{"id":13022,"date":"2018-07-06T10:59:05","date_gmt":"2018-07-06T14:59:05","guid":{"rendered":"https:\/\/mundoagro.cl\/?post_type=columnas&p=13022"},"modified":"2020-07-06T17:34:30","modified_gmt":"2020-07-06T21:34:30","slug":"sin-miedo-al-frio","status":"publish","type":"post","link":"https:\/\/mundoagro.cl\/sin-miedo-al-frio\/","title":{"rendered":"Sin miedo al fr\u00edo"},"content":{"rendered":"

Se llama heladas a\u00a0 la\u00a0 exposici\u00f3n\u00a0 a\u00a0 temperatura\u00a0 del\u00a0 aire\u00a0 igual\u00a0 o\u00a0 menor\u00a0 a\u00a0 cero\u00a0 cent\u00edgrados,\u00a0 frente\u00a0 a\u00a0 la\u00a0 que\u00a0 el\u00a0 agua\u00a0 se\u00a0 congela.\u00a0 Heladas\u00a0 intensas\u00a0 por\u00a0 extenso\u00a0 per\u00edodo\u00a0 de\u00a0 tiempo\u00a0 pueden\u00a0 causar\u00a0 da\u00f1o\u00a0 en\u00a0 tejidos\u00a0 vegetales\u00a0 sensibles.\u00a0 Para\u00a0 frutales,\u00a0 esta\u00a0 combinaci\u00f3n\u00a0 ocurre\u00a0 en\u00a0 primavera,\u00a0 con\u00a0 condiciones\u00a0 meteorol\u00f3gicas\u00a0 inestables\u00a0 en\u00a0 el\u00a0 momento\u00a0 en\u00a0 que\u00a0 los\u00a0 tejidos\u00a0 vegetales\u00a0 est\u00e1n\u00a0 m\u00e1s\u00a0 tiernos\u00a0 y\u00a0 expuestos\u00a0 (floraci\u00f3n\u00a0 y\u00a0 cuaja).\u00a0 En\u00a0 las\u00a0 \u00faltimas\u00a0 temporadas,\u00a0 ha\u00a0 prevalecido\u00a0 la\u00a0 incertidumbre\u00a0 acerca\u00a0 de\u00a0 la\u00a0 ocurrencia\u00a0 de\u00a0 heladas\u00a0 que\u00a0 puedan\u00a0 causar\u00a0 da\u00f1o\u00a0 a\u00a0 huertos\u00a0 frutales.\u00a0 Heladas\u00a0 importantes,\u00a0 por\u00a0 magnitud\u00a0 y\u00a0 duraci\u00f3n,\u00a0 ocurrieron\u00a0 en\u00a0 septiembre\u00a0 de\u00a0 2013,\u00a0 cuando\u00a0 afectaron\u00a0 carozos,\u00a0 perales\u00a0 y\u00a0 vides\u00a0 en\u00a0 O\u2019Higgins,\u00a0 y\u00a0 kiwis\u00a0 en\u00a0 El\u00a0 Maule.\u00a0 En\u00a0 octubre\u00a0 de\u00a0 2014\u00a0 se\u00a0 registr\u00f3\u00a0 una\u00a0 helada\u00a0 de\u00a0 menor\u00a0 magnitud,\u00a0 pero\u00a0 con\u00a0 manzanos\u00a0 reci\u00e9n\u00a0 cuajados\u00a0 en\u00a0 El\u00a0 Maule,\u00a0 y\u00a0 una\u00a0 serie\u00a0 de\u00a0 heladas\u00a0 en\u00a0 los\u00a0 primeros\u00a0 d\u00edas\u00a0 de\u00a0 septiembre\u00a0 de\u00a0 2016\u00a0 afect\u00f3\u00a0 a\u00a0 cerezos\u00a0 con\u00a0 avanzada\u00a0 fenolog\u00eda,\u00a0 tambi\u00e9n\u00a0 en\u00a0 El\u00a0 Maule.\u00a0 Esto\u00a0 evidencia\u00a0 la\u00a0 necesidad\u00a0 de\u00a0 conocer\u00a0 el\u00a0 fen\u00f3meno\u00a0 de\u00a0 la\u00a0 helada\u00a0 y\u00a0 su\u00a0 efecto\u00a0 sobre\u00a0 los\u00a0 frutales,\u00a0 como\u00a0 las\u00a0 diferentes\u00a0 alternativas\u00a0 de\u00a0 control,\u00a0 para\u00a0 enfrentar\u00a0 estas\u00a0 situaciones\u00a0 con\u00a0 el\u00a0 mayor\u00a0 acierto.<\/p>\n

