Kalpa: It supports the various systems of yajna, yaaga and People in veda kaala mostly made their living on the banks of rivers and used to pray the nature. vaayu, jalam and agni were considered as the nature gods and by offering them they believed would yield good results. As time passed, they believed that the offerings through agni will yield faster results scientifically. Since carrying agni from place to place would be difficult, they reduced changing their living places frequently and started living at one place permanently, that is how it is believed that the villages, towns were developed. The simple agni aaraadhanaa developed to yajnas and yaagas. The usage of various sooktas from vedas in yaagas also started. From this stage development took place to the requirement of rutviks called, hotaa, adhvaryu, udghaataa and brahmaa. Simultaneously the usage of various homa dravyas developed. During this period to standardize these procedures of yajnas and yaagas, granthas developed. They are called kalpas. Since these granthas were written in soorta type, they are called kalpa sootras. By writing kalpa sootras the procedures have been regularized and became easy to adopt by people of subsequent generations. Kalpa sootras are of 4 types.1. shrauta sootras 2. smaarta sootras 3. gruhya sootras and shulba sootras. smaarta sootras are considered as dharma sootras. kalpa sootras are written by bhadrabaahu. shukla yajurveda sootras are written by kaatyaayana.

1. shrauta sootras: These are based on yajna karma kaandas from braahmana granthas of The 14 types of yajnas from vedas procedures are conducted based on these sootras. Many sootras were said to be present during earlier days. But present time, two are available based on rugveda. 1. aashvalaayana 2. shaankhyaayana. ashvalaayana was the disciple of shaunaka as people believe. shaankhyaayana sootras are concluded as older, based on the linguistic comparison. This is based on shaankhyaayana or also named as kausheetakee braahmana of rugveda and written by suyajna. There are 12 chapters in ashvalaayana and 18 chapters in shaankhyaayana sootras.

shukla yajurveda has kaatyaayana shrauta sootra. It has 26 chapters. There is a karkaachaarya bhaashya on this.

krishna yajurveda has 8 shrauta sootras namely: 1. baudhaayana, 2. aapastamba 3. satyaashaadha or hiranyakeshee 4. vaikhaanasa 5. bhaaradwaja 6. vaadhoola 7. vaaraaha and 8. maanava shrauta sootras.

 baudhaayana considered to be from 800BC and hiranya keshi baudhaayana sootram, also known as satyaashaadha, is older than aapastamba shrauta sootra.

saamaveda samhita has kauthuma samhita, jaimineeya samhita and ranaayaneeya samhita.

atharvaveda has vaitaana shrauta sootraa, from gopatha braahmana.

1. gruhya sootras: These give procedures for doing samskaaras of human, right from birth to death and the various nitya, naimittika kaarya procedures are detailed here. There are 7 types of gruha yajnaas. 1. pitru yajna, 2. paarvana ashtikam, 4. sraavani, 5. aashvayuji, 6. aagrahaayanee, 7. chaitree yajnas-pancha mahaa yajnas-deva, bhoota, pitru, rushi, manushya yajnas and gruha nirmaana, gruhapravesha, travelling/prayaana, etc procedures and shaastra requirements are detailed in these gruhya sootras.

There are two gruhya sootras for the above aashvalaayana and shaankhaayana shaakhaas of rugveda. aashvalaayana has 4 chapters and gives about gruhya samskaaras. shaankaayana has 6 chapters and details about gruha nirmaana and gruha pravesha procedures.

shukla yajurveda has two paraashara, and baijavaapa gruhya sootras.

krishna yajurveda has baudhaayana, aapastamba, hiranya keshi, vaikhaanasa, bhaardwaaja (from taittireeya shaakhaa) and maanava (from maitraayani shaakhaa)-There are totally 6 gruhya sootras. There are also baudhaayna gruhya sootras.

gobhilya gruhya sootra from kauthuma shaakhaa and khaadhira gruhya sootra from ranaayaneeya shaakhaa.

 For atharvaveda, the gruhya sootra is kashika gruhya sootram. In this indrajaala vidyaa is available. aushadha related issues are also discussed.

2. dharma sootras: chaaturvarna dharmas, aashrama dharmas, raaja dharmas are detailed in these sootras.

saama veda has gautama dharma sootra and it is considered old. In this there are 28 chapters.  In this nitya karma, raaja dharma, varna dharma, and praayashchitta karma procedures are given.

krishna yajur veda has baudhaayana dharma sootra which is older than aapastamba dharma sootra but later to gautama.

In Andhra Pradesh and Telangana, there are many followers of aapastamba sootra. People consider that aapastamba is from Andhra area. Also, it is believed that people from Andhra godaavari area, came from yamunaa river area and settled long back.

 In aapastamba dharma shaastra some procedures are not there which are followed by paanini.  Hence aapastamba is considered as earlier than paanini.

3. shulbha sootras: The Geometrical procedures to be adopted during yajnas and yaagas are detailed in these sootras. Just as in the case of other above sootras shulba sootras were said to be there for all veda shaakas. But only shulba sootras concerning to vaidika karma kaanda of yajurveda are available now.

For shulka yajurveda only kaatyaayana shulba sootra is available.

For krishna yajurveda -bodhaayana, aapastamba, maanava, maitraayaneeya, vaaraaha, vaadhula shulba sootraah are available.

baudhaayana shulba sootra is vaster and contains the procedures to prepare yajna vedikas, geometrical rules and procedure to make homa kundas, and various diversities are discussed.

Out of all sootrakaaras bodhaayana, aapastamba and vashishta are considered prominent.

First three vedaangas including praatishaakhyas, protect the veda shabda whereas last three vedaangas give the interpretation of veda shabda and procedures for implementation.

 The details written above about vedaangas is taken from the grantha “samskruta saahitya charitra” by Achaarya A. Ramulu, Samskruta Professor and HOD of OU. Written in Telugu.