Prithvi or Earth is also regarded as mother to humans as prithvi supports and secures humans and living organisms on it.

But now the question arises why mother? Why not father? Usually in puranic descriptions Creation is associated with Males and support and development of that creation is associated with the females.

(Q)But Puranic texts also convey more importance to females than males then why is that so?

The reason is creation requires less time and effort.

But its sustenance and development requires more time as well as more effort. This thing makes sense practically as well as technically. The biggest example is of human reproduction. The male has his actual effort for reproduction for some time, but

female supports and sustains the child for 9 months approx. thus females have more importance.

In the same way Earth does not creates Humans practically but creates such environment and conditions which enables their sustenance. Thus Earth is called as mother.

-First statement is Used by Indian Author Devdutt Pattanaik 

                    The word Prithvi ( पृथ्वी ) means  the Vast One. Prithvi is in the sets of devas (divine one). Her Abode is considered to be Vaikuntha as she is described as consort of Sri Vishnu.

Pruthvi is also considered to be physical form of Lakshmi devi.

Her abode is also considered as earth itself as she is described as Cow in many texts. So we can summarize entire Earth to be present in cows. It is assumed that Each and every complex element (basics as per ayurved are present in a cow such as: 1.Agni, 2.Vayu, 3.Indra, 4.Vishnu,etc in many forms agni as a form of heat, vayu as a fom of sound, Indra as a form of indri or nervous system, etc)

Her consorts are Sri Vishnu and Dyaus Pitr (द्यौष्पितृ) (He is also assumed to be physical form of vishnu). She has many children but the most described children are Sita (consort of Sri Ram) And Mangal (Mars). This statement tells us that mars is derived from earth. 
Now mars has been derived from earth so the purans describe mars has been formed after earth and from the material of earth itself.

                  As Pṛthvī Mātā (“Mother Earth”) she is complementary to Dyaus Pita (“Father Sky”). In the Rigveda, Earth and Sky are primarily addressed in the dual as Dyavapṛthivi. She is associated with the cow. Prithu, an incarnation of Vishnu, milked her in cow’s form.

                             Prithvi is always associated to be the Provider, sustainer and enricher. Due to these qualities Prithvi has many names, these names describes the mother like qualities of prithvi. The names are as follows:

The quality of provider:

Names	Meaning
Bhumi	Soil
Dharti	Nurturing Mother
Dharitri	Nurturer
Janitra	Birthplace
Medini	Nurturer
Prshni	Mother of Plants
Vanaspatinam Grbhir Osadhinam	Womb of Forest Trees and Herbs
Vishvadhaya	All-Nourishing
Vishvagarbha	World’s Womb
Vishvamshu	Producer of Everything
Vishvasvam	Source of Everything

The quality of provider:

Names	Meaning
Dhar	Upholder
Drdha	Steady One
Ksama	Patient One
Sthavara	Stable One
Vishdava	All-Preserving
Vishvadharini	All-Supporting
Vishvamhara	All-Bearing

The quality of provider:

Names	Meaning
Ratnagarbha	Repository of Gems
Ratnavati	Abounding in Jewels
Vasundhara	Bearer of Treasure