Predicting Corn N Response Using Alkaline Mineralizable-Nitrogen and Haney Soil Health Tool-Nitrogen in TN

Progress report for OS21-149

Project Type: On-Farm Research
Funds awarded in 2021: $20,000.00
Projected End Date: 03/31/2023
Grant Recipient: University of Tennessee
Region: Southern
State: Tennessee
Principal Investigator:
Dr. Nutifafa Adotey
University of Tennessee
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Project Information

Abstract:

Current N fertilizer recommendation for corn in TN does not account for potentially mineralizable N; hence, there is a possibility for either over or under application of N fertilizer. The purpose of this project is to assess the adequacy of alkaline mineralizable-N (AH-N) and Haney Soil Health Tool's estimated biological N (EB-N) to predict corn N needs. Two small plot on-farm trials were conducted at two locations in west TN to (1) evaluate the relationships of alkaline mineralizable N and HSHT with N response, (2) develop N fertilizer rate calibration using alkaline-hydrolyzable N, and (3) compare current UT fertilizer recommendation, HSHT N fertilizer recommendation, and alkaline-hydrolyzable fertilizer recommendation. The results for first objective is presented in this report. Correlation of check plots with AH-N resulted in a significant linear regression model for 0-6- and 12-18-inch depths at preplant. At preplant, the best predictive relationship between the check plots and AH-N was found at the 12-18-inch depth (R2 = 0.46). In contrast, the correlation between the check plots and EB-N was not significant at all depths.

Project Objectives:

A replicated small plot on-farm trial will be conducted at two locations in west TN to address the adequacy of alkaline mineralizable-N and HSHT -N to predict corn N needs”. The specific objectives of the on-farm trials are to: (1) evaluate the relationships of alkaline mineralizable N and HSHT with N response, (2) develop N fertilizer rate calibration using alkaline-hydrolyzable N, and (3) compare current UT fertilizer recommendation, HSHT N fertilizer recommendation, and alkaline-hydrolyzable fertilizer recommendation.

Cooperators

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Research

Materials and methods:

Two replicated on-farm trials were conducted at Jackson, TN and Milan, TN on a Calloway Silt Loam (35°44'01.2"N 88°51'23.9"W) and a Lexington Silt Loam (35°47'58.2"N 88°45'46.2"W), respectively to address the adequacy of alkaline mineralizable-N and HSHT-N to predict corn N needs.

The Jackson location was managed in a no-till corn-soybean rotation system and was planted to soybeans the previous year. On the other hand, the Milan location was managed in a no-till continuous cotton system.

Prior to fertilizer application, six core samples were collected from each plot at 0-6 and 6-12-inch depths on 04/2/2021 and 04/06/2021 at the Jackson and Milan location, respectively. After the soil sample was air dried, ground to pass through a 2-mm sieve, and thoroughly mixed, it was analyzed for routine chemical properties and soil ammonium and nitrate by the Brookside Laboratories Inc. Prior to planting, the Jackson location received P and K, which was applied with a commercial spreader truck while P and K fertilizer were hand applied at the Milan location during planting. Before N fertilizer application, six core samples were collected from the 0 lb N ac-1 plots at four depths 0-6, 6-12, 12-18, 0-18, and 0-24 inches on 04/2/2021 and 04/06/2021 at the Jackson and Milan location, respectively. However, sidedress N samples were not collected at the Milan location due weather conditions.

The soil health was characterized using the Haney Soil Health Tool at three depths: 0-6, 6-12, and 12-18 inches. Soil health parameters measured include soil pH (1:1), buffer pH, soluble salts (1:1); organic matter (LOI); H3A-4 extractable Ca, Mg, K, Na, S, P, Mn, Zn, B, Fe, and Al; H3A-4 extractable phosphate; H3A-4 extractable available nitrogen (NH4+-N and NO3--N); water extractable organic carbon, water extractable total nitrogen; soil respiration (IR Gas Analyzer), and overall soil health score. All samples were analyzed by Brookside Laboratories Inc. The alkaline-hydrolyzable N was evaluated at 5 soil depths 0-6, 6-12, 12-18, 0-18, and 0-24 inches using the method by Roberts et al., (2011). All samples were analyzed by the N-Star Soil Testing Laboratory. Data from soil analysis to (a) estimate plant available N from HSHT test (H3A-4 extractable available nitrogen + N release). The N release is a function of the mineralizable N and will be computed using water extractable organic carbon, water extractable total nitrogen, and soil respiration, (b) Compare H3A-4 extractable Ca, Mg, K, Na, S, P, Mn, Zn, B, Fe, and Al; H3A-4 extractable phosphate; H3A-4 extractable available nitrogen (NH4+-N and NO3--N) to routine soil test/ recommendations, and (c) Evaluate the relationship between HSHT’s plant available N, HSHT’s mineralizable N (estimated biological N), and alkaline-hydrolyzable N using linear regression analysis.

