Dear Sri Siva,
It is learnt from the Horti Authorities that the rows should be provided in East West direction and trench should be taken in North South direction.
You can go for either Trench system or Pits system, which suits your land well. Both are good.
IIHR recommendations: ( which we are following from years )
take one tractor load of FYM and heap it in a shaded place, with a uniform height of 1 1/2 ft. Add/spread on top 100 kgs of neem cake ( oiled cake ). Mix it well all around and pour sufficient water on top. ( mix should not be watery,water drenching and should be only wet/humid sufficiently.)
Cover the top with wet jute gunny bags.spread little/required water for couple of days and check the bottom mix temperature, which should be normal temp, which is required .
Once the bottom temp is normal, add/mix, each of 2/5 kgs , 1. Trichoderma Viride, Psuedomonas, Paceilomysis and PSB in the above mix, along with 10 kgs of jaggery , which is mixed in water,
and thoroughly mix it again, and cover the mix with wet gunny bags. Spray required water on the top daily and after 10 to 15 days, we will found Fungal/white formation on the inner/bottom side of
the gunny bags. It indicates, the mix is ready for application in the land.
This mix is sufficient for 1 to 3 acres, depends on the crop and soil.
Try to repeat this process , once in 3/6 months, as required. As stated by IIHR, This will take care of All most , soil borne diseases.
We should see that, no drenching of pesticides, like Chloryphyrifos etc and no mixing of Thimmet, Carbofuran 3G,10G in the same land soil. If mixed, the purpose will not be fulfilled.
with best wishes, g.p.rao, farmer