Study of Dynamics SPAD and NDVI Values of Potato Plants According to the Differentiated Fertilization

Abstract

Potato fertilization (especially nitrogen fertilization) has repercussions on the dynamics of plant growth and the production and quality. Recent results of research on the dynamics of NDVI and SPAD values of potatoes indicates ample opportunities to use these non-invasive measures to monitor the condition of vegetation in different crop growing conditions (Puiu et al. 2012, Shukla et al. 2007). The researches were conducted to obtain information on the possibilities of non-invasive assessment of NPK fertilization effects on the state of potato plants growing in non-irrigated conditions. Between 2013-2014, at NIRDPSB Brasov (Romania) were performed measurements of vegetation index NDVI, chlorophyll content and measurements of plant varieties Christian and Roclas harvested in dynamic, on two levels of nitrogen fertilization, N100 and N200 NPK reports 1: 1: 1 and 1: 0.9: 2. On the second decade of June 2013, the NDVI mean of Christian variety plants was 88.7, compared to 86.9 at Roclas variety. The SPAD values were 46.6 and 44.7. On 2014, a year with higher humidity, NDVI average values ​​were higher on both varieties (91.6 and 90.8) and the SPAD values were lower ​​(41.8 and 41.5). NDVI values of potato plants from fertilized variants were statistically differentiated according by variety, especially in the second part of the growing season. Through SPAD values differentiation of fertilization variants has been possible throughout the entire period observed. Hydrothermal conditions of vegetations limits the separation of fertilization variants with NDVI measurements, while SPAD values reflect supply plants with nitrogen.