GROWTH OF Plumbago capensis, Thunb. IN SANDY SOIL AS AFFECTED BY SOIL AMENDMENTS AND FERTILIZATION

GROWTH OF Plumbago capensis, Thunb. IN SANDy soil AS AFFECTED BY SOIL AMENDMENTS and FERTILIZATION

M. M. M Hussein; H.A. Mansour  and H.A. Ashour

Ornamental Horticulture Department, Faculty of Agriculture, Cairo  University, Egypt.

ABSTRACT

This study was conducted at the Experimental Nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, during the two successive seasons of 2006 and 2007. The aim of this work was to investigate the response of Plumbago capensis plants, grown in sandy soil, to some soil amendments and chemical fertilization treatments. Clay, composted sewage sludge and taffla were incorporated into the sandy soil at a ratio of 4:1 (sand : soil amendment, v/v). After planting, the plants were fertilized with the commercial slow-release chemical fertilizer "Haiflow" (16 N - 8 P₂O₅ -16 K₂O) at the rates of 21 or 45 g fertilizer/plant/3 months, or with a conventional chemical NPK fertilizer (8 N - 4 P₂O₅ - 8 K₂O) at the rates of 14 or 30 g fertilizer/plant/month. In addition to the soil amendment and chemical fertilization treatments, plants receiving no soil amendment or chemical fertilization treatments were used as the control.

Results showed that clay and composted sewage sludge (as soil amendments) or chemical fertilization treatments increased the values recorded for the different vegetative and flowering parameters, as well as the contents of total chlorophylls, carotenoids, total carbohydrates, N, P and K, compared to the untreated plants. Clay was the most effective soil amendment in promoting vegetative and flowering characteristics (giving the highest mean values for plant height, stem diameter, number of branches/plant, leaf area, root length, fresh and dry weights of leaves, stems and roots/plant, number of inflorescence/plant, fresh and dry weights of inflorescences/plant and inflorescence diameter), as well as the contents of total chlorophylls and carotenoids, total carbohydrates, N, P and K. Raising the fertilization rate of each chemical fertilizer resulted in steady increases in values of all the studied parameters. The conventional NPK fertilizer gave generally higher values for most of the vegetative and flowering characteristics, as well as chemical components, compared to the slow-release fertilizer "Haiflow".

Combining clay with the highest rate of the conventional NPK fertilizer (30 g/plant/month) resulted in the highest values for vegetative and flowering parameters, as well as the contents of total chlorophylls, carotenoids, total carbohydrates, N, P and K.

From the obtained results, it can be recommended that, for the best vegetative and flowering characteristics of Plumbago capensis plants grown in sandy soil, the soil should be amended with clay and the plants should be supplied with 30 g/plant/month of the conventional chemical fertilizer (8% N - 4% P₂O₅ - 8% K₂O).

Key words: Plumbago capensis, fertilization, soil amendments, taffla, sludge, clay.

INTRODUCTION

Plumbago capensis, Thunb. (Family: Plumbaginaceae) is an ornamental semi-climbing shrub, native to South Africa. The plants grow well outdoors and have to be protected from frost in winter. In addition to its uses as a flowering climber or shrub for landscape purposes, previous studies reported the presence of an anti fungal protein acting against Trichosporium vesiculosum and Macrophomina phaseolina in the crude extract of P. capensis Modhumita et al. (2002). The roots are a rich source of 1, 4 naphthoquinone, plumbagin, exhibiting a wide range of pharmacological activities such as anti-bacterial, anti-fungal, anticoagulant, anti-fertility, anti-cancer activity, as reported by Yuan and Tung  (2005). 

It can therefore be stated that Plumbago capensis has an enormous potential for use as an ornamental shrub, a medicinal plant, and for pest control. This is particularly important in newly-reclaimed desert areas, where much of the landscape development takes place, and where large areas of medicinal plants are cultivated. In such areas, common cultural practices include regular chemical NPK fertilization, and the use of amendments to improve the soil physical and chemical characteristics.