TIPOS\u00a0 DE\u00a0 HELADA<\/p>\n

\"sin<\/a>Son\u00a0 dos\u00a0 los\u00a0 tipos\u00a0 de\u00a0 heladas\u00a0 que\u00a0 afectan\u00a0 a\u00a0 la\u00a0 agricultura\u00a0 chilena:\u00a0 helada\u00a0 por\u00a0 radiaci\u00f3n\u00a0 y\u00a0 helada\u00a0 de\u00a0 advecci\u00f3n\u00a0 o\u00a0 polar.\u00a0 La\u00a0 helada\u00a0 radiativa\u00a0 se\u00a0 produce\u00a0 por\u00a0 p\u00e9rdida\u00a0 de\u00a0 energ\u00eda\u00a0 desde\u00a0 el\u00a0 suelo\u00a0 a\u00a0 la\u00a0 atm\u00f3sfera\u00a0 durante\u00a0 la\u00a0 noche.\u00a0 \u00c9stas\u00a0 son\u00a0 t\u00edpicas\u00a0 de\u00a0 condiciones\u00a0 postfrontales\u00a0 en\u00a0 invierno,\u00a0 dadas\u00a0 por\u00a0 d\u00edas\u00a0 despejados,\u00a0 sin\u00a0 viento\u00a0 y\u00a0 baja\u00a0 humedad\u00a0 relativa.\u00a0 La\u00a0 temperatura\u00a0 de\u00a0 dichas\u00a0 heladas\u00a0 no\u00a0 suelen\u00a0 ser\u00a0 menor\u00a0 a\u00a0 -3\u00b0C\u00a0 y\u00a0 no\u00a0 influye\u00a0 m\u00e1s\u00a0 all\u00e1\u00a0 de\u00a0 los\u00a0 primeros\u00a0 tres\u00a0 metros\u00a0 de\u00a0 altura.\u00a0 Por\u00a0 otro\u00a0 lado,\u00a0 las\u00a0 heladas\u00a0 advectivas\u00a0 son\u00a0 masas\u00a0 de\u00a0 aire\u00a0 fr\u00edo\u00a0 que\u00a0 se\u00a0 desplazan\u00a0 desde\u00a0 el\u00a0 Polo\u00a0 Sur.\u00a0 Al\u00a0 contrario\u00a0 de\u00a0 las\u00a0 heladas\u00a0 radiativas,\u00a0 al\u00a0 contener\u00a0 una\u00a0 gran\u00a0 masa\u00a0 de\u00a0 aire,\u00a0 pueden\u00a0 alcanzar\u00a0 30\u00a0 metros\u00a0 de\u00a0 altura\u00a0 y\u00a0 con\u00a0 temperatura\u00a0 similar\u00a0 en\u00a0 todo\u00a0 su\u00a0 perfil,\u00a0 de\u00a0 al\u00a0 menos\u00a0 -3\u00a0 \u00f3\u00a0 -4\u00a0 \u00b0C.\u00a0 \u00c9stas\u00a0 son\u00a0 t\u00edpicas\u00a0 de\u00a0 primavera\u00a0 y\u00a0 demarcan\u00a0 perfectamente\u00a0 su\u00a0 paso\u00a0 de\u00a0 acuerdo\u00a0 a\u00a0 la\u00a0 topograf\u00eda.\u00a0 Un\u00a0 evento\u00a0 de\u00a0 este\u00a0 tipo\u00a0 puede\u00a0 permanecer\u00a0 por\u00a0 muchas\u00a0 horas\u00a0 afectando\u00a0 al\u00a0 frutal\u00a0 (5\u00a0 a\u00a0 7\u00a0 horas).\u00a0 Son,\u00a0 sin\u00a0 duda,\u00a0 las\u00a0 heladas\u00a0 m\u00e1s\u00a0 destructivas\u00a0 para\u00a0 la\u00a0 fruticultura,\u00a0 por\u00a0 sus\u00a0 caracter\u00edsticas\u00a0 y\u00a0 por\u00a0 el\u00a0 momento\u00a0 en\u00a0 que\u00a0 ocurren,\u00a0 cuando\u00a0 los\u00a0 tejidos\u00a0 frutales\u00a0 son\u00a0 m\u00e1s\u00a0 sensibles\u00a0 a\u00a0 la\u00a0 baja\u00a0 temperatura.<\/p>\n

DA\u00d1O\u00a0 POR\u00a0 HELADA<\/p>\n

Se\u00a0 han\u00a0 descrito\u00a0 dos\u00a0 formas\u00a0 por\u00a0 las\u00a0 cuales\u00a0 los\u00a0 tejidos\u00a0 vegetales\u00a0 son\u00a0 da\u00f1ados\u00a0 en\u00a0 presencia\u00a0 de\u00a0 helada.\u00a0 El\u00a0 descenso\u00a0 de\u00a0 temperatura\u00a0 produce\u00a0 un\u00a0 gradiente\u00a0 de\u00a0 potencial\u00a0 h\u00eddrico\u00a0 en\u00a0 el\u00a0 tejido,\u00a0 a\u00a0 medida\u00a0 que\u00a0 el\u00a0 agua\u00a0 de\u00a0 los\u00a0 espacios\u00a0 intercelulares\u00a0 va\u00a0 congel\u00e1ndose.\u00a0 Con\u00a0 ello,\u00a0 el\u00a0 agua\u00a0 contenida\u00a0 en\u00a0 el\u00a0 protoplasma\u00a0 celular\u00a0 (parte\u00a0 de\u00a0 la\u00a0 c\u00e9lula\u00a0 que\u00a0 incluye\u00a0 la\u00a0 membrana,\u00a0 citoplasma\u00a0 y\u00a0 n\u00facleo) comienza\u00a0 a\u00a0 salir,\u00a0 hasta\u00a0 producirse,\u00a0 eventualmente,\u00a0 plasm\u00f3lisis\u00a0 celular.\u00a0 As\u00ed,\u00a0 el\u00a0 da\u00f1o\u00a0 ocurre\u00a0 una\u00a0 vez\u00a0 que\u00a0 la\u00a0 c\u00e9lula\u00a0 no\u00a0 puede\u00a0 retornar\u00a0 a\u00a0 su\u00a0 estado\u00a0 original.\u00a0 La\u00a0 otra\u00a0 forma\u00a0 de\u00a0 da\u00f1o\u00a0 se\u00a0 debe\u00a0 a\u00a0 la\u00a0 acci\u00f3n\u00a0 destructiva\u00a0 de\u00a0 los\u00a0 cristales\u00a0 de\u00a0 hielo,\u00a0 formados\u00a0 durante\u00a0 la\u00a0 helada.\u00a0 Si\u00a0 el\u00a0 descenso\u00a0 de\u00a0 temperatura\u00a0 es\u00a0 muy\u00a0 r\u00e1pido,\u00a0 no\u00a0 da\u00a0 tiempo\u00a0 a\u00a0 la\u00a0 salida\u00a0 de\u00a0 agua\u00a0 de\u00a0 la\u00a0 c\u00e9lula\u00a0 y\u00a0 se\u00a0 producen\u00a0 cristales\u00a0 de\u00a0 hielo\u00a0 intracelulares\u00a0 que\u00a0 provocan\u00a0 la\u00a0 destrucci\u00f3n\u00a0 de\u00a0 sus\u00a0 componentes.\u00a0 Otra\u00a0 v\u00eda\u00a0 similar\u00a0 se\u00a0 atribuye\u00a0 a\u00a0 los\u00a0 cristales\u00a0 de\u00a0 hielo\u00a0 formados\u00a0 en\u00a0 los\u00a0 espacios\u00a0 intercelulares,\u00a0 que\u00a0 da\u00f1ar\u00edan\u00a0 la\u00a0 membrana\u00a0 citoplasm\u00e1tica,\u00a0 al\u00a0 tiempo\u00a0 que\u00a0 \u00e9sta\u00a0 aumenta\u00a0 de\u00a0 volumen\u00a0 por\u00a0 ingreso\u00a0 violento\u00a0 de\u00a0 agua,\u00a0 ocasionado\u00a0 por\u00a0 el\u00a0 incremento\u00a0 de\u00a0 la\u00a0 temperatura\u00a0 ambiental\u00a0 al\u00a0 retirarse\u00a0 la\u00a0 helada\u00a0 (Yuri,\u00a0 1992).\u00a0 Por\u00a0 lo\u00a0 anterior,\u00a0 se\u00a0 se\u00f1ala\u00a0 que\u00a0 una\u00a0 alta\u00a0 velocidad\u00a0 en\u00a0 el\u00a0 cambio\u00a0 de\u00a0 temperatura\u00a0 del\u00a0 aire\u00a0 incrementa\u00a0 el\u00a0 da\u00f1o\u00a0 de\u00a0 la\u00a0 helada.<\/p>\n

