蔬菜质量分级和销售渠道拓展对菜农收益的影响研究

农业是我国的基础产业，蔬菜作为农产品的一个必要组成部分，其发展水平对农民生活生产有重要影响。蔬菜品质区别大而且供给链较长，且蔬菜的市场价格时高时低，这种不稳定性使菜农的蔬菜出售价格不高，对菜农有不利影响。因此，在我国现有的市场条件下，寻找一种保障菜农基本利润的措施以提高菜农的收益是很有必要的。通过理论推导，得出了蔬菜质量分级和销售渠道拓展能够有效提高菜农的利润，提出了相应的政策建议。

Influence of sampling position and quantity of spectrumon nondestructive measurement in guava

It is important to select optimum spectra sampling position and quantity in noninvasive examination ofguava based on near-infrared diffuse reflection. Firstly, 12 kinds of spectra were collected from top, equator and bottom,respectively, then models were built based on 1 spectrum in equator, average spectrum of 4 spectra in equator and averagespectrum of 12 spectra all over the samples. The prediction results demonstrated that the model based on average spectrumof 12 spectra all over the samples was the best, with Rp=0.962, RMSEP=0.432; the model based on average spectrum of 4spectra in equator was better, with Rp=0.793, RMSEP=0.588; the model based on 1 spectrum in equator was the worst,with Rp=0.687, RMSEP=0.438. At last, 23 wavelengths were derived through successive projections algorithm. The modelbased on the 23 wavelengths produced Rp=0.902, RMSEP=0.438. As a result, the average transmission spectra all over top,equator and bottom contain the sample internal quality information adequately. The model based on the all over averagespectrum had better result than the models based on single point or average spectrum over single district.