![Dr.AB Jadhav, AC, Pune
1] pH affects the stability and performance of insecticides
Pesticide performance (especially insecticides) can be dramatically affected if the water
you use is alkaline (with a pH between 7.5 and 9.0). This can lead to alkaline hydrolysis,
which causes the pesticide to decompose to an inactive form – resulting in poor insect
control.
The solution:
Decomposition can be slowed or prevented by using an acidifying product solution to
achieve a pH level of 6.0 or below. Acidified pesticide sprays frequently provide improved
initial pest control and longer residual control.
CLICK HERE for list outlining recommended pH levels for a number of common
insecticides, fungicides and herbicides (by product name and active ingredient).
2. Your pH impacts solubility and nutrient uptake.
Nutrients must be present in water-soluble form for effective plant uptake. Fertilizer and
nutrient products that have a neutral pH and low water solubility make it hard for plants
to immediately absorb the nutrients.
The solution:
Acidifying the water to a safe level will increase solubility of nutrients within the spray
tank, making them more readily available for plant uptake. Where quick response is
desired, such as in fast-growing crops or where deficiency correction is urgent, this effect
is especially important.](https://image.slidesharecdn.com/ssac353mechanismofnutrienttransport-210916085445/85/Ssac-353-mechanism-of-nutrient-transport-30-320.jpg)
Ssac 353 mechanism of nutrient transport
- 1. Dr.AB Jadhav, AC, Pune Topic No. 25 & 26 Mechanism of nutrient transport from soil to plants roots Factors affecting nutrient availability to plants. Measures to overcome deficiencies and toxicities. Marks: 06 Dr. Anand. B. Jadhav, Assistant Professor College of Agriculture, Pune [email protected]
- 2. Dr.AB Jadhav, AC, Pune Nutrient Uptake by Plants Mechanisms for transport of nutrients form soil to root rhizosphere/surface Mechanisms for Nutrient uptake by the plants (Inside the cell)
- 3. Dr.AB Jadhav, AC, Pune Nutrient uptake by plants Exchangeable ions + surface adsorption Soil Air Solid phases + minerals OM + Microbes Rainfall + Evaporation + Drainage, addition of fertilizers
- 4. Dr.AB Jadhav, AC, Pune Mechanism of Nutrient Transport from Soil to Root Mass flow Diffusion Root Interception
- 5. Dr.AB Jadhav, AC, Pune
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- 7. Dr.AB Jadhav, AC, Pune Mass flow occurs when plant nutrient ions and other dissolved substances are transported in the flow of water to the root that results from transpiration water uptake by the plant Mass flow can also take place in response to evaporation and percolation of the soil water Amount of nutrients reaching to roots by mass flow is determined by Rate of water flow Water consumption of plants Average nutrient concentration in soil solution 1) Mass Flow
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- 9. Dr.AB Jadhav, AC, Pune 2) Diffusion Diffusion occurs when ions moves from an area of high concentration to one of low concentration As plant roots absorbs nutrients from the surrounding soil solution, the nutrient concentration at the root surface decreases compared with the bulk soil solution. Therefore a nutrient concentration gradient is established that causes ions to diffuse towards plant roots A high plant requirement for a nutrient results in a large concentration gradient, favoring a high rate of ion diffusion from sol solution to the root surface
- 10. Dr.AB Jadhav, AC, Pune Diffusion is governed by Fick’s Law The rate of nutrient diffusion is directly proportional to the concentration gradient dc/dt = De A dc/dx dc/dt = Rate of diffusion (Change in concentration C with time t) dc/dx = Concentration gradient (Change in concentration C with distance x De = Effective diffusion coefficient A = Cross sectional area through the ions diffuse
- 11. Dr.AB Jadhav, AC, Pune 3) Root Interception
- 12. Dr.AB Jadhav, AC, Pune Factors Affecting Nutrient Availability 1) Soil Texture 2) Soil Structure 3) Soil Reaction 4) Soil Temperature 5) Moisture Supply 6) Composition of Soil Air 7) Soil Available Nutrients 8) Total Nutrients Content 9) Microbial Activity 10) Soil Organic Matter
- 13. Dr.AB Jadhav, AC, Pune 1. Soil Texture Texture Relative proportion of sand, silt and clay has profound effect on different properties of soil Light textured soils Fine textured soils Low water capacity High water capacity Less water holding capacity High water holding capacity Less organic matter content More organic matter content Little or no swelling or shrinkage High swell and shrinkage in soil High leaching of nutrients Less leaching
- 14. Dr.AB Jadhav, AC, Pune 2. Soil Structure Structure Arrangement of soil separates is called ……. Despite adequate nutrient supply, unfavorable physical condition resulting from a combination of the size, shape arrangement and mineral composition of the soil particles, may lead to poor crop growth and activity of microbes. Basic requirement for crop growth in terms f physical conditions of soils are….. Adequate soil moisture Aeration Optimum soil temperature Freedom from mechanical stress
- 15. Dr.AB Jadhav, AC, Pune Adequate soil moisture Aeration Optimum soil temperature Tillage/Mulching/Irrigation Incorporation of OM Liming o other amendments Root penetration, microbial activity Soil Structure Indirectly Affects….