Corn was planted on 04/19/2021 and 04/28/2021 at the Jackson and Milan location, respectively, to achieve a final stand of approximately 32,000 - 33,000 plants per acre. Field was then partitioned into plots with 10-ft alleyways. Plots were four rows wide x 30 feet long and each treatment combinations were replicated four times in a randomized complete block design. At planting, 60 lb N/acre was hand applied as ANVOL®-treated urea. Side-dress N was hand broadcast at the V6 stage corn at respective application rates on (Table 1). Nitrogen was applied as a two-way split (at planting + sidedress). The nitrogen fertilizer treatments included: 0, (60 + 0), (60 + 60), (60 + 120), (60 + 150), and (60 + 180) lb N ac-1. At tassel, a composite leaf sample consisting of 15 youngest fully matured leaves were collected for tissue N. At maturity, the two center rows of corn in each plot were harvested by hand and then threshed using a small plot combine harvester with an automatic weighing scale and a moisture meter.

Information collected at harvest was used to (a) estimate the N rate required to attain the relative maximum grain yield at each location using the linear-plateau regression, (b) correlate HSHT’s mineralizable N and alkaline-hydrolyzable N to check plot grain yield, (c) develop N fertilizer rate calibration using alkaline-hydrolyzable N, and (d) compare current UT fertilizer recommendation, HSHT N fertilizer recommendation, and alkaline-hydrolyzable fertilizer recommendation. Standard agronomic and pest management practices were based on University of Tennessee recommendations.

 

   

Research results and discussion:

Soil properties

Soil organic matter (SOM), estimated nitrogen release, and Mehlich III extractable phosphorus (P), potassium (K), boron (B), manganese (Mn) iron (Fe), copper (Cu) and Zinc (Zn) were higher at the 0-6 inch compared to the 6-12-inch depth. The decline in SOM, K, and P from 0-6 to 6-12-inch depth supports the prediction that soil organic matter and the most limiting nutrients for plants tend to have shallow distributions. Mehlich III extractable calcium (Ca), magnesium (Mg), sulfur (S) and sodium (Na) increased with depth. This soil property trend was observed at both trial locations (Table 1). Apart from soil organic matter, Ca, Mg, and B, the measured soil properties at the Jackson location were higher than those at the Milan location.

Table 1. Mean preplant chemical properties of soil at 0-6 and 6-12-inch depths collected from the Jackson and Milan locations. Nutrient concentrations are based on Mehlich III extraction (n =24).

Location

Depth

TEC

pH

OM

ENR

P

K

Ca

Mg

S

Na

B

Fe

Mn

Cu

Zn

 

inches

meq/100 g

 

%

N/A

------------------------------------------ppm-------------------------------------------

Jackson

0-6

8.5

6.1

2.0

61

24

108

1148

98

10

10

0.4

206

320

1.7

2.7

 

6-12

12.2

6.0

1.4

49

12

94

1588

132

21

15

0.3

151

141

1.3

0.8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Milan

0-6

11.7

6.1

2.4

69

16

99

1573

118

10

11

0.7

157

166

1.2

1.4

 

6-12

12.5

6.2

1.8

55

5

88

1710

179

15

16

0.6

129

125

1.1

0.6

TEC, Total Exchangeable Cation; OM, Organic Matter; ENR, Estimated Nitrogen Release

Mehlich III and H3A-4 extractable nutrients

The relationship between Mehlich-III and H3A-4 extractable nutrients at depths (0-6 and 6-12-inch) locations (Jackson and Milan) is presented in Figure 1. Mehlich III and H3A-4 extractable nutrients were significantly correlated and showed a positive linear relationship with the combined data across soil depths and locations except Ca. On average, Mehlich-III extracted approximately 75% more P, 36% more K, 78% more Ca, 73% more Mg, 61% more S, 17% more Na, 43% more B, 86% more Fe, 44% more Zn, 93% more Mn, and 83% more Cu than H3A-4 extractable nutrients (Figure 2). The H3A-4 extracting solution consists of a dilute mixture of four weak acids with a weakly buffered pH of approximately 3.75, that may account for the lower concentration of H3A-4 extractable nutrients. Phosphorus, sulfur, boron, and manganese correlated well (R2 = 0.75 - 0.95) while potassium, zinc, copper, iron, and sodium correlated moderately (R2 = 0.39 – 0.61). Although the relationships between some nutrient appear highly correlated, existing calibration and correlation data relating conventional soil test to relative yield may not be appropriate for current mineral fertilizer recommendations.

