Untitled - MendelNet 2013 - Mendelova zemědělská a lesnická ...

MENDELNET 2013As can be seen from the Table 2, the prediction of soil temperature can not be done from the airtemperature in the ground of wheat canopy recorded at the same time, because coefficients ofdetermination were very low. As it was found out by cross correlation analysis, the bestinterrelationships between these two variables were achieved in 3 hours delay for the soiltemperature in 50 mm and 5 hour delay for 100 mm. After the time correction the determinationcoefficient reached values from 0.76 to 0.88 for 50 mm and 0.61 to 0.74 for 100 mm.Table 2 Regression analysis of dependence of soil temperatures in different depth on airtemperatures from non-corrected (non) and corrected (corr) dataYEAR STAGE 50 mm (non) 50 mm (corr) 100 mm (non) 100 mm (corr)I.y = 0.4499x + 6.4706 y = 0.5348x + 5.5539 y = 0.2523x + 8.2858 y = 0.3772x + 6.9439R² = 0.59 R² = 0.83 R² = 0.30 R² = 0.672010 II.y = 0.5324x + 6.0649 y = 0.5971x + 5.2177 y = 0.3547x + 8.1985 y = 0.452x + 6.923R² = 0.67 R² = 0.84 R² = 0.45 R² = 0.72III.y = 0.5076x + 8.043 y = 0.5649x + 7.0587 y = 0.3119x + 11.086 y = 0.4104x + 9.3943R² = 0.71 R² = 0.88 R² = 0.43 R² = 0.74I.y = 0.2681x + 7.7316 y = 0.3526x + 6.8404 y = 0.1399x + 8.7943 y = 0.2512x + 7.6228R² = 0.44 R² = 0.76 R² = 0.19 R² = 0.612011 II.y = 0.3715x + 7.9594 y = 0.4522x + 6.872 y = 0.2324x + 9.4364 y = 0.3426x + 7.9506R² = 0.54 R² = 0.81 R² = 0.30 R² = 0.66III.y = 0.2904x + 11.016 y = 0.3678x + 9.7235 y = 0.146x + 13.005 y = 0.2538x + 11.21R² = 0.51 R² = 0.81 R² = 0.23 R² = 0.68The knowledge concerning soil temperature is inevitable for modelling of some plant growth anddevelopment models and it is sometimes used for the prediction of pathogens and pest occurrence.Bergjofrd and Skljevag (2011) reported that daily global radiation at plant level and soiltemperature (20 mm) were the only two climatic factors found to have significant effects onperiodic changes in fructan concentration in wheat seed. Different tillage systems can alsoinfluence the temperature of soil and the growth of wheat (He Jing Li 2012).For these purposes the data recorded in standard climatological stations are usually used. Asmentioned above, they can differ from actual temperatures in or under the crop stands. For thesereason the comparison of data recorded should be made in different crop stands and soilmanagement systems as well.CONCLUSIONSAs is evident from analyses, the course of temperatures can significantly differ in soil under variousplant cover and from ones measured in plant stand. The regression lines describing relationshipbetween soil temperature under grass cover and the temperature under wheat canopy was dependenton the wheat developmental stage and year. The best interrelationships between air temperaturemeasured in the ground of wheat stand and soil temperature were achieved in 3 hours delay for thesoil temperature in 50 mm and 5 hour delay for 100 mm. These results must be taken in account toprecision of prediction models of some harmful agent’s occurrence, in models of crop and yielddevelopment etc.97 | P age