En\u00a0 frutales,\u00a0 floraci\u00f3n\u00a0 y\u00a0 postcuaja,\u00a0 corresponden\u00a0 a\u00a0 los\u00a0 estados\u00a0 fenol\u00f3gicos\u00a0 en\u00a0 que\u00a0 los\u00a0 tejidos\u00a0 son\u00a0 m\u00e1s\u00a0 sensibles\u00a0 a\u00a0 temperatura\u00a0 de\u00a0 congelaci\u00f3n,\u00a0 dado\u00a0 su\u00a0 car\u00e1cter\u00a0 terso\u00a0 por\u00a0 su\u00a0 temprana\u00a0 edad.\u00a0 Heladas\u00a0 advectivas,\u00a0 de\u00a0 gran\u00a0 magnitud\u00a0 t\u00e9rmica\u00a0 (temperatura\u00a0 igual\u00a0 o\u00a0 menor\u00a0 a\u00a0 -3\u00a0 \u00b0C)\u00a0 y\u00a0 duraci\u00f3n\u00a0 (cuatro\u00a0 horas\u00a0 o\u00a0 m\u00e1s),\u00a0 pueden\u00a0 ocasionar\u00a0 importantes\u00a0 da\u00f1os\u00a0 a\u00a0 las\u00a0 flores\u00a0 o\u00a0 frutos\u00a0 reci\u00e9n\u00a0 formados.\u00a0 Heladas\u00a0 de\u00a0 este\u00a0 tipo\u00a0 pueden\u00a0 causar\u00a0 desde\u00a0 ca\u00edda\u00a0 de\u00a0 frutos\u00a0 reci\u00e9n\u00a0 cuajados\u00a0 hasta\u00a0 deformidad\u00a0 o\u00a0 formaci\u00f3n\u00a0 de\u00a0 russet\u00a0 en\u00a0 forma\u00a0 de\u00a0 anillo,\u00a0 t\u00edpico\u00a0 da\u00f1o\u00a0 de\u00a0 helada.<\/p>\n

MONITOREO\u00a0 Y\u00a0 PREDICCI\u00d3N<\/p>\n

Es\u00a0 importante\u00a0 establecer\u00a0 la\u00a0 din\u00e1mica\u00a0 de\u00a0 la\u00a0 temperatura\u00a0 del\u00a0 aire,\u00a0 tanto\u00a0 para\u00a0 anticipar\u00a0 la\u00a0 ocurrencia\u00a0 de\u00a0 una\u00a0 helada\u00a0 como\u00a0 para\u00a0 estimar\u00a0 el\u00a0 momento\u00a0 de\u00a0 puesta en\u00a0 marcha\u00a0 del\u00a0 sistema\u00a0 de\u00a0 control.\u00a0 En\u00a0 la\u00a0 actualidad,\u00a0 si\u00a0 bien\u00a0 se\u00a0 pueden\u00a0 predecir\u00a0 los\u00a0 eventos\u00a0 de\u00a0 helada,\u00a0 y\u00a0 son\u00a0 difundidos\u00a0 a\u00a0 trav\u00e9s\u00a0 de\u00a0 alertas\u00a0 y\u00a0 boletines,\u00a0 a\u00a0 nivel\u00a0 predial\u00a0 es\u00a0 necesario\u00a0 monitorear\u00a0 la\u00a0 temperatura,\u00a0 para\u00a0 decidir\u00a0 el\u00a0 sistema\u00a0 de\u00a0 control\u00a0 y\u00a0 su\u00a0 inicio.<\/p>\n

\"sin<\/a>La\u00a0 masividad\u00a0 que\u00a0 ha\u00a0 adquirido\u00a0 el\u00a0 uso\u00a0 de\u00a0 estaciones\u00a0 meteorol\u00f3gicas\u00a0 autom\u00e1ticas\u00a0 en\u00a0 los\u00a0 huertos,\u00a0 as\u00ed\u00a0 como\u00a0 la\u00a0 penetraci\u00f3n\u00a0 y\u00a0 versatilidad\u00a0 de\u00a0 las\u00a0 tecnolog\u00edas\u00a0 digitales,\u00a0 ha\u00a0 supuesto\u00a0 un\u00a0 cambio\u00a0 sustantivo\u00a0 en\u00a0 las\u00a0 herramientas\u00a0 disponibles\u00a0 en\u00a0 fruticultura.\u00a0 En\u00a0 este\u00a0 sentido,\u00a0 destaca\u00a0 el\u00a0 esfuerzo\u00a0 combinado\u00a0 para\u00a0 sacar\u00a0 adelante\u00a0 la\u00a0 Red\u00a0 Agroclim\u00e1tica\u00a0 Nacional\u00a0 (RAN)\u00a0 as\u00ed\u00a0 como\u00a0 el\u00a0 impulso\u00a0 que\u00a0 ha\u00a0 dado\u00a0 FIA\u00a0 a\u00a0 las\u00a0 iniciativas\u00a0 en\u00a0 predicci\u00f3n\u00a0 de\u00a0 heladas,\u00a0 desarrolladas\u00a0 por\u00a0 el\u00a0 Centro\u00a0 de\u00a0 Bioinform\u00e1tica\u00a0 y\u00a0 Modelamiento\u00a0 Molecular\u00a0 (CBSM)\u00a0 de\u00a0 la\u00a0 Universidad\u00a0 de\u00a0 Talca\u00a0 y\u00a0 por\u00a0 INIA.\u00a0 El\u00a0 sistema\u00a0 de\u00a0 monitoreo\u00a0 y\u00a0 alerta\u00a0 temprana\u00a0 del\u00a0 CBSM\u00a0 utiliza\u00a0 t\u00e9cnicas\u00a0 de\u00a0 inteligencia\u00a0 artificial\u00a0 y\u00a0 el\u00a0 de\u00a0 INIA\u00a0 se\u00a0 basa\u00a0 en\u00a0 predicci\u00f3n\u00a0 meteorol\u00f3gica.<\/p>\n

En\u00a0 la\u00a0 l\u00ednea\u00a0 de\u00a0 la\u00a0 adaptaci\u00f3n\u00a0 de\u00a0 la\u00a0 agricultura\u00a0 en\u00a0 el\u00a0 milenio,\u00a0 se\u00a0 distingue\u00a0 el\u00a0 proyecto\u00a0 FIA\u00a0 liderado\u00a0 por\u00a0 el\u00a0 Dr.\u00a0 Fernando Santib\u00e1\u00f1ez,\u00a0 que\u00a0 ha\u00a0 culminado\u00a0 en\u00a0 la\u00a0 publicaci\u00f3n\u00a0 del\u00a0 Atlas\u00a0 Agroclim\u00e1tico\u00a0 de\u00a0 Chile,\u00a0 un\u00a0 aporte\u00a0 mayor\u00a0 para\u00a0 el\u00a0 desarrollo\u00a0 agr\u00edcola\u00a0 del\u00a0 pa\u00eds.<\/p>\n

