Ideal transition pattern of nitrate concentration for improving quality of spinach Spinacea oleracea L. and effect of drip fertigation on the sugar and oxalate concentration

(pp. 25–32)

The effectiveness of drip fertigation, which is known to control fertilizer application, for reducing nitrate in spinach and for improving the other qualities of spinach was investigated. Fertilizer application can be controlled effectively by drip fertigation. In 2002 and 2003, two spinach cultivars were grown in a plastic greenhouse with 4, 8 or 12 g N m^?2 of fertilizer application by drip fertigation, and with 8, 12 or 16 g N m^?2 of fertilizer application as a basal application. Nitrate concentration of petiole sap extracted by a garlic squeezer was significantly correlated with the water-extractable nitrate concentration. Nitrate concentrations of petiole sap extracted from plants treated with 12, 8 and 4 g N m^?2 of fertilizer by drip fertigation were constant, gradually decreased and significantly decreased, respectively, during the last 2 weeks. When nitrate concentration decreased during the last week, nitrate concentration in spinach at harvest was less than 3,000 mg kg^?1 FW. Thus it was thought that the pattern of the time course of nitrate in petiole xylem sap is a good indicator for getting spinach with low nitrate. The sugar concentration was negatively correlated with applied nitrogen quantity and the nitrate concentration. The total oxalic acid concentration in spinach treated by drip fertigation was significantly lower than that in spinach treated by basal application, independent of the amount of applied nitrogen. Thus drip fertigation is advantageous for improving crop quality.     

Effect of phosphogypsum application on the growth and Ca uptake of Komatsuna Brassica rapa L. cv. Natsurakuten

(pp. 1–7)
Application of phosphogypsum PG and limestone to Andisol were compared in terms of their effects on the growth and uptake of Ca in Komatsuna Brassica rapa L. cv. Natsurakuten. The studies were carried out in soil pot cultures, and both PG and limestone were applied to the Andisol at the rates of 0, 0.30, 0.75, 1.50 g kg⁻¹ in the form of CaO.

• 1) 

  Limestone application resulted in an increase in the soil pH. On the other hand, no change was observed in the case of PG application at pH 6.1 ± 0.1 regardless of the application rate. Both soil EC and water-soluble Ca increased in proportion to the PG application rate, and this increase was approximately 5 times greater than that observed when limestone was applied at 1.50 g kg⁻¹. The w-Ca/ex-Ca ratio (water-soluble Ca: 1 M acetic acid-extractable Ca) was clearly increased from 0.12 up to 0.26 in PG, while the value was slightly decreased from 0.12 to 0.05 in limestone.

       
  
  

Desalination of sea water by akadama soil and akadama soil-inorganic adsorbents mixtures

(pp. 25–32)
The effectiveness of drip fertigation, which is known to control fertilizer application, for reducing nitrate in spinach and for improving the other qualities of spinach was investigated. Fertilizer application can be controlled effectively by drip fertigation. In 2002 and 2003, two spinach cultivars were grown in a plastic greenhouse with 4, 8 or 12 g N m⁻² of fertilizer application by drip fertigation, and with 8, 12 or 16 g N m⁻² of fertilizer application as a basal application. Nitrate concentration of petiole sap extracted by a garlic squeezer was significantly correlated with the water-extractable nitrate concentration. Nitrate concentrations of petiole sap extracted from plants treated with 12, 8 and 4 g N m⁻² of fertilizer by drip fertigation were constant, gradually decreased and significantly decreased, respectively, during the last 2 weeks. When nitrate concentration decreased during the last week, nitrate concentration in spinach at harvest was less than 3,000 mg kg⁻¹ FW. Thus it was thought that the pattern of the time course of nitrate in petiole xylem sap is a good indicator for getting spinach with low nitrate. The sugar concentration was negatively correlated with applied nitrogen quantity and the nitrate concentration. The total oxalic acid concentration in spinach treated by drip fertigation was significantly lower than that in spinach treated by basal application, independent of the amount of applied nitrogen. Thus drip fertigation is advantageous for improving crop quality.     

