Blog 5 - Environment and Agroecosystems

-

Blog 5 - Environment and Agroecosystems

Pecan production sites

Most of the pecan production takes place in the Southern States of North America. The rating in 2014 was as listed underneath.

1.       Georgia                                76 million pounds
2.       New Mexico                        67 million pounds
3.       Texas                                    61 million pounds
4.       Arizona                                21 million pounds
(Marzolo, 2015).

While the pecan productions in Georgia, New Mexico and Arizona remained stable, the production value has increased in Texas. (Marzolo, 2015).

Climate of the production areas



Figure 1 Climograph of Atlanta, Georgia. (US climate data, 1981-2010 normals).
Figure 2 Climograph of Santa Fe, New Mexico. (US climate data, 1981-2010 normals)


Figure 3 Climograph of Austin, Texas. (US climate data, 1981-2010 normals).

Figure 4 Climograph of Phoenix, Arizona. (US climate data, 1981-2010 normals).

Since the states Georgia, Texas, New Mexico and Arizona cover such a vast surface it is hard to pinpoint the climate of each state since this can differ per district.

We can distinct several significant production categories. The production of pecans in dry, low elevation (>460 meters) and the dry, high elevation areas (between 730-1220 meters). The DL areas can be found in Texas near Crystal City, Arizona in the Red Rock area and in California east of Fresno. The DH areas are located in Arizona near Tucson and the land between El Paso and Las Cruces New Mexico – Texas. The most humid production site is in Georgia. (Sparks, 2000).

Optimal situation for the pecan

Due to the water requirements of the pecan tree it is most likely to be found in humid areas. The humidity influences the growing degree days positively. But, the tree can also be found in more semi-arid area if it is subject to flooding. (Sparks, 2000).

The average monthly maximum is 28 degrees Celsius in summer and lower than 23 degrees Celsius in winter. The average monthly minimum is 16 degrees Celsius in summer and  8 degrees Celsius in winter. (South Africa Department of Agriculture, Forestry and Fisheries, n.d.). Pecan cultivars do not stand to well against frost. It needs at least 190-200 frost-free days per year, but looking back to the average monthly minimum, this would not be ideal. (Sparks, 2000).

Therefore, the dry, low elevation areas are less suitable for pecan production for they are simply too hot and dry. Arizona is good example as a dry semi-arid area. (See figure 1.4). The temperatures are higher than ideal for the pecan tree and irrigation could be a problem in summer, when there is a limited supply of rainfall. The dry, high elevation areas could be more suitable due to the lower temperatures. Frost, however is undesirable. Therefore, winter in New Mexico and Texas could be a challenge. (See figures 1.2 and 1.3). The production sites in Georgia are ideal, because of the adequate rainfall throughout the year (See figure 1.1) the plants and the temperatures are manageable for the crop to deal with. The humidity, unfortunately, provides problems with fungi.

Environmental condition that can have serious consequences

There are several things that can have damaging impact on the pecan trees.
-         -  A sufficient supply of water, loose soil and full sun to prevent stressed trees
-         -  Wind or heavy rain damage
-         -  Freeze damage
-       -    Insect damage
-        -   Disease/ fungi damage
(Leschmann, 2017).

We will go deeper into frost damage. The pecan tree can withstand frost, for a short time during winter with the temperatures not dropping too low. When it comes down to early or late frost or deep frost for a prolonged time damage will occur. (South Africa Department of Agriculture, Forestry and Fisheries, n.d.).

Frost can have of consequence that the pistils and catkins freeze completely, which makes the trees unable to reproduce and from nuts for at least a year. (Western Farm Press, 2010). 

Signs of freezing are vertical splits in bark and wood that appear dry and gray. Later, in spring the limbs will appear dead and new growth will occur from the ground up. It could also be that a dead limb faces new growth, which dies as well. (Leschmann, 2017).

Studies have shown that the height of the tree will impact the amount of frost damage on the tree. There was a clear difference between trees of 12 feet and 25 feet high. Often when it freezes radiation frost is a result. This means that the earth surface is colder than higher up, in the air. (Reid, 2014).

References

Leschmann, T. (2017, September 21). About Damaged Pecan Trees. Retrieved from Garden Guides: http://www.gardenguides.com/132031-damaged-pecan-trees.html
Marzolo, G. (2015, August). Pecans. Retrieved from Agricultural Market Resource Centre: http://www.agmrc.org/commodities-products/nuts/pecans/
Reid, W. (2014, April). Frost damage and tree height. Retrieved from NorthenPecans Blogspot: http://northernpecans.blogspot.co.uk/2014/04/frost-damage-and-tree-height.html
South Africa Department of Agriculture, Forestry and Fisheries. (n.d.). Retrieved from Cultivation of pecans: http://www.nda.agric.za/docs/pecan/pecan.htm
Sparks, D. (2000). Pecan in Warm Climate. In A. Erez, Temperate Fruit Crops in Warm Climates (pp. 381-403). Dordrecht: Springer.
US climate data. (1981-2010 normals). Capitol, State. Retrieved from US climate data: https://www.usclimatedata.com/climate/
Western Farm Press. (2010, August). Hedging revives freeze-damaged pecans. Retrieved from Western Farm Press: http://www.westernfarmpress.com/tree-nuts/hedging-revives-freeze-damaged-pecans

Comments

Post a Comment

Popular posts from this blog

Blog 2 - Pecan Tree Anatomy and Morphology

-
Image
Blog 2 - Pecan Tree Anatomy and Morphology When wanting to know a plants anatomy and morphology one often starts with a simple distinction between a monocot and a dicot plant. Morphology is the study of the form and structure of plants, while anatomy covers the arrangement of cells, tissues, organs and other structures. Thus, knowing the differences between the two types will give one insight how a plant grows and what it will need to be able to develop. You can distinguish the two types by going over a simple checklist. Figure 1 Detailed picture of a monocot and dicot (Flowering plants monocotyledon and dicotyledon science lesson in English, 2017) Pecan: monocot or dicot? We will do a test in order to classify the pecan tree. Looking at the leaves of the pecan tree we can see that the leaf veins are not parallel, which classifies the pecan as a dicot plant. (Carya illinoinensis (Wangenh.) K. Koch, 2017) . Figure 2 Pecan leaves  (Pecan Tree Leaves, 20...
Read more

Blog 11 - Organic Agriculture

-
Blog 11 - Organic Agriculture What are the problems when moving from conventional to organic practices? The most occurring problems when cultivating organic pecan is found in weed and pest management. Weeds will limit growth, for the trees will have to compete with the weeds. But perhaps most harmful will be plant diseases. The most common pecan diseases are caused by fungal pathogens, such as scab, so control is of upmost importance. (Texas A&M Agrilife Extension, n.d.) Aphids and weevil control is also an important factor to keep in mind. (Mizell, 2015) . It takes 3 years of transformation to be able to get an organic certification. if one plants new trees it can take 10 years before the trees will bear nuts. (Mizell, 2015) . Therefore, disease-resistant varieties have to be chosen. Also, a lot of organically approved substances are used to control the fungi and insects. The University of Florida has done research on organic production by R. F. Mizell. This publicati...
Read more