farmOS/modules/farm/farm_crop/farm_crop.module

<?php
/**
 * @file
 * Code for the Farm Crop feature.
 */

include_once 'farm_crop.features.inc';

/**
 * Implements hook_help().
 */
function farm_crop_help($path, $arg) {

  // View of Plantings.
  if ($path == 'farm/assets/plantings') {
    return t('Plantings can be used to represent groups of plants (eg: a field of corn, or a group of seedlings), or they can be used to represent individual plants (eg: in the case of nurseries). For more information, see the <a href="@plantings_doc_url">Plantings</a> documentation.', array('@plantings_doc_url' => url('https://farmOS.org/guide/assets/plantings')));
  }

  // View of Seedings.
  elseif ($path == 'farm/logs/seedings') {
    return t('Seeding logs represent when <a href="@plantings_url">Planting assets</a> are seeded directly into the ground (or into containers). For more information, see the <a href="@plantings_doc_url">Plantings</a> documentation.', array('@plantings_url' => url('farm/assets/plantings'), '@plantings_doc_url' => url('https://farmOS.org/guide/assets/plantings')));
  }

  // View of Transplantings.
  elseif ($path == 'farm/logs/transplantings') {
    return t('Transplanting logs represent when <a href="@plantings_url">Planting assets</a> are transplanted from one place to another. For more information, see the <a href="@plantings_doc_url">Plantings</a> documentation.', array('@plantings_url' => url('farm/assets/plantings'), '@plantings_doc_url' => url('https://farmOS.org/guide/assets/plantings')));
  }
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function farm_crop_form_farm_asset_form_alter(&$form, &$form_state, $form_id) {

  // Get the farm asset entity from the form.
  $asset = $form['farm_asset']['#value'];

  // If the asset is not a planting, bail.
  if (empty($asset->type) || $asset->type != 'planting') {
    return;
  }

  // If this is a new planting form, display a link to the planting quick form
  // for convenience.
  if (!empty($form['farm_asset']['#value']->is_new)) {
    drupal_set_message(t('Tip: Use the <a href="@path">Planting Quick Form</a> to quickly record a planting and create seedings and other logs associated with it in one step.', array('@path' => url('farm/quick/planting'))));
  }
}

/**
 * Implements hook_farm_ui_entities().
 */
function farm_crop_farm_ui_entities() {
  return array(
    'farm_asset' => array(
      'planting' => array(
        'label' => t('Planting'),
        'label_plural' => t('Plantings'),
        'view' => 'farm_plantings',
      ),
    ),
    'log' => array(
      'farm_seeding' => array(
        'label' => t('Seeding'),
        'label_plural' => t('Seedings'),
        'view' => 'farm_log_seeding',
        'farm_asset' => 'planting',
        'weight' => -90,
      ),
      'farm_transplanting' => array(
        'label' => t('Transplanting'),
        'label_plural' => t('Transplantings'),
        'view' => 'farm_log_transplanting',
        'farm_asset' => 'planting',
        'weight' => -80,
      ),
    ),
    'taxonomy_term' => array(
      'farm_crops' => array(
        'label' => t('Crop/variety'),
        'label_plural' => t('Crops/varieties'),
        'view' => 'farm_crops',
        'farm_asset' => 'planting',
        'asset_view_arg' => 2,
      ),
      'farm_crop_families' => array(
        'label' => t('Crop Family'),
        'label_plural' => t('Crop Families'),
      ),
    ),
  );
}

/**
 * Implements hook_farm_ui_entity_views().
 */
function farm_crop_farm_ui_entity_views($entity_type, $bundle, $entity) {
  $views = array();

  // If the entity is a taxonomy_term...
  if ($entity_type == 'taxonomy_term') {
    switch ($entity->vocabulary_machine_name) {

      // Farm crop family.
      case 'farm_crop_families':
        $views[] = 'farm_crops';
        break;
    }
  }

  return $views;
}

/**
 * Implements hook_farm_log_categories().
 */
function farm_crop_farm_log_categories() {

  // Provide an "Plantings" log category.
  return array('Plantings');
}

/**
 * Implements hook_farm_log_categories_populate().
 */
function farm_crop_farm_log_categories_populate($log) {
  $categories = array();
  if (in_array($log->type, array('farm_seeding', 'farm_transplanting'))) {
    $categories[] = 'Plantings';
  }
  return $categories;
}

/**
 * Implements hook_feeds_importer_default_alter().
 */
function farm_crop_feeds_importer_default_alter(&$importers) {

  // Add extra field mappings to plantings.
  $name = 'farm_asset_planting';
  if (!empty($importers[$name])) {
    $mappings = array(
      array(
        'source' => 'Crop/variety',
        'target' => 'field_farm_crop',
        'term_search' => '0',
        'autocreate' => 1,
        'language' => 'und',
      ),
      array(
        'source' => 'Season',
        'target' => 'field_farm_season',
        'term_search' => '0',
        'autocreate' => 1,
        'language' => 'und',
      ),
    );
    $importer_mappings =& $importers[$name]->config['processor']['config']['mappings'];
    $importer_mappings = array_merge($importer_mappings, $mappings);
  }

  // Add extra field mappings to seedings.
  $name = 'log_farm_seeding';
  if (!empty($importers[$name])) {
    $mappings = array(
      array(
        'source' => 'Source/supplier',
        'target' => 'field_farm_seed_source',
        'unique' => FALSE,
        'language' => 'und',
      ),
    );
    $importer_mappings =& $importers[$name]->config['processor']['config']['mappings'];
    $importer_mappings = array_merge($importer_mappings, $mappings);
  }
}

/**
 * Implements hook_feeds_tamper_default_alter().
 */
function farm_crop_feeds_tamper_default_alter(&$feeds_tampers) {

  // If farm_import is not installed, bail.
  if (!module_exists('farm_import')) {
    return;
  }

  // Make crop/variety required.
  $feeds_tamper = farm_import_feeds_tamper_plugin('farm_asset', 'animal', 'Crop/variety', 'required');
  $feeds_tampers[$feeds_tamper->id] = $feeds_tamper;

  // Explode crop/variety so it supports multiple values, and trim whitespace.
  $feeds_tamper = farm_import_feeds_tamper_plugin('farm_asset', 'planting', 'Crop/variety', 'explode');
  $feeds_tampers[$feeds_tamper->id] = $feeds_tamper;
  $feeds_tamper = farm_import_feeds_tamper_plugin('farm_asset', 'planting', 'Crop/variety', 'trim');
  $feeds_tampers[$feeds_tamper->id] = $feeds_tamper;
}