1. National Analysis

This report covers the period from April to July 2020. Winter wheat had reached maturity in June and July. Maize and soybean planting started in April and finished in May. Maize reached the silking stage and soybean was in the bloom and pod setting stage by late July. In general, the crop conditions were generally favorable nationwide.

Figure 3.42 United States’ crop condition, April - July 2020

Figure.X 4_7_USA

Figure.X Crop condition development graph based on NDVI

Slightly more humid and cooler weather was observed in this monitoring period with rainfall 6% above average, temperatures 0.5 ℃ below average  and PAR 2% lower as compared to the 15YA.  At the national scale, biomass was estimated to be 2% below the 5YA, due to lower PAR. Significantly above average rainfall occurred in Illinois (12%), Iowa (14%), Missouri (15%), Alabama (7%), Georgia (7%), Florida (18%), Washington (10%), and South Carolina (19%). On the contrary, the northeastern region of the United States and the eastern part of the Corn Belt suffered from a light precipitation deficit. This includes Pennsylvania (-11%), Vermont (-13%), Indiana (-15%), Ohio (-4%), Michigan (-5%). The rainfall time series show that it flucutated around the longterm average, and no prolonged dry spell was observed.  Temperatures in the eastern United States and northern Great Plains were 0.5-1.5 °C lower than average. In mid-April, a cold wave had swept across the central and southern United States, causing significantly below-average temperatures and delaying the planting of maize. With the exception of some states located in the Northeast and North Plains, most areas of the United States experienced lower PAR than usual, such as Illinois (-5%), Iowa (-4%) and Missouri (-5%). 

Figure **: rainfall departure compared to 15YA (left) and time series of rainfall (right)

Figure.X temperature departure compared to 15YA (left) and time series of temperature (right)

Figure ** PAR departure compared to 15YA

The USA encompasses a wide range of agro-climates. Nationwide, VCIx was at 0.88, indicating generally favorable conditions, but there were some differences in crop conditions in major food producing areas of the United States. In the southern Great Plains, VCIx was below 0.5, whereas it was higher than 1 in the western corn belt. Using the spatial clustering method, our analysis divides the mainland of the United States into five categories based on the NDVI anomaly dataset. In the Southern Great Plains, drier than normal conditions prevailed over most of the monitoring period, causing a negative departure of NDVI. But the crop conditions improved significantly  in July. From April to the end of May 2020, the crop conditions in the corn belt suffered from wet and cold conditions, which caused some delays in planting and early crop development. As in the south, the conditions improved greatly in July. From April to July 2020, crop conditions in the southeastern United States remained at a relatively favorable level, and the NDVI anomalies remained positive. At the end of July, 90% of arable land was cropped, which was 1% below the 5YA. 

In short, with the exception of some areas in the Southern Great Plains, crop conditions in most major crop producing areas in the United States were favorable. In the next monitoring period, all spring and summer crops will enter the grainfilling stage and reach maturity. 

Figure.X Maximum VCI

Figure.X Spatial distribution of NDVI profiles

2. Regional Analysis

2.1 Corn Belt

This is the most important corn and soybean producing area in the United States. It includes Illinois, Iowa, Minnesota, Wisconsin, Ohio and Michigan. Compared with the 15YA, the agro-climatic conditions in the area during the monitoring period were slightly more humid and cooler. Precipitation was 5% higher, while temperature and PAR were 1 ºC and 2% below average. The crops developed more slowly than usual, which explains the slightly below-average NDVI values in May and June. However, the crops recovered to average levels by July. The VCIx value of 0.93 also indicates favorable crop growth in the region and the outlook for the soybean and maize crops is favorable. 

