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Productive performance of Atriplex canescens forage for 30 years of exclusion and grazing in different seasons of the year in the North of Mexico
The shortage of forage in rangeland of northern Mexico is becoming more serious every year. Using some shrubs such as saltbush ( Atriplex canescens ( Pursh ) Nutt. ), can be a feeding strategy because of its high nutritional value. Additionally, its utilization improves ecosystems. Therefore, the use of shrubs improves the productivity of rangelands. The objective of this study was to determine whether the exclusion and / or livestock grazing affect dry matter production of saltbush scrub parvifolio in northern Mexico. Production of dry matter in kg / ha during the four seasons (2012-2013) (free-range grazing vs. exclusion) was determined. The plots are distributed in two sites. To collect forage samples quadrant method was used. The data were analyzed using PROC GLM of SAS. The results were a highly significant difference ( p< 0.0001 ) was found between the grazing exclusion treatment and the free grazing treatment during every season of the year, for the grazing exclusion site (spring, summer, fall and winter), means of (97.5, 355, 262.5, 95 kg MS/ha, respectively) were found and for the grazing site (65, 274, 144.5, 52.5 kg MS/ha, respectively). Also, a highly meaningful difference between both grazing exclusion and free grazing treatments of (p<0.0022) was found, whose means are (202.5 and 134 kg MS/ha, respectively). With the above we conclude that the shrubs that remained in grazing exclusion can improve the productivity of rangelands and solve the shortage of fodder in times of crisis. On the other hand, where there had been free grazing, the implementation of management strategies to reduce the negative effects of over-consumption of this shrub by livestock is fundamental.
Keywords: forage, chamizo, fourwing saltbush, grazing, exclusion