Corn/Soybean Efficient Fertility Management - Manure

Transcription

1 Corn/Soybean Efficient Fertility Management - Manure Robert Mullen Nutrient Management/Soil Fertility Specialist Ohio State University January 24, 2008

2 Overview Soil test, soil test, soil test! Making recommendations from analysis Manure applications How much nutrient is supplied Economic value of nutrient Supplementation with commercial fertilizers 1/28/2008 Licking Co. 2

3 Generating Recommendations Look at soil test P level Field 3 NPA 14 ppm (28 lb/acre) What is critical value from Tri-State Fertilizer Guide 1/28/2008 Licking Co. 3

4 Generating Recommendations Critical levels for soil test phosphorus K at CEC Crop P ppm (lb/acre) ppm (lb/acre) Corn 15 (30) 88 (175) 100 (200) (200) (250) Soybean 15 (30) 88 (175) 100 (200) 125 (250) 150 (200) Wheat 25 (50) 88 (175) 100 (200) 125 (250) 150 (200) 1/28/2008 Licking Co. 4

5 Generating Recommendations A little bit low 28 lb/acre (STP) and 30 lb/acre (critical value) We need to apply some P Application rate is given in pounds P 2 O 5 per acre Soil test Yield potential, bu/acre ppm (lb/acre) lb P 2 O 5 /acre (10) (20) (30-60) (70) (80) /28/2008 Licking Co. 5

6 Generating Recommendations Build-up, maintenance, and drawdown concept (this applies to potassium as well) P 2 O 5 recommendation, lbs/a Critical Level (Corn = 15 ppm) Build Up Maintenance Draw Down SOIL TEST P, ppm 1/28/2008 Licking Co. 6

7 Generating Recommendations Build-up Designed to increase soil test value to critical level in 4 years Over-application of 1 lb of P 2 O 5 will not increase soil test by one unit Maintenance Designed to maintain soil test level Draw-down Designed to draw-down soil test level 1/28/2008 Licking Co. 7

8 Generating Recommendations Relationship between applied/removed P and soil test level Generically, for every 6-18 lb of P 2 O 5 applied or removed soil test will change by 1 ppm Available P Precipitated and sorbed P clay soil /28/2008 Licking Co. 8

9 Generating Recommendations For our example, soil test was 28 lb/acre which is below critical level for P Recommendation is between 35 and 60 lbs of P 2 O 5 per acre If fertilizing a rotation (say corn and beans), you will want to apply a little more P 2 O 5 to satisfy both crops (include crop removal of subsequent crop) 1/28/2008 Licking Co. 9

10 Generating Recommendations Example 2 Soil test level is 100 lb P/acre Well above critical value WE DO NOT NEED TO SUPPLY P!!! 1/28/2008 Licking Co. 10

11 Generating Recommendations Evaluate soil test K level Example 1 Soil test level of 85 ppm (170 lb/acre) CEC of 11.0 meq/100g What is the critical value? 1/28/2008 Licking Co. 11

12 Generating Recommendations Critical levels for soil test K K at CEC Crop P ppm (lb/acre) ppm (lb/acre) Corn 15 (30) 88 (175) 100 (200) 125 (250) 150 (200) Soybean 15 (30) 88 (175) 100 (200) 125 (250) 150 (200) Wheat 25 (50) 88 (175) 100 (200) 125 (250) 150 (200) 1/28/2008 Licking Co. 12

13 Generating Recommendations Soil test Soil test level is low 85 ppm compared to critical value of 100 ppm Yield potential, bu/acre ppm (lb/acre) lb K 2 O/acre (50) (100) (150) ( ) (280) (300) For soil with a CEC of 10 1/28/2008 Licking Co. 13

14 Generating Recommendations Example 1 Need to supply between 60 and 95 lb K 2 O per acre for corn crop If fertilizing a rotation, probably need to add more (subsequent crop removal) Like P, over-application of 1 pound of K 2 O does raise soil test level 1 unit More like 2-6 pounds of K 2 O have to be removed or added to change soil test level by 1 ppm 1/28/2008 Licking Co. 14

15 Generating Recommendations Example 2 Soil test K level 400 lb/acre CEC of 24 Above critical value DO NOT NEED TO SUPPLY K! 1/28/2008 Licking Co. 15

16 Generating Recommendations May be necessary to consider crop removal Crop Unit of yield Nutrient removed per unit of yield Corn Wheat P 2 O 5 K 2 O lb per unit Grain Bushel Silage Ton Soybeans Bushel Grain Bushel Straw Bushel Alfalfa Ton /28/2008 Licking Co. 16