SISTEMAS\u00a0 DE CONTROL\u00a0 PASIVO<\/p>\n

Los\u00a0 sistemas\u00a0 de\u00a0 control\u00a0 de\u00a0 helada\u00a0 se\u00a0 clasifican\u00a0 en\u00a0 orden\u00a0 a\u00a0 su\u00a0 forma\u00a0 de\u00a0 acci\u00f3n,\u00a0 como\u00a0 pasivos\u00a0 o\u00a0 activos\u00a0 (FAO,\u00a0 2010).\u00a0 En\u00a0 la\u00a0 primera\u00a0 categor\u00eda\u00a0 se\u00a0 incluyen\u00a0 medidas\u00a0 culturales,\u00a0 desde\u00a0 la\u00a0 m\u00e1s\u00a0 b\u00e1sica\u00a0 e\u00a0 importante\u00a0 que\u00a0 es\u00a0 la\u00a0 elecci\u00f3n\u00a0 del\u00a0 lugar\u00a0 para\u00a0 un\u00a0 proyecto\u00a0 agr\u00edcola\u00a0 definido.\u00a0 En\u00a0 este\u00a0 sentido,\u00a0 es\u00a0 recomendable\u00a0 conocer\u00a0 el\u00a0 r\u00e9gimen\u00a0 de\u00a0 temperaturas\u00a0 anual\u00a0 de\u00a0 la\u00a0 localidad en\u00a0 cuesti\u00f3n.\u00a0 As\u00ed,\u00a0 es\u00a0 posible\u00a0 enterarse\u00a0 de\u00a0 la\u00a0 ocurrencia\u00a0 de\u00a0 heladas\u00a0 en\u00a0 temporadas\u00a0 anteriores,\u00a0 su\u00a0 frecuencia,\u00a0 magnitud\u00a0 y\u00a0 duraci\u00f3n.\u00a0 Este\u00a0 tipo\u00a0 de\u00a0 consulta\u00a0 es\u00a0 cada\u00a0 vez\u00a0 m\u00e1s\u00a0 solicitada\u00a0 al\u00a0 Laboratorio\u00a0 de\u00a0 Ecofisiolog\u00eda\u00a0 del\u00a0 Centro\u00a0 de\u00a0 Pom\u00e1ceas,\u00a0 en\u00a0 general\u00a0 para\u00a0 la\u00a0 evaluaci\u00f3n\u00a0 del\u00a0 potencial\u00a0 de\u00a0 una\u00a0 localidad\u00a0 para\u00a0 proyectos\u00a0 de\u00a0 explotaci\u00f3n\u00a0 frut\u00edcola.\u00a0 En\u00a0 la\u00a0 actualidad\u00a0 existe\u00a0 una\u00a0 amplia\u00a0 oferta\u00a0 de\u00a0 informaci\u00f3n\u00a0 agroclim\u00e1tica,\u00a0 y\u00a0 de\u00a0 f\u00e1cil\u00a0 acceso\u00a0 a\u00a0 trav\u00e9s\u00a0 de\u00a0 recursos\u00a0 digitales,\u00a0 para\u00a0 su\u00a0 an\u00e1lisis.\u00a0 De\u00a0 no\u00a0 contar\u00a0 con\u00a0 estos\u00a0 datos,\u00a0 la\u00a0 experiencia\u00a0 de\u00a0 huertos\u00a0 en\u00a0 la\u00a0 zona\u00a0 ser\u00e1\u00a0 relevante\u00a0 de\u00a0 conocer.<\/p>\n

