Workshop: 4R Nutrient Stewardship Principles and Practices

Transcription

1 Workshop: 4R Nutrient Stewardship Principles and Practices Dr. Terry L. Roberts, President Dr. Munir Rusan, Consulting Director, Middle East Dr. Kaushik Majumdar, Vice President, Asia, Africa, and the Middle East

2 Workshop purpose: to provide an overview of 4R nutrient stewardship and its supporting scientific principles Outline: 1. Review the scientific principles of 4Rs based on IPNI s 4R manual (Terry Roberts) 2. 4R fertigation for efficient nutrient management in irrigated agriculture (Munir Rusan) 3. Nutrient Expert fertilizer decision support tool to support 4R fertilizer recommendations (Kaushik Majumdar)

3 The manual provides scientific principles of the 4Rs

4 Learning modules and case studies are included in the manual

5 Sustainable agriculture Definition Accommodating the growing demand for production without compromising the natural resources upon which agriculture depends. The concept of sustainability is multidimensional applies to social, economic, and environmental dimensions simultaneously.

6 4R Nutrient Stewardship applying the right Click nutrient to edit source, Master at the right title rate, style right time, and right place is an essential tool in the development of sustainable agricultural systems.

7 4R Nutrient Stewardship and Sustainable Agriculture Implementation of 4R Nutrient Stewardship can positively influence the sustainability of agricultural systems beyond the immediate benefits of improved crop nutrition and production.

8 Click to edit Master title style The 4R Nutrient Stewardship Concept 4R Plant Nutrition Manual: Chapter 2

9 Source, Rate, Time, and Place describe any nutrient application

10 Right means Sustainable Right source, rate, time, and place Outcomes valued by stakeholders

11 Examples of key scientific principles Key Scientific Principles The Four Rights (4Rs) Source Rate Time Place Ensure balanced supply of nutrients Assess nutrient supply from all sources Assess dynamics of crop uptake and soil supply Recognize crop rooting patterns Suit soil properties Assess plant demand Determine timing of loss risk Manage spatial variability

12 Examples of Practical Choices Practical Choices The Four Rights (4Rs) Source Rate Time Place Commercial fertilizer Livestock manure Compost Crop residue Test soils for nutrients Calculate economics Balance crop removal Pre-plant At planting At flowering At fruiting Broadcast Band/drill/inje ct Variable-rate application Ensure practices are in accord with principles

13 Equal attention to all 4Rs Balance attention to all 4Rs Rate: easily overemphasized Source, Time, Place: often require major changes and investments

14 The 4Rs interconnect with each other with local soil and climate factors with management of soils and crops other factors can limit productivity even when levels of plant nutrients are adequate

15 The 4Rs connect to the cropping system Soil water, air, and temperature influence nutrient availability. genetic yield potential weeds insects diseases mycorrhizae soil texture & structure drainage compaction salinity temperature precipitation solar radiation

16 The 4Rs influence many performance indicators Social, Economic and Environmental performance Influenced by crop and soil management as well Whole system outcomes Resource use efficiencies: Energy, Labor, Nutrient, Water Soil erosion Nutrient balance Yield Net profit Biodiversity Nutrient loss Water & air quality Affordable & accessible food Ecosystem services Farm income Return on investment Quality Yield stability Working conditions

17 Stakeholders have a say on performance indicators Stakeholders define goals Indicators relate to goals Producers choose practices

18 Producers choose practices Practices selected to suit local site-specific soil, weather, and crop conditions Conditions may change even on the day of application Local decisions preferred

19 BMP adoption and evaluation farm level Adaptive management Farm Level Producers, Crop advisers DECISION Accept, revise, or reject ACTION Change in practice EVALUATION of OUTCOME Cropping System Sustainability Performance LOCAL SITE FACTORS Climate Policies Land Tenure Technologies Financing Prices Logistics Management Weather Soil Crop demand Potential losses Ecosystem vulnerability

20 BMP adoption and evaluation regional level Logistics and science Regional Level Agronomic Scientists, Agri-service Providers Farm Level Producers, Crop advisers DECISION SUPPORT based on scientific principles OUTPUT Recommendation of right source, rate, time, and place (BMPs) DECISION Accept, revise, or reject ACTION Change in practice EVALUATION of OUTCOME Cropping System Sustainability Performance LOCAL SITE FACTORS Climate Policies Land Tenure Technologies Financing Prices Logistics Management Weather Soil Crop demand Potential losses Ecosystem vulnerability

21 BMP adoption and evaluation policy level Infrastructure and incentive Policy Level Regulatory, Infrastructure, Product Development Regional Level Agronomic Scientists, Agri-service Providers Farm Level Producers, Crop advisers DECISION SUPPORT based on scientific principles OUTPUT Recommendation of right source, rate, time, and place (BMPs) DECISION Accept, revise, or reject ACTION Change in practice EVALUATION of OUTCOME Cropping System Sustainability Performance LOCAL SITE FACTORS Climate Policies Land Tenure Technologies Financing Prices Logistics Management Weather Soil Crop demand Potential losses Ecosystem vulnerability

22 Sustainability indicators are longterm Short-term efficiencies can lead to long-term soil nutrient depletion Nutrient balance in context of inputs and outputs

23 Source, Rate, Time, and Place Every application has all four Get all four right! Completely interconnected 4R Nutrient Stewardship emphasizes impact on outcomes

24 Click to edit Master title style Scientific Principles Supporting RIGHT SOURCE 4R Plant Nutrition Manual: Chapter 3

25 Scientific principles for Right Source Consider rate, time, and place of application Supply nutrients in plant-available form Suit soil physical and chemical properties Recognize synergisms among nutrient elements and sources Recognize blend compatibility Recognize benefits and sensitivities to associated elements

26 Each plant nutrient has specific and irreplaceable functions Of the 17 essential plant nutrients, 14 of them are supplied from the soil Micronutrients are just as important as macronutrients, but the amount required is very small Micronutrients Primary & Secondary Macronutrients Values are relative concentrations