Scatter graph showing the relationship between Mehlich III extractable and H3A-4 extractable nutrients (ppm) at 0-6 and 6-12-inch depths from the Jackson and Milan locations
Figure 1. Relationship between Mehlich III extractable and H3A-4 extractable nutrients (ppm) at 0-6 and 6-12-inch depths from the Jackson and Milan locations

Correlation of alkaline mineralizable N and HSHT’s plant available N with N response

The mineralized N  component of the Haney Soil Health Test (HSHT), often reported as estimated biological N (EB-N) was estimated using water extractable organic carbon, water extractable total nitrogen, and soil respiration). Data on the parameters used to compute EB-N are presented in Tables S1, S2, & S3. Estimated biological N was assessed at preplant for both locations; however, at sidedress (V6 growth stage), EB-N was evaluated at only the Jackson location. At both locations, preplant EB-N decreased significantly with depth, with EB-N at the 0-6-inch depth being at least 50% higher than the other depths. There was no significant difference between EB-N at the 6-12- and 12-18-inch depths, regardless of location (Figure 2 A & B). Estimated biological N at sidedress was significantly lower when compared to the preplant N (Figure 3A; Table S4). In contrast to preplant EB-N, sidedress EB-N increase with soil depth. 

Bar graph showing preplant HSHT’s estimated Biological N at (A) Jackson and (B) Milan & alkaline hydrolyzable N at (C) Jackson and (D) Milan at 0-6, 6-12, and 12-18-inch depths.
Figure 2. Preplant HSHT’s estimated biological N at (A) Jackson and (B) Milan & alkaline hydrolyzable N at (C) Jackson and (D) Milan at 0-6, 6-12, and 12-18-inch depths.
Bar graph showing sidedress (A) HSHT’s Estimated Biological N and (B) Alkaline hydrolyzable N at 0-6, 6-12, and 12-18-inch depths in Jackson location.
Figure 3. Sidedress (A) HSHT’s estimated biological N and (B) Alkaline hydrolyzable N at 0-6, 6-12, and 12-18-inch depths in Jackson location.

Supplementary Table S1. Preplant Haney soil health test and alkaline-hydrolyzable nitrogen at 0-6, 6-12, 12-18, 0-18, 0-24-inch depths collected from the Jackson location.

Location

Depth

SR

WEOC

WEON

SHS

NO3-

NH4+

HAN

EB-N

PAN

AH-N

 

inches

 

ppm

ppm

 

ppm

ppm

ppm

lb/a

lb/a

lb/a

Jackson

0-6

121

194

15

12

1.5

2.8

8.6

30

39

65

Jackson

0-6

69

161

11

11

0.6

3.4

8.0

22

30

67

Jackson

0-6

97

179

13

15

< 0.5

2.2

5.4

27

32

63

Jackson

0-6

67

176

13

11

0.5

3.0

7.0

26

33

67

 

 

 

 

 

 

 

 

 

 

 

 

Jackson

6-12

22

96

6.5

4.8

0.5

4.0

9.0

12

21

40

Jackson

6-12

16

89

3.2

3.6

< 0.5

4.4

9.8

4.5

14

39

Jackson

6-12

14

93

5.3

3.8

< 0.5

3.6

8.2

6.6

15

31

Jackson

6-12

26

87

4.6

4.8

< 0.5

4.1

9.2

9.2

18

44

 

 

 

 

 

 

 

 

 

 

 

 

Jackson

12-18

14

81

3.5

3.4

< 0.5

4.3

9.6

4.9

15

33

Jackson

12-18

10

83

4.0

3.1

< 0.5

3.2

7.4

4.0

11

36

Jackson

12-18

20

84

3.0

4.0

< 0.5

4.8

10.6

5.8

16

36

Jackson

12-18

9

76

7.5

3.2

< 0.5

3.1

7.2

7.3

15

32

 

 

 

 

 

 

 

 

 

 

 

 