滴灌施氮肥对盆栽玉米生长的影响

本研究通过滴灌施氮肥与常规的基施氮肥进行比较试验,以了解两种不同的施肥方式下施用不同品种氮肥对氮肥利用率的影响。试验设10个处理,所选用的氮肥品种有:尿素、硝酸铵、硝酸钙、硫酸铵。试验结果表明,同基施氮肥+滴灌处理相比,滴灌施氮肥处理能显著提高氮肥的利用率,其增幅达8.75%～21.50%,有利于玉米对氮肥的吸收及生物量的积累;在同一灌溉施肥条件下施用不同品种的氮肥时,各处理间的氮肥利用率表现出一定的差异性,其中硝酸钙处理的氮肥利用率显著低于另外3种氮肥处理。     

不同灌溉施氮肥方式对香蕉根系生长的影响

试验通过在渗滤池中种植香蕉，研究了滴灌施氮肥和浇灌施氮肥两种施肥方式对香蕉根系生长的影响。结果表明，合理施用氮肥能显著促进香蕉根系的生长，如在滴灌施氮肥条件下香蕉二级根的根表面积比对照增加了52％；对香蕉而言，滴灌施肥技术是一种理想的灌溉施肥方式，与浇灌施肥相比，它能显著增大香蕉二级根的根表面积，其增幅达15％。     

Effects of differences in the nitrogen composition of paste-like fertilizer applied as side dressing on growth and the nitrate concentration of spinach (Spinacia oleracea L. var. crispa)

pp. 849–857

To evaluate the effects of differences in nitrogen composition in paste-like fertilizers applied as side dressing, growth and nitrate concentration of spinach (Spinacia oleracea L. var. crispa) grown in containers were examined and compared to standard fertilization using a compound fertilizer (standard, N, P₂O₅ and K₂O applied to the soil at a rate of 120 mg kg^?1). Three kinds of paste-like fertilizer, which differ in nitrogen source, i.e. urea, a 1:1 mixture of urea and residual liquid with fermented molasses (RLFM) and RLFM, were applied to the soil as side dressing at a rate that was 20% below the standard. Dry matter production and N uptake in spinach treated with paste-like fertilizers was comparable to that treated with standard fertilizer, while the nitrate concentration in spinach treated with paste-like fertilizers was lower than that treated with standard fertilizer. Among the paste-like fertilizers, the nitrate concentration in spinach decreased with the increasing rate of RLFM, in which the major N sources were composed of proteins and amino acids.

To understand the possible explanation for better growth and low nitrate concentration in spinach treated with paste-like fertilizer despite the lower application rate, N concentrations of ammonium, nitrate and organic N were assessed temporally by leaching water from fallow plots. At the initial time of incubation, the nitrate concentration in the leaching water from the standard fertilizer was higher than that from paste-like fertilizer treatments. The paste-like fertilizer composed of urea, however, showed a higher concentration of organic N which was supposed to be urea. The fertilized-N of the standard and paste-like fertilizer composed of urea might be immediately eluviated by irrigation. However, N concentration in the leaching water after treatments with paste-like fertilizer composed of RLFM was lower than that of the former treatments, suggesting that fertilized-N might remain localized. The amount of N eluviated during incubation showed a negative correlation with the viscosity of the paste-like fertilizer. The highest viscosity was observed in the paste-like fertilizer composed of RLFM, followed by a 1:1 mixture of urea and RLFM, and the paste-like fertilizer composed of urea was the lowest in viscosity. Therefore, it was suggested that the paste-like fertilizer composed of RLFM or a 1:1 mixture of urea and RLFM showed limited N leaching due to the high viscosity. Therefore, spinach could take up N efficiently.     