El\u00a0 siguiente\u00a0 aspecto\u00a0 a\u00a0 considerar\u00a0 es\u00a0 la\u00a0 topograf\u00eda\u00a0 del\u00a0 terreno,\u00a0 dado\u00a0 que\u00a0 el\u00a0 aire\u00a0 fr\u00edo\u00a0 se\u00a0 deposita\u00a0 y\u00a0 desplaza\u00a0 por\u00a0 las\u00a0 zonas\u00a0 m\u00e1s\u00a0 bajas\u00a0 del\u00a0 relieve.\u00a0 \u00c9sta\u00a0 determinar\u00e1\u00a0 sectores\u00a0 m\u00e1s\u00a0 sensibles\u00a0 a\u00a0 da\u00f1o\u00a0 por\u00a0 helada\u00a0 y\u00a0 el\u00a0 sistema\u00a0 de\u00a0 control\u00a0 m\u00e1s\u00a0 apropiado\u00a0 a\u00a0 implementar,\u00a0 como\u00a0 su\u00a0 eficacia.\u00a0 La\u00a0 disposici\u00f3n\u00a0 de\u00a0 cortinas\u00a0 cortaviento\u00a0 se\u00a0 utiliza\u00a0 como\u00a0 drenaje\u00a0 de\u00a0 la\u00a0 masa\u00a0 de\u00a0 aire\u00a0 fr\u00edo,\u00a0 de\u00a0 modo\u00a0 de\u00a0 desviarla\u00a0 y\u00a0 que\u00a0 no\u00a0 contacte\u00a0 la\u00a0 plantaci\u00f3n.\u00a0 Estos\u00a0 muros\u00a0 pueden\u00a0 ser\u00a0 naturales,\u00a0 tal\u00a0 es\u00a0 el\u00a0 caso\u00a0 de\u00a0 alamedas,\u00a0 o\u00a0 artificiales,\u00a0 como\u00a0 el\u00a0 uso\u00a0 de\u00a0 mallas.\u00a0 Para\u00a0 su\u00a0 implementaci\u00f3n,\u00a0 es\u00a0 necesario\u00a0 un\u00a0 correcto\u00a0 an\u00e1lisis\u00a0 del\u00a0 movimiento\u00a0 de\u00a0 la\u00a0 masa\u00a0 de\u00a0 aire\u00a0 fr\u00edo,\u00a0 para\u00a0 que\u00a0 no\u00a0 resulte\u00a0 el\u00a0 efecto\u00a0 contrario,\u00a0 reteniendo\u00a0 el\u00a0 aire\u00a0 m\u00e1s\u00a0 fr\u00edo\u00a0 sobre\u00a0 el\u00a0 huerto.\u00a0 Otro\u00a0 cuidado\u00a0 es\u00a0 la\u00a0 sombra\u00a0 que\u00a0 podr\u00edan\u00a0 producir\u00a0 sobre\u00a0 las\u00a0 hileras\u00a0 pr\u00f3ximas,\u00a0 que\u00a0 suele\u00a0 disminuir\u00a0 el\u00a0 color\u00a0 de\u00a0 la\u00a0 fruta\u00a0 o\u00a0 reducir\u00a0 la\u00a0 actividad\u00a0 fotosint\u00e9tica\u00a0 de\u00a0 los\u00a0 \u00e1rboles\u00a0 afectados.\u00a0 Otro\u00a0 manejo\u00a0 cultural\u00a0 se\u00a0 refiere\u00a0 al\u00a0 manejo\u00a0 del\u00a0 suelo\u00a0 y\u00a0 el\u00a0 riego.\u00a0 El\u00a0 suelo\u00a0 debe\u00a0 ser\u00a0 considerado\u00a0 como\u00a0 un\u00a0 enorme\u00a0 cuerpo\u00a0 que \u00a0trasfiere\u00a0 calor.\u00a0 Para\u00a0 que\u00a0 lo\u00a0 absorba\u00a0 durante\u00a0 el\u00a0 d\u00eda\u00a0 y\u00a0 lo\u00a0 transfiera\u00a0 lentamente\u00a0 a\u00a0 la\u00a0 atm\u00f3sfera\u00a0 durante\u00a0 la\u00a0 noche,\u00a0 se\u00a0 recomienda\u00a0 mantenerlo\u00a0 h\u00famedo,\u00a0 con\u00a0 la\u00a0 cubierta\u00a0 vegetal corta\u00a0 y\u00a0 mullida\u00a0 la\u00a0 superficie,\u00a0 reduciendo\u00a0 el\u00a0 relieve.\u00a0 En\u00a0 especies\u00a0 m\u00e1s\u00a0 sensibles\u00a0 al\u00a0 fr\u00edo,\u00a0 como\u00a0 el\u00a0 kiwi,\u00a0 se\u00a0 suele\u00a0 proteger\u00a0 el\u00a0 tronco\u00a0 con\u00a0 diversos\u00a0 materiales\u00a0 aislantes.\u00a0 En\u00a0 cuanto\u00a0 a\u00a0 diferencias\u00a0 entre\u00a0 cultivares,\u00a0 estas\u00a0 ser\u00edan\u00a0 m\u00ednimas,\u00a0 si\u00a0 bien\u00a0 no\u00a0 hay\u00a0 experiencia\u00a0 consistente.\u00a0 En\u00a0 cerezos,\u00a0 la\u00a0 sensibilidad\u00a0 entre\u00a0 cultivares\u00a0 se\u00a0 atribuye,\u00a0 en\u00a0 gran\u00a0 medida,\u00a0 al\u00a0 avance\u00a0 del\u00a0 estado\u00a0 fenol\u00f3gico\u00a0 de\u00a0 las\u00a0 yemas.\u00a0 En\u00a0 manzanos,\u00a0 existen\u00a0 portainjertos\u00a0 con\u00a0 diferente\u00a0 sensibilidad\u00a0 al\u00a0 fr\u00edo.\u00a0 Sin\u00a0 embargo,\u00a0 las\u00a0 selecciones\u00a0 resistentes\u00a0 fueron\u00a0 desarrolladas\u00a0 para\u00a0 soportar\u00a0 el\u00a0 invierno,\u00a0 extremadamente\u00a0 fr\u00edo\u00a0 de\u00a0 climas\u00a0 templados\u00a0 continentales,\u00a0 como\u00a0 en\u00a0 el\u00a0 norte\u00a0 de\u00a0 Europa,\u00a0 Norteam\u00e9rica\u00a0 y\u00a0 Asia.<\/p>\n

\u00c1rboles\u00a0 con\u00a0 una\u00a0 condici\u00f3n\u00a0 h\u00eddrica,\u00a0 nutricional\u00a0 y\u00a0 sanitaria\u00a0 adecuada\u00a0 aumentan\u00a0 su\u00a0 tolerancia\u00a0 a\u00a0 las\u00a0 heladas,\u00a0 al\u00a0 contar\u00a0 con\u00a0 mayor\u00a0 n\u00famero\u00a0 de\u00a0 fotosintatos\u00a0 en\u00a0 sus\u00a0 tejidos\u00a0 m\u00e1s\u00a0 sensibles.<\/p>\n

\"sin<\/a>Algunos\u00a0 agroqu\u00edmicos\u00a0 usados\u00a0 en\u00a0 control\u00a0 de\u00a0 helada\u00a0 tienen\u00a0 el\u00a0 mismo\u00a0 principio\u00a0 de\u00a0 acci\u00f3n,\u00a0 aumentando\u00a0 los solutos\u00a0 y\u00a0 con\u00a0 ello\u00a0 disminuyendo\u00a0 el\u00a0 punto\u00a0 de\u00a0 congelaci\u00f3n\u00a0 del\u00a0 tejido.\u00a0 El\u00a0 control\u00a0 de\u00a0 bacterias\u00a0 es\u00a0 otra\u00a0 medida\u00a0 que\u00a0 fortalece\u00a0 la\u00a0 respuesta\u00a0 de\u00a0 la\u00a0 planta\u00a0 frente\u00a0 a\u00a0 un\u00a0 evento\u00a0 de\u00a0 helada.<\/p>\n

El\u00a0 retraso\u00a0 del\u00a0 desarrollo\u00a0 de\u00a0 las\u00a0 yemas\u00a0 en\u00a0 primavera\u00a0 es\u00a0 una\u00a0 alternativa\u00a0 para\u00a0 escapar\u00a0 de\u00a0 probables\u00a0 heladas.\u00a0 Esto\u00a0 se\u00a0 logra\u00a0 retrasando\u00a0 la\u00a0 salida\u00a0 del\u00a0 receso\u00a0 o\u00a0 el\u00a0 avance\u00a0 fenol\u00f3gico\u00a0 de\u00a0 las\u00a0 yemas,\u00a0 asperjando\u00a0 agua\u00a0 al\u00a0 \u00e1rbol\u00a0 como\u00a0 refrigerante.\u00a0 El\u00a0 despliegue\u00a0 de\u00a0 cubiertas\u00a0 antilluvia\u00a0 tempranamente\u00a0 en\u00a0 cerezos\u00a0 tambi\u00e9n\u00a0 es\u00a0 una\u00a0 pr\u00e1ctica\u00a0 usada\u00a0 para\u00a0 reducir\u00a0 el\u00a0 da\u00f1o\u00a0 de\u00a0 heladas,\u00a0 pero\u00a0 adelantar\u00eda\u00a0 el\u00a0 desarrollo\u00a0 de\u00a0 las\u00a0 yemas.<\/p>\n