Jackson

0-18

-

-

-

-

-

-

-

-

-

-

Jackson

0-18

-

-

-

-

-

-

-

-

-

48

Jackson

0-18

-

-

-

-

-

-

-

-

-

49

Jackson

0-18

-

-

-

-

-

-

-

-

-

44

 

 

 

 

 

 

 

 

 

 

 

 

Jackson

0-24

-

-

-

-

-

-

-

-

-

-

Jackson

0-24

-

-

-

-

-

-

-

-

-

52

Jackson

0-24

-

-

-

-

-

-

-

-

-

45

Jackson

0-24

-

-

-

-

-

-

-

-

-

-

SR, Soil Respiration; WEOC, Water Extractable Organic Carbon; WEON, Water Extractable Organic Nitrogen; SHS, Soil Health Score; NO3-, H3A-4 extractable available nitrate; NH4+, H3A-4 extractable available ammonium; HAN, H3A-4 Extractable Available Nitrogen; EB-N, Estimated Biological N; PAN, Plant Available N; AH-N, Alkaline-Hydrolyzable Nitrogen

Supplementary Table S2. Preplant Haney soil health test and alkaline-hydrolyzable nitrogen at 0-6, 6-12, 12-18, 0-18, 0-24-inch depths collected from the Milan location.

Location

Depth

SR

WEOC

WEON

SHS

NO3-

NH4+

HAN

EB-N

PAN

AH-N

 

inches

 

ppm

ppm

 

ppm

ppm

ppm

lb/a

lb/a

lb/a

Milan

0-6

92

148

15

14

3.0

4.1

14

29

44

72

Milan

0-6

94

121

12

13

1.9

2.0

8

25

33

71

Milan

0-6

-

 -

 -

1.5

4.4

12

11

23

92

Milan

0-6

91

169

13

14

1.9

3.2

10

25

36

89

 

 

 

 

 

 

 

 

 

 

 

 

Milan

6-12

30

85

3.6

5.1

0.5

5.3

12

7.2

19

46

Milan

6-12

35

87

2.6

5.5

0.7

5.8

13

5.2

18

49

Milan

6-12

26

83

3.5

4.6

0.7

5.0

11

7.0

18

53

Milan

6-12

18

124

0.2

-

-

-

17

0.2

18

46

 

 

 

 

 

 

 

 

 

 

 

 

Milan

12-18

18

81

4.5

3.8

< 0.5

3.8

9

7.8

16

39

Milan

12-18

11

70

2.1

2.7

0.6

5.5

12

2.6

15

41

Milan

12-18

11

93

2.9

3.3

0.6

5.9

13

2.8

16

36

Milan

12-18

10

94

4.4

3.3

0.7

3.9

9

3.7

13

-

 

 

 

 

 

 

 

 

 

 

 

 

Milan

0-18

-

-

-

-

-

-

-

-

-

-

Milan

0-18

-

-

-

-

-

-

-

-

-

56

Milan

0-18

-

-

-

-

-

-

-

-

-

50

Milan

0-18

-

-

-

-

-

-

-

-

-

57

 

 

 

 

 

 

 

 

 

 

 

 

Milan

0-24

-

-

-

-

-

-

-

-

-

49

Milan

0-24

-

-

-

-

-

-

-

-

-

58

Milan

0-24

-

-

-

-

-

-

-

-

-

51

Milan

0-24

-

-

-

-

-

-

-

-

-

-

SR, Soil Respiration; WEOC, Water Extractable Organic Carbon; WEON, Water Extractable Organic Nitrogen; SHS, Soil Health Score; NO3-, H3A-4 extractable available nitrate; NH4+, H3A-4 extractable available ammonium; HAN, H3A-4 Extractable Available Nitrogen; EB-N, Estimated Biological N; PN, Plant Available N; AH-N, alkaline-hydrolyzable Nitrogen

Supplementary Table S3. Sidedress Haney soil health test and alkaline-hydrolyzable nitrogen at 0-6, 6-12, 12-18, 0-18, 0-24-inch depths collected from the Jackson location.