滴灌施氮对烤烟氮素吸收利用及土壤无机氮分布的影响

为明确适合烤烟生长并降低土壤氮素损失的滴灌施氮策略,为烤烟生产提供理论指导。以烤烟品种K326为材料,在盆栽条件下,研究了滴灌施氮对烤烟氮素积累、分配和利用及土壤无机氮含量与分布的影响。结果表明:移栽后28 d滴灌追氮一次,增加追氮比例,叶片的氮素含量、氮素积累量和分配比例增加,根和茎的氮素积累量和分配比例降低,烟株表观氮素利用率提高;土壤无机氮含量升高,土壤无机氮的表观盈余量降低。移栽时施氮50%,移栽后28和42 d滴灌追氮两次的氮素利用率显著高于追氮一次处理;而追氮比例为70%和90%时,氮素利用率低于追氮一次处理。移栽后滴灌追氮两次提高了距滴注点垂直距离5～20 cm和水平距离15～20 cm土层的土壤无机氮含量,降低了距滴注点垂直距离20～25 cm土层的土壤无机氮含量。从烟株氮素利用,土壤无机氮分布及盈余量等方面考虑,移栽时施氮50%,移栽后28 d滴灌追氮35%,42 d滴灌追氮15%可作为生产中参考的滴灌施肥制度。     

滴灌施肥对菠萝产量、品质及经济效益的影响

通过在徐闻县对当地普遍种植的巴厘种菠萝展开不同管理方式的对比研究,探讨了滴灌施肥与常规施肥对菠萝产量、 品质以及经济效益的影响。试验设3个处理, 空白对照、 常规施肥和滴灌施肥。结果表明,与常规施肥相比,在菠萝上使用滴灌施肥技术,产量可达到81405 kg/hm2,增产39.04%,果实内在品质无下降,但商品品质得到大幅度提高,商品果率为95.73%,较常规处理高11.51%。净收入较常规施肥处理高69670 Yuan/hm2 ,增长92.07%,节省用工成本1125 Yuan/hm2,产出投入比由2.00∶1上升到2.97∶1。N、 P2O5分别节省42.84%、 52.67%。滴灌施肥对菠萝的产量、 商品品质以及经济效益提高有积极影响。     

滴灌施肥时水肥顺序对番茄根系分布和产量的影响

利用田间试验，在日光温室内研究了滴灌施肥灌溉系统运行方式和施氮量对番茄根系分布和产量的影响。取先施氮和先灌水两种运行方式；施氮量取372 kg/hm²和204 kg/hm²两个水平。收获后取根样，用WinRHIZO软件对各处理的整根特征参数和根密度垂直分布进行分析。结果表明，随着施氮量的增加整根的根长、根表面积、根体积和根干重均显著增加，各层土壤的根密度也随之增加。施氮量一定时，先施氮处理中整根的根长大于先灌水处理，而根表面积、根体积和平均直径都小于先灌水处理。在垂直剖面上，先灌水处理使上层土壤的根密度增加，而先施氮处理使下层土壤的根密度增加。运行方式对根长和各土层根长密度的影响主要体现在直径小于1 mm的根系上，这部分根系占整个根系的比例和产量之间有很好的相关关系。各处理间产量的差异未达显著性水平。     

不同水氮管理对苋菜和菠菜的产量及硝酸盐含量的影响

通过田间试验研究不同水氮管理对苋菜和菠菜的产量、水分利用效率及硝酸盐含量的影响。结果表明,在同一水分处理条件下,不同的土壤供氮水平对苋菜和菠菜的产量均无显著差异,而各水分处理间也无显著差异,但水分利用效率却以W1处理(农民习惯灌水方式)为最低;苋菜和菠菜中硝酸盐含量主要受土壤的供氮量的影响,其次是土壤含水量,因此,降低土壤供氮量的同时适当降低土壤含水量,是提高水分利用效率和蔬菜品质的有效方法之一。     

滴施不同铵硝比例氮肥对马铃薯生长的影响

在盆栽试验条件下,以滴灌施肥方式探讨滴施不同铵硝比例氮肥对马铃薯生长、产量和品质的影响。研究结果表明:在本试验条件下,滴施不同铵硝比例氮肥对马铃薯植株生物量的积累差异不显著;滴施铵态氮肥有利于提高马铃薯块茎中N的浓度,而滴施硝态氮肥有利于提高马铃薯块茎中Ca的浓度;滴施不同铵硝比例氮肥处理马铃薯的淀粉含量、干物质含量、灰分含量等均差异不显著,块茎产量也差异不显著,但马铃薯商品薯比例以滴施铵硝比例为50/50氮肥处理的最高,达到92.01%。     