27 Most soils do not contain the appropriate balance of nutrients for unrestricted plant growth Plants require a balance of all the essential nutrients for yield and quality Most soils are low in at least one essential nutrient; preventing plants from reaching their potential Appropriate fertilizer applications overcome these limitations

28 Nutrients need to be in plant-available forms for uptake Nutrients are only taken up by roots when dissolved in water Insoluble nutrients are not immediately useful for plant nutrition

29 Once in the plant, the nutrient source is no longer important Plant roots primarily take up inorganic nutrients The source of nutrient is not a factor for plant nutrition For example, nitrate is the same from fertilizer, manure, or soil organic matter

30 There is no one right source for every soil and crop condition Each crop, soil, and farmer has different needs and objectives for example: Farmer issues: Fertilizer availability? Product price? Application equipment? Environmental concerns? Soil and Crop issues: Ammonia loss from broadcast urea? Gaseous loss of nitrate from wet soil? Runoff of P from applications on the soil surface?

31 Healthy plants need a sufficient supply of every essential nutrient for maximum yield and quality Avoid focusing only on the macronutrients, although they are required in largest quantity An adequate supply required, but nutrient availability must also match peak periods of plant demand Correct other soil conditions that may limit nutrient uptake, such as acidity, compaction, or salinity

32 How to select the Right source? First determine what nutrients are needed to achieve the production goals Identify potential nutrient limitations with soil and plant analysis Nutrient omission plots may be useful where laboratory testing is not available

33 Consider the accompanying nutrients in the fertilizer - two examples Phosphate sources MAP (NH 4 H 2 PO 4 ) or DAP (NH 4 ) 2 HPO 4 ) Both fertilizers contain identical elements, but have very different properties Potassium sources KCl, K 2 SO 4, K 2 SO 4 2MgSO 4, KNO 3, K 2 S 2 O 3 All contain soluble potassium, but the accompanying nutrient changes the properties

34 Importance of balanced plant nutrition It is insufficient to focus on each nutrient in isolation All nutrients must function together for yield and quality goals If one essential nutrient is limiting growth, then none of the other nutrients will be efficiently utilized (see Learning Module 3.5-1).

35 Nutrient interactions Whenever any fertilizer source is added to soil, it will impact the behavior of other nutrients Ammonium can enhance phosphorus availability Excess potassium can restrict magnesium uptake High phosphate concentration can impair zinc uptake Limestone additions can improve phosphorus and molybdenum solubility, but decrease copper, iron, manganese, and zinc

36

37

38 Scientific Principles Supporting Click to edit Master title style RIGHT RATE 4R Plant Nutrition Manual: Chapter 4

39 Scientific principles for Right Rate Consider source, time, and place of application Assess plant nutrient demand Assess soil nutrient supply Assess all available nutrient sources Predict fertilizer use efficiency Consider soil resource impacts Consider economics

40 Nutrient demand is related to yield target Setting realistic yield targets Potential yield Maximum attainable yield Attainable yield in an average season 10% above 3 to 5-year average yield Yield goal is not yield limit

41 Mechanisms influencing soil supply Mineralization/immobilization Adsorption/desorption Precipitation/dissolution Reduction/oxidation Root interception, mass flow, diffusion

42 Factors affecting nutrient availability N P K S Ca and Mg Micros Soil ph x x x x x x Moisture x x x x x x Temperature x x x x x x Aeration x x x x x x Soil organic matter x x x x x Amount of clay x x x x x x Type of clay x x x x Crop residues x x x x x x Soil compaction x x Nutrient status of soil x x x Other nutrients x x x x Crop type x x x x Cation exchange capacity (CEC) x x x % CEC saturation x

43 Ways of assessing soil nutrient supply Soil test is the best tool to assess indigenous nutrient supplying capacity of soils Nutrient omission plot studies can also be used in absence of soil testing facility

44 Consider all available nutrient sources Adjust rates of externally applied nutrients for: Native soil supply Organic manure Irrigation water Crop residues Biological N fixation

45 Fertilizer use efficiency Plants cannot utilize 100% of the externally applied nutrients due to inherent sinks and loss mechanisms Fixation by inorganic and organic soil components Microbial immobilization Leaching Volatilization

46 FUE can be estimated by several ways Agronomic efficiency (AE) = (Y - Y 0 )/F Recovery efficiency (RE) = (U - U 0 )/F From nutrient omission plot data, with known AE or RE F = (Y - Y 0 )/AE or F = (U - U 0 )/RE 4R Nutrient Stewardship raises both yields and FUE

47 Consider Soil Resource Impacts Nutrient application rates that optimize plant growth: Contribute more C to the soil as crop residues Build up soil organic C Improve soil structure Improve soil water and nutrient holding capacity Maintain optimum soil test levels (P and K)

48 Soil resource impact on right rate Rate estimation is governed by soil test Apply less than the crop removal when soil test is high and vice versa For P and K fixing soils, apply additional amounts to compensate for fixation Test soils every 3 to 5 years to ensure that nutrients are maintained at sufficient level

49

50

51 Scientific Principles Supporting Click to edit Master title style RIGHT TIME 4R Plant Nutrition Manual: Chapter 5

52 To assist in rate determination, the manual provides tables of: Nutrient uptake for selected crops Dry matter and nutrient composition of manure Annual N fixation by legumes Nutrient removal for selected crops

53 Principles supporting Right Time Consider source, rate, and place of application Assess timing of plant uptake Assess dynamics of soil nutrient supply Recognize dynamics of soil nutrient loss Evaluate logistics of field operations

54 Crop uptake dynamics and fertilizer timing Example: Corn Most crop nutrient uptake and dry matter accumulation follows S shaped or sigmoid patterns Iowa S. Univ., 2008

