已知等差数列\(\{a_{n}\}\) 的前\(n\)项和为\(S_{n}\)，\(a_{1}=λ\) \((\) \(λ > 0\) \()\)，\(a_{n+1}=2 \sqrt {S_{n}}+1\) \((n∈N*)\)．
\((I)\)求 \(λ\) 的值；
\((II)\)求数列\(\{ \dfrac {1}{a_{n}a_{n+1}}\}\) 的前 \(n\)项和\(T_{n}\)．