In the holy Quran, paying zakat has been mentioned at 32 places whereas khums is mentioned once only however maulanas stress more on khums.
What do you say?

First of all I wish to tell you that the term zakat used in Quran is a vast term and can be taken in two meanings; general and specific. In general term, zakat belongs to any kind of charity and help to poor and needy people and it may be obligatory or recommended but zakat in a specific term is used only for obligatory charity which has it's own terms and conditions; those are mentioned in "Tauzeehul Masail". Zakat is obligatory on nine things, in which Gold and silver are completely excluded in this era due to it's term and conditions in our fiqh and the others things are dependent to have an immovable property like agricultural land or orchard and a few other things are dependent upon having animal husbandry etc. Therefore obligatory zakat doesn't relate to or become obligatory for general public rather khums belongs to the general public domain comparatively to the obligatory zakat because it becomes obligatory on money saving at the end of every year. Therefore it's generally more emphasized to pay by people even though it's mentioned only once in the Holy Quran. Apart from it, Khums has basically six parts, Three of them are for Allah, Holy Prophet (pbuh) and his progeny (pbut) and the other three parts are peculiar for a very poor class of the comuunity, traveler and orphans. So the first three parts of khums now belong to the master of our time (a.j.) and in his absence to his general representatives (Maraje) and our maraje spend it in socio-religious activities to make firm and save the foundations of religion. Yes of course, it should be emphasized to pay the recommended zakat (like mustahab sadqa) and generally people are already doing this by their own interest Alhmdulillah. so Ulama don't feel a need to emphasize on recommended deed as much as obligatory deed like khums.