Effects of nitrogen fertigation frequency on yield and nitrogen retention in drip-irrigated cotton

Fertigation techniques have been widely used in drip-irrigated cotton. The timing of nitrogen (N) fertilizer injections then becomes a management question producers need guidance on. This study investigated the effect of nitrogen (N) fertigation frequency on drip-irrigated cotton. Experiments were conducted in the Southeastern Anatolia Region of Turkey in 2011 and 2012. A split-plot experimental design was applied. The main plots contained two different lateral spaces: A, one drip-line (lateral) per row; and B, one lateral for every two rows. Sub-plots were designed with different frequencies of fertigation as follows: a, the application of fixed amount of N at each irrigation cycle (5 days); b, the application of fixed amount of N every two irrigation cycles (10 days); and c, the application of one-fifth of the total N between the first irrigation and first flowering, two-fifths between the first flowering and formation of the first boll, and one-fifth between the formation of the first boll and last irrigation cycle. One-fifth of the total N was applied to the soil at sowing in all treatment regimens. The maximum cotton yield (4120 kg ha^?1) and highest total N content (2.57–2.94%) in the leaves were obtained with one lateral for every two rows and the application of fixed amount of N every two irrigation cycles (10 days). One-fifth of the total N might be applied to the soil at sowing, and the remaining N should be applied in equal doses (an average of 7 fertigations) every two irrigation cycles (10 days) by fertigation. However, further research fertigation methods for cotton, including the amount of N that needs to be applied and the use of different injection systems, is required.     

光质对菠菜草酸、单宁及硝酸盐积累效应的影响

用彩色荧光灯得到红光、蓝光和黄光,以白光为对照,研究不同光质对菠菜产量,草酸、单宁及硝酸盐积累的影响。结果表明,处理间的菠菜叶柄和叶片硝酸盐和草酸含量的变化不同,但地上部生长量的变化趋势相同。叶片占植株地上部鲜质量的比例高于叶柄。不同处理叶片和叶柄鲜质量依次为白光(对照)>黄光>红光>蓝光。红光处理有利于干物质和碳水化合物的形成与积累。菠菜叶柄的硝酸盐含量显著高于叶片,是积累硝酸盐的主要场所,并且各处理间叶片硝酸盐和单宁含量的差异远大于叶柄。白光和黄光处理下,菠菜叶片草酸含量大于叶柄,而红光和蓝光处理则相反,其中红光处理草酸含量最低。菠菜在红光处理下生物量虽不高,但可极大地降低硝酸盐和草酸含量,提高菠菜品质。     

供氮水平对菠菜产量、硝酸盐和草酸累积的影响

采用溶液培养方法研究了不同供氮水平对菠菜生物量、硝酸盐和不同形态草酸含量的影响。结果表明,供氮水平由4.mmol/L增加到8.mmol/L,菠菜产量显著增加,继续提高氮水平对产量没有显著影响。叶片中的维生素C(Vc)含量随着供氮浓度从4.mmol/L提高到8.mmol/L而显著增加,再增加氮水平,叶片中的Vc含量明显下降;而菠菜叶柄Vc的含量则随供氮水平的提高显著下降。叶片硝酸盐含量随着氮浓度的提高而增加,当供氮水平由4mmol/L增加到8.mmol/L时,叶柄硝酸盐含量显著下降,而氮水平由8.mmol/L提高到20.mmol/L时,叶柄硝酸盐含量则随之升高。供氮浓度从4.mmol/L增加到8.mmol/L,叶片可溶态草酸含量略有下降,再提高供氮水平则明显上升,供氮水平低于12.mmol/L时,叶柄中的可溶态草酸和菠菜叶片和叶柄中的草酸总量则随着氮水平的提高而升高,高于12.mmol/L草酸含量反而降低。由此可见,菠菜在供氮浓度为8mmol/L(N2)时能够获得较高的产量和Vc含量,较低的硝酸盐和草酸含量,表明适宜的供氮水平下可获得高产优质的菠菜。     

