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North AmericaCrop and environmental conditions in major production zones

Authors: 超级管理员 | Edit: xingqiang

Compared to the other major production zones, the potential biomass ratio in the North American MPZ is rather stable and high, with a value of 0.92, about 5 percent above the other MPZs, an indicator of the efficiency of the food production systems (table 2.2). Table 2.2 also illustrates uncultivated arable land decreased by about 1 percentage point (0.72) this year, compared with the recent past (the last five years). Logically, cropping intensities also decreased during the same time frame, by about 2.5 percentage points. According to figure 2.2a the un cropped arable land is mostly located in the southern and central mid-west.

Table 2.2 North America MPZ: Croppingintensity, uncultivated arable land, and potential biomass ratio



2013 value

11-year average (2002-12)

5-year average (2008-12)

2002-13 normalized trend

Coefficient of correlation

Significance level of trend

Difference between 2013 and 11-year average

Difference between 2013 and 5-year average

Cropping intensity (%)

135

136

137

-0.94

0.108

-

-1.3

-2.5

Uncultivated arable land (%)

1.80

2.21

2.52

1.09

0.045


-0.41

-0.72

Potential biomass ratio

0.917

0.907

0.902

0.000

-0.071

 

0.010

0.015

Note: The normalized trend is the 2002-2013 trend normalized by dividing it by the eleven-year average. Significance level of the trend is *for p<=0.05 and ** for p<=0.01.

As far as environmental variable trends are concerned, PAR increased significantly over the last twelve years. As shown in table C.1 in the Annex, compared with last year and the recent past, rainfall increased and temperature decreased by approximately the same percentage (5 percent compared with recent five years).

For the two recent seasons (winter and summer crops) the most notable features for this MPZ include a wet early winter (November 2012)in the south-west of the zone (Louisiana and Texas) followed by very variable rainfall in Louisiana. Temperature was significantly below average in (i) parts of the mid-west wheat growing areas (Colorado) during much of the winter wheat season up to April, as well as in (ii) North and South Dakota and southern Saskatchewan during March and April. The first area is also where uncroppedarable land patches are concentrated. The area from Wyoming to South Alberta was also affected by the cold spell, though less markedly; the area experienced warmer than average temperatures in January and February.

Long-term biomass trends for this MPZ indicate a decrease in biomass for an area from the southern Great Lakes area (Indiana and Ohio) alonga south-west oriented line into the cotton belt (Louisiana and Arkansas), thenalong the coast in Texas as far as the Mexican border. Compared with the lastfive years, the biomass index is generally favorable in the south (except alongthe eastern coast) and unfavorable in two areas: (i) in an area centered on Iowa, Illinois and Missouri, and (ii) in the northeastern part of the MPZ. 

VHI-based drought profiles show average to better than average conditions over most of the MPZ from October 2012 to September 2013,with the exception of drought conditions from February to June in part of the western MPZ, covering about 20 percent of its area. Favorable conditions were recorded in most of the southeast from March.

Overall, winter wheat temperature and rainfall planting conditions appear to be favorable. Planting was now completed and the crop isat early stages.

Figure 2.2 Environmental and crop production indices for the North America MPZ


                     a. Cropped and uncropped arable land                             (b) cropping index                                

 

e. VHIdeparture from the previous five years for period indicated in f.


g.Rainfall departure from the previous five years for period indicated in h.Rainfall profile


i.               Temperaturedeparture from the previous five years for period indicated in j. temprature profile

Figure 2.3 shows that irrigation is actually very widespreadin the MPZ, even if it may be of very marginal importance locally. Poor cropcondition (marked in red) coincides with the April cold spell. Rice growingareas in the Mississippi valley appear to have enjoyed rather good conditionsfrom March to September. 

Figure 2.3 Clustering of VHI profiles ofirrigated areas in North America since October 2012