Mdule 1: Overview f sil fertility, plant nutritin, and nutrient management T view the chapter fr this tpic click here.
Mdule 1: Overview Intrductin Understanding the principles f sil fertility is vital t efficient nutrient management prfitable crp prductin envirnmental prtectin Seventeen chemical elements are essential fr plant grwth: are needed in different amunts by the plant vary in mbility within the plant vary in cncentratin in harvested crp cmpnents Imprtant aspects t knw: amunt f each nutrient needed fr ptimum ecnmic yield amunt remved by a crp with harvest nutrient transfrmatins within the sil ptential mbility f nutrients that might affect water quality
Mdule 1: Overview Essential plant elements Element Surce Cncentratin Nn-mineral Primary Macrnutrients Secndary Nutrients Carbn (C ) Air 45% Oxygen (O) Air/Water 45% Hydrgen (H) Water 6% Nitrgen (N) Air/Sil 1-5% Ptassium (K) Sil 0.5-1% Phsphrus (P) Sil 0.1-0.5% Calcium (Ca) Sil 0.2-1% Magnesium (Mg) Sil 0.1-0.4% Sulfur (S) Sil 0.1-0.4% Mineral Micrnutrients Chlrine (Cl) Sil 0.01-0.1% Irn (Fe) Sil 50-250ppm Manganese (Mn) Sil 20-200ppm Brn (B) Sil 6-60ppm Zinc (Zn) Sil 25-150ppm Cpper (Cu) Sil 5-20ppm Mlybdenum (M) Sil 0.05-0.2ppm Nickel (Ni) Sil 0.1-1ppm
Mdule 1: Overview Essential plant elements T be classified as essential, the element needs t meet the fllwing criteria: the plant cannt cmplete its life cycle (seed t new seed) withut it the element s functin cannt be replaced by anther element the element is directly invlved in the plant s grwth and reprductin
Mdule 1: Overview Plant uptake f nutrients Each nutrient is taken up in an inic r charged frm. Knwing what frm f a nutrient the plant absrbs helps us t better understand n what cntrls the cycling and mvement f that nutrient in sil. Understanding nutrient functins and mbility within the plant are useful in diagnsing nutrient deficiencies. Nutrient uptake by rts is dependent n: rt grwth and sil explratin the ability t absrb nutrients the nutrient cncentratin at the rt surface Nutrients are in cntact with rts by three mechanisms: rt interceptin diffusin mass flw
Mdule 1: Overview Plant Uptake f Nutrients Element Frm Nitrgen (N) NO 3- (nitrate), NH 4+ (ammnium) Ptassium (K) K + Phsphrus (P) H 2 PO 4-, HPO -2 4 (phsphate) Calcium (Ca) Ca +2 Magnesium (Mg) Mg +2 Sulfur (S) SO -2 4 (sulfate) Chlrine (Cl) Cl - (chlride) Irn (Fe) Fe +2 (ferrus), Fe +3 (ferric) Manganese (Mn) Mn +2 Brn (B) H 3 BO 3 (bric acid), H 2 BO 3- (brate) Zinc (Zn) Zn +2 Cpper (Cu) Cu +2 Mlybdenum (M) MO -2 4 (mlybdate) Nickel (Ni) Ni +2
Mdule 1: Overview Nutrient Mbility within the Plant Mbile nutrients Nitrgen (N) Phsphrus (P) Ptassium (K) Chlride (Cl) Magnesium (Mg) Mlybdenum (M) Immbile nutrients Sulfur (S) Calcium (Ca) Irn (Fe) Zinc (Zn) Manganese (Mn) Brn (B) Cpper (Cu) Nickel (Ni)
Mdule 1: Overview Timing f Nutrient Uptake by Plants 100 Relative Accumulatin (%) 80 60 40 20 Ptassium Nitrgen Phsphrus Dry Matter 0 Days after emergence Example: grwing seasn accumulatin patterns f K, N, P, and dry mater in crn.
Mdule 1: Overview Crp Respnse t Nutrient Supply Maximum efficiency Crp Yield (bu/acre) Zne A Zne B Zne C Zne D Nutrient Rate (lb/acre) Relatinship between crp yield and essential nutrient applicatin rate.
Mdule 1: Overview Nutrient Interactins K Availability Crn Yield (bu/acre) High Medium Lw N Rate (lb/acre) Ptassium imprves yield respnse t N fertilizer and N use efficiency.
Mdule 1: Overview Nutrient Diagnstic Methds: Crrelatin, Calibratin, and Interpretatin Nutrient diagnstic methds are tls fr determining plant nutrient needs: sil testing plant analysis crp canpy sensing The develpment f a diagnstic methd fr a given nutrient invlves three steps: selecting a sil r plant test r analysis r methdlgy that is related t a specific crp nutritin need r respnse t applicatin field crrelatin f test results with crp yield, amunt f nutrient taken up by plants, and/r sme ther desirable crp characteristic field calibrating the test result in terms f its effect n sme desirable crp characteristic, such as yield respnse develping sufficiency interpretatins Fertilizer recmmendatins are then based n interpretatin f test results frm calibrated methds and fertilizer respnse trials.
Mdule 1: Overview Nutrient Diagnstic Methds: Crrelatin, Calibratin, and Interpretatin 100 Relative Yield 80 60 Wheat Crn Sybean 40 20 Sil P Availability (ppm) Different crp respnses frm different sil Bray-1 P levels.
Mdule 1: Overview Nutrient Diagnstic Methds: Crrelatin, Calibratin, and Interpretatin Lw applicatin rate High applicatin rate Crp Respnse t a Given Nutrient Sil Nutrient Availability Crp yield respnse t a lw and high rate f a given nutrient as related t the riginal sil nutrient level.
Mdule 1: Overview Nutrient Diagnstic Methds: Crrelatin, Calibratin, and Interpretatin Nutrient Index Level Very lw Lw Optimum High Meaning f Index Level fr Crps Applying the nutrient will be beneficial ver 80% f the time 65% f the time 5% f the time less than <1% f the time Surce: Iwa State University Extensin publicatin PM 1688.
Mdule 1: Overview Steps in Nutrient Management Planning 1. Obtain accurate sil infrmatin fr each field r management unit within a field. 2. Estimate realistic crp yield ptential based n sil prductivity r yield mapping, crp rtatin and intended management. 3. Calculate plant nutrient applicatins required. 4. Determine the plant-available nutrients in any livestck manure r ther by-prduct amendments. 5. Estimate any applicable residual nutrient cntributins frm fertilizer r manure applied in previus seasns, r previus legume crp effects n sil N supply.
Mdule 1: Overview Steps in Nutrient Management Planning 6. Determine need fr purchase f ff-farm nutrients, such as fertilizer r manure. 7. If necessary, use an applicable envirnmental risk assessment tl (mainly fr N and P). 8. Apply animal manure and cmmercial fertilizer t supply nutrients nly when needed and using practices that ensure high use efficiency. 9. Keep recrds f nutrient surces, applicatin dates, rates, and methds. 10. Remember that nutrient management plans need t be accurate, understandable, and defendable.