In west Texas, cotton has become an important crop in the last several decades. However, in this hot, dry part of the country there is little rainfall, so farmers irrigate their cotton fields. They must also regularly fertilize the cotton fields because the soil is very sandy. Figure 37.2 shows the record of annual productivity (measured in kilograms of cotton per hectare of land) since 1960 in a west Texas cotton field. Use these data to answer the following questions.

Figure 37.2
-Based on the information provided in Figure 37.2, what is the most likely cause of the decline in productivity?

Question

In west Texas, cotton has become an important crop in the last several decades. However, in this hot, dry part of the country there is little rainfall, so farmers irrigate their cotton fields. They must also regularly fertilize the cotton fields because the soil is very sandy. Figure 37.2 shows the record of annual productivity (measured in kilograms of cotton per hectare of land) since 1960 in a west Texas cotton field. Use these data to answer the following questions.
  
Figure 37.2
-Based on the information provided in Figure 37.2, what is the most likely cause of the decline in productivity?

Quizplus · Accepted Answer

The decline in productivity is likely due to salination, as indicated by the increasing soil water potential. Salination occurs when irrigation water contains soluble salts that accumulate in the soil over time and reduce the water potential of the soil, making it more difficult for plants to absorb water. This in turn can lead to decreased productivity. The other answer choices are less likely explanations, as there is no indication in the graph of resistance to fertilizer or water, or of water accumulation in the soil. Additionally, the decline in productivity is unlikely to be solely due to irrigation, as the use of irrigation is necessary for cotton production in this region.

In West Texas, Cotton Has Become an Important Crop in the Last