Making tables with lots of footnotes and aligning the caption

Question

I learnt Latex last month and am trying to write a large document with it. I have managed the text and figures, but not tables. Although my table is centered, I would like my caption to begin along with the first cell of the table rather than the full left indent like a normal paragraph.

I also have many footnotes which pertain to the whole table rather than specific parts of the table. I tried using \tablefootnote, but no text seems to appear. Also, I don't want the numbers, just the text.

\documentclass[a4paper, oneside]{book}
\usepackage[left=35mm, right=15mm, top=20mm, bottom=15mm]{geometry}
\usepackage{setspace}
\usepackage{fixltx2e}
\usepackage{graphicx}
\usepackage{float}
\usepackage{tabularx}
\usepackage{amssymb}
\usepackage{booktabs} % For \toprule, \midrule and \bottomrule
\usepackage{pgfplotstable} % Generates table from .csv
\usepackage{longtable}    %Allows multi-page tables
\usepackage{rotating}     %Allows for single page landscape using \sidewaystable{}
\usepackage{pdflscape}     %Allows for landscape
\usepackage{multirow}      %Allows for merging across rows
\usepackage{tablefootnote} 
\usepackage{footnote}

\begin{document}

\begin{table}[h!]
\begin{center}
\caption{Proximate phenolic and carbohydrate content}
\label{Table4}
 \begin{tabular}{c c c c c c c} 
 \toprule
 &\multicolumn{2}{c}{\textbf{Leaf}}& &\multicolumn{2}{c}{\textbf{Roots}}\\
\cline{2-3}\cline{5-6} 
 \textbf{Plant} & \textbf{Colour} & \textbf{Density} &  &\textbf{Colour} & \textbf{Density}\\
 \midrule
 Sample1&26.1$\pm$0.7$^{c}$ &172.3$\pm$9.0& & 25.5$\pm$6.8$^{b}$&83.7$\pm$4.5$^{a}$\\
 Sample2&53.9$\pm$2.0$^{d}$&129.5$\pm$3.2& &29.4$\pm$4.8$^{b}$&11.7$\pm$1.8\\
 Sample3&32.5$\pm$3.2$^{c}$&163.3$\pm$6.5& &96.8$\pm$18.1&64.4$\pm$1.3\\
 Sample4&54.2$\pm$2.3$^{d}$&82.6$\pm$7.5& &28.9$\pm$3.0$^{b}$&35.7$\pm$1.2\\
 Sample5&28.4$\pm$3.9$^{c}$&172.1$\pm$6.3& &26.9$\pm$5.1$^{b}$&78.8$\pm$2.8$^{a}$\\
 Sample6&50.0$\pm$2.0$^{d}$&112.3$\pm$5.3& &54.1$\pm$5.7&48.1$\pm$7.1\\
 \bottomrule
\end{tabular}
\end{center}
\footnotesize{Values expressed in \%(mg.mg$^{-1}$)}\\
\footnotesize{Values with same superscript are statistically similar (OW-ANOVA,p \textless 0.01)}\\
\footnotesize{NSP=Non-starch polysaccahride}
\end{table}

\end{document}

I tried to be clever, but didn't work for the second caption:

\begin{table}[h!]
\begin{center}
\caption{Proximate phenolic and carbohydrate content}
\label{Table4}
 \begin{tabular}{c c c c c c c} 
 \toprule
 &\multicolumn{2}{c}{\textbf{Leaf}}& &\multicolumn{2}{c}{\textbf{Roots}}\\
\cline{2-3}\cline{5-6} 
 \textbf{Plant} & \textbf{Colour} & \textbf{Density} &  &\textbf{Colour} & \textbf{Density}\\
 \midrule
 Sample1&26.1$\pm$0.7$^{c}$ &172.3$\pm$9.0& & 25.5$\pm$6.8$^{b}$&83.7$\pm$4.5$^{a}$\\
 Sample2&53.9$\pm$2.0$^{d}$&129.5$\pm$3.2& &29.4$\pm$4.8$^{b}$&11.7$\pm$1.8\\
 Sample3&32.5$\pm$3.2$^{c}$&163.3$\pm$6.5& &96.8$\pm$18.1&64.4$\pm$1.3\\
 Sample4&54.2$\pm$2.3$^{d}$&82.6$\pm$7.5& &28.9$\pm$3.0$^{b}$&35.7$\pm$1.2\\
 Sample5&28.4$\pm$3.9$^{c}$&172.1$\pm$6.3& &26.9$\pm$5.1$^{b}$&78.8$\pm$2.8$^{a}$\\
 Sample6&50.0$\pm$2.0$^{d}$&112.3$\pm$5.3& &54.1$\pm$5.7&48.1$\pm$7.1\\
 \bottomrule
\end{tabular}
\end{center}
\begin{tabular}
\footnotesize{Values expressed in \%(mg.mg$^{-1}$)}\\
\footnotesize{Values with same superscript are statistically similar (OW-ANOVA,p \textless 0.01)}\\
\footnotesize{NSP=Non-starch polysaccahride}
\end{tabular}
\end{table}