SISTEMAS\u00a0 DE\u00a0 CONTROL\u00a0 ACTIVOS<\/p>\n

\u2022\u00a0 CALEFACTORES: La\u00a0 emisi\u00f3n\u00a0 de\u00a0 calor\u00a0 constituye\u00a0 un\u00a0 sistema\u00a0 de\u00a0 control\u00a0 activo,\u00a0 en\u00a0 el\u00a0 cual\u00a0 se\u00a0 entrega\u00a0 calor\u00a0 a\u00a0 la\u00a0 atm\u00f3sfera\u00a0 mediante\u00a0 quema\u00a0 de\u00a0 alg\u00fan\u00a0 combustible.\u00a0 Lo\u00a0 m\u00e1s\u00a0 com\u00fan\u00a0 es\u00a0 el\u00a0 uso\u00a0 de\u00a0 calefactores\u00a0 a\u00a0 petr\u00f3leo.\u00a0 Dado\u00a0 que\u00a0 se\u00a0 entrega\u00a0 calor\u00a0 directo\u00a0 al\u00a0 aire,\u00a0 el\u00a0 cambio\u00a0 de\u00a0 temperatura\u00a0 no\u00a0 es\u00a0 uniforme,\u00a0 logr\u00e1ndose\u00a0 aumentos\u00a0 de\u00a0 2-3\u00a0 \u00b0C,\u00a0 y\u00a0 de\u00a0 1\u00a0 \u00b0C\u00a0 al\u00a0 considerar\u00a0 el\u00a0 promedio\u00a0 en\u00a0 los\u00a0 primeros\u00a0 tres\u00a0 metros\u00a0 desde\u00a0 el\u00a0 suelo\u00a0 (FAO,\u00a0 2010).\u00a0 Por\u00a0 esto,\u00a0 los\u00a0 artefactos\u00a0 deben\u00a0 distribuirse\u00a0 lo\u00a0 m\u00e1s\u00a0 homog\u00e9neo\u00a0 posible\u00a0 en\u00a0 el\u00a0 huerto,\u00a0 70\u00a0 a\u00a0 150\u00a0 unidades\u00a0 por\u00a0 hect\u00e1rea,\u00a0 dependiendo del\u00a0 equipo.\u00a0 Los\u00a0 calefactores\u00a0 actuales,\u00a0 de\u00a0 alta\u00a0 eficiencia\u00a0 y\u00a0 prolongada\u00a0 vida\u00a0 \u00fatil,\u00a0 poseen\u00a0 un\u00a0 estanque\u00a0 de\u00a0 veinte\u00a0 litros,\u00a0 lo\u00a0 que \u00a0le\u00a0 confiere\u00a0 una\u00a0 autonom\u00eda\u00a0 de\u00a0 alrededor\u00a0 de\u00a0 diez\u00a0 horas.\u00a0 Sin\u00a0 duda\u00a0 que\u00a0 la\u00a0 gran\u00a0 ventaja \u00a0es\u00a0 el\u00a0 bajo\u00a0 costo\u00a0 que\u00a0 involucra\u00a0 este\u00a0 sistema.\u00a0 Sin\u00a0 embargo,\u00a0 ofrece\u00a0 un\u00a0 control\u00a0 limitado\u00a0 frente\u00a0 a\u00a0 heladas\u00a0 polares,\u00a0 de\u00a0 gran\u00a0 magnitud,\u00a0 y\u00a0 es\u00a0 necesario\u00a0 un\u00a0 importante\u00a0 despliegue\u00a0 de\u00a0 personal\u00a0 para\u00a0 su\u00a0 operaci\u00f3n\u00a0 (encendido\u00a0 y\u00a0 reabastecimiento), \u00a0as\u00ed\u00a0 como\u00a0 un\u00a0 amplio\u00a0 sitio\u00a0 de\u00a0 acopio.\u00a0 Por\u00a0 lo\u00a0 dem\u00e1s,\u00a0 ser\u00e1\u00a0 \u00fatil\u00a0 contar\u00a0 con\u00a0 una\u00a0 reserva\u00a0 de\u00a0 petr\u00f3leo\u00a0 en\u00a0 el\u00a0 huerto.<\/p>\n

\u2022\u00a0 TORRES\u00a0 DE\u00a0 VIENTO: El\u00a0 movimiento\u00a0 de\u00a0 aire\u00a0 es\u00a0 el \u00a0sistema\u00a0 de\u00a0 control\u00a0 de\u00a0 helada\u00a0 de\u00a0 mayor\u00a0 proyecci\u00f3n\u00a0 en\u00a0 los\u00a0 huertos\u00a0 chilenos,\u00a0 a\u00a0 trav\u00e9s\u00a0 de\u00a0 la\u00a0 implementaci\u00f3n\u00a0 de\u00a0 las\u00a0 llamadas\u00a0 torres\u00a0 de\u00a0 viento.\u00a0 En\u00a0 su\u00a0 versi\u00f3n\u00a0 fija,\u00a0 \u00e9sta\u00a0 se\u00a0 compone\u00a0 de\u00a0 una \u00a0h\u00e9lice\u00a0 de\u00a0 seis\u00a0 metros\u00a0 de\u00a0 di\u00e1metro\u00a0 dispuesta\u00a0 sobre\u00a0 una\u00a0 torre\u00a0 de\u00a0 diez\u00a0 metros\u00a0 de\u00a0 alto.\u00a0 Un\u00a0 potente\u00a0 motor\u00a0 a\u00a0 petr\u00f3leo\u00a0 o\u00a0 gas\u00a0 activa\u00a0 la\u00a0 h\u00e9lice\u00a0 y\u00a0 la\u00a0 hace\u00a0 girar\u00a0 en\u00a0 360\u00a0 \u00b0C.\u00a0 Dado\u00a0 un \u00a0leve\u00a0 \u00e1ngulo\u00a0 de\u00a0 incidencia\u00a0 (6-7\u00a0 \u00b0\u00a0 desde\u00a0 la\u00a0 horizontal),\u00a0 es\u00a0 capaz\u00a0 de\u00a0 incorporar\u00a0 aire\u00a0 desde\u00a0 capas\u00a0 superiores\u00a0 y\u00a0 remover\u00a0 el\u00a0 m\u00e1s\u00a0 fr\u00edo\u00a0 pr\u00f3ximo\u00a0 a\u00a0 la \u00a0superficie,\u00a0 de\u00a0 alrededor\u00a0 de\u00a0 siete\u00a0 hect\u00e1reas. \u00a0Al\u00a0 mezclar\u00a0 o\u00a0 invertir\u00a0 el\u00a0 aire,\u00a0 evita\u00a0 el\u00a0 contacto\u00a0 del\u00a0 aire\u00a0 fr\u00edo\u00a0 con\u00a0 el\u00a0 huerto.\u00a0 Hay\u00a0 que\u00a0 considerar\u00a0 que\u00a0 ante\u00a0 una\u00a0 gran\u00a0 helada\u00a0 advectiva,\u00a0 este\u00a0 sistema\u00a0 podr\u00eda\u00a0 no\u00a0 resultar\u00a0 efectivo,\u00a0 debido\u00a0 a\u00a0 la \u00a0altura\u00a0 de\u00a0 la\u00a0 enorme\u00a0 masa\u00a0 de\u00a0 aire.\u00a0 Para\u00a0 estos\u00a0 casos,\u00a0 se\u00a0 aumenta \u00a0su\u00a0 eficacia\u00a0 al\u00a0 complementarla\u00a0 con\u00a0 emisi\u00f3n\u00a0 de\u00a0 calor.<\/p>\n