无机硒肥对土壤有效氮含量及菠菜品质的影响

【目的】研究不同浓度亚硒酸钠(Na_2SeO_3)对土壤脲酶活性、铵态氮(NH_4^+-N)和硝态氮(NO_3~–-N)含量及菠菜品质的影响,综合分析Na_2SeO_3在土壤-根部-作物之间被吸收、转运、转化的可能路径,为生物强化生产富硒农产品及调控硒的安全水平提供参考。【方法】进行连续42天盆栽试验,共设置4个处理,每千克土施Na_2SeO_3 0 (对照)、1、10、30 mg,分别于定植后的14、28、42天测定菠菜叶可溶性糖、可溶性蛋白、维生素C、硝酸盐含量,并测定土壤铵态氮、硝态氮含量及土壤脲酶活性等指标。【结果】在菠菜生长期间,≤10mg/kg Na_2SeO_3处理可使土壤脲酶活性表现为先被激活后减弱至对照水平,土壤硝态氮含量也表现出相同的变化趋势,但铵态氮变化趋势正好相反;30 mg/kg Na_2SeO_3处理对土壤脲酶活性没有明显的影响,在整个培养时期与对照水平相当,土壤NH_4^+-N含量后期明显减少,转化成的NO_3~–-N含量明显增加,有利于菠菜吸收利用。同等Na_2SeO_3添加量条件下,Na_2SeO_3对三个取样时间菠菜叶的硝酸盐、维生素C (Vc)、可溶性蛋白、可溶性糖含量影响各异。1 mg/kg Na_2SeO_3处理组可使菠菜叶的硝酸盐含量明显增加,Vc含量先增后减,可溶性蛋白含量减少,可溶性糖含量没有变化;10 mg/kg处理组可使菠菜叶中的硝酸盐、可溶性糖含量表现为先增后减,Vc含量、可溶性蛋白含量均有不同程度增加;30 mg/kg处理组可使菠菜叶的硝酸盐含量先增后减,可溶性蛋白、可溶性糖含量减少,Vc含量没有变化。【结论】不同浓度亚硒酸钠对土壤有效氮及菠菜品质有不同程度的影响。富硒作物生产中无机硒肥施用量要综合考虑硒在作物体内的转化率及硒对作物品质影响的各项因素而确定。     

适量施肥提高土壤残留硝态氮利用率及菠菜产量

针对菜地耕层土壤硝态氮残留量较高和当季肥料氮利用率低的问题, 该研究通过田间注射外源标记氮（15N）微区试验,在土体15 cm（N15）和30 cm（N30）设置标记点,同时设置不施氮肥（N0）、传统施氮量（N1）、传统施氮量的70%（N2）和传统施氮量的40%（N3）4个施氮处理,研究土壤耕层残留硝态氮对菠菜产量及当季氮肥利用率的影响。结果表明：土体15和30 cm标记处理下传统施氮量70%和40%处理,与传统施氮处理的菠菜产量相比较均未达到显著差异（p＞0.05）,但菠菜对标记氮的利用率随施氮量降低而提高,N3N15处理残留氮利用率为22.7%,分别是N1N15、N2N15处理的2.1倍、1.3倍;N3N30处理残留氮利用率为27.5%,分别是N1N30、N2N30处理的3.8和2.2倍。无论是有标记处理还是无标记处理,肥料氮利用率均随施氮量的增加而降低,15 cm标记处理中,N3处理当季氮肥利用率为45%,是N1处理的3.5倍,N2处理的3.4倍;30 cm标记处理中,N3处理当季氮肥利用率为43.8%,是N1处理的4.2倍,N2处理的3.7倍。说明氮肥施用量降低到传统施氮量的40%,不会明显降低菠菜产量,土壤中残留氮素却得到了充分的利用,明显提高当季氮肥利用率,为蔬菜生产中合理降低氮肥施用,减少无机氮素残留提供理论依据。     