17 Manure Applications Nitrogen basis Manure application rate based upon crop nitrogen need Phosphorus basis Manure application rate based upon crop phosphorus need 1/28/2008 Licking Co. 17

18 Crop Nutrient Need Nitrogen related to yield level At least theoretically Phosphorus and potassium Need to achieve soil test critical level Or provide annually via fertilization 1/28/2008 Licking Co. 18

19 Determining Manure Rates Based upon: Soil test levels for P Crop yield Previous crop Manure nutrient content Nutrient removal of P Timing of application N risk index P risk index 1/28/2008 Licking Co. 19

20 Manure Analysis 1/28/2008 Licking Co. 20

21 Determining Manure Rates Soil test levels (phosphorus) Too high can limit manure application Crop yield Average of last five crops taken from the field Sets N application rate Previous crop Manure nutrient content Ammonium-N, organic-n, P 2 O 5 1/28/2008 Licking Co. 21

22 Determining Manure Rates Nutrient removal How much P will be removed based on yield potential and crop removal? Timing of manure application Affects nitrogen availability (nitrogen presentation) How is manure applied Incorporated or surface applied 1/28/2008 Licking Co. 22

23 Calculating Manure Rates Example 1 Soil test P 37 ppm Crop yield potential (corn) 160 bu/acre Previous crop soybean Manure analysis Ammonium-N 35 lb/1000 gal Organic-N 21 lb/1000 gal P 2 O 5 23 lb/1000 gal K 2 O 21 lb/1000 gal Timing of application Nov. Incorporation? Yes 1/28/2008 Licking Co. 23

24 Example 1 Cont d Low soil test P value means we can apply manure on N basis Nitrogen rate recommendation 160 lb N/acre 35 lb ammonium-n/1000 gal & 21 lb organic-n/1000 gal 17.5 lb of PAN/1000 gal (ammonium-n) 6.9 lb of PAN/1000 gal (organic-n) Total of 24 lb of PAN/1000 gal 1/28/2008 Licking Co. 24

25 Example 1 Cont d Manure application rate on N-basis 160 lb N/acre needed & 24 lb PAN/1000 gal, so 6600 gal/acre application rate 1/28/2008 Licking Co. 25

26 Example 1 Cont d How much P 2 O 5 will be applied? 6600 gal/acre * 23 lb P 2 O 5 /1000 gal = 152 lb P 2 O 5 /acre How much K 2 O will be applied? 6600 gal/acre * 21 lb K 2 O/1000 gal = 139 lb K 2 O/acre 1/28/2008 Licking Co. 26

27 Example 1 Cont d Supplying enough N, P, and K Do not need supplemental fertilizer If the N rate is not trusted, conduct PSNT sampling in the spring to determine if additional N is warranted. 1/28/2008 Licking Co. 27

28 Calculating Manure Rates Example 2 Soil test P 120 ppm Crop yield potential (corn) 160 bu/acre Previous crop soybean Manure analysis Ammonium-N 35 lb/1000 gal Organic-N 21 lb/1000 gal P 2 O 5 23 lb/1000 gal K 2 O 21 lb/1000 gal Timing of application Nov. Incorporation? Yes 1/28/2008 Licking Co. 28

29 Example 2 Cont d Relatively high soil test P level Unlikely to be able to apply on N-basis, most likely restricted to P-basis for manure application P-basis applications restricted to nutrient removal of rotation Estimating P crop removal 160 bushel per acre corn crop; 50 bushel per acre soybean crop Total P 2 O 5 removed 99 lb/acre 1/28/2008 Licking Co. 29

30 Example 2 Cont d We can only apply enough manure to supply 99 lb P 2 O 5 /acre So.99 lb P 2 O 5 /acre divided by 23 lb P 2 O 5 /1000 gal 4300 gal/acre application rate So how much N will we apply? 4300 gal/acre * (24 lb PAN/1000 gal) So.105 lb N/acre 1/28/2008 Licking Co. 30

31 Example 2 Cont d What was N need? 160 lb N/acre We have a deficit of 55 lb N/acre (we need some commercial fertilizer to make up the difference) 1/28/2008 Licking Co. 31

32 Take Home Message Quantify nutrients supplied with manure! Those nutrients have economic value (more than they historically have had) Quantification allows us to determine if commercial fertilization is necessary And how much commercial fertilizer we need 1/28/2008 Licking Co. 32

33 Questions? Thanks!!!!!! Useful webpages Agronomic Crops Team OSU Fertility web page Crop Observation and Recommendation Network (CORN) 1/28/2008 Licking Co. 33