This monitoring period covers the growth and harvest of maize, rice, soybean and spring wheat. In general, crop condition was mixed due to abundant precipitation but below average sunshine in the Corn Belt and Northern Plain, destructive Fire in California and Hurricane Florence.

Nationwide, above average precipitation (+10%) was observed in the United States, however with large differences between States. In the Corn Belt Iowa recorded a 70% excess of rain,  Illinois (+18%), Michigan (+27%), Wisconsin (+62%), Indiana (+16%) and Ohio (+19%). Abundant rain also fell over the Northern Plains, including Nebraska (+47%), North Dakota (+46%) and South Dakota(+38%). In the Southeast Hurricane Florence also contributed large rainfall amounts in September. Dry climatic condition prevailed in the western part of the United States. Rainfall in California, Washington and Oregon States was below average by 21%, 33% and 47%, respectively. 

The Corn Belt and Northern Plain are the major Maize, Soybean, and Spring Wheat producing zones. Abundant precipitation replenished soil moisture for summer crops in both regions, while excessive precipitation was also accompanied by a reduction of sunshine: RADPAR was below average by 6%, 5%, 5%, 4%, 3%, 2% in Arkansas, Iowa, Wisconsin, Minnesota, Nebraska, and Ohio, respectively. The combined impact of above average rainfall and deficit of RADPAR on summer crops is reflected by Maximum VCI (VCIx) and Spatial distribution of NDVI profiles. Favorable and even above-average crop condition occurred in most Corn Belt States, although NDVI had been below average since mid-July. The Northern Plains experienced better crops than the Corn Belt, with the most favorable condition in North Dakota, and South Dakota.

Currently, the cropped land fraction is above average by 2%, and cropping intensity is normal.

Altogether, CropWatch estimates 2018 Wheat and Maize to be are below 2017 output 3.9% and 2.1%, while Rice and Soybean are up by 1.0% and 2.8%, respectively.

Figure.X Crop calendar of USA

Figure.X Crop condition development graph based on NDVI_United States

Figure.X Maximum VCI

图.X Spatial distribution of NDVI profiles

Figure.X Spatial distribution of NDVI profiles

Table CropWatch‐estimated maize, rice and soybean production for United States in 2018 (thousand tons)

Regional Analysis

Considering that winter wheat was harvested during the previous reporting period, only Maize, Spring wheat, rice production zones were selected for further analysis, especially in the Corn Belt, Lower Mississippi, Northern Plains, Northwest and Southeast.

The Corn Belt is the most important Maize and Soybean production zone of the United States. RAIN was above average by 35% and almost all states received abundant precipitation, including Iowa (+70%), Illinois (+18%), Michigan (+27%), Wisconsin (+62%), Indiana (+16%) and Ohio (+19%). Excessive precipitation was paralleled by reduced  sunshine (-3%), and RADPAR (about -5%) in Iowa, Wisconsin and Minnesota. Sufficient precipitation replenished soil moisture but the photosynthesis was reduced by low RADPAR. As a result, crop condition was below the recent 5 year average and last year since mid-July. 

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  Figure.X Crop condition development graph based on NDVI Corn Belt

The Lower Mississippi is the top rice producer of the United States, but it is also an important soybean and cotton production area. NDVI profiles indicated crop condition was comparable to the previous 5 year average.  The region was dominated by cloudy and rainy weather; precipitation was above average by 19% while RADPAR was below average by 3%. The abundant water benefited rice and the fair crop condition is reflected by a  VCIx value of 0.9.

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  Figure.X Crop condition development graph based on NDVI_Lower Mississippi

The major spring wheat and an important maize production zones of the United States are the Northern Plains. Spring wheat was harvested before September, and  the NDVI time series profile indicated that crop condition was above average at that time. In the current reporting period, the Northern Plains were dominated by wet weather condition, and RAIN was significantly above average (+ 32%) with average RADPAR. The good crop condition was also confirmed by VCIx (0.93). It is worth noting that the cropped land fraction was significantly above average by 14%. Altogether, CropWatch analyses indicate above average crop condition in the Northern Plains.

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  Figure.X Crop condition development graph based on NDVI_Northern Plains

The Northwest is an important winter wheat and sprint wheat production zone of the United States. Crop condition in this region was below average. The rainfall was significantly below average by 32%, and RADPAR was well above average by 4%. This period is the growing and harvesting season of spring wheat and sowing season of winter wheat; the dry weather condition accelerated soil moisture loss and had a negative impact on crop growth. Cropped land fraction was above average by 5% and at 0.83 the maximum VCI indicator is fair for the reporting period. Mainly due to drought, below average crop condition is estimated by CropWatch for the Northwest.

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  Figure.X Crop condition development graph based on NDVI_Northwest

The Southeast is an  important cotton and maize production zones of the United States. Slightly below average crop condition was indicated by the NDVI time series. Wet, warm, and sunny weather condition was recorded in this monitoring period (RAIN, TEMP and RADPAR were above average by 11%, 0.3℃ and 5%, respectively). In September,  South Carolina suffered from hurricane Florence which caused floods are damaged crops. Agronomic indicators were fair in this reporting period; cropped land fraction is only slightly above average (+1%), and VCIx was 0.89. Considering the negative impact of the hurricane, crop condition is assessed as slightly below average.  

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  Figure.X Crop condition development graph based on NDVI_Southeast

Table *: American agroclimatic indicators by sub-national regions, current season's values and departure from 15YA, July-October 2018

Table *: American agronomic indicators by sub-national regions, current season's values and departure from 5YA, July-October 2018