What value of sodium adsorption ratio would classify soil as sodic?Group of answer choices210Above 135

To determine the classification of soil as sodic based on the Sodium Adsorption Ratio (SAR), it's important to understand the properties of SAR in soil science. The SAR is a measure of the degree to which sodium displaces other cations such as calcium and magnesium on the soil exchange sites. High levels of sodium can lead to soil dispersion and degradation, affecting its structure and fertility.

Typically, the SAR value helps categorize soil into different types which are crucial for agricultural and environmental management. Based on common classification systems, soils with a SAR greater than 13 are generally considered sodic.

Considering the options presented:

1. 210: This is significantly above the threshold for sodicity.
2. Above 135: This option is less clear, as it suggests a higher range, but does not specify a minimum SAR value.

Given this information, a SAR value above 13 is typically used for classification as sodic soil. Therefore, both options of 210 and Above 135 would classify the soil as sodic. However, the option of 210 more definitively indicates highly sodic soil compared to Above 135.

Final Answer

The value of sodium adsorption ratio that would classify soil as sodic is above 13, which includes both choices provided (210 and Above 135).