The nutrients supplied by NPK fertilization are necessary for the various biochemical processes that occur within the plant, and that are essential for normal plant growth and development (Devlin, 1975). Different NPK fertilization treatments have been reported to favourably influence the growth and flowering of different ornamental plants, including Buxus sempervirens (Musselwhite et al., 2004), Sanchezia speciosa (Said, 2004), Viola odorata (Mouhamed, 2004), and several other plant species.

Soil amendments may be of organic origin, such as composted sewage sludge, or may simply be soils such as clay (as recommended by El-Sherif et al., 1982), or taffla [as recommended by El-Bassiouny (1990), which have better characteristics than the poor sandy soil of the reclaimed areas. Composted sewage sludge has also shown considerable potential for use in the landscape industry for improving impoverished soils (Smith, 1992). Sewage sludge can be used as a backfill component when transplanting trees and shrubs; it eliminates the need for additional fertilizers in the first year and continues to release nutrients for several years (Gouin, 1993).

This study was conducted with the aim of investigating the effect of different NPK fertilization treatments, and the feasibility of using different soil amendments, on the growth and chemical composition of Plumbago capensis plants grown in a sandy soil.

MATERIALS AND METHODS

This study was conducted at the Experimental Nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, during the two successive seasons of 2006 and 2007, with the aim of investigating the response of Plumbago capensis plants to some soil amendments added during the preparation of the sandy soil, followed by the application of Haiflow as a slow-release chemical fertilizer, or conventional NPK fertilization during the growing season.

On 1^st of February, 2006 and 2007 plantlets of  Plumbago capensis, Thunb.were  obtained from the nurseries of Awlad El-Saman, El-Qanater El-Khaireya, (Qalyoubia Governorate).The plantlets, 25 cm tall with 2 branches/plant, were planted individually in plastic pots (30-cm diameter) filled with sand, sand + clay (4:1, v/v), sand + composted sewage sludge (4:1, v/v) or sand + taffla (4:1, v/v). The sand was obtained from the Giza desert, while the clay was obtained from the experimental nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University. The composted sewage sludge was obtained from Abou–Rawash station (Giza Governorate), and taffla was obtained from El-Saffe area (Giza Governorate). The physical and chemical characteristics of sand, clay and taffla are shown in Table 1, while the physical and chemical characteristics of the composted sewage sludge are presented in Table 2. The pots were placed in a sunny area, and thick polyethylene sheets were spread underneath the pots to prevent the roots from growing into the soil.

In both seasons, the fertilization treatments were applied from 1^st March till 1^st September, 2006 and 2007 (in the first and second seasons, respectively). The plants received monthly applications of a conventional soluble chemical fertilizer, or were supplied every three months with the slow-release fertilizer Haiflow (16-8-16, N : P₂O₅: K₂O). The conventional NPK fertilizer was prepared by mixing 173.913 g urea (46% N), 258.065 g calcium superphosphate (15.5% P₂O₅), 166.666 g potassium sulphate (48% K₂O), and 401.356 g sand as an inert component, giving 1 kg of the NPK mixture (with a formula of 8-4-8, and a ratio of 2:1:2). Immediately after preparation of this fertilizer mixture, it was incorporated into the soil to a depth of about 2 cm, at rates of 14 or 30 g/pot/month. Haiflow was applied at the rate of 21 or 45 g/ pot every 3 month. Unfertilized plants were also included in the experiment as a control. The conventional NPK fertilizer rates provided the same amount  of

Table 1: Physical and chemical characteristics of sand and the soil amendments (clay and taffla) used for growing Plumbago capensis plants during the 2006 and 2007.

Table 2: Physical and chemical characteristics of the composted sewage sludge used as a soil amendment for growing Plumbago capensis plants during the 2006 and 2007 seasons.

elements given by the slow release fertilizer rates. Common cultural practices were followed.

