Gobhilagrihyasutra 1.4.29

1.4.29

svayaṃ tv evā ''sasyaṃ baliṃ hared yavebhyo 'dhy ā vrīhibhyo, vrīhibhyo 'dhy ā yavebhyaḥ; sa tv āsasyo nāma balir bhavati:

He himself, however, should offer the Âsasya Bali, from the barley(-harvest) till the rice(-harvest), and from the rice(-harvest) till the barley(-harvest). This is called the Âsasya Bali.
This Bali is called â-sasya, because it is offered until (â) the next crop (sasya) is ripe. As to the regulation that the sacrificer has to offer it himself, compare above, Sûtras 15-19.