Otro\u00a0 aspecto\u00a0 a\u00a0 considerar\u00a0 es\u00a0 la\u00a0 topograf\u00eda\u00a0 del\u00a0 huerto,\u00a0 de\u00a0 modo\u00a0 que\u00a0 con\u00a0 relieves\u00a0 pronunciados,\u00a0 la\u00a0 torre\u00a0 fija\u00a0 perder\u00eda\u00a0 campo\u00a0 efectivo\u00a0 de\u00a0 acci\u00f3n.\u00a0 Si\u00a0 bien\u00a0 responde\u00a0 a\u00a0 una\u00a0 alta\u00a0 inversi\u00f3n\u00a0 (US$\u00a0 35.000\/unidad),\u00a0 la\u00a0 decisi\u00f3n\u00a0 de\u00a0 implementar\u00a0 este\u00a0 sistema\u00a0 en\u00a0 el\u00a0 huerto\u00a0 es\u00a0 compensada\u00a0 por\u00a0 la\u00a0 superficie\u00a0 cubierta\u00a0 y\u00a0 el\u00a0 bajo\u00a0 costo\u00a0 operacional.<\/p>\n

\u2022\u00a0 ASPERSI\u00d3N: La\u00a0 aspersi\u00f3n\u00a0 de\u00a0 agua\u00a0 al\u00a0 \u00e1rbol\u00a0 por\u00a0 medio\u00a0 de\u00a0 riego\u00a0 elevado\u00a0 es\u00a0 el\u00a0 sistema\u00a0 m\u00e1s\u00a0 efectivo\u00a0 en\u00a0 controlar\u00a0 heladas,\u00a0 incluso\u00a0 del\u00a0 tipo\u00a0 advectiva.\u00a0 Su\u00a0 acci\u00f3n\u00a0 se\u00a0 basa\u00a0 en\u00a0 el\u00a0 calor\u00a0 liberado\u00a0 por el\u00a0 agua\u00a0 al\u00a0 congelarse.\u00a0 Es\u00a0 una\u00a0 t\u00e9cnica\u00a0 muy\u00a0 usada\u00a0 en\u00a0 zonas\u00a0 manzaneras\u00a0 con\u00a0 presencia\u00a0 frecuente\u00a0 de\u00a0 heladas\u00a0 y\u00a0 con\u00a0 disponibilidad\u00a0 de\u00a0 agua,\u00a0 tal\u00a0 como\u00a0 en\u00a0 Sudtirol\u00a0 o\u00a0 en\u00a0 el\u00a0 Estado\u00a0 de\u00a0 Washington.\u00a0 A\u00a0 pesar\u00a0 de\u00a0 su\u00a0 eficiencia,\u00a0 este\u00a0 sistema\u00a0 muestra\u00a0 una\u00a0 serie\u00a0 de\u00a0 limitantes\u00a0 que\u00a0 complejizan\u00a0 su\u00a0 aplicaci\u00f3n,\u00a0 por\u00a0 lo\u00a0 que\u00a0 es\u00a0 poco\u00a0 usado \u00a0en\u00a0 Chile.\u00a0 Adem\u00e1s,\u00a0 del\u00a0 gran\u00a0 volumen\u00a0 de\u00a0 agua\u00a0 que\u00a0 utiliza,\u00a0 \u00e9sta\u00a0 debe\u00a0 estar\u00a0 disponible\u00a0 desde\u00a0 fines\u00a0 de\u00a0 invierno.<\/p>\n

El\u00a0 sistema\u00a0 de\u00a0 aspersi\u00f3n,\u00a0 debe\u00a0 operar\u00a0 en\u00a0 forma\u00a0 simult\u00e1nea\u00a0 en\u00a0 todo\u00a0 el\u00a0 huerto,\u00a0 a\u00a0 diferencia\u00a0 del\u00a0 sistema\u00a0 de\u00a0 riego,\u00a0 y\u00a0 sin\u00a0 interrupci\u00f3n\u00a0 durante\u00a0 todo\u00a0 el\u00a0 tiempo\u00a0 que\u00a0 permanezca\u00a0 la\u00a0 helada\u00a0 en\u00a0 el\u00a0 sector.\u00a0 El\u00a0 tejido\u00a0 vegetal\u00a0 debe\u00a0 mojarse\u00a0 cada\u00a0 30\u00a0 segundos\u00a0 para\u00a0 su\u00a0 correcta\u00a0 protecci\u00f3n\u00a0 (Iglesias,\u00a0 2017).\u00a0 Esto\u00a0 implica\u00a0 una\u00a0 gran\u00a0 carga\u00a0 de\u00a0 agua\u00a0 congelada\u00a0 sobre\u00a0 los\u00a0 \u00e1rboles,\u00a0 por\u00a0 lo\u00a0 que\u00a0 se\u00a0 hace\u00a0 necesario\u00a0 contar\u00a0 con\u00a0 una\u00a0 estructura\u00a0 de\u00a0 soporte\u00a0 robusta\u00a0 y\u00a0 un\u00a0 sistema\u00a0 de\u00a0 generaci\u00f3n\u00a0 de\u00a0 energ\u00eda\u00a0 aut\u00f3nomo\u00a0 de\u00a0 emergencia.<\/p>\n

