node_save JSON field formats
It's important to understand that the Services module is closely tied to the Drupal Forms API, meaning that the JSON delivered via POST/PUT is sometimes dependent on the Widget that is selected for the field(s) in question, so it won't always match what is delivered via GET.

That being said, I can see some problems with your JSON. Try these instead:

integer, text field

"field_scrap_weight": {
  "und": [ { "value": "1" } ] 
},


node reference

"field_surplus_location": {
  "und": [ { "target_id":"... (256)" } ]
},


long text w/summary, text area widget

"body": {
  "und": [ {
    "value": "dd"
  } ]
}


Often times it appears you are missing the wrapping [], this indicates the delta value for the field's item, i.e. it's an array so you can pile up extra values if your field is configured for more than 1 value.

The entity reference field can be any text, but the target id must be wrapped in the parenthesis.

The Date field is the trickiest and I would advise looking at the following answers:


https://drupal.stackexchange.com/a/78925/10645
https://drupal.stackexchange.com/a/180101/10645
https://www.drupal.org/node/1898072


If you're looking to POST/PUT exactly what is delivered via GET, then check out the Services Entity module and this extra configuration that can be added to jDrupal.