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1.
Abstract. The repeated application of pig slurry to agricultural soils may result in an accumulation of salts and a risk of aquifer pollution due to nitrate leaching and salinization. Under Mediterranean conditions, a field experiment on a sandy loam soil (Typic Xerofluvent) was performed with maize (Zea mays) in 1998, 1999 and 2001 to study the effects of applying optimal (P1) and excessive rates (P3) of pig slurry on soil salinization, nitrate leaching and groundwater pollution. The rate of pig slurry was established considering the optimal N rate for maize in this soil (170, 162 and 176 kg N ha?1 for 1998, 1999 and 2001, respectively). Pig slurry treatments were compared to an optimal N rate supplied as urea (U) and a control treatment without N fertilizer (P0). The composition of the slurries showed great variability between years. Mean NO3? leaching losses from 1998 to 2001 were 329, 215, 173 and 78 kg N ha?1 for P3, P1, U and P0 treatments, respectively. The amount of total dissolved salts (TDS) added to the soil in slurry application between 1998 and 2001 was 2019 kg TDS ha?1 for the P1 treatment and 6058 kg TDS ha?1 for the P3 treatment. As a consequence, the electrical conductivity (EC) of the slurry‐treated soils was greater than that of the control soil. The EC correlated significantly with the sodium concentration of the soil solution. Over the entire experimental period, 2653, 2202 and 2110 kg Na ha?1 entered the aquifer from the P3, P1 and P0 treatments, respectively. The P3 treatment did not significantly increase grain production in 1999 and 2001 compared with that achieved with the optimal N rate treatment (P1). This behaviour shows the importance of establishing application guidelines for pig slurry that will reduce the risk of soil and groundwater pollution.  相似文献   
2.
新鲜蔬菜硝酸盐含量测定的改进试粉法   总被引:11,自引:0,他引:11  
 为适应新鲜蔬菜硝酸盐快速检测的需要, 在现有试粉法的基础上对硝酸盐测定的试粉法进行了改良研究。结果表明, 本研究建立的直接以去离子水浸提蔬菜匀浆, 混合试粉配方为柠檬酸∶一水硫酸锰∶无水对氨基苯磺酸∶N - 1 - 萘乙二胺盐酸盐∶细锌粉= 30∶4∶1.6∶0.8∶1, 其加入量为0.1 g的改进试粉法, 对于溶液中硝酸盐含量在0~20 mg/L范围时, 显色吸光值与硝酸盐含量呈现良好的线性关系, 相关系数达0.9999, 方法回收率在97.7%~104.5%之间, 相对标准偏差2.71%。用本改进试粉法测定11种蔬菜的硝酸盐含量与国标法测定结果的t检验具有一致性。  相似文献   
3.
大白菜不同品种对硝酸盐积累差异的研究   总被引:6,自引:0,他引:6  
陶正平 《园艺学报》2005,32(4):698-700
 将17个大白菜品种在高浓度氮素水平下营养液栽培, 分析各品种不同时期硝酸盐含量, 发现不同品种之间硝酸盐含量差异达到极显著, 最高和最低者相差两倍以上。硝酸还原酶的活性同硝酸盐含量相关性达到显著负相关, 但是也有硝酸盐含量低, 同时硝酸还原酶活性也低的品种, 通过分析认为可以通过育种途径培育出硝酸盐低积累量的品种。  相似文献   
4.
复合微生物肥料在无公害蔬菜栽培上的效应初报   总被引:13,自引:1,他引:13  
施用复合微生物肥料使番茄产量提高 7.3 %~ 11.1% ,可溶性固形物含量提高 0 .9%~ 1.3 % ,硝酸盐含量降低 2 7.2 %~ 3 4 .8% ;苦瓜产量提高 10 .7%~ 16.1% ,硝酸盐含量降低 2 8.7%~ 3 6.1% ;菜薹产量提高 7.2 %~ 15.1% ,硝酸盐含量降低 55.6%~ 61.5%。各处理产品中的硝酸盐含量及有害元素的含量 ,均符合无公害蔬菜产品质量标准要求  相似文献   
5.
白菜不同品种对硝酸盐吸收积累差异原因初探   总被引:10,自引:0,他引:10  
 用两组积累硝酸盐不同的白菜品种作试材,测定其吸收硝酸盐的速率、动力学常数Km与V一、硝酸还原代谢库内硝酸根浓度(MPS)和硝酸还原酶活性(NRA),结果表明,不同白菜品种吸收硝酸根的速率、Km与V 、MPS、NRA存在较大的差异;硝酸盐积累的差异主要是由于吸收硝酸根的速率不同,与硝酸根在其体内的运转、代谢并无显著直接相关。  相似文献   
6.
Although the effects of cover crops (CC) on various soil parameters have been fully investigated, less is known about the impacts at different stages in CC cultivation. The objective of this study was to quantify the influence of CC cultivation stages and residue placement on aggregates and microbial carbon (Cmic). Additionally, the influence of residue location and crop species on CO2 emissions and leached mineralized nitrogen (Nmin) during the plant degradation period was also investigated. Within an incubation experiment, four CC species were sown in soil columns, with additional columns being kept plant‐free. After plant growth, the columns were frozen (as occurs in winter under field conditions) and then incubated with the plant material either incorporated or surface‐applied. With CC, concentrations of large and medium macroaggregates were twice that of the fallow, confirming positive effects of root growth. Freezing led to a decrease in these aggregate size classes. In the subsequent incubation, the large macroaggregates decreased far more in the samples with CC than in the fallow, leading to similar aggregate size distributions. No difference in Cmic concentration was found among the CC cultivation stages. CO2 emissions were roughly equivalent to the carbon amounts added as plant residues. Comparison of columns with incorporated or surface‐applied residues indicated no consistent pattern of aggregate distribution, CO2 emission or Cmic and Nmin concentrations. Our results suggest that positive effects of CC cultivation are only short term and that a large amount of organic material in the soil could have a greater influence than CC cultivation.  相似文献   
7.
Abstract

The usefulness of the nitrate‐specific ion electrode (NE) for the determination of nitrate nitrogen (NO3‐N) in surface and ground water was determined. The NE method had several advantages that made it superior to the phenoldisulfonic acid (PDS) method in our environmental quality studies. Samples could be analyzed quickly and with a minimum of sample preparation. Sample coloration and soluble salts did not interfere with the performance of the electrode. Range of detection without dilution was much wider than by the PDS method. Also, the values obtained by the NE method, although slightly greater than those obtained by the PDS method, were satisfactory.  相似文献   
8.
利用超声波对化肥控失材料(LCM)进行修饰改性,结果表明对硫酸铵的控失效果随处理时间呈现先升高然后降低的规律,峰值出现在5min.本文对其机理进行初步探讨.  相似文献   
9.
10.
玉米果穗发育的生理特性研究   总被引:1,自引:0,他引:1       下载免费PDF全文
为了探讨玉米优良自交系选育中出现短苞叶品种的原因,从生理角度分析了两玉米自交系品种穗轴与苞叶生长发育变化趋势。结果表明:四个时期中139号苞叶硝酸还原酶活性非常低,对照1号的稍高一些。139号苞叶谷氨酰胺合成酶活性小于1号,且1号的酶活性变化较平缓。139号雌穗轴硝酸还原酶活性变化剧烈,授粉后15d达高峰,明显大于1号。139号雌穗轴谷氨酰胺合成酶活性前三时期始终大于1号,最后一时期二者几乎相等,但1号的酶活性变化平缓。就上述结果从氮代谢方面分析了139号苞叶与穗轴发育失调的原因。  相似文献   
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