Agronomic and physiological responses of a tomato crop to nitrogen input

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• 作者：Antonio Elia ; ^{a.elia@unifg.it} ; Giulia Conversa
• 关键词：Partial factor productivity ; Agronomical NUE ; Physiological NUE ; Apparent N recovery efficiency ; NNI ; N dilution curve ; N uptake ; RUE ; Specific leaf N
• 刊名：European Journal of Agronomy
• 出版年：2012
• 期刊代码：42_11610301
• 类别：abs
• 出版时间：July, 2012
• 卷：40
• 期：Complete
• 页码：64-74
• 文件大小：1159 K

摘要

Two field experiments were carried out during 2005 and 2006 to study the effect of four N-fertilization rates (0 (N₀), 100 (N₁₀₀), 200 (N₂₀₀), and 300 (N₃₀₀) kg ha^鈭?) on yield, growth, N uptake, and N use efficiency of processing tomato in a silty-clay soil under Mediterranean conditions. N supply positively affected LAI (leaf area index), radiation use efficiency (RUE), above-ground dry weight (DW) and N accumulation. The respective maximum values 4.6, 1.16 g MJ^鈭?, 13.4 Mg ha^鈭?, and 383 kg ha^鈭? were detected with N_300. However, passing from the N₂₀₀ to the N₃₀₀ rate, the DW and the N tissue content mostly increased in the vegetative organs resulting in lower total and marketable yield, attributable mainly to the lower number of fruit in N₃₀₀ plants. N excess exacerbates the unbalanced vegetative/reproductive plant growth which occurred when seasonal temperatures negatively affected crop productivity by reducing fruit load. Maximum total and marketable yield were obtained with the N₂₀₀ rate and were respectively 155 and 119 Mg ha^鈭? in 2005 and 135 and 104 Mg ha^鈭? in 2006 season. N supply quadratically decreased the agronomical (NUEa) and physiological (NUEp) N use efficiency, these indices reaching a maximum with the N₂₀₀ rate (NUEa = 11.8 kg kg^鈭?, NUEp = 15.1 kg kg^鈭?). However, increasing N supply decreased partial factor productivity and the efficiency in N fertilizer recovery linearly to 24 and 0.55 kg kg^鈭?. Nitrogen nutrition index (NNI) was 0.8 in N₀ plants and increased up to 1.3-1.4 with N₃₀₀. Under Mediterranean conditions and with the specific tomato cultivar, the N₂₀₀ rate can be considered the most efficient both in terms of yield and NUE, and the respective NNI values of 1.15-1.23 (in the period from maximum LAI to harvest) could be associated with the optimal N nutritional status of the crop indicating that the minimal N concentration to obtain the maximum above-ground DW is higher than that proposed as critical for this crop. From an environmental standpoint, a 200 kg ha^鈭? of nitrogen fertilizer dose would put this production system in N balance, with N removal from the field being close to 200 kg ha^鈭? with a yield goal of 100-120 kg ha^鈭? of marketable fruits containing 1.97 kg Mg^鈭? of N.