Impact of pesticides on soil


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Impact of pesticides on soil

  1. 1. Review on Impact Of Pesticides on Soil and its components. Pranay Krishnan MSc EVS Part 1 Roll No 15
  2. 2. Abstract • In this study, we see the impact of pesticide use on soil components and specifically that of enzymes. • The experiment is designed using the host plant as Cabbage. • Experiment done in the Gudi village in the Maharashtra-Karnataka border. • Experiment shows how the use of various pesticides result in the decline in enzyme activity in the soil. • Review summarizes the impact, effect and management techniques used to reduce pesticide impact.
  3. 3. Key Words • Mineralization. • Pesticides. • Mobility. • Half Life. • Persistence.
  4. 4. Introduction • Pesticides is any component of organic or inorganic origin that is used in order to curb the growth of any limiting factor affecting the growth of a particular crop thereby facilitating better growth. • It covers a wide range of compounds including insecticides, fungicides, herbicides, rodenticides, mollu scicides, nematicides, plant growth regulators and others. • In this review we will be studying the different impacts a pesticide has on soil and other components.
  5. 5. Pesticides and India • India ranks 10th in terms of worldwide pesticide consumption. • Pesticide Consumption in India was 40672 MT (Technical grade) during the year 2005. • There are 186 registered pesticides in India, but of which 85 are technical grade produced within the country. • The per hectare consumption in India is 570 g/ha against 2500 g/ha in USA, 3000 g/ha in Europe and 12000 g/ha in Japan. • Pesticide consumption in India is the lowest at 0.5 kg per hectare as against 17 kg per hectare in Taiwan, 12 kg ha-1 in Japan, 6.6 kg ha-1 in Korea, 7 kg ha-1 in USA and 2.5 kg ha-1 in Europe. • Among all the crops grown in India, pesticide consumption in cotton is highest (44.5%) followed by paddy (22.8%), sorghum (8.9%), vegetables (7%), wheat (6.4%), pulses (2.8%) and others (7.6%). • Among the vegetable crops in India, cabbage is the maximum pesticide consuming crop.
  6. 6. Classification of Pesticides • Grouped into 2 main types 1. Hydrophobic, persistent, and bioaccumulable pesticides that are strongly bound to soil: Eg: organochlorine, DDT, endosulfan, endrin, hep tachlor,lindane and their TPs. Most of them are now banned in agriculture but their residues are still present.
  7. 7. 2. Polar pesticides: Represented mainly by herbicides but they include also carbamates, fungicides and some organophosphorus insecticide TPs. They can be moved from soil by runoff and leaching, thereby constituting a problem for the supply of drinking water to the population
  8. 8. Impact of Pesticides • Though beneficial, they contaminate soil ecosystem and pose threat to the balance equilibrium among various groups microorganisms and components in soil • Important process like mineralization, nitrification and phosphorus recycling are dependent much on the balanced equilibrium existing among various groups of organisms in the soil. • They disturb the presence of soil enzymes which are very key for the above processes and for matter turnover.
  9. 9. • Due to repeated application, insects are getting resistant to the different cidal agents. • Also these high concentration of these pesticides result in their absorption by plants leading to various ill effects in the entire ecosystem.
  10. 10. Soil Contamination Pesticides have various characteristics that determine how they act once in soil. • Mobility. • Half life. • Persistence.
  11. 11. Effect on soil fertility • Soil has millions of tiny organisms including fungi, bacteria, and a host of others. • These microorganisms play a key role in helping plants utilize soil nutrients needed to grow and thrive. • Microorganisms also help soil store water and nutrients, regulate water flow, andfilter pollutants.
  12. 12. Heavy treatment of soil with pesticides • Causes populations of beneficial soil microorganisms to decline. • Sometimes pesticides have a negative impact in the available NPK from soil.
  13. 13. Key Enzymes • Dehydrogenase. • Phosphatase. • Urease.
