Nutrient and carbon balances in organic vegetable production on an irrigated, sandy soil in northern Oman
Nutrient and carbon balances in organic vegetable production on an irrigated, sandy soil in northern Oman
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DOI：
10.1002/jpln.201000318
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发表时间：
2011-08
影响因子：
2.5
通讯作者：
Konrad Siegfried;H. Dietz;E. Schlecht;A. Buerkert
中科院分区：
文献类型：
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作者：
Konrad Siegfried;H. Dietz;E. Schlecht;A. Buerkert
我们对亚热带地区灌溉有机种植系统的养分和碳(C)通量的了解是有限的。因此，在阿曼索哈尔附近的一个有机种植系统试验中，测量了24个月的矿质氮(N)和磷(P)的淋失，NH3，N2O，CO2和CH4的气体排放，以及总物质平衡，包括260d的总种植期。在4个重复的灌溉沙土上进行的试验包括两种肥料类型(ORG1和ORG2)，其C/N比分别为19和25，中性洗涤纤维(NDF)与可溶性碳水化合物(SC)的比例分别为17和108。以矿质肥料(MIN)处理和等量矿质氮、磷、钾(K)处理为对照。这三个处理与萝卜(Raphanus Sativus L.)其次是花椰菜(Brassica oleracea L.var.或胡萝卜(Daucus carota subsp.大蒜)。在24个月的实验期内，气态N的平均排放量分别为MIN 45 kg ha-1(59%NH3-N，41%N2O-N)、ORG1 55 kg Nha-1(69%NH3-N，31%N2O-N)和49 kg Nha-1(59%NH3-N，41%N2O-N)。碳损失分别为6.2tha-1(98%CO2-C，2%CH4-C)，9.7tCha-1(99%CO2-C，1%CH4-C)，10.6tha-1(98%CO2-C，2%CH4-C)。基于交换树脂的矿质氮累积淋失量分别为30 kg ha-1/min，10 kg ha-1/ORG1和56 kg ha-1/ORG2。萝卜-胡萝卜和萝卜-花椰菜分别有361 kg N ha-1和196 kg P ha-1和299 kg N ha-1和184 kg P ha-1的表观盈余，同时伴随着-59 kg ha-1和-73 kg ha-1的钾素亏缺。MIN、ORG1和ORG2小区的净碳平衡：萝卜-胡萝卜为-7.3、-3.1和1.5t C ha-1，萝卜-花椰菜为-5.0、1.3和4.6 t C ha-1。这一结果突显了在精耕细作、灌溉的亚热带土壤中维持土壤碳水平的难度。
Our understanding of nutrient and carbon (C) fluxes in irrigated organic cropping systems of subtropical regions is limited. Therefore, leaching of mineral nitrogen (N) and phosphorus (P), gaseous emissions of NH3, N2O, CO2, and CH4, and total matter balances were measured over 24 months comprising a total cropping period of 260 d in an organic-cropping-systems experiment near Sohar (Oman). The experiment on an irrigated sandy soil with four replications comprised two manure types (ORG1 and ORG2) characterized by respective C : N ratios of 19 and 25 and neutral detergent fiber (NDF)-to-soluble carbohydrates (SC) ratios of 17 and 108. A mineral-fertilizer (MIN) treatment with equivalent levels of mineral N, P, and potassium (K) served as a control. The three treatments were factorially combined with a cropping sequence comprising radish (Raphanus sativus L.) followed by cauliflower (Brassica oleracea L. var. botrytis) or carrot (Daucus carota subsp. sativus). Over the 24-months experimental period gaseous N emissions averaged 45 kg ha–1 (59% NH3-N, 41%N2O-N) for MIN, 55 kg N ha–1 (69% NH3-N, 31%N2O-N) for ORG1, and 49 kg N ha–1 (59% NH3-N, 41% N2O-N) for ORG2. Carbon losses were 6.2 t ha–1 (98% CO2-C, 2% CH4-C) for MIN, 9.7 t C ha–1 (99% CO2-C, 1% CH4-C) for ORG1, and 10.6 t ha–1 (98% CO2-C, 2% CH4-C) for ORG2. Exchange resin–based cumulative leaching of mineral N amounted to 30 kg ha–1 for MIN, 10 kg ha–1 for ORG1, and 56 kg ha–1 for ORG2. Apparent surpluses of 361 kg N ha–1 and 196 kg P ha–1 for radish-carrot and 299 kg N ha–1 and 184 kg P ha–1 for radish-cauliflower were accompanied by K deficits of –59 kg ha–1 and –73 kg ha–1, respectively, for both cropping systems. Net C balances for MIN, ORG1, and ORG2 plots were –7.3, –3.1, and 1.5 t C ha–1 for radish-carrot and –5.0, 1.3, and 4.6 t C ha–1 for radish-cauliflower. The results underline the difficulty to maintain soil C levels in intensively cultivated, irrigated subtropical soils.