55 Crop uptake dynamics and fertilizer timing continued Rice Bertsch, 2005

56 Timing by growth stage may be beneficial in some crops Wheat - most N should be applied before the jointing stage, but some applied late-season during heading may increase grain protein Cotton - majority of N and K taken up after first flower; in some cases foliar application after this point can improve yield and/or quality

57 Assessing dynamics of soil nutrient supply Most soils can supply at least some of the nutrient requirements of a crop Soils with low nutrient holding capacity require more emphasis on critical application timing

58 Right Time depends on dynamics of the nutrient cycle

59 Soil testing and application timing Soil test level is a helpful tool in assessment of soil nutrient supply Provides some idea of the probability of response to fertilizer application At lower soil test levels, application timing is more critical Higher soil test levels allow more flexibility in timing

60 Assessing dynamics of soil nutrient supply Questions to ask/keep in mind Are there issues with immobilization or other processes that might disrupt nutrient supply? Does the soil have the potential to compromise availability of added nutrients over time? (e.g., P in highly acid or alkaline soils)

61 Assessing dynamics of soil nutrient loss Losses of N and P have the most potential for environmental impact Mechanisms of loss for N and P are very different P normally lost through runoff, making placement important in avoidance

62 Nitrogen loss potential and timing Nitrogen can be lost through pathways such as Leaching Denitrification Runoff Where there is high potential for N loss during the season, timing is especially important

63 Nitrate-N in soils N occurs in several forms in soils, one of them is nitrate Most nitrate in soils is produced from the process of nitrification Nitrification is the biologically driven conversion of ammonium-n to nitrate-n

64 Nitrate-N in soils Nitrate is subject to loss through leaching and denitrification, particularly in wetter environments Nitrate may accumulate in soils in arid environments where leaching potential is low Soil testing for nitrate with deep (60 cm or 2 ft.) samples is useful in accounting for all available N in more arid environments

65 Fall application of N for spring planted crops Spring application is best, but fall application can be an option Should be done after soil temperature is <50 F (10 C) Inhibitor technology can be useful

66 Fall application of N for spring planted crops: An example Parameter (mean of 15 years, ) Time of N Application Fall Fall + N-Serve Spring Yield (bu/a) Economic return over fall applied N ($/A/yr) Flow-weighted NO 3 -N (mg/l) in tile drainage water N recovery in grain (%) Randall, 2008

67 Logistics of field operations affect timing decisions Application timing decisions are governed by practicality As farm size has increased, logistics of planting and input timing have changed Fall input, where reasonable, can save valuable time in the spring P and K by nature lend themselves to early application, but precautions should be taken with fall N application

68 Enhanced efficiency fertilizer technology may ease timing pressure Where logistics demand a single, one-time application, EE fertilizer technologies may be useful These technologies include: Slow and controlled release fertilizer Nitrification and urease inhibitors

69

70

71 Click to edit Master title style Scientific Principles Supporting Right Place 4R Plant Nutrition Manual: Chapter 6

72 Principles supporting Right Place Consider source, rate, and time of application Consider where plant roots are growing Consider soil chemical reactions Suit the goals of the tillage system Manage spatial variability

73 Examples of differences in root architecture Weaver, 1926

74 Root plasticity Drew, 1975

75 Influx, millionth of a milligram of P per meter of maize root length per day Nutrient uptake by plant roots Maximum influx Influx as it approaches the maximum Solution concentration, milligrams of P per liter Barber, 1984

76 Nutrient uptake rate changes during the season mg P per m of root per day mg K per m of root per day Phosphorus Potassium Plant age, days From Mengel and Barber, 1974

77 Nutrient placement options Broadcast Banded Point injected Combinations

78 Nutrient placement options

79 Nutrient placement options

80 Soil and Root Reactions to Band Placement Key effects of banding: Concentration of nutrients Higher localized soil solution concentrations Faster diffusion rates Root proliferation (N and P)

81 Application rate affects fertilized soil volume Higher rates: Extend the volume of fertilized soil Bring fertilizer granules or droplets closer Increase the longevity of fertilized soil

82 Placement affects fertilized soil volume Broadcasting nutrients over time (conservation tillage) Banding nutrients in the same location over time Banding nutrients in different locations over time Increasing time

83 Early season crop needs Banded nutrients near the seed: Are in close proximity to a limited root system Provide concentrated supplies when influx rates are highest Increase the rate of nutrient diffusion to roots

84 Factors to consider for seed-placed fertilizer Adjust rates for: Seed sensitivity Fertilizer salt index Width of seed furrow Soil texture Soil moisture Amount of tolerable stand loss

85 Reducing nutrient losses with banding Sub-surface banding keeps nutrient concentrations lower at the soil surface reducing: Runoff losses Losses accompanying soil erosion Gaseous losses of N

86 Percent of the plant P coming from the band Starter fertilizer: NH 4+ and P should be placed together lb P 2 O 5 /A lb P 2 O 5 /A + 10 lb N/A, mixed lb P 2 O 5 /A + 10 lb N/A, separate Phosphate added to bulk soil, lb P 2 O 5 /A Miller and Ohlrogge, 1958 Soil test P, ppm

87 Foliar fertilization Nutrients in the gaseous state enter the leaves through the stomata Nutrients in solution enter the leaves through small pores in the epidermis of the plant leaf Foliar with adjuvant Foliar fertilization creates small, localized supplies of nutrients that have a short duration Effective when soil supplies are limited

88 Limitations of foliar fertilization Factors limiting the effectiveness of foliar fertilization: Plants with thicker cuticle layers Runoff of fertilizer from leaves Washing off of fertilizer by rain Drying of liquid fertilizer on the leaf Limited translocation of some nutrients within the plant Leaf damage

89 Managing spatial variability Right place goes beyond place within the soil to place within the landscape Example: P Index helps target areas where P applications need to be reduced or sub-surface placement should be utilized. P loss vulnerability Low (clear) Medium High Sharpley, Gburek, USDA-ARS, Beegle, Penn State, University Park, PA

90

91

92 4R Fertigation for efficient nutrient management in irrigated agriculture Dr. Munir Rusan, Consulting Director, Middle East

93 Outline What is fertigation? Why fertigation is necessary for arid & semiarid region? Advantages of fertigation 4R Fertigation: Selecting right Source of both nutrients & irrigation water, IW Selecting right Rate of both nutrients & IW application Selecting right Time of both nutrients & IW application Selecting right Place of both nutrients & IW application Conclusion

94 4Rs can be applied to any cropping systems including: rainfed agriculture, and irrigated agriculture, open or protected agriculture, hydroponic or soilless culture Fertigation None of these cropping systems can be perfectly sustainable, but the adoption of the 4R is the way to optimize sustainability.