RESULTS AND DISCUSSION

I. Vegetative and flowering characteristics

1-Effect of soil amendments

 The data presented in Tables (3 - 8) showed that in both seasons, the addition of clay or composted sewage sludge as soil amendments to the sandy soil had a generally favourable effect on the vegetative and flowering characteristics of Plumbago capensis plants (in most cases), as compared to plants grown in sand only or sand + taffla.

 Clay was clearly the most effective soil amendment for promoting vegetative and flowering characteristics of Plumbago capensis plants, giving the highest mean values for plant height, stem diameter, number of branches/plant, leaf area, root length, fresh and dry weights of leaves, stems and roots/plant, number of inflorescence/plant, fresh and dry weights of inflorescences/ plant and diameter of inflorescence, followed by composted sewage sludge. Moreover, the increases in most of the studied parameters (viz., stem diameter, number of branches, leaf area and leaves and stems fresh weight/plant, dry weight of stems/ plant, number of inflorescence/ plant, fresh and dry weights of inflorescences/ plant and diameter of inflorescence) were significant when clay was used as the soil amendment, compared to the other tested soil amendments. This may be attributed to the ability of the negatively charged clay particles to attract and hold the positively charged cations in the soil, and to provide the plant roots with these cations (i.e. clay has a high cation exchange capacity). Also, clay has a high water-holding capacity, which allows higher absorption of water and nutrients from the soil, and enables photosynthesis to occur efficiently within the plant leaves (Hartmann et al., 1981). These results are in agreement with the findings of Hussein (2003) on Senna occidentalis plants.

 Generally, the addition of taffla to sandy soil did not improve the vegetative and flowering chracteristics of Plumbago capensis plants, as compared to plants grown in sand only. This may be attributed to the relatively high salinity of taffla as shown in Table 1.

2- Effect of NPK fertilizer treatments:

   Data presented in Tables (3-8) indicated that, in both seasons, addition of any rate of the two types of fertilizers (conventional NPK fertilizers or Haiflow) increased the values of the vegetative and flowering parameters of Plumbago capensis plants, compared to the unfertilized plants (control). These results are in agreement with the findings of Hussein (2002) on Cryptostegia grandiflora, Mansour (2002) on Senna sulfurea and Hussein (2003) on Senna occidentalis.

Table 3: Effect of soil amendments and fertilization treatments on plant height (cm), stem diameter (mm) and number of branches/ plant in Plumbago capensis plants during the 2006 and 2007 seasons.

* S = Sand           C = Clay                             T = Taffla               CS= Composted sewage sludge

**Haiflow 1= 21 g/ Pot/ 3 Months                   Haiflow 2= 45 g/ Pot/ 3 Months

    NPK 1= 14 g/ Pot/ Month                             NPK 2= 30 g/ Pot/ Month

Table 4: Effect of soil amendments and fertilization on fresh weights of leaves, stems and roots (g/ plant) in Plumbago capensis plants during the 2006 and 2007 seasons.

* S = Sand               C = Clay                   T = Taffla                    CS= Composted sewage sludge

**Haiflow 1= 21 g/ Pot/ 3 Months             Haiflow 2= 45 g/ Pot/ 3 Months

    NPK 1= 14 g/ Pot/ Month                       NPK 2= 30 g/ Pot/ Month

Table 5: Effect of soil amendments and fertilization dry weights of leaves, stems and roots (g/ plant) in Plumbago capensis plants during the 2006 and 2007 seasons.

* S = Sand                   C = Clay                  T = Taffla                    CS= Composted sewage sludge

**Haiflow 1= 21 g/ Pot/ 3 Months                Haiflow 2= 45 g/ Pot/ 3 Months

    NPK 1= 14 g/ Pot/ Month                         NPK 2= 30 g/ Pot/ Month

Table 6: Effect of soil amendments and fertilization on leaf area (cm²), root length (cm) and number of inflorescences/ plant in Plumbago capensis plants during the 2006 and 2007 seasons.

