# Estimating Corn Yield before Harvest

Filed Under:
Publication Number: P3935
View as PDF: P3935.pdf

Predicting corn yield before harvest is popular with growers, but these estimates can be misleading. It is important to be careful when calculating estimated yields. You must determine the number of ears in 1/1,000 of an acre, average kernels per row, average rows per ear, and average value for seed weight based on the growing conditions.

## Counting Harvestable Ears

Yield estimate accuracy increases with more sites tested. Yield estimates should be determined from at least five—and preferably ten—sites within a field. Field data collection is based on a 1/1,000-acre area. Table 1 gives row length needed to equal a 1/1,000-acre area for popular corn row widths. It is likely that actual yield will be 10 percent higher or lower than the estimated yield because of variation in plant uniformity, health, and height, and soil moisture levels in a field.

Table 1. Row width and length needed to equal 1/1,000 of an acre.

Row width (inches)

Row length (to equal 1/1,000 acre)

30

17 ft 5 in

36

14 ft 6 in

38

13 ft 10 in

40

13 ft 1 in

## Yield Estimate Equation

• Step 1. Count the number of harvestable ears in the length of row equivalent to 1/1,000 of an acre. For 30-inch rows, this will equal 17 feet 5 inches.
• Step 2. Count the number of kernel rows and kernels per row on every fifth ear, and determine an average for each yield component. Do not count small kernels located on the butt or ear tip. If variability in crop development exists within a given field, increase the sample size for better yield estimates.
• Step 3. To determine the yield, transfer the values from steps 1 and 2, rounded to the nearest number, to Table 2, 3, or 4 depending on the current year’s growing conditions.

### Example

30 ears in 1/1,000 of an acre

14 kernel rows per ear

30 kernels per row

In a good irrigated corn field with no stress from pollination to physiological maturity, use Table 2 to find the yield estimate is 164 bushels per acre. If your growing conditions were evaluated as extreme stress in dryland corn from pollination to physiological maturity, use Table 4 to find the yield estimate is 113 bushels per acre.

Table 2. Yield estimates for irrigated corn with no stress from pollination to physiological maturity.

Ears per 1/1,000 acre

Average rows/ear = 12

Average rows/ear = 14

Average rows/ear = 16

Average rows/ear = 18

Kernels/row

Kernels/row

Kernels/row

Kernels/row

25

30

35

40

45

25

30

35

40

45

25

30

35

40

45

25

30

35

40

45

Bushel/acre

Bushel/acre

Bushel/acre

Bushel/acre

27

105

126

147

168

190

123

147

172

196

221

140

168

196

225

253

158

190

221

253

284

28

109

131

153

175

196

127

153

178

204

229

146

175

204

233

262

164

196

229

262

295

29

113

136

158

181

204

132

158

185

211

238

151

181

211

241

271

170

204

238

271

305

30

117

140

164

187

211

136

164

191

218

246

156

187

218

250

281

176

211

246

281

316

31

121

145

169

193

218

141

169

197

226

254

161

193

226

258

290

181

218

254

290

326

32

125

150

174

200

225

146

175

204

233

262

166

200

233

266

300

187

225

262

300

337

33

129

154

180

206

232

150

180

210

240

270

172

206

240

274

309

193

232

270

309

347

34

133

159

186

212

239

155

186

216

248

278

177

212

248

283

318

199

239

278

318

358

35

136

164

191

218

246

159

191

223

255

287

182

218

255

291

328

205

246

287

328

368

Table 3. Yield estimates for average growing conditions from pollination to physiological maturity.

Ears per 1/1,000 acre

Average rows/ear = 12

Average rows/ear = 14

Average rows/ear = 16

Average rows/ear = 18

Kernels/row

Kernels/row

Kernels/row

Kernels/row

25

30

35

40

45

25

30

35

40

45

25

30

35

40

45

25

30

35

40

45

Bushel/acre

Bushel/acre

Bushel/acre

Bushel/acre

27

90

108

126

145

163

105

126

148

169

190

120

145

169

193

217

136

163

190

217

244

28

94

112

131

150

169

109

131

153

175

197

125

150

175

200

225

141

169

197

225

253

29

97

116

136

155

175

113

136

158

181

204

129

155

181

207

233

146

175

204

233

262

30

100

120

141

161

181

117

141

164

187

211

134

161

187

214

241

151

181

211

241

271

31

104

124

145

166

187

121

145

170

194

218

138

166

194

221

249

156

187

218

249

280

32

107

128

150

171

193

125

150

175

200

225

143

171

200

228

257

161

193

225

257

289

33

110

132

155

177

199

129

155

180

206

232

147

177

206

236

265

166

199

232

265

298

34

114

136

159

182

205

133

159

186

212

239

152

182

212

243

273

171

205

239

273

307

35

117

141

164

187

211

137

164

191

219

246

156

187

219

250

281

176

211

246

281

316

Table 4. Yield estimates for stressed dryland corn from pollination to physiological maturity.

Ears per 1/1,000 acre

Average rows/ear = 12

Average rows/ear = 14

Average rows/ear = 16

Average rows/ear = 18

Kernels/row

Kernels/row

Kernels/row

Kernels/row

25

30

35

40

45

25

30

35

40

45

25

30

35

40

45

25

30

35

40

45

Bushel/acre

Bushel/acre

Bushel/acre

Bushel/acre

27

73

87

102

117

131

85

102

119

136

153

97

117

136

156

175

109

131

153

175

197

28

76

91

106

121

136

88

106

123

141

159

101

121

141

161

181

113

136

159

181

204

29

78

94

110

125

141

91

110

128

146

164

104

125

146

167

188

117

141

164

188

211

30

81

97

113

130

146

94

113

132

151

170

108

130

151

171

194

122

146

170

194

219

31

84

100

117

134

151

98

117

137

156

176

112

134

156

178

201

126

151

176

201

226

32

86

104

121

138

156

101

121

141

161

181

115

138

161

184

207

130

156

181

207

233

33

89

107

125

142

160

104

125

146

166

187

119

142

166

190

214

134

160

187

214

240

34

92

110

128

147

165

107

128

150

171

193

122

147

171

196

220

138

165

193

220

248

35

94

113

132

151

170

110

132

154

176

198

126

151

176

202

227

142

170

198

227

255

Publication 3935 (POD-08-23)

Revised by Bill Burdine, PhD, Extension Specialist, North Mississippi Research and Extension Center, from the original by Dennis Reginelli, former Regional Extension Specialist for Agronomic Crops.

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## Authors

### Dr. Bill Burdine, Jr.

Extension Specialist II
Agronomic Crops