95 P Fe K N P Fe K N N P K Fe N P Fe K Fertigation is the application of soluble and compatible fertilizers through IW Can be practiced with any irrigation system. However, due water scarcity, it is practiced dominantly with pressurized irrigation systems; drip irrigation systems being the most efficient irrigation method Fertigation controls 4R components more precisely than other system

96 Why Fertigation? Fertigation for Arid and Semiarid Region is not a choice but a mandatory & prerequisite: Rainfall is low and poorly distributed Agric. production can be practiced only with irrigation Water Resources are Limited Cultivable Land are limited Water & Soil Fertility are the Main 2 Limiting Factors of Agriculture Production These 2 factors can be simultaneously and best managed with fertigation

97 Under these conditions (scarcity of water & cultivable land): Horizontal expansion is limited- limited water & land resources Agric. Intensification - main approach to increase food: Ag. Intensification Intensive use of inputs, where fertilizer use is considered the leading factor > 50% of World food production is attributed to fertilizers use (FAO) Growing Environmental concern with Ag. Intensification Therefore, water and fertilizer should be managed sustainably (that is be economically feasible, environmentally and socially acceptable -Eco-intensification) This can be better achieved with fertigation

98 Current & Future Trends: Due to scarcity of water resources: farmers are switching from surface to pressurized irrigation drip is the common practice

99 Conventional Fertilization to Fertigation

100 Fertigation Main Advantages: Precisely control source, rate, time and place of application (4R) Increase the yield Improves both WUE & FUE, saving water & fertilizers Reduces nutrients leaching below the root zone Save energy, time and cost Saline, shallow and with- slope soils can better be cultivated others

101 Research has proven superiority of fertigation Squash yield, T/ha (Rate of N2-fertig = Rate of NS-soil application d ab a N2 f N0 N1 N2 N3 NS kg/ha bc c N2s Rusan, Nutrient Cycling in Agroecosystem 67: 1-10, 2003 Fertigation of 65 kg N/ha performed better than soil application of 128 kg N/ha

102 N fertigation: Enhances plant biomass and Increase density and depth of root, Resulting in higher evapo-transpriration (water consumption) and WUE WUE (kg/mm) by Squash with N fertigation vs soil application b a b c 0.0 N1 fertigation N2 fertigation N3 fertigation Ns=N2 soil appl Rusan, Nutrient Cycling in Agroecosystem 68: 1-11, 2004

103 Nitrogen Utilization efficiency Using Isotopic 15 N Labelled Fertilizer N Derived from N Fertilizer (% and Uptake) & N Utilization Efficiency (NUE) were more than double for fertigation vs soil application Fruit Shoot Fruit Shoot Total NUE N dff N uptake dff N uptake dff Trt Kg ha -1 % Kg N ha -1 Kg N ha -1 % N0 0 N c 39.8 c 24.1 c 7.4 b 31.5 c 47.9 a N b 45.4 b 44.1 b 15.4 a 59.5 b 45.3 a N a 49.7 a 46.3 a 17.6 a 63.9 a 32.4 b NS d 33.5 d 20.0 d 6.0 b 26.0 d 20.3 c dff = Derived from fertilizer N1, N2, N3 = Fertigation trts & NS = Soil application trt N2 = NS Rusan, Nutrient Cycling in Agroecosystem 68: 1-11, 2004

104 Components of Nitrogen Utilization Efficiency Trts N Rate FNUEp FNUEa RE PFP kg ha -1 kg kg 1 N N a a 0.73 a a N b b 0.72 a b N b c 0.44 b c NS b 9.42 c 0.43 b c * N1, N2, N3 = Fertigation trts & NS = Soil application trt Physiological FNUE (FNUEp), kg kg -1 = (FWf - FWc) / (TNUPf TNUPc) Agronomical FNUE (FNUEa), kg kg -1 = (FWf - FWc) / NA Recovery Efficiency (RE), kg kg -1 = (TNf - TNc) / NA Partial Factor Productivity (PFP), kg kg -1 = (FWf / NA) FWf = fruit weight of fertilizer treatment FWc = fruit weight of control treatment TNUPf = total N uptake by fruit and shoot in fertilizer treatment TNUPc = total N uptake by fruit and shoot in control treatment NA = nutrient applied Rusan, Nutrient Cycling in Agroecosystem 68: 1-11, 2004

105 With Drip Irrigation: Limited soil wet zone Shallow root depth Limited zone for fertilizer placement Higher depletion rate so requires higher frequency of application of W + F Higher interaction among nutrients Concentrated soil solution salinity High nutrients interaction Available concentration < Apparent due to higher ionic strength. a i = Ƒ * c i ; a = activity = availability; C = concentration; Ƒ = activity coefficient DRIPPER

106 Pattern of Accumulation of Nutrients & Salts in the Irrigated Volume by a Dripper Irrigation Water DRIPPER H 2 PO 4 Ca NH 4 K Fe Saturated Zone Leached Zone Higher salts and mobile nutrients NO 3 NO 3 Accumulation of Salts & NO 3

107 Under these conditions, I mean nutrient management in such small and concentrated soil zone is very challenging. However, this can be achieved with fertigation thru accurately controlling the Source, Rate, Time & Place of Water + Fertilizer application That is by fertigation, we can Apply Water + Fertilizer together using the right source of F+W, right rate of F+W, right time of F+W right place of F+W

