Estimating Residual Wheat Dry Matter from Remote Sensing Measurements
2002; American Society for Photogrammetry and Remote Sensing; Volume: 68; Issue: 11 Linguagem: Inglês
ISSN
2374-8079
AutoresDonald C. Rundquist, Nereu Augusto Streck,
Tópico(s)Remote Sensing and LiDAR Applications
Resumoatmospheric CO,, it is important to maintain a cover of postPlant left in the field after harvest is an important harvest residue as a sink for carbon (Schlesinger, 1999; Bruce et product of agricultural ecosystems. A laboratory experiment al.y lgg9; RObertsOnetal., 2000). was carried out with the objectives of (I) testing optical remote The benefits of maintaining a cover of crop resip sensing as a means of measuring the amount of wheat residue due comprise a rationale for quantifying the amount of that dry matter (DM), and (2) the between the material present in agricultural fields. Such quantification, amount of wheat residue and reflectance indices. Six however, is not only difficult but also laborious. Two simple backgrounds (three types of soil with dry and wet surfaces) approaches, intercept and photographic, have been used and increasing amounts of wheat residue DM (0, 20, 50, 100, (Laflen eta]., 1981; Corak eta]., 1993; Morrison eta]., 1993). 150, 200, 250, 300, 400, 800, and 1500 g/m2) were used. A The former measures the presence or absence of residue at a equation was used to estimate DM based on two finite number of points in a field (i.e., at grid locations) reflectance indices, the Cellulose Absorption Index (CAI) and whereas the latter n~akes use of aerial or terrestrial photographs the Normalized ~jff~~~~~~ index (NDI). When cAI was used as Or images and either manual or computerized methods to cominput, the model performed well with an average error of about pare the area of residue versus the area of bare soil. ~oth meth50 g/m2 and the residue was discriminated from soil up to a od~ attempt to n~easure the percentage of soil covered by dose of^^ of about 600 g/m2. when was used, the model residual material, but are not useful for measuring the amount was only able to discriminate from soil when DM was (i.e., total dry matter) of residue. Although percent residue less than about 300 g/m2, with an average error of estimation cover comprises important information, those interested in cargreater than 100 g/mZ. Limitations of this study include the bon seek the actual amount (e-g.7 kg/ha) of fact that moisture and weathering were not considered. matter remaining after harvest. Few studies have addressed the issue of estimating the amount of residue in fields using remote
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