تحميل كتاب تطبيقات GIS في الزراعة Application GIS in Agriculture pdf

تحميل كتاب تطبيقات GIS في الزراعة Application GIS in Agriculture pdf ، استكمالا لسلسلة تعلم Learn GIS نقدم لكم في هذه المقالة كتاب تطبيقات GIS في الزراعة Application GIS in Agriculture pdf ، من تأليف Francis J. Pierce ، David Clay.

An Introduction In Contents of the book Application GIS in Agriculture pdf

Nitrogen Management in Sugar Beet Using Remote Sensing and GIS

Sugar beet is a foreign crop to many people, although most people in the United States eat the fruits of its production regularly — sugar. Where sugar beet is grown for seed production, it is a biennial crop, grown to full maturity over two years. However, if sugar beet is grown for sugar processing, it is an annual crop; sown in the spring and harvested in the fall. At harvest, there are two components that are important: the green, leafy tops, and the sugar storage component of the root .

Sugar beet cannot be grown everywhere. The presence of rocks is not good for harvest or processing. A more important component of production is the local availability of sugar beet processing facilities. Without processing plants nearby, sugar beet production would not be profitable. Transportation costs can rapidly consume the value of the product. Conversely, if nearby growers decided not to grow sugar beets, the factories would be in financial trouble, since transportation costs to move more distant production into the factory would make production costs prohibitive.
Consequently, there has been a close relationship between sugar beet processors and growers. In some areas, such as the Red River Valley in Minnesota and North Dakota, the relationship has been especially strong due to the development of grower cooperatives.

Early in the development of the sugar beet industry, researchers found that there was a unique relationship between nitrogen (N) fertilizer application and sugar beet production. As N fertilizer rates increased, sugar yields decreased.1 During sugar beet refining, the nitrogenous impurities within the root also increase the cost of processing. Growers are therefore encouraged not to over-fertilize with N.

Sugar beets can use N from fertilizer as well as from residual N in the soil. In the 1970s, the concept of using soil sampling and nitrate analysis of soil as an approach to manage residual N was proposed.2 In a very short time, soil sampling for N management in sugar beets was widespread in the Red River Valley of Minnesota and North Dakota.

Sugar beet harvest is unique compared to most other crops grown in the United States. In some cultures, sugar beet tops are harvested and removed from the field as a livestock feed before or at root harvest. However, in the United States, the sugar beet tops are removed using a defoliator that cuts the tops off along with a very small part of the root crown and distributes the beaten-up leaves on the soil surface. The lifter , which immediately follows the defoliator, lifts the beets from the ground to a truck for shipment to the processor. Distribution of nutrients at sugar beet harvest is different than production of cereal grain and oil seed crops, where most of the plant nutrients move to the grain and seed. When grain and oil seed is harvested, most of the plant nutrients are also removed. In sugar beets, many nutrients, including N, remain in the foliage.
The concept of treating sugar beet tops as a green manure was first reported in France.4 The results of this study showed that sugar beet tops provided significant N to the subsequent crop and should be treated as a green manure crop — a crop that is grown partially to maturity, but is terminated before harvest and all the nutrients returned to the soil for use by the next crop. Organic farmers often use this principle to provide N and other nutrients to subsequent crops to limit the use of commercial fertilizers.

The color of leaves at harvest is related to the amount of N contained within the plant.5–9 Yellow sugar beet tops at harvest suggest that the leaves contain low levels of N, while green tops suggest that the plants contain a substantial amount of N. Leaf color can be used as a basis for N credits from sugar beet. For yellow leaves, no N credit is provided, while for dark green leaves, a credit of 90 kg ha–1 is provided. Remote sensing can be used to assess plant color.

Low-cost LANDSAT data can be purchased by sugar cooperatives. LANDSAT data have a pixel size of approximately 30 m. These data can be processed to produce a number of different products. One of the most popular is the N Difference Vegetation Index (NDVI) ((red–NIR)/(red + NIR)). The imagery that is most useful for assessing residual N is collected between August and October. Imagery closer to harvest is preferred, but due to possible interference by cloud cover, imagery obtained earlier in the summer can be used to increase the chance of a successful image in any given area.

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