108 4R Fertigation Irrigation Pipe Source Rate Time Place Example of scientific principle Ensure 1. balanced supply of nutrients, 2. Solubility, and Compatibility with irrigation water 3. Suitability to soil chemical and physical properties Asses nutrient supply from all sources and plant demand, Recognize irrigation requirement and frequency, soil texture and growth stage Asses dynamics of crop uptake and soil supply Determine timing of loss risks Recognize soil texture and irrigation frequency Soil moisture level and climatic conditions Recognize crop rooting patterns, irrigation method and soil texture. Manage spatial variability Example of practical choices Solid fertilizer Liquid fertilizer Suspension fertilizer Single vs compound fertilizers Salt index of fertilizer Quality of IW Test soils for nutr. Calculate economics Balance crop removal Test and calibrate fertigation head Pre-plant At planting At flowering At fruiting Continuously Every other irrig. Fertigate with surface irrigation Fertigate with subsurface irrigation Fertigate with drip, sprinkler or surface irrigation methods

109 Right source of nutrients for fertigation To select the right nutrient source for fertigation consider the following: Determine soil nutrients levels to recognize deficient nutrients Recognize impact of accompanying ions on environment & public health Recognize the feasibility, accessibility and affordability of the source applied and its impact on the income of the farmer Source must supply all nutrients needed in a balanced way to prevent any negative or antagonistic interactions among nutrients avoid accumulation of certain nutrients avoid depletion of certain nutrients Source must be water soluble - most important factors for fertigation, especially when preparing fertilizer solutions from dry fertilizers

110 Right source of nutrients for fertigation To select the R1 for fertigation consider the following: Source should be suitable for soil chemical and physical properties to Ensure maximum crop recovery efficiency and Minimize losses of nutrients through leaching, fixation, volatilization Effect on soil ph, EC, structure.. others Source must be in the right combination with the Rate, Time and Place Source should have low salt

111 Source must be compatible with other fertilizers and Irrigation water Compatibility 1. Between fertilizers and other fertilizers a. Interaction among fertilizers in the stock solution b. Solubility products of different fertilizers 2. Between fertilizers and Irrigation water a. Hard water b. ph c. HCO3 d. Temperature 3. Between fertilizers and irrigation methods a. Boron b. Chloride

112 Interactions and compatibility among fertilizers Actual solubility of individual fertilizer in the fertilizer stock solution is less than the theoretical one Solubility products of various fertilizers can react with each others and form precipitates, leading to clogging problems and reduce the actual nutrients concentration. For example: Calcium nitrate with any sulfates = formation of CaSO 4 precipitate Ca(NO 3 ) 2 + (NH 4 ) 2 SO 4 CaSO Calcium nitrate with any phosphates = formation of Ca phosphate precipitate Ca(NO 3 ) 2 + NH 4 H 2 PO 4 CaHPO Magnesium nitrate with MAP/DAP = formation of Mg phosphate precipitate Mg(NO 3 ) 2 + NH 4 H 2 PO 4 MgHPO Ammonium sulfate with KCl or KNO 3 = formation of K 2 SO 4 precipitate SO 4 (NH 4 ) 2 + KCl or KNO 3 K 2 SO Phosphorus with iron = formation of iron phosphates precipitate Fe + NH 4 H 2 PO 4 FeHPO 4 +..

113 Assuming a grower wants to prepare stock solution from following fertilizers: KNO 3, Ca(NO 3 ) 2, MAP, MgSO 4, cationic micronutrients and acid: Ca(NO 3 ) 2 is not compatible with MAP or with cationic micronutrients MgSO 4 is not compatible with Ca(NO 3 ) 2 and micronutrients. Acid should be in a separate tank for ph adjustment. Therefore 3 tanks are needed to prepare 3 different solutions to avoid incompatibility limitation. That is: Tank A: MAP and magnesium sulfate Tank B: Potassium nitrate, calcium nitrate and micronutrients Tank C: Acid. Tank A: MAP MgSO 4 Tank B: KNO 3 Ca(NO 3 ) 2 Micronutrients Tank C: Acid

114 _ NH 4 NO 3 Fertilizers Mixing UREA (NH 4 ) 2 (NH 4 ) 2 KCl K 2 SO 4 KNO 3 Ca SO 4 HPO (NO 4 3 ) 2 NH 4 NO 3 UREA OK _ (NH 4 ) 2 OK OK SO 4 (NH 4 ) 2 OK OK OK _ HPO 4 KCl OK OK X OK K 2 SO 4 OK OK OK OK OK _ KNO 3 OK OK X OK OK OK Ca (NO 3 ) 2 OK OK X X OK X OK _

115 Corrosivity Source should not be corrosive to the equipment used fertilizers should be flushed from irrigation system after fertilization Kind of metal Ca(NO 3 ) 2 (NH 4 ) 2 SO 4 NH 4 NO 3 Urea Phos. Acid DAP Galvanized iron Sheet aluminum No 1 1 No 2 2 Stainless steel No No No No 1 No Bronze No 2 4 Brass No 2 4 No = none 1 = slight 2 = moderate 3 = considerable 4 = severe

116 Cooling effect Recognize effect of temperature on solubility of fertilizers used Most dry fertilizers (such as KCl, Urea) absorb heat from the water upon dissolution (endothermic reaction): The temperature of the solution is lowered Total solubility of the fertilizer decreases Dilution of phosphoric acid generate heat (exothermic reaction): The temperature of the solution is increased Therefore it should be added before the addition of urea or KCl, which have an endothermic reaction

