Research On The Micro-climate Temporal-spatial Distribution With Verify Estimation Model Of Solar Greenhouse

Solar greenhouse is mainstream agricultural facilities in China. Research on solar greenhouse environment distribution was used to control greenhouse environment, optimize crop growth process and forecast disease occurrence. Greenhouse environment parameters were measured in different cucumber stubble. Using Ordinary kriging method, Solar radiation, temperature and humidity distribution in greenhouse were simulated. The estimation model of leaf temperature above the cucumber canopy and relative humidity were established using the outside meteorological data and the inside greenhouse parameters based on the principle of energy balance and the water dynamic balance in greenhouse. Cucumber downy mildew (Pseudoperonospora cubensis)were imported using the results of the temperature and humidity modeling. The results were presented as below.1. Solar radiation distribution of different cucumber stubble greenhouse gradually reduced from above canopy to bottom canopy.The value of solar radiation was 500W/m2 on sunshine in seasons, and the value of solar radiation was below 100W/m2 on cloudy in seasons. horizontal gradient of solar radiation was like "M" in greenhouse. On the same canopy height, the value of solar radiation of south and north locations exceed middle location.2. Temperature spatial distribution of different cucumber stubble greenhouse was not uniform under different weather conditions. Gradient of Temperature was well distributed on night in different cucumber stubble, and no significant difference between the temperature measurement points. In spring, horizontal temperature gradient gradually reduced from east to west at 13 o ’clock on sunshine and cloudy days, and the maximum temperature at central location in middle canopy on overcast day, and gradient of temperature was well distributed on rain day. In summer, temperature gradient gradually reduced form southeastern corner to north on different canopy heights. In autumn, horizontal temperature gradient of above canopy gradually reduced from south to north at 13 o’clock on sunshine, overcast and rain days, horizontal temperature gradient of middle canopy gradually reduced from middle to east and west sides, horizontal gradient of temperature of bottom canopy was opposite. In winter, horizontal temperature gradient of above canopy gradually reduced from middle to south and north sides at 13 o’clock on sunshine and overcast days, and horizontal temperature gradient of middle and bottom canopy gradually reduced from middle to east and west sides.3. Humidity spatial distribution of different cucumber stubble greenhouse was not uniform under different weather conditions. There was not significant difference about night humidity in spring and summer stubble cucumber greenhouse. The values of night humidity were exceeded 60% in spring, and exceeding 80% in summer. Significant difference was existed about night humidity in autumn and winter stubble cucumber greenhouse. In autumn, the difference values of horizontal humidity gradient were 2% on above and middle canopy, and the difference value of horizontal humidity gradient was 10% on bottom canopy. Horizontal temperature gradient gradually reduced from south to north. In winter night, humidity values exceeded 90% on north side of greenhouse. Difference value between horizontal humidity gradient of bottom canopy was 5% under different weather. Difference value between horizontal humidity gradient of above canopy was 6% on rain day, because film dripping caused humidity difference increasing.4. The estimation models were verificated by the date of September and October of 2014. The differences of the actual and the estimated leaf temperature and relative humidity above the canopy in greenhouse were computed using the root mean square error (RMSD). The results showed that the RMSD of the actual and the estimated leaf temperature were 0.016℃ and 0.024, and the actual and the estimated air humidity were 0.15% and 0.13% in September and October, respectively. Combining with estimated leaf temperature and humidity values, the primary infection warning models for cucumber downy mildew (Pseudoperonospora cubensis) estimated the condition of cucumber downy mildew infected, then using air temperature inside greenhouse, the date of disease occurrence was estimated by incubation period model of cucumber downy mildew, which meet with the actual happen date.At present, Measuring Solar greenhouse environment just used one sensor in greenhouse under actual production conditions. Solar greenhouse was closed or semi-closed facilities, the rule of greenhouse micro-climate distribution was not uniform,and had spatial diversity, the measured value could not represent the whole of greenhouse environment.Using Spatial interpolation method, the temperature and humidity distribution was simulated under different height canopy. Not only accurately understood distribution inside the greenhouse environment, but also forecasted the occurrence of greenhouse plant disease timely,through the environment all-round monitoring.