* S = Sand                   C = Clay                   T = Taffla                CS= Composted sewage sludge

**Haiflow 1= 21 g/Pot/ 3 Months                Haiflow 2= 45 g/Pot/ 3 Months

    NPK 1= 14 g/pot/month                           NPK 2= 30 g/ Pot/ Month

Table 7: Effect of soil amendments and fertilization on fresh and dry weights (g/ plant), as well as diameter (mm)   of inflorescences/ plant in  Plumbago capensis plants during the 2006 and 2007 seasons.

* S = Sand               C = Clay                       T = Taffla                CS= Composted sewage sludge

**Haiflow 1= 21 g/Pot/ 3 Months                 Haiflow 2= 45 g/Pot/ 3 Months

    NPK 1= 14 g/Pot/Month                            NPK 2= 30 g/Pot/Month

Table 8: Effect of soil amendments and fertilization on aveage fresh and dry weights of inflorescence (g) in Plumbago capensis plants during the 2006 and 2007 seasons.

                *S = Sand            C = Clay                       T = Taffla                    CS= Composted sewage sludge

**Haiflow 1= 21 g/ Pot/ 3 Months           Haiflow 2= 45 g/ Pot/ 3 Months

NPK 1= 14 g/ Pot/ Month                     NPK 2= 30 g/ Pot/ Month

    Moreover, with either one of the two types of fertilizer, raising the application rate resulted in a steady increase in the values of most of the vegetative and flowering chracteristics. The favourable effect of the NPK fertilization treatments on the vegetative growth characteristics (compared to the control) can be explained by the important role of N, P and K in the different physiological processes within the plant, which in turn affect the plant growth. Also, nitrogen is present in the structure of protein molecules, while phosphorus is an essential constituent of nucleic acids and phospholipids, and potassium is essential as an activator for enzymes involved in the synthesis of certain peptide bonds (Devlin, 1975).

  In many cases, at the same NPK rates, conventional NPK fertilization gave better results than Haiflow, with no significant difference between them. In most cases, using the highest conventional NPK fertilization rate (30 g/pot/month) gave insignificantly different values than the highest values recorded for vegetative and flowering characteristics.

3- Effect of combinations of NPK fertilizer and soil amendments:

  Regarding the interaction between the effects of addition of soil amendments and the fertilization treatments, the data recorded on the vegetative and flowering characteristics of Plumbago capensis plants (Tables 3-8) show that, in most cases, the highest values recorded for the different vegetative and flowering characteristics were obtained from plants grown in sand + clay, and supplied with the highest rates of slow-release or conventional NPK fertilizers, with no significant difference between them in most cases. On the other hand, in most cases, the lowest values for many of the studied growth parameters were obtained from unfertilized plants (control) that were grown in sand only, or in sand amended with taffla.

II – Chemical composition:                       

1–Contents of pigments [total chlorophylls (a+b) and carotenoids]:

 The data presented in Table 9 showed that soil amendments had a favourable effect on the synthesis and accumulation of pigments in Plumbago capensis plants. In both seasons, plants grown in sand amended with any of the tested soil amendments had higher contents of total chlorophylls (a+b) and carotenoids in their leaves, compared to control plants. These results are in agreement with the findings of Hussein and Mansour (2001) on Paspalum vaginatum turfgrass, Hussein(2002) on Cryptostegia grandiflora, Mansour (2002) on Senna sulfurea and Hussein (2003) on Senna occidentalis.