117 Right Source of irrigation water (Water Quality Parameters): Hard waters: high content of Ca and Mg (> 50 ppm), bicarbonates (> 150 ppm) and alkaline ph (> 7.5) Ca+Mg (from water) will precipitates with phosphate & sulfate from fertilizers Ca forms lime scale (calcium carbonate precipitate): It is recommended: CO Ca 2+ CaCO 3 (at ph > 7.5) Use fertilizers with acid reaction (for P; phosphoric acid, MAP) Periodically inject acid into the irrigation system to dissolve precipitates and unclog the drippers Add Ca & Mg fertilizers according to their level in the irrigation water

118 Right source of irrigation water (Water Quality Parameters): A. Ammonia is a common N source used in fertigation If NH3 is injected into hard water (rich in Ca, Mg), may lead to: For example: Increase ph of the solution (NH 3 + H 2 O = NH OH - ) Precipitate Ca and Mg as CaCO3 and Mg CO3 Clog the emitters, filters, pipes IW with EC=0.2 ds/m and 10 mg/l of Ca+Mg, can safely tolerate an NH 3 N concentration of 30 g/l (30000 ppm) While IW with EC=0.8 ds/m and 30 mg/l of Ca+Mg can only tolerate an NH3-N concentration of 1 g/l (1000 ppm) While IW with EC=2.5 ds/m and 200 mg/l of Ca+Mg can only tolerate an NH3-N concentration of 0.25 g/l (250ppm). Possible solutions: Add inhibitors to "Hard water" as sodium hexametaphosphate or ammonium polyphosphate to sequester Ca+Mg & decrease precipitation Neutralize the ph with acids

119 Anionic composition of the irrigation water (mainly, bicarbonate, sulfate, chloride and boron): B. Anionic composition of the irrigation water (mainly, bicarbonate, sulfate, chloride and boron): 1. Bicarbonate anions: a. Increases ph of the solution b. Decreases actual solubility of fertilizers c. Enhances precipitation of Ca and Mg d. Stimulates salting out fertilizer solution e. Inactivates Fe and Zn in plant tissues 2. Chloride & sulfate anions tend to increase salinity 3. Sulfate anions enhance precipitation of Ca, Mg and Fe (SO 4 )

120 Anionic composition of the irrigation water (mainly, bicarbonate, sulfate, chloride and boron): C. ph of the irrigation water: 1. Indicator of precipitation and clogging problems 2. Indicator of relative conc. of ions (Na, HCO3, HMs etc) 3. Solubility of fertilizer is lower with higher ph D. Total Suspended Solids (TSS), Turbidity: Solid particles may: 1. Act as a nucleus for precipitation in solution 2. Clog the dripper, and precipitate in the irrigation lines. 3. Clog soil pores and affect water permeability in the soil Therefore, whenever IW contain high TSS, filters must be used to remove the sediments.

121 Right Rate of nutrients application for fertigation: It important to apply the right rate of nutrient application to: Make sure the crop is receiving the required amount of nutrients, but avoiding excess Avoid application of excess fertilizer at one time that may cause: Salt damage fertigation deals with concentrated solution Unnecessary fertilizer cost Reduce profitability Adverse impacts on natural resources (water, soil, air) Nutrients accumulation in agricultural products above acceptable levels

122 Right Rate of nutrients application for fertigation: The following should be considered to determine and select the right rate: Recognize the attainable yield, target yield or yield goal of the crop, considering the specific field where the crop is grown Recognize the nutrient requirement, or removal for the crop yield Recognize the water and irrigation requirements of the crop Recognize the right irrigation scheduling of the crop Recognize the pattern of nutrient uptake by the crop - The uptake rate of the primary essential nutrients follows the rate of biomass accumulation Assess available nutrients from all sources (soil, water, manure and others)

123 Rate of nutrient application from mineral fertilizers (RATE): RATE of N = NR NS + NW + NO 100 FUE Where; NR = nutrient requirement of the crop, kg/ha NS = nutrients from the soil, kg/ha NO = nutrients from organic fertilizer, kg/ha MW = nutrients from irrigation water, kg/ha FUE = fertilizer use efficiency in %

124 Right Time of nutrients application for fertigation: Pattern of nutrient uptake: For example, The uptake of N and K is initially slow, followed by a rapid increase during the flowering stage. K uptake peaks during fruit development. The uptake rate of P and secondary nutrients (Ca and Mg) is relatively constant during the growing season for the tomato crop.

125 Right Time of nutrients application for fertigation: The following considerations are necessary for selecting the right time of nutrient application: Consider the source, rate and placement being used Method of irrigation (the most important factor) Type and geometry of the root system Consider the dynamics of the nutrient in the soil (mineralization, precipitation, adsorption, etc) Consider the dynamics of the nutrient uptake by the crop Consider the potential losses of the nutrient from the soil (leaching, volatilization, fixation, immobilization) Movement mechanism of nutrient in soil (mass flow/diffusion/contact exch.)

126 Right Time of nutrients application for fertigation: Soil physical and chemical properties (texture, water holding capacity, nutrient buffer capacity, ph, CEC): In fine texture, injecting fertilizer in the middle of the irrigation cycle resulted in better distribution than when injected in at the beginning or at the end of irrigation. Injecting at the beginning resulted in nutrient leaching from the root zone while injection at the end did not completely flush the fertilizer from the system, and thus did not reach the roots. In coarse textured soil where leaching potential is high, injecting mobile nutrient such as nitrate fertilizers during the last third period was better and prevented nitrate leaching. For immobile nutrients injection at the beginning of irrigation would give a more uniform distribution.

127 Right fertigation scheduling - right rate and right time: Fertigation scheduling is the process of determining the right rate and right time of IW+F application In fertigation, the right rate and time are closely linked and follow the rate and time of irrigation water application. Therefore, over-irrigation or under-irrigation will lead to overfertilization or under-fertilization. It can be based on either direct soil water measurement, plant moisture measurement or by using climatic data.

