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The changes of mineral nitrogen content in clay loam Cambisol in sustainable and organic agriculture
clay loam organic and sustainable farming system winter wheat straw green manure
2010/1/19
The changes of mineral nitrogen content in clay loam Cambisol in sustainable and organic agriculture.
基于PCA_SVR的油菜氮素光谱特征定量分析模型（Rape Nitrogen Content Spectral Character Models Based on PCA_SVR Method）
油菜 氮素 光谱分析
2009/5/22
研究了采用光谱分析技术对油菜植株全氮进行定量分析的方法。采用逐步回归法对氮素的光谱特征波长进行选择，为克服光谱变量间多重共线性的影响，对变量进行了主成分分析（PCA），为提高模型的拟合优度，应用支持向量机回归(SVR)建立油菜氮素的定量分析模型。对不同氮素水平的油菜冠层光谱数据进行分析，结果表明，406、460、556、634、662、675nm的光谱反射率与油菜含氮量呈极显著相关。植株全氮SVR...
Nitrogen content and its uptake by maize as influenced by some meteorological elements and fertilization
maize N content N uptake temperature saturation deficit
2008/11/13
The experiment was conducted during the period 1982�1987 at the field station Sredec, Stara Zagora region on leached Smolnitza soil. Two maize hybrids (300 and 700 FAO) grown under irrigation a...