A field experiment with wheat was conducted with four different nitrogen and four different water stress levels, and hyperspectral reflectances in the 350-2500 nm range were recorded at six crop phenostages for two years (2009-2010 and 2010-2011). Thirty-two hyperspectral indices were determined using the first-year reflectance data. Plant nitrogen (N) status, characterized by leaf nitrogen content (LNC) and plant nitrogen accumulation (PNA), showed the highest R 2 with the spectral indices at the booting stage. The best five predictive equations for LNC were based on the green normalized difference vegetation index (GNDVI), normalized difference chlorophyll index (NDCI), normalized difference 705 (ND 705 ) index, ratio index-1dB (RI-1dB) and Vogelman index a (VOGa). Their validation using the second-year data showed high R 2 (>0.80) and ratio of performance to deviation (RPD; >2.25) and low root mean square error (RMSE; <0.24) and relative error (<10%). For PNA, five predictive equations with simple ratio pigment index (SRPI), photochemical reflectance index (PRI), modified simple ratio 705 (mSR 705 ), modified normalized difference 705 (mND 705 ) and normalized pigment chlorophyll index (NPCI) as predicting indices yielded the best relations with high R 2 > 0.80. The corresponding RMSE and RE of these ranged from 1.39 to 1.13 and from 24.5% to 33.3%, respectively. Although the predicted values show good agreement with the observed values, the prediction of LNC is more accurate than PNA, as indicated by higher RMSE and very high RE for the latter. Hence, the plant nitrogen stress of wheat can be accurately assessed through the prediction of LNC based on the five identified reflectance indices at the booting stage.

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Present study focuses on interventions to reduce vibration transmitted to power tiller operator. In this study two operations (namely: standing mode and transportation) and three forward speeds (1.0, 1.5 and 2.0 kmh-1) were selected. In both selected operations vibration magnitudes were maximum at 2.0 kmh-1. In the standing mode vibration magnitudes in x, y and z direction were 5.83, 1.37 and 2.36 ms -2 at 2.0 kmh-1. In transportation vibration magnitudes were 6.81, 1.49, 2.82 ms-2 respectively in x, y and z direction at 2.0 kmh-1. The selection of vibration isolators were done on the basis of the transmissibility curves and the isolation region. The selected isolators were installed at interface between engine and the chassis. These interventions along with previously developed bush and sheet type interventions reduced vibrations up to 50.24, 69.06 and 59.08 % at 1.0, 1.5 and 2.0 kmh-1 in stationary mode. In transportation vibration reduction were 52.96, 65.98 and 36.67 % at 1.0, 1.5 and 2.0 kmh-1, respectively. The vibration reduction were high in stationary mode than transportation mode because in stationary mode vibration comes only from the engine but in transportation vibration comes from engine and the surface profile as well.