Location

Depth

SR

WEOC

WEON

SHS

NO3-

NH4+

HAN

NR

PAN

AH-N

 

inches

 

ppm

ppm

 

ppm

ppm

ppm

lb/a

lb/a

lb/a

Jackson

0-6

-

-

-

-

-

-

-

-

-

-

Jackson

0-6

34

214

7

8.4

< 0.5

1.3

1.8

3.6

13

66

Jackson

0-6

43

213

4

8.9

1.9

3.5

5.4

10.8

16

68

Jackson

0-6

19

234

7

7.2

1.7

2.9

4.6

9.2

13

72

 

 

 

 

 

 

 

 

 

 

 

 

Jackson

6-12

9

170

5

4.9

< 0.5

4.3

4.8

9.6

12

35

Jackson

6-12

10

157

3

4.4

0.7

2.3

3.0

6.0

7

43

Jackson

6-12

7

169

4

4.4

< 0.5

2.3

2.8

5.6

7

38

Jackson

6-12

12

187

3

5.2

< 0.5

2.8

3.3

6.6

8

46

 

 

 

 

 

 

 

 

 

 

 

 

Jackson

12-18

8

165

3

4.5

< 0.5

4.1

4.6

9.2

11

30

Jackson

12-18

7

147

2

3.8

0.6

3.4

4.0

8.0

9

32

Jackson

12-18

9

145

3

4.1

< 0.5

2.9

3.4

6.8

8

36

Jackson

12-18

9

172

2

4.6

0.7

4.1

4.8

9.6

10

34

 

 

 

 

 

 

 

 

 

 

 

 

Jackson

0-18

17

166

4

5.4

0.7

3.8

4.5

9.0

12

34

Jackson

0-18

13

162

2

4.7

0.7

2.6

3.3

6.6

8

44

Jackson

0-18

10

251

6

6.6

< 0.5

2.4

2.9

5.8

8

46

Jackson

0-18

13

186

7

5.7

0.6

2.0

2.6

5.2

9

44

 

 

 

 

 

 

 

 

 

 

 

 

Jackson

0-24

18

171

2

5.4

0.7

3.0

3.7

7.4

9

36

Jackson

0-24

23

166

3

5.9

< 0.5

2.6

3.1

6.2

9

44

Jackson

0-24

14

201

5

5.9

< 0.5

1.6

2.1

4.2

7

40

Jackson

0-24

12

194

8

5.9

0.7

3.5

4.2

8.4

12

43

SR, Soil Respiration; WEOC, Water Extractable Organic Carbon; WEON, Water Extractable Organic Nitrogen; SHS, Soil Health Score; NO3-, H3A-4 extractable available nitrate; NH4+, H3A-4 extractable available ammonium; HAN, H3A-4 Extractable Available Nitrogen; EB-N, Estimated Biological N; PN, Plant Available N; AH-N, alkaline-hydrolyzable Nitrogen

Alkaline hydrolyzable N (AH-N) was estimated using the direct distillation procedure outlined by Roberts et al., (2009), which involves a 7-minute distillation using 10 mL of NaOH. Alkaline hydrolyzable N was estimated at preplant for both locations; however, at sidedress (V6 growth stage), AH-N was evaluated at only the Jackson location. At both locations, AH-N decreased significantly with depth, where the AH-N at the 0-6-inch depth was significantly higher than the other depths, but there was no significant difference beyond the 0-6-inch depth for both locations (Figure 2 C & D). AH-N at sidedress was significantly lower when compared to the preplant N (Figure 3B). However, sidedress AK-N, exhibited similar trend as preplant N with respect to the relationship between AH-N and soil depth. A significant positive relationship (R2 > 0.8) was observed between organic matter and AH-N, meaning the lower AH-N observed with depth and sampling time may partly be attributed to lower soil organic matter content. 

Relationship between AH-N and EB-N at preplant and sidedress across soil depths and locations is presented in Figure4. Alkaline-hydrolyzable exhibited a negative significant linear relationship with EB-N over soil depth and location, regardless of the time of soil sampling. At preplant and sidedress, the highest R2 value for the AH-N and EB-N was 0.15 and 0.65 at the 0-6-inch and 12-18 inch-depth, respectively. 

Scatter graph showing the relationship between Alkaline-Hydrolyzable N and HSHT estimated biological N at (A) preplant from the Jackson and Milan locations and (B) sidedress from Jackson location at 0-6, 6-12, and 12-18-inch depths
Figure 4. Relationship between Alkaline-Hydrolyzable N and HSHT estimated biological N at preplant from the Jackson and Milan locations and sidedress from Jackson location at 0-6, 6-12, and 12-18-inch depths

Application of N significantly increased corn yields at both locations (Figure 5). The Jackson and Milan locations exhibited a significant and a positive response to fertilizer N. Corn response to N at the Jackson location did not plateau. In contrast, grain yield increased with N rate until a plateau was reached where yield stabilized at the Milan location. The predicted fertilizer N rate required to maximize yield at the Milan location was 162 lb N a-1. Correlation of check plots with AH-N resulted in a significant linear regression model for 0-6- and 12-18-inch depths at preplant (Figure 6). At preplant, the best predictive relationship between the check plots and AH-N was found at the 12-18-inch depth (R2 = 0.46). In contrast, the correlation between the check plots and EB-N was not significant at all depths (Figure 6).

