engleski

Nitrate-Nitrogen rates in Petiole Sap of Potato Crop (Solanum tuberosum L.)

Nitrate-nitrogen is a primary limiting factor in planth growth and quality.Insufficient supply or oversupply of this element is a serious issue. Field data presented here are related to potato (Solanum tuberosum L.) experiment in Bosnia and Herzegovina in 2007, where we have compared three potato cultivars: Liseta, Romano and Adora, receiving similar nitrogen treatments (0, 100 and 200 kg N ha-1). In this trial we have measured the amount of nitrate nitrogen in the plant at four stage of the potato crop vegetation (65, 75, 85 and 95 days after sowing). Measurement has been performed by Cardy-ion meter on leaf petiole sap and compared with percentage of nitrogen in potato leaves. With this meter we can ensure the right amount of nitrogen at the right time for the higher production of potato crop. Leaves petioles were the most responsive to N treatment in terms of nitrate concentrations as they accumulate nitrates more than other parts of plants.As we recorded, the concentration of nitrates of leaf petiole sap, declined with plant ageing, as the reduction and binding into organic compounds took place. However, such effects are probably a reflection of favorable environmental condition for a higher nitrogen mineralization in late growth period. Water stress also have influence on nitrate-nitrogen content in plants as over participation decrease concentration of N-NO3 in petiole sap, while dry period leads to accumulation of N-NO3 in petiole sap. Nitrate-nitrogen rate in petiole sap was influenced by soil nitrogen supply which is directly affected by rainfall or irrigation of this trial as the nitrogen is a good predictor of yield response to different fertilization rates. The objective of this study was to estimate nitrates contents measured by Cardy-ion meter and to link observations with total leaf nitrogen obtained from standard laboratory analysis. On bases of regression analyzes we will see relationship between nitrate-nitrogen and total nitrogen in potato tubers. We will also show reflection of increasing nitrogen doses on NO3-N measured by Cardy -ion meter and total nitrogen measured by Kjeldal methods. Measurements of nitrate-nitrogen rate in potato crop by Cardy-ion meter may be use in a way to reduce sampling time period required for precisely determining fertilization and for prevention over fertilization. For this matter we want to show how the plant analyses are depended on nitrogen fertilization, the type of cultivar and climate.

fertilization; nitrates; nitrogen; petiole sap; Solanum tuberosum L.

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