- 16. Dr.AB Jadhav, AC, Pune Component Per cent 1 Mineral matter 45 2 Soil water 25 3 Soil air 25 4 Organic matter 5 Soil Composition (Volume basis)
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- 18. Dr.AB Jadhav, AC, Pune Optimum pH: for more availability of nutrients in soil 6.5 to 7.5 Acidic pH : More availability of Fe, Mn, Zn and Cu Alkaline pH: less availability of P, Fe, Mn, Zn and Cu More availability of Mo and B at high pH Continuous and slow persisting action of this acid removes large quantities of Ca and Mg by dissolution and leaching. This release of acids Decomposition of organic matter releases Organic acids like carbonic acids Inorganic acids like Sulphuric and nitric acids 3. Soil Reaction (pH)
- 19. Dr.AB Jadhav, AC, Pune 4. Soil Temperature Soil temperature affects most of he physical chemical and biological properties of soil Physical Properties Indirectly affects soil texture and structure Chemical Properties Nutrient availability, pH EC Dissolution Precipitation Biological Properties Decomposition Root growth Microbial growth/population Germination Suitable temp. for microbes 25 to 350C
- 20. Dr.AB Jadhav, AC, Pune 5. Soil Moisture Nutrient availability & root penetration Root inerception, mass flow, diffusion Soil moisture affects various phenomenon soil Moisture at FC- optimum nutrient availability Excess moisture- leaching losses Mineralization Microbial activity/decomposition
- 21. Dr.AB Jadhav, AC, Pune 6. Soil Air Soil reaction Microbial activity & population Decomposition/ mineralization Symbiotic N-fixation Nutrient availability Root growth
- 22. Dr.AB Jadhav, AC, Pune Composition of Soil Air
- 23. Dr.AB Jadhav, AC, Pune Mineralization Leaching losses Immobilization Fixation of nutrients Clay Al-P Fe-P Soil Available Nutrients
- 24. Dr.AB Jadhav, AC, Pune Total Nutrient Content • Total nutrient content may be high in soil but its availability may be less • Conversion of total to available is a biochemical processes mediated by microbes. • Microbes and OM content plays imp. role for mineralization • Soil may have higher nutrient content but to make them available various factors are involved. • Some soils have high fertility but may not be productive.
