Variable declaring problem

Tanks. I will not use 10 sensor in the future because with 6 sensor all pin of the 328 is used but could you make me an example of your "constant value line numSoilSamples that is equal to 6" because i think i don't understand.

this is the modified code:

#include <EasyTransfer.h>

//create object
EasyTransfer ET; 

struct SEND_DATA_STRUCTURE{
  //put your variable definitions here for the data you want to send
  //THIS MUST BE EXACTLY THE SAME ON THE OTHER ARDUINO
  int soil[7];

};

//give a name to the group of data
SEND_DATA_STRUCTURE mydata;

void setup(){
  Serial.begin(9600);
  //start the library, pass in the data details and the name of the serial port. Can be Serial, Serial1, Serial2, etc.
  ET.begin(details(mydata), &Serial);

  for(int i=2;i<14;i++){
    pinMode(i,OUTPUT);
    digitalWrite(i, LOW);
  }

  for(int i=0;i<6;i++){
    pinMode(i,INPUT);
  }

}

void loop(){
  //send the data
  for (int i=0;i<6;i++){
    sensorRead(i);
    ET.sendData();
    
  }
}

void sensorRead(int sensor){
  digitalWrite(sensor*2, HIGH);
  digitalWrite(sensor*2+1, LOW);
  delay(1000);
  int val1 = analogRead(sensor-1);
  digitalWrite(sensor*2, LOW);
  digitalWrite(sensor*2+1, HIGH);
  delay(1000);
  int val2 = 1023 - analogRead(sensor-1);
  mydata.soil[sensor] = (val1 + val2) / 2;
  digitalWrite(sensor*2, LOW);
  digitalWrite(sensor*2+1, LOW);
}