Figure.X  crop condition development graph based on NDVI (left) and Time series rainfall profile (right)

2.2 Lower Mississippi

This is the most important rice producing area and an important soybean producing area in the United States. It includes Arkansas, Louisiana, Mississippi and Missouri. Rice reached the heading stage in July. The agro-climatic conditions in the lower Mississippi were close to the average with average rainfall (+ 3%) and temperature (-0.7°C), while the average PAR was 3% lower than 15YA. In early May and June, the deficit in precipitation in the area resulted in below average crop conditions. By July, the crop conditions returned to close to average. The VCIx value reached 0.91, which also indicates favorable crop growth conditions in this region.

Figure.X  crop condition development graph based on NDVI (left) and Time series rainfall profile (right)

2.3 NorthWest

This is an important winter wheat producing area in the United States, including Washington and Idaho. Winter wheat reached maturity and was mostly harvested by the end of July. Compared with the 15 YA, rainfall was 9% above average, temperature was 0.4℃ below average, and PAR was 4% below average. The precipitation time series show that the rainfall in the northwestern region was lower than average in early and mid-April, and subsequently gradually recovered to above-average levels.The NDVI development profile indicates that the crop conditions were below average in April and May, but subsequently returned to average levels. The below average conditions in the early part of this reporting period can be attributed to below average rainfall in April, which also impacted  CALF (-4%). By the end of July, crop condtions were generally favorable. 

Figure.X  crop condition development graph based on NDVI (left) and Time series rainfall profile (right)

2.4 Northern Plains

This is the most important spring wheat and sunflower producing area in the United States and the second most important corn and soybean producing area. It includes North Dakota, South Dakota, Nebraska and Montana. This monitoring period covers the planting, germination, silking and dough stages of corn; the sowing, emergence, heading and grain filling stages of spring wheat; the sowing, emergence, flowering and pod-setting stages of soybean. Compared with the 15 YA, the northern plain had experienced nearly average weather conditions, with rainfall 4% higher and temperature (-0.7 ºC) and PAR (-1%) lower than the 15YA. After sowing and emergence, the spring and summer crops in July all entered silk (corn), flowering (soybean) and heading (spring wheat) stages. Cooler and wetter conditions in North and South Dakota delayed the timely planting of the spring crops. However, by the end of July the crops had caught up and their NDVI reached slightly higher than average levels, especially in South Dakota and Montana. A VCIx value as high as 0.95 also indicates favorable crop growth in this region.

图.X Crop condition development graph based on NDVI

2.5 Southeast

This is an important cotton production area in the United States, including Georgia, Alabama and North Carolina.  During the monitoring period, the agro-climatic conditions in this region were favorable. Compared with the 15 YA, rainfall was 16% higher,  temperature 0.6 ℃ lower and PAR 3% below average. Abundant rainfall helped sustain vigorous crop growth, although rainfall in July was far below average. The VCIx value, which reached 0.93, also indicates favorable crop growth in the region. 

Figure.X Crop condition development graph based on NDVI and time series rainfall profile

2.6 Southern Plains

This is the most important winter wheat, sorghum and cotton producing area in the United States. It includes Kansas, Oklahoma, Texas, and eastern Colorado. Texas is the largest cotton producing state and Kansas the largest winter wheat producing state in the United States. During this monitoring period, the southern plain experienced a sligthly wetter season than normal: Compared to the 15YA, rainfall was 9% higher, temperatures 0.3 ºC below average and PAR  2% below average. The monitoring period covers the grainfilling and harvesting stages of winter wheat and the planting, square and boll fixing stages of cotton. The development profile of NDVI shows that the crop conditions were significantly below average in  May and June, howerver, they improved in July. At the same time, the proportion of cultivated land has dropped by 4% compared to the 5YA. All in all, crop conditions were slightly below average by the end of this monitoring period. 

Figure.X crop condition development graph based on NDVI (left) and Time series temperature profile (right)

Table 3.75 United States’ agroclimatic indicators by sub-national regions, current season’s values and departure from 15YA, April - July 2020

Table 3.76  United State agro-climatic indicators by sub-national regions, current season's values and departure from 5YA average, April - July 2020