Scatter graph showing corn response to N fertilizer application at the (A) Jackson and (B) Milan locations.
Figure 5. Corn response to N fertilizer application at the  Jackson and Milan locations.
Scatter graph showing Figure 6. Relationship between relative grain yield of check plot and alkaline-hydrolyzable nitrogen at three depths:0-6, 6-12, and 12-18-inch from the Jackson and Milan locations
Figure 6. Relationship between relative grain yield of check plot and alkaline-hydrolyzable nitrogen at three depths:0-6, 6-12, and 12-18-inch from the Jackson and Milan locations

Results for Objectives (2) develop N fertilizer rate calibration using alkaline-hydrolyzable N, and (3) compare current UT fertilizer recommendation, HSHT N fertilizer recommendation, and alkaline-hydrolyzable fertilizer recommendation will be provided after the second-year research.

 

Participation Summary
2 Farmers participating in research

Educational & Outreach Activities

8 Webinars / talks / presentations
1 Workshop field days

Participation Summary:

Education/outreach description:

Results gathered from trials were communicated through traditional and new avenues, including in-service training, grain conferences, county row crop producer meetings, UT’s Soil and Nutrient Management website (https://utcrops.com/soil/projects/). Results from trials were communicated to UT/TSU agents at the Row Crop In-service Trainings on 12/15/2021 and 12/16/2021. Findings were shared at the 2022 East/Middle Tennessee Grain Conference, Tullahoma, TN (2/1/2022) and 2022 West Tennessee Grain Conferences and Soybean Producers Conference, Dyersburg, TN (2/3/2022) with more than 500 attendees. In addition, this information was also presented at 7 county row crop production meetings. Some of the findings will be presented at both in-person and virtually at the Milan No-Till field day which will be held on Thursday, July 28, 2022. A one-page report on the project will be posted on UT Soil and Nutrient Management website on 4/30/2022.

Learning Outcomes

300 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation

Project Outcomes

Project outcomes:

The intent of this project is to influence and promote the three pillars of sustainability: (i) profitability over the long term, (ii) stewardship of our nation’s land, air & water, and (ii) quality of life for farmers, ranchers, and their communities.

Profitability over the long term

The research and extension components of this project activity will bring in-depth information on N fertilizer recommendations to the front door of the agricultural stakeholders to increase the success of farmers, ranchers and small/rural businesses. There is a possibility for over or under application of N fertilizer based on the current N management recommendations. However, a reliable crop response based on mineralizable N may eliminate such concerns by recommending the appropriate amount of N. Appropriate amounts may save significant amounts of fertilizer use, which reduce production cost and increase profitability. In addition, right amount of N fertilizer may eliminate under application, ensuring enough N for optimum plant growth, development, and yield. Increased crop yield can contribute to improve profitability.

Stewardship of our nation’s land, air & water

Nitrogen, unlike most nutrients, is unstable and hence susceptible to several loss pathways including ammonia volatilization, denitrification, run offs, and leaching. Thus, a major challenge is to minimize N loss and maintain optimum productivity with minimal adverse impact on the environment and other ecosystem services. Based on 4Rs nutrient stewardship program, applying the right amount of fertilizer is one of the strategies to optimize efficiency of N fertilizer use and minimize nitrous oxide emissions, ammonia volatilization, and contamination of surface and ground water by nitrate. At the core of this proposal is to determine if mineralizable N component of the soil can predict crop response. Identifying the above relationship will assist to generate site-specific N fertilizer recommendations or recommend the right amount of N fertilizer. More importantly, this project offers an important opportunity for specialist and scientist on the project to interact with producers on relevant topics that protect natural resources including 4Rs nutrient stewardship, nutrient management, N loss, etc.

Quality of life for farmers, ranchers, and their communities

The primary rural occupation in the US is agriculture and its incumbent to adopt management practices preserves the natural resources to meet the increasing demand for food production. This project seeks to improve crop productivity, increase income, and maintain/increase the success of farmers, ranchers, and small/rural businesses.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.