Evaluation of silicon as a nutritional supplement for greenhouse zinnia production

Greenhouse production of floricultural crops uses soilless substrates, which have limited amounts of plant-available silicon (Si) compared to mineral soils. The inclusion of Si supplements in greenhouse production has proven beneficial for several crops. The goal of this study was to evaluate the incorporation of Si supplements for improved flower quality of greenhouse-produced zinnia (Zinnia elegans). In the first study, quantitative horticultural traits and leaf Si, macronutrient and micronutrient concentrations were compared between Si-treated and control plants. The Si supplements evaluated were rice husk ash substrate incorporation, hydrous potassium silicate (KSiO₃) substrate incorporation or weekly KSiO₃ substrate drenches, and weekly sodium silicate (NaSiO₃) foliar sprays. Several horticultural traits differed in Si-treated plants. The flower and stem diameters were larger in plants supplemented with at least one rate of each Si supplement. Reduced plant heights and 3–5-day delays in anthesis occurred in plants supplemented with weekly KSiO₃ drenches. Leaf Si concentrations were 1.2–3.3-fold higher in Si-supplemented plants, while the macronutrients, N, S, Mg, and Ca, were lower and K was higher only in KSiO₃-supplemented plants. In a second study, the effects of weekly KSiO₃ drenches and weekly NaSiO₃ foliar sprays on the leaf resistance of zinnia plants were evaluated. Only the NaSiO₃ foliar sprays moderately increased leaf resistances. While not supporting an active role for Si in reducing transpiration, NaSiO₃ foliar sprays may form antitranspirant film that increases leaf resistance. Thus, the beneficial effects of Si supplementation on greenhouse-produced zinnia depend on the form and rate of Si used.     

连作对设施甜瓜生长和光合作用以及养分吸收和产量品质的影响

【目的】探明连作对设施甜瓜的影响。【方法】以在连作0、1、3、5、7、10 a(年)土壤中种植的‘豫甜香’品种为研究对象,分别测定其生长、光合作用及果实产量、品质等。【结果】植株长势随连作年限的增加而减弱,且根部发育受阻。植株净光合速率、叶绿素总量、蒸腾速率和气孔导度均随连作年限的增加而下降,但叶绿素a/b比值升高。伸蔓期叶片、蔓和根中的全氮(N)含量均随连作年限的增加而下降,而花期和坐果期则增加。连作条件下磷(P)基本稳定。全钾(K)含量随连作年限的增加而下降。长年连作条件下果实的总酸含量明显升高,而可溶性固形物和总糖含量则降低。【结论】设施甜瓜种植3~5 a时出现连作障碍问题。长期连作不利于甜瓜生长,使根发育受阻,不利于光合作用及根部等养分的吸收积累,使果实产量下降、口感变差。因此,设施甜瓜最好不要连作超过5 a。     

Effects of chemical and organic fertilizers on the growth,flower quality and nutrient uptake of Anthurium andreanum, cultivated for cut flower production

Sustainable agriculture has become a concern, due to the pressures of the “energy crisis” and issues of “environmental protection”. The use of organic fertilizer made from agricultural waste regenerates natural resources and reduces the consumption of fossil energy as well as phosphorus (P) and potassium (K) deposits. There is scant information available concerning the use of organic fertilizer as the sole source of nutrients in flower production, especially in the cultivation of flowers in a soilless condition. The objective of this study was to develop an organic fertilization management system to replace the chemical fertilization management of the cut flower production of Anthurium andreanum Lind. cultivated under soilless conditions. Four fertilization treatments were carried out consisting of two chemical fertilizers [controlled release fertilizer (CRF) and a chemical nutrient solution (CNS)], and two organic fertilizers [pea and rice hull compost (PRHC) and cattle dung with tea leaf residue compost (CDTC)]. The effects of the various fertilizations on A. andreanum were evaluated based on plant growth, nutrient uptake, and cut flower quality during the 1-year experimental period. The results show that the growth, yield, and cut flower quality of plants receiving PRHC were the same as those receiving CNS and CRF, indicating that PRHC can substitute for CRF and CNS as a nutrient source for cut flower production of A. andreanum cultivated in soilless condition. The plants that received the CNS and PRHC treatments had a significantly increased leaf number and new leaf growth area than those that received the CRF and CDTC treatments. The plants receiving the CDTC showed the lowest increase in leaf area and number of flowers. The retardant growth of plants treated with CDTC has been explained as being due to less carbon (C) being assimilated, most likely as the result of an insufficient supply of nitrogen (N) and manganese (Mn) toxicity. The petiole and peduncle length of the plants receiving the CRF were the shortest, which might be due to the low level of potassium (K) accompanying the magnesium (Mg) deficiency. Even though there were significant differences in the N and K concentrations of the plants among the different treatments, no significant differences were observed in the cut flower quality. In short, the organic fertilizer PRHC can meet the nutrient requirements of A. andreanum cultivation for the cut flower production under soilless conditions.     

不同追肥处理对大棚酸性土壤养分含量及树仔菜生长的影响

以大棚树仔菜为试材,分别施用复合肥和酸性土壤改良营养液追肥,比较分析2种不同追肥处理对树仔菜嫩梢产品农艺性状、品质、产量和土壤有效养分含量的影响,为改善大棚酸性土壤环境、树仔菜化肥减施增效等提供理论依据。结果表明,酸性土壤改良营养液追肥处理的试验区土壤pH值提高了0.69个单位;试验区土壤有效磷含量变化趋势与对照区的差异显著,而有机质、有效磷、速效氮和速效钾含量变化趋势与对照区的差异不显著;酸性土壤改良营养液追肥处理的树仔菜嫩梢样品可食部分节杆长度、直径显著高于对照区,叶片数和分枝数显著低于对照区,单株质量差异不显著;同年6-12月试验区树仔菜产品总产量比对照区提高了6.90%,样品中蛋白质和维生素C含量比对照区分别提高了19.7%、31.2%,镉含量比对照区的降低了25.9%。