from the simple model presented here. The objective is not to analyze the determinants of soil quality but rather to determine how well subjective measures of soil quality predict true measures (as proxied by laboratory results). The models are first run with individual subjective indicators in order to identify how well each variable predicts the index score independently, then with all subjective variables, in order to analyze the predictive power of the subjective indicators as a whole. Note that subjective soil texture was included rather than type, as the “other, specify” category of the soil type question consisted primarily of soil colors and as such, correlation between soil type and color was a concern.

Results of the regression analysis are presented in Table 5. Immediately evident is the low explanatory power of the subjective indicators of soil quality, as expressed by the R<sup>2</sup> , which ranges from 0.002 to 0.060. Specifications (1), (2), and (3), which look at the individual subjective indicators separately, suggest that soil color explains more of the variation in the soil quality indices and carbon content than do the subjective questions on overall quality and texture. The direction of the coefficients on _red_ and _white/light_ soils are as expected – they have a lower soil quality index score or organic carbon content than black soils. Coarse soils would be expected to have lower levels of nutrient availability, and therefore greater soil fertility, and this is reflected in the results, albeit with limited magnitude in the WA SQI model.

The descriptive analysis on the subjective assessment of overall soil quality invoked little confidence in its relationship with objective soil quality, at least in this particular sample. This sentiment is reflected in the regression analysis. The subjective assessment of overall soil quality had no significant relationship with the WA SQI when self-reported soil color and texture were controlled for. In the model on the SA

**_Table 5._** _SQI Regression Analysis, No Fixed Effects_

|_Dependent Variable:_||SA|SQI|||WA S|QI|||Organic C|arbon(%)||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|_Specification:_|(1)|(2)|(3)|(4)|(1)|(2)|(3)|(4)|(1)|(2)|(3)|(4)|
|self-reported soil quality|||||||||||||
|fai~~r~~<br>poo~~r~~|-0.024<br>-0.375*|||0.138*<br>-0.011|~~-~~0.009**<br>~~-~~0.017**|||-0.002<br>-0.005|0.003<br>-0.265**|||0.143**<br>0.023|
|self-reported color|||||||||||||
|re~~d~~<br>(collapsed, 'black' omitted)||-0.623***||-0.640***||-0.033***||-0.032**~~*~~||-0.570***||-0.588***|
|white/ligh~~t~~||-0.889***||-0.866***||-0.027***||-0.025**~~*~~||-0.609***||-0.586***|
|self-reported soil texture|||||||||||||
|(collapsed, 'fine' ommitted)|||||||||||||
|between coarse and fin~~e~~|||-0.067|-0.02|||-0.008*|-0.005|||-0.054|-0.022|
|coars~~e~~|||-0.428***|-0.239*|||-0.015**|-0.009|||-0.379***|-0.265**|
|constant|~~4~~.640***|5.039***|4.675***|5.001***|~~0~~.461***|0.475***|0.460***|0.478**~~* ~~|3.364***|3.712***|3.409***|3.674***|
|N|1677|1677|1677|1677|1677|1677|1677|1677|1677|1677|1677|1677|
|R<sup>2</sup>|0.002|0.048|0.006|0.052|0.005|0.041|0.004|0.043|0.002|0.053|0.008|0.060|
|Independent Var Mean~~:~~||4.|61|||0.46||||3.|35||
|Independent Var. Std Dev~~:~~<br>||1.|59|||0.08||||1.|22||

Robust standard errors. *** p<0.01, ** p<0.05, * p<0.1 21