  Among the three types of soil amendments, clay gave the highest contents of total chlorophylls and carotenoids, followed by composted sewage sludge, whereas taffla was the least effective soil amendment in this respect. Chemical fertilization was also very beneficial in terms of increasing the pigments content in Plumbago capensis plants. In both seasons, the lowest contents of total chlorophylls and carotenoids were found in leaves of unfertilized (control plants). Increases in the chlorophylls content as a result of fertilization treatments have been recorded by Bytnerowicz et al. (1990) on ponderosa pine, and El-Shewaikh (2000) on Brunfelsia calycina. Application of most rates of conventional NPK or slow-release fertilizers resulted in significant increases in the contents of pigments, compared to the control. Within each type of fertilizer, raising the application rate increased the pigments content. The increase in the total chlorophylls content as a result of raising the fertilization rate is in agreement with the results reported by Paswan and Machahary (2000) on bahiagrass (Paspalum notatum), and  Hussein and Mansour (2001) on Paspalum vaginatum. In most cases, when the two chemical fertilizers were applied at rates providing equivalent supplies of nutrients, conventional NPK fertilization was more effective than Haigrow for increasing the contents of total chlorophylls and carotenoids. In both seasons, monthly application of the highest rate of conventional NPK gave the highest contents of total chlorophylls and carotenoids.

Table 9: Effect of soil amendments and fertilization on total chlorophylls, carotenoids (mg/g fresh matter), and total carbohydrates percent in Plumbago capensis plants during the 2006 and 2007 seasons.

*  S = Sand    C = Clay         T = Taffla       CS= Composted sewage sludge

**Haiflow 1= 21 g/  Pot/ 3 Months              Haiflow 2= 45 g/ Pot/ 3 Months

    NPK 1= 14 g/ Pot/  Months                      NPK 2= 30 g/ Pot/  Months

   The favourable effect of soil amendments and chemical fertilization on the synthesis and accumulation of chlorophyll may be attributed to the availability of nitrogen (supplied by soil amendments and chemical fertilizers), which is essential in the structure of porphyrin, found in such metabolically important compounds as chlorophyll. Also, nitrogen is needed for the synthesis of the protein molecules to which chlorophyll is bound, or in which it is embedded Taiz and Zeiger (1998).

  Regarding the interaction between soil amendments and chemical fertilization, the data in Table 9 showed that in both seasons, using clay as a soil amendment, combined with application of the highest NPK rate, resulted in the highest contents of total chlorophylls and carotenoids, compared to values obtained from any other combination of soil amendments and chemical fertilization treatments.

2-Total carbohydrates percent:

   Results of chemical analysis of the dry herb of Plumbago capensis (Table 9) showed that, in most cases, the content of total carbohydrates was significantly increased as a result of addition of the different types of soil amendments during soil preparation, compared to the control. In both seasons, clay was the most effective soil amendment for increasing the content of total carbohydrates, followed by composted sewage sludge, whereas taffla was the least effective soil amendment in this respect. These results are in agreement with the findings of Hussein (2003) on Senna occidentalis plants.

The data in Table 9, also showed that chemical fertilization was beneficial for the synthesis and accumulation of carbohydrates in the herb of Plumbago capensis plants. In both seasons, the values recorded were significantly higher in plants receiving any of the different chemical fertilization treatments, compared to the control. Similar increases in the carbohydrates content have been reported by Osman (1996) on Araucaria excelsa and Hussein (2003) on Senna occidentalis plants.

   Within each type of chemical fertilizer, raising the application rate increased the carbohydrates content. Conventional NPK fertilization treatments were generally more effective than Haiflow treatments for increasing the carbohydrates content. In both seasons, the highest values were obtained from plants fertilized with the highest NPK rate (30 g/pot/month). The increase in the content of total carbohydrates as a result of raising the rate of NPK or slow-release fertilizers is similar to that reported by Emarah (1998) on Cynodon dactylon, C. transvaalensis and Tifway (C. dactylon x C. transvaalensis) and Hussein and Mansour (2001) on Paspalum vaginatum.

