Non-Destructive Estimation Oilseed Rape Nitrogen Status using Chlorophyll Meter
Chlorophyll meter, soil plant analysis development (SPAD) is a simple, portable diagnostic tool that measures the greenness or relative content of leaves. The objective of this study is to analyze the relationships between the chlorophyll meter readings of the functional leaves at different stages and the nitrogen content of the oilseed rape leaves, and analyze the variation laws of the SPAD values of the oilseed rape in different growth stage and different fertilizer levels by using the spatial distribution maps of the geographic information system (GIS) software. The experiment is conducted in the farm of Zhejiang University. Three nitrogen fertilizers and two repeated experiments are carried on in this research. The result shows that SPAD values can represent the nitrogen content of the oilseed rape leaves with the correlation coefficient of 0.863, and different growth stages and different fertilizer levels have different SPAD values, but the variation laws is regular, which is beneficial for the further nitrogen management, so interim stage from bud to anthesis was recommended as the optimal management stage for nitrogen fertilizer recommendations