Emergencia y sobrevivencia de gramíneas con diferentes secuencias de humedad-sequía en tres tipos de suelo

Abstract

Land degradation can be reversed using revegetation. Reseeding in degraded pastures is high risk, and requires knowledge of grass species behavior under several precipitation regimens. A study was done to evaluate germination and survival of native and introduced gramineas in an arid environment under different wet-dry sequences and in different soil types. The experiment was conducted under greenhouse conditions. Soils were collected from abandoned crop land in central Chihuahua, Mexico. Wet-dry sequences were determined based on 35 years of regional precipitation data for July. Three native grasses and three introduced grasses were planted in three soil types and subjected to four wet-dry sequences. A treatment was one grass species in one soil type with one wet-dry sequence. Data was analyzed with an ANOVA under a linear model using categorical data analysis, by species and soil type. Emergence and survival increased with increased moisture in all soils and species. The highest survival percentages ranged from 20 to 50 %, depending on soil type, wet-dry sequence and grass species. Of the native grasses, blue grama (Bouteloua gracilis) and side oats (Bouteloua curtipendula) had the lowest establishment percentage, while green sprangletop (Leptochloa dubia) had a higher survival index in all three soil types. Of the introduced grasses, weeping love grass (Eragrostis curvula) and Wilman love grass (Eragrostis superba) had he highest survival percentages, Wilman love grass had the best adaptation range, and Kleingrass (Panicum coloratum) did not have an aceptable survival index. These grass growth and development data are vital for planning successful reseedings.El objetivo del trabajo fue estimar el efecto de diferentes patrones de humedad sequía sobre la emergencia y sobrevivencia de gramíneas, en tres tipos de suelo de áreas de cultivo abandonadas en el estado de Chihuahua, en condiciones de invernadero. Las secuencias fueron seleccionadas de los patrones más comunes de como la precipitación se presentó en 35 años durante el mes de julio (mes de mayor precipitación). Los tratamientos fueron la combinación de tres tipos de suelo, cuatro secuencias de humedad sequía y seis gramíneas. Los datos se sometieron a un análisis de varianza en un modelo lineal con datos categóricos, en el que se realizaron análisis individuales por especie en cada uno de los tipos de suelo. La emergencia y sobrevivencia de los zacates se incrementó (