Would this solution work in landscape format? I have tables of that variety as well

Answer 1

Here is my suggestion using threeparttable for the tablenotes. The caption alignment is also done with threeparttable in combination with an appropriate captionsetup. In order to improve the alignment of the numbers in the table, I have added the siunitx package:

\documentclass[a4paper, oneside]{book}
\usepackage[left=35mm, right=15mm, top=20mm, bottom=15mm]{geometry}
\usepackage{setspace}
\usepackage{fixltx2e}
\usepackage{graphicx}
\usepackage{float}
\usepackage{tabularx}
\usepackage{amssymb}
\usepackage{booktabs} % For \toprule, \midrule and \bottomrule
\usepackage{pgfplotstable} % Generates table from .csv
\usepackage{longtable}    %Allows multi-page tables
\usepackage{rotating}     %Allows for single page landscape using \sidewaystable{}
\usepackage{pdflscape}     %Allows for landscape
\usepackage{multirow}      %Allows for merging across rows
\usepackage{tablefootnote} 
\usepackage{footnote}

\usepackage{threeparttable}
\usepackage{caption}
\captionsetup{singlelinecheck=false}
\usepackage{siunitx}
\sisetup{input-uncertainty-signs=\pm, 
         separate-uncertainty=true}
        
\begin{document}

\begin{table}[h!]
\centering
\begin{threeparttable}
\caption{Proximate phenolic and carbohydrate content}
\label{Table4}
\sisetup{table-format=2.1(3), 
         table-space-text-post=\tnote{a}, 
         table-align-text-post=false}
 \begin{tabular}{l S S S S} 
 \toprule
 &\multicolumn{2}{c}{\textbf{Leaf}}& \multicolumn{2}{c}{\textbf{Roots}}\\
\cmidrule(r){2-3}\cmidrule(l){4-5} 
 {\textbf{Plant}} & {\textbf{Colour}} & {\textbf{Density}} & {\textbf{Colour}} & {\textbf{Density}}\\
 \midrule
 Sample1 & 26.1 \pm 0.7\tnote{c} & 172.3 \pm 9.0 & 25.5 \pm 6.8\tnote{b} & 83.7 \pm 4.5\tnote{a} \\
 Sample2 & 53.9 \pm 2.0\tnote{d} & 129.5 \pm 3.2 & 29.4 \pm 4.8\tnote{b} & 11.7 \pm 1.8          \\
 Sample3 & 32.5 \pm 3.2\tnote{c} & 163.3 \pm 6.5 & 96.8 \pm 18.1         & 64.4 \pm 1.3          \\
 Sample4 & 54.2 \pm 2.3\tnote{d} & 82.6  \pm 7.5 & 28.9 \pm 3.0\tnote{b} & 35.7 \pm 1.2          \\
 Sample5 & 28.4 \pm 3.9\tnote{c} & 172.1 \pm 6.3 & 26.9 \pm 5.1\tnote{b} & 78.8 \pm 2.8\tnote{a} \\
 Sample6 & 50.0 \pm 2.0\tnote{d} & 112.3 \pm 5.3 & 54.1 \pm 5.7          & 48.1 \pm 7.1          \\
 \bottomrule
\end{tabular}
\footnotesize
Values expressed in \%(mg.mg$^{-1}$)

Values with same superscript are statistically similar (OW-ANOVA,p \textless 0.01)
 
NSP=Non-starch polysaccharide
\end{threeparttable}
\end{table}



\end{document}