کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4508914 1624467 2014 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Evaluation of optical sensor measurements of canopy reflectance and of leaf flavonols and chlorophyll contents to assess crop nitrogen status of muskmelon
ترجمه فارسی عنوان
ارزیابی حسگرهای نوری اندازه گیری بازتاب کانوپی و برگ فلاونول ها و محتویات کلروفیل برای بررسی وضعیت نیتروژن محصول ماهی قزل آلا
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم زراعت و اصلاح نباتات
چکیده انگلیسی


• Reflectance indices, flavonols and chlorophyll were sensitive to crop N status.
• These optical measures were linearly related to crop N content for most of crop.
• Relationships to crop NNI were equal or slightly better than with N content.
• NBISPAD and NDVI were best predictors of crop N content and NNI for most of crop.
• Composite equations often developed for 2–3 successive weekly measures.

Nitrogen losses from intensive vegetal production systems are commonly associated with contamination of water bodies. Sustainable and optimal economic N management requires correct and timely on-farm assessment of crop N status to detect N deficiency or excess. Optical sensors are promising tools for the assessment of crop N status throughout a crop or at critical times. We evaluated optical sensor measurement of canopy reflectance and of leaf flavonols and chlorophyll contents to assess crop N status weekly throughout a muskmelon crop. The Crop Circle ACS 470 was used for reflectance measurement, the SPAD 502 for leaf chlorophyll, and the DUALEX 4 Scientific for leaf chlorophyll and flavonols. Four indices of canopy reflectance (NDVI, GNDVI, RVI, GVI), leaf flavonols and chlorophyll contents and the nitrogen balance index (NBI), the ratio of chlorophyll to flavonols contents, were linearly related to crop N content and to crop Nitrogen Nutrition Index (NNI) throughout most of the crop. NBI most accurately predicted crop N status; in five consecutive weekly measurements, R2 values were 0.80–0.95. For NDVI during the same period, R2 values were 0.76–0.87 in the first three measurements but R2 values in the last two measurements were 0.39–0.45. Similar relationships were found with the three other reflectance indices. Generally, the relationships with NNI were equal to or slightly better than those with crop N content. These optical sensor measurements provided (i) estimation of crop N content in the range 1.5–4.5%, and (ii) an assessment of whether crop N content was sufficient or excessive for optimal crop growth for NNI ranges of 0.8–2.0. Composite equations that integrated the relationships between successive measurements with the optical sensors and crop N content or NNI for periods of ≥2 weeks (often 2–3 weeks) were derived for most indices/parameters. Overall, these results demonstrated the potential for the use of these optical sensor measurements for on-farm monitoring of crop N status in muskmelon.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: European Journal of Agronomy - Volume 58, August 2014, Pages 39–52
نویسندگان
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