- 25. Dr.AB Jadhav, AC, Pune Organic Matter Mineralization/im mobilization Decomposition causes nutrient release Microbial activity & population Symbiotic N- fixation/Chelating agent Release of fixed nutrients Improvement in physical properties & Enhances WHC
- 26. Dr.AB Jadhav, AC, Pune Plant Species Variety Rooting pattern Climate Season Humidity Temperature
- 27. Dr.AB Jadhav, AC, Pune Irrigation • Quality • Management • Type of irrigation Fertilizer • Application method • Type of fertilizer • Time of application
- 28. Dr.AB Jadhav, AC, Pune Management/cultivation • Tillage • Compaction • Problematic soil
- 29. Dr.AB Jadhav, AC, Pune Measures to Overcome Deficiencies and Toxicities. Maintenance of soil physical properties of soil Soil test based use of fertilizers Irrigation water testing Organic manure application Use of multi-nutrient containing fertilizers Use of micronutrients as per the deficiency symptoms through foliar spray
- 30. Dr.AB Jadhav, AC, Pune 1] pH affects the stability and performance of insecticides Pesticide performance (especially insecticides) can be dramatically affected if the water you use is alkaline (with a pH between 7.5 and 9.0). This can lead to alkaline hydrolysis, which causes the pesticide to decompose to an inactive form – resulting in poor insect control. The solution: Decomposition can be slowed or prevented by using an acidifying product solution to achieve a pH level of 6.0 or below. Acidified pesticide sprays frequently provide improved initial pest control and longer residual control. CLICK HERE for list outlining recommended pH levels for a number of common insecticides, fungicides and herbicides (by product name and active ingredient). 2. Your pH impacts solubility and nutrient uptake. Nutrients must be present in water-soluble form for effective plant uptake. Fertilizer and nutrient products that have a neutral pH and low water solubility make it hard for plants to immediately absorb the nutrients. The solution: Acidifying the water to a safe level will increase solubility of nutrients within the spray tank, making them more readily available for plant uptake. Where quick response is desired, such as in fast-growing crops or where deficiency correction is urgent, this effect is especially important.
- 31. Dr.AB Jadhav, AC, Pune 3. Foliar sprays require an acidic pH for proper absorption. Foliar absorption is pH dependent. The pH level regulates the complex electrostatic repulsion and attraction phenomena within the plant’s cuticle. For example, it is believed that the optimal pH level for phosphate absorption and utilization is between 3 – 3.7. There is evidence that zinc is absorbed best at a pH range between pH 4.1 – 4.9. While much research needs to be done, it is clear that optimal pH levels vary according to each nutrient and its carrier. The solution: Again, acidify the water and seek the advice of an agronomy professional if required. 4. Extreme pH imbalances can burn the plant surface. Plants are generally tolerant of sprays with a wide range of pH. Naturally, extremes at either end of the pH scale should be avoided. Phytotoxicity is a chief concern. A spray solution with a significant pH imbalance can “burn” the plant, and result in soft tissue death, stunting, russeting, leaf spotting, dead leaf tips, dead areas between leaves and distortion of the leaves and reproductive organs The solution: Avoid extreme pH levels in a spray solution. Spray solutions should not be acidified if they contain lime, lime sulfur, or fixed copper products where copper may become solubilized by the acidity resulting in possible plant injury. Note: Other factors besides pH that affect phytotoxicity are concentration, salt index, chemical reactivity, and weather conditions.
- 32. Dr.AB Jadhav, AC, Pune Management of pH for Spray Solution As a general practice, spray solutions work best in an acidic solution (pH 4.0 – 6.0). Pesticides are most effective at a pH of 6.0 or below. Phosphate is absorbed best at a pH slightly below 4.0. Most spray products become more soluble as pH decreases. Extremely high or low pH levels can cause leaf burn. Spray solutions should not be acidified if they contain lime, lime sulfur, or fixed copper products, carbonate, hydride. Acid spray solutions help control certain fungi and may be a factor in maintaining populations of some beneficial insects. It starts by knowing the pH level of your water supply. When it comes to product mixing and compatibility, always follow the labels and consult with your farm supply retailer if you have any questions. They may recommend use of an acidifying product or a tank mix adjuvant designed to improve solubility, compatibility and efficacy.
- 33. Dr.AB Jadhav, AC, Pune Soil & Plant Critical limits for Micronutrients Micronu. Critical limit (ppm) Fertilizer Application method Soil Plant Soil (kg ha-1) Foliar - simple salts(%) Chelated Fe < 4.5 < 50 FeSO4 10-40 0.5 0.2 Mn < 2.0 < 20 MnSO4 10-40 0.5 0.1 Zn < 0.6 < 20 ZnSO4 10-40 0.5 0.2 Cu < 0.2 < 4 CuSO4 10-40 0.1 0.1 B < 0.5 < 2 Borax 5-10 0.2 -- Mo < 0.05 < 0.1 Na2MoO4 1-2 0.1 --
- 34. Dr.AB Jadhav, AC, Pune