   The favourable effect of the different chemical fertilization treatments on the content of total carbohydrates may be indirectly attributed to the increase in the content of total chlorophylls as a result of the treatments. As the synthesis of total chlorophylls was promoted, the rate of photosynthesis increased, leading to an increase in carbohydrate synthesis. Also, potassium can act as an activator of several enzymes involved in carbohydrate metabolism Taiz and Zeiger(1998). Moreover, this promotion in the synthesis of total chlorophylls and total carbohydrates as a result of chemical fertilization may explain the increase in vegetative growth that was detected in plants receiving the different chemical fertilization treatments.

  As a result of the interaction between the soil amendments and chemical fertilization treatments, the highest total carbohydrates content (in both seasons) was obtained from pots amended with clay during soil preparation, followed by monthly applications of the highest NPK rate.

3- Contents of N, P and K:

The results recorded in the two seasons (Table 10) showed that the uptake and accumulation of N, P and K in Plumbago capensis plants were enhanced by using soil amendments, since control plants had lower N, P and K contents than plants grown in sand amended with different soil amendments (in most cases). Among the three soil amendments, clay gave the significantly higher contents of N, P and K, thus, it appeared to be the most effective in promoting the uptake of nutrients, in both seasons. On the other hand, taffla was the least effective soil amendment for promoting nutrient uptake and accumulation, since it gave lower contents of N, P and K compared to those obtained with other soil amendments, in both seasons.

As shown in Table 10, the contents of the three main nutrients (N, P and K) exhibited a similar trend of response to the different chemical fertilization treatments. In both seasons, the lowest contents of the three nutrients were recorded in the herb of control plants. Raising the fertilization rate increased the contents of the three nutrients, regardless of the type of chemical fertilizer applied. The increase in the contents of nutrients in the tissues of herb as a result of increasing fertilization rates can be easily explained, since raising NPK levels in the root medium led to more vegetative and root growth. This may be accompanied by more absorption of essential elements from the soil, and their accumulation in plant tissues (Jain, 1983). Similar increases in the N, P and K contents as a result of raising the fertilization rates have been reported by Goatley et al. (1994) on "Tifgreen" bermudagrass (Cynodon dactylon x C transvaalensis), and Razmjoo et al. (1996) on creeping bentgrass (Agrostis palustris). In both seasons, the highest contents of N, P and K were obtained from the herb of plants fertilized with the highest rates of NPK (30 g / pot/ month).

The conventional NPK fertilizer appeared to be more effective than Haiflow (a slow-release fertilizer) for increasing the contents of the three nutrients. These results are in agreement with the findings of Hummel and Waddington (1981), who reported that N content was greater in clippings of Poa pratensis plants fertilized with water soluble N sources. Also, Emarah (1998) on Cynodon dactylon, C. transvaalensis and Tifway (C. dactylon x C. transvaalensis), and Hussein and Mansour (2001) on Paspalum vaginatum, reported that N, P and K contents were greater in clippings of plants fertilized with water soluble NPK sources than in plants fertilized with slow release fertilizers.

Table 10: Effect of soil amendments and fertilization on N%, P% and K% of dry matter in Plumbago capensis plants during the 2006 and 2007 seasons.

 *S = Sand  C = Clay       T = Taffla            CS= Composted sewage sludge   **Haiflow 1= 21 g/ Pot/ 3 Months   

    Haiflow 2= 45 g/ Pot/ 3 Months      NPK 1= 14 g/ Pot/ Month              NPK 2= 30 g/ Pot/ Month

Regarding the interaction between the effects of soil amendments and chemical fertilization on the contents of N, P and K, the data in Table (10) showed that in both seasons, using clay as a soil amendment before planting Plumbago capensis plants, followed by monthly application of the highest NPK rate resulted in the highest N, P and K contents compared with other treatment combinations.

          Conclusively, from the above results, it can be recommended that, for the best vegetative and flowering parameters of Plumbago capensis plants grown in sandy soil, the soil should be amended with clay and the plants should be supplied with 30 g/plant/month of the conventional chemical fertilizer (8% N - 4% P₂O₅ - 8% K₂O).

