Comparative Research on Monitoring Methods for Nitrate Nitrogen Leaching in Tea Plantation Soils

Abstract

Abstract Background and aims Great concern has long been raised about nitrate leaching in cropland due to its possible environmental side effects in ground water contamination. we conducted a comparative study on monitoring methods for nitrate N leaching in tea plantation soils.Methods Here we employed two common techniques to measure nitrate leaching in tea plantation soils in subtropical China. Using drainage lysimeter as a reference method, the adaptability of estimating drainage and nitrate leaching by combining the water balance equation with the suction cup technique was investigated.Results The final cumulative leachate volume for the calculated and measured method was 721.43 mm and 729.92 mm respectively during the study period. Meanwhile, The cumulative nitrate leaching loss from the lysimeter and suction cup-based method was 47.45 kg ha− 1 and 43.58 kg ha− 1 under lysimeter nitrate concentrations ranging from 7 mg L− 1 to 13 mg L− 1, 156.28 kg ha− 1 and 79.95 kg ha− 1 under lysimeter nitrate concentrations exceeding 13 mg L− 1.Conclusion The suction cup-based method could be an alternative way of monitoring nitrate leaching loss within a certain range of nitrate concentrations in leachate. Besides, lower results occurred in suction cup samplers due to lack of representative samples which mainly leached via preferential flow when in strong leaching events. Thus, it is advisable to increase sampling frequency under such special conditions. The results of this experiment can serve as a reference and guidance for the application of ceramic cups in monitoring nitrogen and other nutrient-ion leaching in tea plantation soils.