Winter wheat was the main crop that was grown during this monitoring period.  It went through the tillering, greening, jointing and heading stages. Land preparation and planting of maize, rice and soya bean began in April. Overall, conditions for winter crops were below the five-year average due to a drought in the major winter wheat production areas.

The marked heterogeneity of agro-climatic conditions and phenology led to significant differences in crop growing conditions between regions. Rainfall and temperatures were 5% and 1.0°C above the 15-year average, respectively, and radiation was 5% below, resulting in potential biomass 4% above the 15-year average. Kansas, the leading winter wheat producing state, suffered from rainfall deficits (RAIN -23%). The resulting drought conditions impacted growth and yield formation. Cold temperatures and slightly below average rainfall in Idaho (RAIN -6%), Washington (RAIN: -6%) and Oregon (RAIN -4%) hampered the growth of winter crops and the planting of spring crops. Rainfall in California was well above average (RAIN +60%) and the VCIx of 0.75 was close to average.

The national cropped arable land fraction (CALF) was 46%, 11% below the five-year average. The national VCIx value was 0.71 and the crop production index (CPI) was 1.04, indicating average crop conditions for the observation period. VCIx values below 0.5 indicated that poor crop conditions were widespread in the southern high plains and the Northwest. Drought caused by lack of rainfall led to poor crop conditions in the winter wheat production area in the Southern Highplains, while cooler than usual temperatures in the northwest delayed the growth of winter wheat in the Northwest. 

In short, CropWatch, conditions for winter wheat in the Southern Plains were unfavorable, whereas in the Northwest, below average temperatures caused slow crop growth.

(a). Phenology of United States from January to April 2023

(b). Crop condition development graph based on NDVI

(c). Time series rainfall profile

(d). Time series temperature profile

(e). Maximum VCI

(f). Spatial distribution of NDVI profiles

(g) Forecasted anomaly of air temperature (2m) in June 2023 by FGOALS-f2 system

Regional Analysis

Winter crops are grown mainly in the Southern Plains (No. 207), Northwest (No. 206) and California (No. 201). Winter wheat growth conditions are highly spatially heterogeneous due to different agroclimatic, agronomic and irrigation infrastructure conditions.

(1) Southern Plains (207)

The Southern Plains is the main winter wheat producing region in the United States. It includes the states of Kansas, Oklahoma and Texas. Overall, crop conditions in the region were poor, as indicated by below average CALF (-10%), low VCIx (0.68) and low CPI (0.89).
Conditions varied greatly within this region. On average, the Southern Plains experienced wet and warm weather, characterized by above average rainfall (RAIN +11%) and temperature (TEMP +0.9℃), and low RADPAR (-6%), resulting in average potential biomass (0%). Kansas, a major winter wheat producing state, experienced dry and warm weather with below average rainfall (RAIN -23%) and above average temperatures (0.6°C), which accelerated soil moisture loss. The VCIx of 0.54 and CALF of 49% were below the 5-year average and the crop production index (CPI) of 0.89 indicates poor crop conditions. Oklahoma (RAIN +14%, TEMP 0.8℃) and Texas(RAIN +15%, TEMP 1℃) experienced wet and warm weather, and the crop condition was near normal. CropWatch assesses the crop situation in the Southern Plains as below average due to poor winter wheat performance in Kansas. 

According to the weather forecast by FGOALS-f2 weather and the subseasonal to seasonal Ensemble Prediction System, air temperature in the Southern Plains at the grain-filling to maturity stage will be above average, which might further lower the wheat yield expectation.

 (h) Crop condition development graph based on NDVI

 (i) Time series rainfall profile

 (j) Time series temperature profile

(2)  Northwest (206)

The Northwest is another important winter wheat production region. It includes the states of Washington and Oregon.  Growing conditions in this region were well below average due to poor agro-climatic conditions. The Northwest experienced below 15-year average rainfall (RAIN -7%), temperature (TEMP -1.5℃) and radiation (-5%), resulting in below average potential biomass (BIOMSS -10%). It is worth noting that the CALF was 42% below the 5-year average, the VCIx was  0.52 and the crop production index (CPI) was only 0.52, all confirming poor growth conditions for winter wheat in the region. In short, CropWatch assessed the crop growth in the Northwest as below average, and crop production is expected to be below average. 

 (k) Crop condition development graph based on NDVI

 (l) Time series rainfall profile

 (m) Time series temperature pofile

(3) California  (201)

California is a major producer of winter wheat, and the most important  producer of vegetables and fruits  in the United States. The winter wheat reached the maturity stage by late April. According to the NDVI profile, the crop conditions were close to the 5-year average.  Wet weather dominated in California with significantly above average rainfall (RAIN +60%), below average temperature (TEMP -2.1°C), and below average RADPAR (-8%). The significantly above average precipitation provided abundant soil moisture for crop growth, resulting in an increase in potential biomass (+18%). The cropped arable land fraction (CALF, -1%) was near average. The VCIx reached 0.78, and the crop production index (CPI) reached 1.03, close to the average. Agro-climatic conditions in California were favourable, and  CropWatch predicts average yield for winter wheat in California.

(n) Crop condition development graph based on NDVI

 (o) Time series rainfall profile

 (p) Time series temperature profile

3.75.United States' agroclimatic indicators by sub-national regions, current season's values and departure from 15YA, January - April 2023

Table 3.76. United States’agronomic indicators by sub-national regions, current season's values and departure, October January - April 2023