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استجابة نباتات البلمباجو المنزرعة فی تربة رملیة لمحسنات التربة ومعاملات التسمید

محمد موسى محمد حسین,   حازم عبد الجلیل منصور,   حسام أحمد عاشور

قسم بساتین الزینة، کلیة الزراعة، جامعة القاهرة- ج.م.ع.

أجـرى هذا البحث فی مشتل التجارب بقسم بساتین الزینة، کلیة الزراعة، جامعـة القاهـرة، خلال الموسـمین المتتالیین 2006 و 2007 بـهـدف دراسة استجابة نبات البلمباجو النامی فی أرض رملیة لبعض مصلحات التربة. تم إضافة الطمی ومخلفات الصرف الصحی المعالجة (الحمأة) والطفلة للرمل بمعدل 1:4 بالحجم (رمل: مصلح من الطمی). بعد الزراعة تم تسمید النباتات بسماد کیماوی بطیء التحلل "هایفلو" ( 16ن – 8 فو₂أ₅ – 16 بو₂أ) بمعدلین 21 أو 45 جم سماد / نبات/3 أشهر أو بسماد کیماوی مرکب تقلیدی ( 8ن – 4 فو₂أ₅ – 8 بو₂أ) بمعدلات 14 أو 30 جم سماد/ نبات/ شهر. بالإضافة إلى ذلک استخدمت نباتات غیر معاملة بمصلحات التربة أو التسمید الکیماوی للمقارنة.

أظهرت النتائج:

 أن الطمی ومخلفات الصرف الصحی المعالجة (الحمأة) کمصلحات للتربة أو التسمید الکیماوی قد أدت إلى زیادة قیم جمیع مؤشرات الصفات الخضریة والتزهیر، بالإضافة إلى محتوى الأوراق من الکلـوروفـیـلات الکلیة والکاروتینویدات وذلک محتوی النبات من کل من الکربوهیدرات الکلیة والنتروجین والفسفور والبوتاسیوم وذلک مقارنة بالنباتات الغیر معاملة. کما أدى استخدام الطمی إلى أفضل نتائج لصفات النمو الخضری والزهری (طول النبات، قطر الساق، عدد الأفرع/ نبات، مساحة الورقة، طول الجذر، الوزن الطازج الجاف للأوراق والسیقان والجذور/ نبات، عدد النورات، الوزن الطازج الجاف للنورات/ نبات، قطر النورة)، وکذلک محتوى الأوراق من الکلـوروفـیـلات الکلیة والکاروتینویدات، والکربوهیدرات، والنسبة المئویة للنتروجین والفسفور والبوتاسیوم. أدت زیادة معدل الإضافة لکل سماد کیماوی إلى الزیادة فی قیم کل الصفات التی درست.

بصفة عامة أعطى سماد NPK التقلیدی قیماً أعلى لمعظم الصفات الخضریة والزهریة والترکیب الکیماوی التی درست وذلک بالمقارنة بسماد "هایفلو" البطیئ التحلل.

أدى استخدام الطمی کمحسن للتربة مع إضافة أعلى معدل من سماد NPK التقلیدی (30 جم سماد/ نبات/ شهر) إلى الحصول على أعلى القیم لمؤشرات النمو الخضری والزهری، وکذلک محتوى الأوراق من الکلوروفیلات الکلیة والکاروتینویدات والنسبة المئویة للکربوهیدرات والنتروجین والفسفور والبوتاسیم.

من النتائج المتحصل علیها یمکن التوصیة بإضافة الطمی کمصلح للتربة الرملیة مع تسمید النباتات بسماد کیماوی مرکب کامل تقلیدی ( 8ن – 4 فو₂أ₅ – 8 بو₂أ) بمعدل 30 جم سماد/ نبات/ شهر، وذلک للحصول على أفضل نمو خضرى وزهرى لنبات البلمباجو المنزرع فی تربة رملیة.