  14. 14. Dehydrogenases • Dehydrogenase does not accumulate extra cellular in soil and are invariably linked to the viability of intact cells. • Hence, its quantification has been recommended as a useful indicator for testing the side effects of agrochemicals. • Dehydrogenase is considered to play a very essential role in the process of organic matter oxidation, particularly in the electron transfer reactions.
  15. 15. Phosphatase and Urease • Soil phosphatases and ureases play a major role in the mineralization and nitrification processes of organic substrates. • Enzymes in soils originate from animal, plant and microbial sources and the resulting soil biological activity includes the metabolic processes of all these organisms. • Phosphorous is a very important plant nutrient.
  16. 16. • In the present study, pesticide use and its impact on selected soil enzymes were investigated with the following objectives- To asses the impact of pesticide use on dehydrogenase, phosphatase and urease activity in soil. To evaluate standard methods of pest and disease management to reduce impact of pesticide residues on soil enzyme activity.
  17. 17. Literature History • Done basically on 3 points: 1. Persistence of pesticide residues in soil and its impact on soil enzymes. 2. Effect of organic and inorganic sources of nutrients on biological activity in soil. 3. Integrated pest management (IPM).
  18. 18. Persistence of pesticide residues in soil and its impact on soil enzymes • Approximately 90-95% lindane and 79-89% endosulfan residues persisted beyond 70 days leading to a decrease in microbial. (Balwinder • Cycon et al. (2005) investigated the effects of insecticide (diazinon), herbicide (linuron) and fungicide (mancozeb+dimethomorph) on the enzymatic activities in soil The results showed that the influence of tested pesticides on dehydrogenase, acid and alkaline phosphatase and urease was diversified. • Kabat and panda (2007) reported 92.8 and 60.2 % inhibition of enzymatic hydrolysis of urea by hydroquinone (concentration- 1 mg/l) and copper sulphate and N thiophosphoric triamide (concentration – 100 mg/l) respectively. • Sushma and Singh (2006) observed that residues of these insecticides were monitored during the entire crop season and their effect on the soil enzymes dehydrogenase, phosphomonoesterase and arginine deaminase were studied. It was observed that in most of cases insecticides have inhibitory effect on soil enzymes. • Shiyin et al. (2004) reported that catalase activities are inhibited when fenvalerate are added to soil in 15 days, and then the activities began to be stimulated.
  19. 19. Effect of organic and inorganic sources of nutrients on biological activity • Dinesh et al. (2000) reported that addition of organic manures increased microbial activity/diversity and C turnover, which subsequently led to greater enzyme synthesis and accumulation in the soil matrix. • Duffy et al. (1994) reported that biological activity in soil was greater with organic farming compared to mixed farming and was the lowest in aerable soils. • Marcote et al. (2001) found that the organic amendments stimulated soil enzyme activity but mineral fertilizers did not.
  20. 20. Materials And Methods • Experimental details Design and layout • The experiment was laid out in Randomized Block Design (RBD) with four replication and five treatments. • Test crop – Cabbage (Brassica oleracea var. capitata) • Variety – Golden Head N50 • Spacing – 45 cm x 45 cm
  21. 21. Treatments • T1 - pest management as per package of practices. • T2 - integrated pest management. • T3 - pest management followed by farmers. • T1 Dimethoate Malathion. • T2 Dimethoate Neem oil. • T3 Dimethoate Endosulfan Indoxacarb.
  22. 22. Pesticide Application Dosages • Endosulfan 35 - 2 ml/L. • Dimethoate -2ml/L. • Neem oil - 2 ml/L. • Indoxacarb 14.5 - 5 ml/10L. • Malathion - 2 g/L.
  23. 23. Methods • Soil samples were collected from top 0 – 15 cm layer from each treatment at harvest. • The collected soil samples were shade dried for five days, ground in wooden pestle and mortar, sieved by passing through 2 mm sieve, mixed thoroughly and partitioned by quartering technique to get a composite working soil sample for its analysis and kept in cold storage till use.