En\u00a0 la\u00a0 actualidad\u00a0 se\u00a0 utilizan\u00a0 aspersores\u00a0 tipo\u00a0 Flipper,\u00a0 de\u00a0 bajo \u00a0caudal,\u00a0 que\u00a0 permiten\u00a0 un\u00a0 mojamiento\u00a0 dirigido\u00a0 sobre\u00a0 la\u00a0 hilera\u00a0 con\u00a0 un\u00a0 ahorro\u00a0 considerable\u00a0 de\u00a0 agua,\u00a0 conveniente\u00a0 para\u00a0 huertos\u00a0 con\u00a0 \u00e1rboles\u00a0 peque\u00f1os.\u00a0 Este\u00a0 sistema\u00a0 es\u00a0 utilizado\u00a0 en\u00a0 huertos\u00a0 de\u00a0 ar\u00e1ndanos\u00a0 en\u00a0 el\u00a0 sur\u00a0 de\u00a0 Chile.\u00a0 Por\u00a0 \u00faltimo,\u00a0 hay\u00a0 que\u00a0 considerar\u00a0 una\u00a0 aplicaci\u00f3n\u00a0 sanitaria\u00a0 para\u00a0 proteger\u00a0 de\u00a0 infecciones\u00a0 el\u00a0 huerto,\u00a0 dada\u00a0 la\u00a0 gran\u00a0 cantidad\u00a0 de\u00a0 agua\u00a0 asperjada\u00a0 sobre\u00a0 \u00e9l.\u00a0 El\u00a0 sistema\u00a0 puede\u00a0 usarse\u00a0 en\u00a0 verano\u00a0 para\u00a0 control\u00a0 da\u00f1o\u00a0 por\u00a0 sol\u00a0 y\u00a0 mejorar\u00a0 el\u00a0 color\u00a0 y\u00a0 condici\u00f3n\u00a0 de\u00a0 la\u00a0 manzana,\u00a0 mediante\u00a0 aspersi\u00f3n\u00a0 en\u00a0 horas\u00a0 de\u00a0 alta\u00a0 temperatura\u00a0 (sobre\u00a0 30\u00a0 \u00b0C).\u00a0 Sin\u00a0 embargo,\u00a0 para\u00a0 este\u00a0 efecto\u00a0 se\u00a0 debe\u00a0 considerar\u00a0 la\u00a0 calidad\u00a0 del\u00a0 agua\u00a0 por\u00a0 el\u00a0 dep\u00f3sito\u00a0 de\u00a0 sales\u00a0 en\u00a0 la\u00a0 piel\u00a0 de\u00a0 la\u00a0 fruta.<\/p>\n

En\u00a0 el\u00a0 escenario\u00a0 de\u00a0 incertidumbre\u00a0 y\u00a0 extremos\u00a0 clim\u00e1ticos\u00a0 que\u00a0 ha\u00a0 prevalecido\u00a0 en\u00a0 las\u00a0 \u00faltimas\u00a0 temporadas,\u00a0 contar\u00a0 con\u00a0 mayor\u00a0 informaci\u00f3n\u00a0 y\u00a0 m\u00e1s\u00a0 alternativas\u00a0 para\u00a0 el\u00a0 monitoreo\u00a0 y\u00a0 control\u00a0 de\u00a0 heladas,\u00a0 permitir\u00e1\u00a0 al\u00a0 fruticultor\u00a0 actuar\u00a0 en\u00a0 forma\u00a0 m\u00e1s\u00a0 certera\u00a0 frente\u00a0 a\u00a0 \u00e9stas.\u00a0 En\u00a0 la\u00a0 decisi\u00f3n\u00a0 del\u00a0 sistema\u00a0 de\u00a0 control\u00a0 de\u00a0 helada\u00a0 a\u00a0 implementar,\u00a0 se\u00a0 deben\u00a0 evaluar\u00a0 m\u00faltiples\u00a0 factores,\u00a0 agron\u00f3micos\u00a0 y\u00a0 comerciales.\u00a0 Dado\u00a0 que\u00a0 los\u00a0 sistemas\u00a0 de\u00a0 control\u00a0 de\u00a0 heladas\u00a0 se\u00a0 basan\u00a0 en\u00a0 la\u00a0 transferencia\u00a0 energ\u00e9tica,\u00a0 los\u00a0 m\u00e1s\u00a0 eficientes\u00a0 son\u00a0 sofisticados\u00a0 y\u00a0 costosos.\u00a0 Estos\u00a0 dependen\u00a0 de\u00a0 la\u00a0 adecuada\u00a0 alimentaci\u00f3n\u00a0 de\u00a0 energ\u00eda,\u00a0 a\u00a0 trav\u00e9s\u00a0 de\u00a0 petr\u00f3leo,\u00a0 gas\u00a0 o\u00a0 electricidad.<\/p>\n

Esta\u00a0 publicaci\u00f3n\u00a0 es\u00a0 parte\u00a0 del\u00a0 libro\u00a0 \u201cHeladas\u00a0 en\u00a0 Fruticultura.\u00a0 Conceptos\u00a0 y\u00a0 Sistemas\u00a0 de\u00a0 Control\u201d\u00a0 (J.A.\u00a0 Yuri;\u00a0 V.\u00a0 Lepe;\u00a0 A.\u00a0 Sep\u00falveda.\u00a0 Ed.\u00a0 UTalca,\u00a0 Chile.\u00a0 56\u00a0 p),\u00a0 que\u00a0 incluye\u00a0 una\u00a0 amplia\u00a0 revisi\u00f3n\u00a0 del\u00a0 fen\u00f3meno,\u00a0 sus\u00a0 da\u00f1os,\u00a0 sistemas\u00a0 de\u00a0 control\u00a0 costos\u00a0 asociados.<\/i><\/p>\n

Escrito\u00a0 por: Valeria Lepe, Jos\u00e9 Antonio Yuri y \u00c1lvaro Sep\u00falveda del Centro de Pom\u00e1ceas, Facultad de Ciencias Agrarias, Universidad de Talca.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Se llama heladas a  la  exposición  a  temperatura  del  aire  igual  o  menor  a  cero  centígrados,  frente  a  la  que  el  agua  se  congela.  Heladas  intensas  por  extenso  período  de  tiempo  pueden  causar  daño  en  tejidos  vegetales  sensibles.  Para  frutales,  esta  combinación  ocurre  en  primavera,  con  condiciones  meteorológicas  inestables  en  el  momento  en  que  los  […]<\/p>\n","protected":false},"author":790,"featured_media":13023,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[7904,180],"tags":[5099,2300,2255,90,5097,5096,177,5100,966,170,4539,5098,2203],"destacados":[],"tematica":[],"acf":[],"_links":{"self":[{"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/posts\/13022"}],"collection":[{"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/users\/790"}],"replies":[{"embeddable":true,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/comments?post=13022"}],"version-history":[{"count":1,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/posts\/13022\/revisions"}],"predecessor-version":[{"id":13027,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/posts\/13022\/revisions\/13027"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/media\/13023"}],"wp:attachment":[{"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/media?parent=13022"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/categories?post=13022"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/tags?post=13022"},{"taxonomy":"destacados","embeddable":true,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/destacados?post=13022"},{"taxonomy":"tematica","embeddable":true,"href":"https:\/\/mundoagro.cl\/wp-json\/wp\/v2\/tematica?post=13022"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}