128 Right fertigation scheduling - right rate and right time: Selecting the right fertigation scheduling is mainly important under salinity A higher frequency of fertigation, that is an application of low rate but more frequent, is recommended under saline condition to avoid an accumulation of salts in the root zone. The lower the frequency of fertigation, the higher the concentration of the fertigation solution, the higher the salinity level of the fertilizer solution the higher the accumulation of salts in the root zone the higher the leaching of mobile nutrients the higher the precipitation and adsorption of the immobile nutrients the lower the fertilizer use efficiency

129 Right fertigation scheduling - right rate and right time:

130 Right fertigation scheduling - right rate and right time:

131 Right Place of nutrients application for fertigation: Proper placement of fertilizer has several benefits such as: enhancing fertilizer use efficiency, reducing losses, enhancing seed germination and emergence, improving plant establishment, Proper placement of fertilizer should be selected in combination with the right source, rate and time of application. With fertigation, applied fertilizers are placed close to the roots, therefore, application of higher than recommended rates might induce a fertilizer-burn and potentially inhibit root growth.

132 Right Place of nutrients application for fertigation: The right placement of nutrient application depends on several factors including: mobility of the nutrient applied, soil characteristics, form of fertilizer and the developmental pattern of plant roots. proper placement of fertilizer should maximize the probability of being intercepted by the roots, maximize nutrient uptake and minimize nutrient losses.

133 Factors affecting the selection of the right place of nutrient application: Method of irrigation (the most important factor) Consider the type, geometry and distribution of the root system Soil properties (texture, water holding capacity, nutrient buffer capacity, ph, CEC) Planting spacing Consider the source, rate and time of application Consider dynamics of soil nutrients (mineralization, precipitation, adsorption) Consider potential losses of nutrient (leaching, volatilization, fixation, erosion) Consider mechanism of movement: mass flow, diffusion, contact exchange Since drip irrigation results in a small and limited wet soil volume where the active crop roots will be distributed, depletion rate is higher thus F+W must be added more frequently and within the wet soil zone

134 Factors affecting the selection of the right place of nutrient application: In sandy soils, over irrigation can lead to leaching of mobile nutrients below the root zone leaving them positionally not available In clay soils nutrients distribution is mainly affected by their mobility in the soil, their potential of being adsorbed or precipitated in the soil For example, positively charges nutrients (NH 4 & K) tend to be retained at the soil surface On the other hand, negatively charged nutrients (NO 3 & Cl) tend to move freely in the soil and follow the movement of the irrigation water. Some negatively charged nutrients are immobile (phosphate). They precipitate with Ca and Mg in basic soil and with Al and Fe in acid soil Consider the type of interaction between nutrients. For example, coplacement of N and P has a synergistic effect while P and Zn has a antagonistic effect

135 Factors affecting the selection of the right place of nutrient application: Method of of fertigation (fertilizer injection) is a big factor affecting placement The most common fertilizers injection systems are: By-Pass system Venture system Pumping system

136 Conc Time WATER WATER & FERTILIZER FERTILIZER Fertilizer Injection Systems: A. Fertilizer Tank (By-Pass injection system) This system maintains proportional mixing ratio using two mixing mechanisms: Operational principle: Fraction of IW of main line is bypassing thru valve to fertilizer tank to dissolve fertilizer. Then fertilizer solution is injected back to the main irrigation line Advantages: Simple & Inexpensive Disadvantages: Concentration not constant Can not be automated

137 Conc Fertilizer Injection Systems: B. Direct Injection of Fertilizers into Irrigation Line This system maintains proportional mixing ratio using two mixing mechanisms: Venturi setup (Pressure difference): Operational principle: The constriction in the devise accelerates water flow and creates suction effect that pumps fertilizer solution into IW line Advantages: Relatively inexpensive 80 Fair control of fertilizer concentration 60 Disadvantages: 40 High head loss Relatively low discharge rate 20 Main line Injection point Time 4 6 Booster pump Water inlet Venturi injector Fertilizer tank

138 Conc Fertilizer Injection Systems: C. Hydraulic fertilizer injection pumps Operational principle: Water-powered pump (derive its operation energy from irrigation line pressure) draws fertilizer stock solution from the tank and inject it into the irrigation system. Water or electrically-powered. Advantages: No head loss Flexible discharge rates, including high rates Constant concentration and good control over it Disadvantages: Relatively expensive & Need skilled personnel Time

139 Conclusion Adopting the 4Rs principles in fertigation provide a powerful tools for efficient and sustainable nutrient management under irrigated agriculture

140 Nutrient Expert Fertilizer Decision Support Tool Dr. Kaushik Majumdar, Vice President, Asia, Africa, and the Middle East

141 Drivers of Nutrient Expert Development Inappropriate fertilizer use is a growing challenge Average cereal yields at 50-60% of potential yield Reduced fertilizer response Nutrient Mining Environmental Impacts Average crop N recovery estimated at 33-50% Need for large scale extension of improved nutrient management to quickly provide many farmers with a science-based fertilizer guideline tailored to their specific field, crop, season and resource endowment for sustainably improving cereal productivity

142 The Nutrient Expert decision support tool Nutrient Expert is a computer-based decision support tool for crop advisers. It uses the principles of site-specific nutrient management (SSNM). SSNM aims to supply a crop s nutrient requirements tailored to a specific field or growing environment. accounts for indigenous nutrient sources applies fertilizer at optimal rates and at critical growth stages 4Rs (right source, right rate, right time, right place)

143 Estimating plant nutrient requirements Total amount of nutrient needed to achieve a yield target is estimated from the relationship between grain yield and balanced uptake of nutrients at harvest as defined by the QUEFTS model (Janssen et al. 1990) YND YN YP YK YPD YKD YNA YPA YKA Source: Setiyono et al. 2010

144 Nutrient uptake requirements for cereals as predicted using QUEFTS Crop Reciprocal internal efficiency (kg nutrient/1000 kg grain) N P K Rice Maize Wheat Buresh et al Plant and Soil 335: Setiyono et al Field Crops Research 118 (2): IPNI data (Several Publications)

