For agricultural use, long range wireless connectivity is a hard requirement. The Vinduino-R remote sensor board can use the ESP8266 wifi module for short distance, as well as affordable APC modules made by Shenzhen-based company Appcon, for longer range.

You need 2 Appcon modules for a radio link. One at the host, and one at the remote node side.
It's a simple set up: serial data in = serial data out. Multi-node networks can be achieved by timed transmission slots, this is more energy efficient than a mesh network where all stations are continuously operating.

Replacing the default antenna with a "real" antenna gives an instantaneous range increase. Even a quarter wave length wire doubles the range. The popular APC220 operates at 433 MHz, which is not allowed as license-free ISM (Industry, Scientific, Medical) operating frequency in the USA. In Europe and other countries it's OK tho use this frequency, though.

Alternative Appcon modules that use the allowed 915 MHz USA ISM band are APC320 and the more powerful APC340, which also uses secure spread spectrum. I have no information about FCC approval for these modules.

The APC220 can work with 5V supply voltage, APC320 and 340 require 3.3V. The Vinduino-R board has a header that is pin compatible with all APC modules, and has a LDO and power selection strap to set the correct voltage.

Below is an overview of available modules with their high level specifications.