Spatial variability of soil properties and yield of a grazed alfalfa pasture in Brazil

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• 作者：A. C. C. Bernardi ; G. M. Bettiol ; R. P. Ferreira ; K. E. L. Santos…
• 关键词：Soil fertility ; VESPER ; SPRING software ; Variable rate technology (VRT) ; Medicago sativa ; Profitability
• 刊名：Precision Agriculture
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：17
• 期：6
• 页码：737-752
• 全文大小：1,455 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment
  Soil Science and Conservation
  Agriculture
  Meteorology and Climatology
  Statistics for Engineering, Physics, Computer Science, Chemistry and Geosciences
  Remote Sensing and Photogrammetry
  
• 出版者：Springer Netherlands
• ISSN：1573-1618
• 卷排序：17

文摘

Knowledge of the spatial variability of soil properties and of forage yield is needed for informed use of soil inputs such as variable rate technology (VRT) for lime and fertilizers. The objective of this research was to map and evaluate the spatial variability of soil properties, yield, lime and fertilizer needs and economic return of an alfalfa pasture. The study was conducted in a 5.3 ha irrigated alfalfa pasture in Sao Carlos, SP, Brazil that was directly grazed and intensively managed in a 270-paddock rotational system. Alfalfa shoot dry matter yield was evaluated before grazing. Soil samples were collected at 0–0.2 m depth, and each sample represented a group of 2 or 3 paddocks. Apparent soil electrical conductivity (ECa) was measured with a contact sensor. The cost of producing 1 ha of alfalfa was estimated from the amount of lime and fertilizer needed and was then used to estimate the total cost of production for the dairy system. The alfalfa dry matter yield was used to simulate the pasture stocking rate, milk yield, gross revenue and net profit. The spatial variability of soil properties and site-specific liming and fertilizer needs were modeled using semi-variograms with VESPER software, the soil fertility information and economic return were modeled with SPRING software. The results showed that geostatistics and GIS were effective tools for revealing soil and pasture spatial variability and supporting management strategies. Soil nutrients were used to classify the soil spatial distribution map and design site-specific lime and fertilizer application maps. Spatial variation in forage and spatial estimates of stocking and milk yield are adequate pasture management tools. Spatial analyses of needs, forage availability and economic return are management tools for avoiding economic problems, as well as potential environmental problems, caused by unbalanced nutrient supplies and over- or under-grazing.