  24. 24. Observation and Results • Dehydrogenase Activity All the treatments where an insecticide was applied were found to reduce the dehydrogenase enzyme activity significantly in comparison with control. • Phosphatase activity In most of the treatments, significant inhibition of phosphatase activity was recorded reference to the control • Urease Activity Significant reduction in Urease activity was also seen.
  25. 25. Conclusion • Pesticides are a very diverse group of chemicals, hence it is difficult to explore all the ramifications. • Microbial and faunal populations in time get tolerant to pesticides though there is considerable stress on the ecosystem. • Also major biotic processes such as enzyme activity, respiration, carbon and nitrogen mineralization are majorly affected.
  26. 26. Discussion Two main methods in order to curb the harmful effects of pesticides on soil are: • Organic agriculture • Integrated pest management
  27. 27. Organic Farming • Organic farming can be defined as “a system which avoids or largely excludes the use of synthetic inputs (such as fertilizers, pesticides, hormones, feed additives etc.) and to the maximum extent feasible relay upon crop rotations, crop residues, animal manures, off farm organic waste, mineral grade rock additives and biological system of nutrient mobilization and plant protection”.
  28. 28. • It is a holistic approach that offers equivalent gains in the interim and substantially improved gains in the long run. • It is based upon a set of processes resulting in sustainable eco-system, safe food, good nutrition, animal welfare and social justice. • It aims to create ecologically, socially and economically sustainable system of food and fiber production. • Finally it is the best way to encourage uncontaminated food production and at the same time sustain agriculture.
  29. 29. Integrated Pest Management • IPM doesn't rely solely on chemicals for pest control. • Biological control, cultural practices, and timely chemical applications are used to obtain the necessary level of control. • Pesticides are the last line of defense and are used only when pest levels are causing sufficient damage to offset the expense of the application.
  30. 30. Objectives • Scout or monitor crops regularly to check the levels of pest populations and their damage. • Implement available non-chemical control practices, including mechanical, cultural and biological controls, sanitation, and plant resistance. • Use crop rotation , select resistant varieties (plant resistance), thoroughly clean combines between fields to reduce weed seed introductions (sanitation) and use cultivation to control weeds (mechanical control). • Maximize the benefits of naturally occurring biological controls by using pesticides only when necessary and selecting pesticides which are the least harmful to beneficial. For example, some insecticides and fungicides kill predatory mites, which can cause a mite outbreaks later in the season
  31. 31. Project IPM • Only using pesticides that are labeled for the intended crop and pest. • Considering application site characteristics (soil texture, slope, organic matter). • Considering the location of wells, ponds and other water bodies. • Measuring accurately. • Maintaining application equipment and calibrating accurately. • Mixing and loading carefully. • Preventing backsiphoning and spills. • Considering the impact of weather and irrigation. • Storing pesticides safely and securely. • Disposing of wastes safely. • Leaving buffer zones around sensitive areas. • Reducing off-target drift.
  32. 32. References • Abhishek, S. and Ashok, K., 2005, The diamondback moth, Plutella xylostella: a problematic pest of Brassica crop. Advances in Indian Entomology: Productivity Health a Silver Jubilee Supplement – No. 3, 1: 229-240. • Biological control in the tropics: towards efficient biodiversity bioresource management for effective biological control Proceedings the Symposium on Biological Control in the Tropics held at MARDI Training Centre • Ali, M. A. A., Chandrasekar, S. S., Vardarasan, S., Gopakumar, B., Paramaguru, P., • Ponnusamy, V. and Muthusamy, M., 2002, Impact of organic cultivation. • Crops Symposium Placrosym XV, Mysore, India, 10-13 December, 2002, pp.451-456. • Ames, K.N., Reid, C.P. and Ingaham, E.R., 1984, Rhizosphere bacterial population responses to root colonization by VA mycorrhizal fungus. New Phytologist., 96:555- 563. • Amrit, K. and Amarjeet, K., 2005, Impact of imidacloprid on soil fertility and nodulation in mung bean (Vigna radiata). Asian J. Water Environ. Pollution, 2(2): 63-67.