145 Estimating fertilizer nutrient requirements The SSNM approach 1. Identify a yield target (i.e. attainable yield) Depends on climate, variety, and season Yield achieved with best management practices where nutrients were not limiting Indicates the total amount of nutrients that must be taken up by the crop 2. Estimate indigenous nutrient supply Can be determined through use of nutrient omission plots: 0N (PK), 0P (NK), 0K (NP) Yield in nutrient omission plot indicates amount of nutrient from indigenous sources e.g. N-limited yield reflects indigenous N supply 3. Estimate amount of nutrient to be supplied as fertilizer The difference between the total crop demand (attainable yield) and indigenous supply (nutrient-limited yield) will provide an estimate of the amount of nutrient to be supplied as fertilizer Attainable yield 10 t Yield without N fertilizer 5 t Yield potential N from fertilizer Indigenous N supply

146 What is the Knowledge Requirement Minimum dataset Attainable Yield Nutrient Uptake Requirement Soil Nutrient Supplying Capacity Crop Uptake Pattern Further refinement Previous crop history What crop What yield How much nutrient was applied Still further refinement Genotypes Tillage Residue Management Nutrient Input from other sources (Irrigation water etc.)

147 Nutrient Expert: Simplifies implementation of SSNM Nutrient Expert provides SSNM-based fertilizer guidelines for a location using site information that can be easily provided by a farmer or crop adviser Farmer Crop adviser Site & farming information Nutrient Expert DSS Fertilizer recommendation Algorithm Decision rules Agronomic database: multiple locations, diverse conditions Farmer

148 Nutrient Expert: development process Site-specific nutrient management, QUEFTS model Data collection Model development Field validation Version 1 for release Agronomic database: multiple locations, diverse conditions Attainable yield Yield response to N, P, K Fertilizer use efficiency (AE, RE) Nutrient uptake Data analyses Consultation meetings Algorithm development Programming On farm field testing: NE, FP, other fertilizer practices Model adjustment (as needed) software.ipni.net

149 Nutrient Expert is developed through collaboration with local experts and stakeholders Collaboration with target users and stakeholders through consultation meetings Collection of locally-available agronomic data and information Field testing, evaluation, and refinement of the software Building confidence in the concept with collaborators

150 Nutrient Expert recommendation: Tailored to location-specific conditions Consistent with: - right source - right rate - right time - right place Right time Right source Right rate Integration of organics

151 NE provides options for resourceconstrained farmers

152 Nutrient Expert improved maize yield and profit Current situation: farmers yield < attainable yield Parameter Unit Effect of NE (NE FFP) India Indonesia Philippines (n = 412) (n = 26) (n = 190) Grain yield t/ha *** *** *** Fertilizer N kg/ha 6 ns 12 ns +3 ns Fertilizer P 2 O 5 kg/ha 16 *** 5 ns +18 *** Fertilizer K 2 O kg/ha +22 *** +15 *** +18 *** Fertilizer cost USD/ha 1 ns +16 ns +37 *** Gross profit USD/ha +256 *** +234 *** +267 ***

153 Field Performance of Nutrient Expert in China ( ) Current situation: farmers yield attainable yield Parameter Unit Wheat (n = 290) Maize (n = 541) FP NE Soil test FP NE Soil test Grain yield t/ha N kg/ha P 2 O 5 kg/ha K 2 O kg/ha Fert. cost USD/ha Gross profit USD/ha REN % AEN kg/kg REN: apparent recovery efficiency of N (increase in N uptake/applied N) AEN: agronomic efficiency of N (kg yield increase/kg applied N)

154 AE_N (kg/kg) RE_N (%) PFP_N (kg/kg) Nutrient Expert for Rice Improved N Use Efficiency NE OPTS FP NE OPTS FP NE OPTS FP Compared with the FP and OPTS treatments, NE increased AE 23.6% and 15.6%, RE 12.2 and 8.4 percentage points, and PFP 9.1% and 7.5%, for N fertilizer, respectively.

155 Grain yield of wheat (t/ha, 13.5% MC) Morocco: Cropping season Grain yield 2015 (t/ha) Durum Wheat Regions Province (n) SSNM** FFP SSNM - FFP SSNM* * Bread Wheat FFP SSNM - FFP Abda Safi Chaouia Settat Berrechid Fez Sefrou Tadla Fquih bensaleh *Highest yield obtained for durum wheat in the field trial ** Recommendation using Nutrient Expert for Wheat (Morocco)

156 Nutrient Expert reduced GHG emission in wheat with increased yield and profit Northwest India: Source: Sapkota et al. 2014, Field Crops Res. 155:

157 Farm Type 1 [Moderate-resourced commercial maize grower] Farm Type 2 [ Exclusive cultivators with large holding and large family] Farm Type 3 [Low-yielding new maize growers] Farm Type 4 [Moderately resourced family farms] Farm Type 5 [Traditional maize grower] Farm type 6 [Resource-rich commercial seed producers ] Recommendation based on Farmer Resources -$8 -$2 55% 42% -$16 -$5 47% +$10 +$5 37% 64% 73%

158 The best scalable ICT solution for improving rural livelihood

159 Global Program of Nutrient Expert: Current Status Maize, Wheat, Rice, Soybean Wheat Maize Cassava Maize, Wheat, Rice Cotton, Soybean Maize Maize, Cassava Kenya, Zimbabwe: Maize Maize Black: Field-validated model. Available at software.ipni.net Blue: Beta version under field validation Red: Initial stage of model development

160 Nutrient Expert Delivery Progress Region Crop MS Access Web App for Android Web App for PC Windows Andriod gadgets Win/Mac China Hy Maize Wheat Rice Soybean S Asia Hy Maize Wheat Rice SE Asia Hy Maize SSAfrica Hy Maize N Africa Wheat - In development/field validation Target: All current NE tools in web platform by the end of 2017

161 Nutrient Expert app for Android mobile gadgets Tablet Smart phone The app can work offline it does not require Internet to generate a recommendation