Objective:                   

To evaluate the effects of boron fertilizer rate and timing on alfalfa yield and quality.

Personnel:                  

J.A. Torrion, E. Glunk, R.N. Stougaard, A. Sapkota, J. Garner

Summary:       

Boron treatments were applied at five rates with amounts and timing detailed in Table 1. The experimental design was a randomized complete block with four replications. There was a full soil profile beginning at green up; rainfall received in the fall and early spring was above average. From the first green up to the last cutting (April to October 24, 2016) 14.75 inches of rain was received (October received record precipitation of 5.48 inches). Supplemental irrigation was applied when needed from June to September. Height measurements were taken prior to cutting when plants achieved 10% flowering. Three cuttings were made.

No significant differences were observed for height or yield (Table 3). Average total yields were 5.4 T/A. First harvest had the highest yield at 2.4 T/A.  

Significant differences were observed in boron uptake and alfalfa quality (Table 4). Crude protein was highest at second harvest. Significance in boron uptake was observed for all three harvests.

 

Table 1. Total B applied per treatment and application timing.  
Treatment Total B (lb/a/year)  Application
1 Untreated check None
2 0.5 .25 lb/A applied at 3-in regrowth in early spring + .25 lb/A at 3 - in regrowth after first cutting
3 1 .50 lb/A applied at 3-in regrowth in early spring + .50 lb/A at 3 - in regrowth after first cutting
4 2 1.0 lb/A applied at 3-in regrowth in early spring + 1.0 lb/A at 3 - in regrowth after first cutting
5 2 2 lb/A applied at 3-in regrowth in early spring

 

 

Table 2. Materials & methods   
Variety: Pioneer58V09 Fertilizer: 0-0-62
Seeding Date: 5/15/2014 Sulfur Fertilizer: 21-0-0-24S
Julian Date: 135 Boron Fertilizer: 10% Liquid - Agrisolutions
Seeding Rate: 12 lb/A 1st Boron Application Date: 4/11/2016
Previous Crop: Barley 2nd Boron Application Date: 7/5/2016
Tillage: Conventional 1st Harvest Date: 6/13/2016
Irrigation: Yes 2nd Harvest Date: 8/2/2016
Soil Type: Fine sandy loam 3rd Harvest Date: 10/24/2016
Soil Test: 22-18-88  

 

 

Table 3. Effects of boron fertilizer on alfalfa yield       
  1st Harvest - Jun 13  2nd Harvest - Aug 2  3rd Harvest - Oct 24  Harvest Total
  HT YLD HT YLD HT YLD YLD
Treatment in T/A in T/A in T/A T/A
0 lbs B 44 2.0 33 1.6 28 1.4 5.1
0.25 lb B begin + mid season 43 2.6 32 1.6 28 1.4 5.6
0.5 lb B begin + mid season 45 2.6 33 1.5 29 1.4 5.4
1 lb B begin + mid season 46 2.5 33 1.6 29 1.5 5.5
2 lb B begin season 43 2.4 35 1.5 29 1.5 5.4
Mean 44 2.4 33 1.6 29 1.4 5.4
CV 7 20 4 11 4 6 7
LSD ns ns ns ns ns ns ns
Pr>F 0.4898 0.4502 0.0726 0.9166 0.5289 0.2741 0.4377
HT: height, YLD: yield, ns: nonsignificant, B: boron (amount applied begin season same as mid season)       

 

 

Table 4. Boron uptake and hay quality      
  CP ADF NDF TDN RFV B
Treatment % % % % % ppm
1st Harvest - Jun 13
0 lbs B 24.0 34.7 42.9 61.3 135.8 21.3
0.25 lb B begin + mid season 22.5 38.7 47.5 56.9 115.0 25.8
0.5 lb B begin + mid season 23.1 36.9 46.3 58.9 123.0 30.0
1 lb B begin + mid season 22.7 35.0 44.0 60.9 131.3 29.5
2 lb B begin season 22.4 37.6 47.5 55.7 117.0 30.0
LSD ns ns ns ns ns 3
Pr>F (0.05)-B 0.8512 0.5509 0.3537 0.4078 0.4525 0.0003
2nd Harvest - Aug 2
0 lbs B 27.8 33.5 42.4 62.6 138 25.8
0.25 lb B begin + mid season 27 33 39 63.1 151.5 31.5
0.5 lb B begin + mid season 26.7 32 41.3 64.1 144.8 35.5
1 lb B begin + mid season 25.8 34 41.6 62 140.3 39
2 lb B begin season 24.1 35 42 61 137 38.3
LSD 2 ns ns ns ns 7
Pr>F (0.05)-B 0.054 0.1618 0.3698 0.1591 0.3369 0.0051
3rd Harvest - Oct 24
0 lbs B 20.5 33.5 42.6 62.6 137.8 34.3
0.25 lb B begin + mid season 20.7 33.3 41.1 62.8 143 44.8
0.5 lb B begin + mid season 20.3 34.6 42.2 61.4 136.8 53.5
1 lb B begin + mid season 21.1 32.9 39.5 63.1 150.3 54.5
2 lb B begin season 20.2 34.3 40.1 61.7 144.8 55.3
LSD ns ns ns ns ns 8
Pr>F (0.05)-B 0.4609 0.7009 0.3062 0.7127 0.4076 0.0006
CP: crude protein, ADF: acid detergent fiber, NDF: neutral detergent fiber, TDN: total digestible nutrients, RFV: relative feed value, B: boron (amount applied begin season same as mid season)