoschus esculentus L.), an important vegetable crop at different levels of Cd in the soil. Cadmium accumulation was maximum in roots followed by stems, leaves and fruits at 100 mg Cd kg(-1) in the soil. Cd accumulation in lady's finger negatively affected the physiological and biochemical characteristics, growth and yield. The magnitude of negative effect enhanced with increasing Cd concentration. The study suggests that due to higher potential of bioaccumulation of Cd in lady's finger and consequent reductions in growth and yield, this plant may not be a suitable option for cultivation in Cd contaminated soil.

Persistence and efficacy of bifenthrin (25 and 50 g ai ha(-1)), fipronil (50 and 100 g ai ha(-1)) and indoxacarb (70 and 140 g ai ha(-1)) has been studied in okra fruits. The initial deposits varied from 0.259-0.382 microg g(-1) at low and 0.461-0.688 microg g(-1) at high rate of application. The residues persisted upto 10 days with half-life of 1.32-1.58 days for bifenthrin, 0.65-1.12 days for fipronil and 0.58-1.02 days for indoxacarb. Based on ADI, the suggested waiting period was 1 day for bifenthrin and indoxacarb and 3 days for fipronil. All the insecticides were found effective against leafhopper and shoot and fruit borer.

Dissipation of Quinalphos (Ekalux 20 AF) and Methomyl (Lannate 12.5 L) residues were studied in/on Okra (var. Pusa Sawani) fruits and cropped soil at Baruipur, West Bengal, India. The insecticides were applied at 21 days after sowing by foliar spray at the recommended and double the recommended dose (i.e. 500 and 1,000 g a.i. ha(-1) in both the cases). Four sprays were given at 15 days interval in all the cases. The initial build-up residue on Okra fruits was to the magnitude of 3.20 and 7.50 microg g(-1) for Quinalphos, 5.61 and 8.42 microg g(-1) for Methomyl at lower and higher doses respectively. The half-lives (t(1/2)) in Okra fruit were found to be 1.25-1.43 days for Quinalphos and 0.88-0.94 days for Methomyl. The safe waiting period (T(MRL)) determined were 6.7 and 5.3 days at the lower dose of Quinalphos. The corresponding waiting period for Methomyl were 5.7 and 4.9 days. Decontamination process like washing and cooking dislodged 25.50%-81.50% residue depending on insecticides and doses, whereas 20.00%-69.60% surface residue was removed by washing alone. The residues of both insecticides in soil persisted for 6-8 days depending on dose. The half-lives in soil were found to be 1.07-1.20 days for Quinalphos and 0.97-1.25 days for Methomyl.