ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effects of Age of Rubber (Hevea brasiliensis Muell Arg.) Plantation on pH, Organic Carbon, Organic Matter, Nitrogen and Micronutrient Status of Ultisols in the Humid Forest

ผู้เขียน:Effi om Oku, Anthony Iwara, Ekaette Ekukinam

สื่อสิ่งพิมพ์:pdf

Abstract

Micronutrients are required by plants in minute quantities. Literature on the micronutrient status of soils sustaining rubber plantations in the humid forest zone of southern Nigeria is not readily available where a study was carried out on Ultisols to examine the status of manganese (Mn), iron (Fe), Copper (Cu) and zinc (Zn) in rubber plantations aged 7, 16, 39 and 41 yr. A grid sampling method was used to collect soil samples from fi ve quadrats of 10 m ? 10 m in each of the plantation plots. For each plot, fi ve surface (0–15cm) soil samples were randomly collected and composited. The soil samples were analyzed for pH, organic carbon (OC), organic matter (OM), nitrogen (N), Mn, Fe, Cu and Zn. Data were analyzed using analysis of variance and Pearson’s correlation. The soils were strongly acidic (pH 4.0–4.4). The OC status was rated as very low (below 2%) in all the plantation soils. In addition, the OM was rated as low under the trees at 7, 16, and 39 yr whereas, for the 41 year-old plantation, it was rated as high. The Mn and Zn contents were rated as low for the 16, 39 and 41 year-old rubber plantations, whereas they were rated as medium under the 7 year-old rubber plantation. The Mn, Fe and Cu contents varied signifi cantly (P < 0.01 to P < 0.05) with the age of trees, while Zn did not vary (P > 0.05) among the rubber plots. The fertility rating of Fe was toxic or excessive in all the plantations and the levels of Cu were rated high. The results showed that the contents of Zn, Fe, Cu and Mn in the soils decreased with increasing age of rubber plantation. The Mn content was rated as high, medium, medium and low in the 7, 16, 39 and 41 year-old plantations, respectively. The Fe contents were rated as high whereas the Cu contents were rated as medium. With the exception of the 7 year-old plantation, where Zn was rated as medium, the Zn contents were below the critical limits for crop production, with soils in the 16, 39 and 41 year-old rubber plantations benefi ting from its application. The low values of soil pH across the rubber plantation plots did not signifi cantly favour the increase in selected micronutrient levels in the soil. To improve the levels of micronutrients in the rubber plots, it is recommended that biomass burning should be discouraged during replanting as it strips the soil of these nutrients. The use of organo-mineral fertilizer combined with inorganic fertilizers is recommended. Care must be taken not to apply Mn in excess. A rubber-based agroforestry system, as opposed to rubber monocultures is recommended as it would improve the micronutrient levels of the soils in the plantation.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 046, Issue 5, Sep 12 - Oct 12, Page 684 - 693 |  PDF |  Page

ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Soybean Yield and Nutrient Composition as Affected by Soil and Foliar Fertilizations)

ผู้เขียน:Chin THENG PHIV, ชวลิต ฮงประยูร*, ดร.พีระศักดิ์ ศรีนิเวศน์, ศาสตราจารย์, ดร.อรุณศิริ กำลัง, รองศาสตราจารย์, นายยงยุทธ โอสถสภา, รองศาสตราจารย์

สื่อสิ่งพิมพ์:pdf

Abstract

Soil fertilizer application and foliar fertilization offer a possible means of increasing soybean [Glycine max (L.) Merr.] yield in Thailand but little is known of appropriate foliar fertilizer use to supplement soil fertilization. Field experiment was conducted twice to determine the effects of soil N P K fertilization together with foliar fertilizers containing macronutrients and micronutrients on growth, yield and nutrient composition of soybean (Sukhothai 1 and KUSL 20004 cultivars). The treatments were arranged in 3 ? 3 factorial experiment in randomized complete block. Three methods of soil fertilization were control (S0), 18 kg N ha-1 at 7 days after seeding (DAS) (S1), and 18 kg N ha-1 at 7 DAS + 18 – 18 – 18 kg N – P2O5 – K2O ha-1 at 30 DAS (S2). Foliar fertilizer contained both macronutrients and micronutrients. The three methods of foliar fertilization were control (F0), 3 applications at 34, 42 and 49 DAS (F1) and 6 applications at 20, 27, 34, 42, 49 and 56 DAS (F2). Throughout the studies, soil and foliar fertilizations did not significantly affect growth, yield and yield components of soybean. The concentration of N P K Fe and Zn in shoot at 68 DAS and N P K and Ca in leaves at 89 DAS were not consistently affected by soil and foliar fertilizations. The remarkable effects of soil fertilizers on the concentrations of Ca Mn and Cu in shoot, and Mg Fe Mn and Cu in leaves were observed. Foliar fertilizations increased Fe and Cu concentrations in leaves. The nutrient concentrations of soybean shoot and leaves under this investigation were in sufficient ranges which were agreeable with soil test results. This finding indicated that the soil can provide sufficient nutrients for soybean growth and yield under this condition. Therefore, soil and foliar fertilization will not be economically feasible.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 037, Issue 1, Jan 03 - Mar 03, Page 14 - 26 |  PDF |  Page