氮素形态对菠菜可食部分硝酸盐和草酸累积的影响

采用溶液培养试验研究了营养液中硝态氮/铵态氮比例对菠菜地上部可食部分不同器官硝酸盐以及不同形态草酸累积的影响。结果表明,菠菜地上部生物量随供铵比例从0%提高到50%呈增加趋势而后显著下降。叶片和地上部可食部分的硝酸盐含量和累积量均随供铵比例增加而显著下降;叶柄的硝酸盐含量随供铵比例提高而降低,而硝酸盐积累量则先升高后显著下降。叶片是菠菜积累草酸的主要器官,可溶态草酸与草酸总量分别占地上部的56.3%～89.8%和76.6%～87.4%。可溶态草酸是菠菜体内草酸的主要形态,在叶片、叶柄及地上部中所占草酸总量的比例分别在36.7%～83.5%,79.0%～93.3%以及50.0%～83.0%之间。地上部各器官的可溶态草酸含量、难溶态草酸含量和草酸总量以及积累量均随着供铵比例的增加而显著下降,叶片和地上部的草酸含量和积累量的下降幅度均高于叶柄。可见,调节营养液中硝态氮/铵态氮比例可以有效降低菠菜地上部可食部分硝酸盐和草酸的含量和积累量,50/50是营养液中适宜的硝态氮/铵态氮比例,不仅菠菜的生物量最高,而且硝酸盐和各形态草酸的含量以及累积量较低,从而大大减轻了硝酸盐和草酸对人体健康产生的负面影响。     

滴灌水肥一体化条件下施氮量对夏玉米氮素吸收利用及土壤硝态氮含量的影响

河北山前平原夏玉米高产区施肥不合理现象普遍存在,农业面源污染严重。研究华北山前平原水肥一体化条件下夏玉米适宜的氮肥运筹,可为该区氮素优化施用技术及提高氮肥利用效率提供依据。本研究以‘郑单958’玉米品种为材料,于2014—2015年2个玉米生长季,在滴灌条件下设置4个施氮水平(N0:不施氮;N1:120 kg·hm~(-2);N2:240 kg·hm~(-2);N3:360 kg·hm~(-2)),研究滴灌水肥一体化下施氮量对玉米氮素吸收利用和土壤硝态氮含量的影响。结果表明:N0处理的玉米干物质重及产量较其他处理显著降低,N1、N2和N3处理间无显著差异;N1处理的玉米氮含量和氮累积量较N0处理显著增加,施氮量在N1~N3范围内,不同年份间玉米植株氮含量和氮累积量存在一定差异,总体表现为随施氮量的增加而上升的趋势,但随施氮量的增加,植株氮含量和氮累积量上升幅度逐渐降低。N2处理的氮肥收获指数最高。随施氮量增加,氮肥当季回收利用率、氮肥农学效率、氮肥生产效率和氮肥利用效率显著降低;2014年,在0~100 cm土层范围内,4种施氮处理的土壤硝态氮含量均表现为随土层加深逐渐降低;2015年N2和N3处理的土壤硝态氮在80~100 cm土层达到累积峰,经过2年种植后,年施氮量超过240 kg·hm~(-2)的处理,土壤硝态氮淋洗加剧。利用一元二次方程拟合产量与施氮量之间的关系,明确了玉米最高产量的施氮量为199~209 kg·hm~(-2),经济施氮量为174~187 kg·hm~(-2)。综合考虑经济效益和生态效益,该条件下夏玉米滴灌水肥一体化的适宜施氮量为174~187 kg·hm~(-2)。     

喷灌施肥灌溉均匀性对土壤硝态氮空间分布影响的田间试验研究

在2002～2003年冬小麦生育期内进行了喷灌施肥条件下均匀系数对土壤水氮时空分布及淋失影响的田间试验。试验中,喷灌均匀系数设置低、中、高三个处理,灌溉季节内的平均喷灌均匀系数分别为72%、79%和84%,施肥灌溉均匀系数分别为71%、78%和85%。对70和90 cm深度处的土壤水势进行了监测以评估均匀系数对水氮淋失的影响,结果表明,在所研究的喷灌均匀系数范围内深层渗漏量很小。试验结果还指出,土壤硝态氮随时间和空间表现出很强的变化特征,均匀系数变化范围为23%～97%,变差系数的变化范围为0.04～1.00;灌溉季节内土壤硝态氮分布的均匀性主要取决于初始硝态氮分布的均匀程度,而喷灌均匀系数对土壤氮素的空间分布无明显影响。