Foliar Fertilizer

Feed Additive

Fish&prawn Cola

Root Growth Promoter (PGR)

Effects of Penshibao foliar fertilizer on growth and dry matter production of Tomato (Lycopersicon esculentum) under field conditions in Kenya

SK Kimani, BN Nyoike, NG Kungu, JM Kaiyare and PM Wakaba
Kenya Agricultural Research Institute, NARC,Muguga, P.O.Box 30148,Nairobi.

Introduction

Mineral plant nutrients can be supplied by addition into the soil, or be supplied to the leaves as sprays. Fertilizers applied as sprays are generally referred to as foliar fertilizers. The nutrients applied in the foliar sprays are absorbed through the leaves, and this nutrient application has several advantages. Firstly, it reduces the time lag between application and uptake from the soil solution and then through the plant’s vascular system. This is particularly important during the phase of required rapid growth. Secondly, foliar application of nutrients can circumvent the problem of restricted uptake of applied mineral nutrients such as P, K, Fe, Mn and Cu and may be more efficient than application through the soil where they may be fixed or absorbed by soil particles and hence less available to the root system.
However, foliar feeds are applied mainly to supply micronutrients such as Zn, Fe, Cu, Mn, B, molybdenum (Mo), and chlorine (Cl) (Tisdale et al., 1985). The greatest difficulty in supplying macronutrients such as N, P and K is that the foliar sprays are not able to supply adequate amounts. There is also the danger of burning the leaves if very high concentrations of these nutrients are sprayed. The recommended nutrient concentrations are generally less than 1 to 2% in order to avoid foliage injury. To this end therefore, foliar sprays are most effective when supplied as supplements, or complements of soil applied mineral or organic fertilizers. Nitrogen based foliar sprays have been used successfully on apples, citrus, pineapples and a number of other crops. K based sprays have also been used successfully on potatoes, apples, celery, and pineapples.

Manufacturers contend that the foliar feed Penshibao (PSB) has a PH of 2.3 and a density of 1.19 and contains the following:

Table 1.PSB contents according to manufactures

Citric acid and amino acids               ＞ 30%
Zn as sulphate                            ＞ 0.3%
N as urea                                 ＞ 1.4%
P (water soluble)                         ＞ 7.2%
Dissolving agent                          ＞ 30%

From the analytical results of selected parameters done in Kenya subsequently, the values are in agreement (See tables 2)

Analytical results
Table 2. Analysis of some selected parameters at Government Chemist, Nairobi.

Nitrogen (%)                             2.9
Phosphorus (P2O5)                      15.26 (6.17%P)
Potassium (K2O)                          3.54
Calcium (CaO)                             0.36
Trace Elements (ppm)
Iron                                     417
Copper                                    24
Manganese                                  8

Source: KEPHIS,1999

According to the Government Chemist, the chemical constituents are as follows:

Table 3. Analysis of some parameters at KEPHIS, Nairobi

Phosphorus (as P2O5)          30.1                          (＞7.2%)
Nitrogen (N %)                1.99                          (＞1.4%)
Potassium (K %)               1.28                          (＞2.3%)
Zinc (% Zn)                   0.59                          (＞0.3%)
Magnesium (% Mg)              0.006
Copper (% Cu)                 0.03
Fe (% Fe)                     0.18                           (0.04%)

Source: Certificate of analysis. Report reference No.p/MISC VOL II/99/103 of 18th November 1999.

Our previous work, which was submitted to KEPHIS. Had shown PSB to perform well under glasshouse conditions. Consequently, in 2003, a field experiment was set in order to ascertain the performance of PSB under field conditions.

Material and Methods

The experiment was set up at Garden Estate, an area neighboring Thome/Kasarani, Nairobi. The soil is a well drained, very deep, dark reddish brown to dark red, friable clay classified as a humic nitisol (FAQ/UNESCO,1974), and is locally referred to as Kikuyu red clay loam. The rainfall is bimodal with annual average of 1000 mm with the long rains falling in March to May and the short rains falling from mid October to December. The experiment was started in December 2002 to study the effect of PSB on the growth of tomatoes.
Tomato nursery beds were prepared in December 2002.No fertilizer was applied in the beds. Land preparation in readiness for transplanting was done in January 2003. Plots were 5 x 5 m2. there were a total of 15 plots with a separating path of 1m between the plots. Planting holes were spaced at 45 x 60 cm. The holes were 30 cm in diameter and 15cm deep. All plots were pretreated with a soil fumigant (furadan)to control soil-borne pathogens.
Transplanting was done on January 18th at 21 days after sowing.
The experimental design was a randomized complete block design with three replicates.
Fertilizer treatment. These included

1. Diammonium phosphate (DAP0 plus Calcium ammonium nitrate (CAN) and Easy Gro, a commercially available foliar fertilizer. The DAP supplied 18 kg N ha-1, while CAN supplied 52 kg N ha-1 and Easy Gro supplied 23 kg N ha-1.
2. DAP+CAN+PSB. The DAP in this treatment in this treatment supplied 18kg N ha-1, CAN supplied 52kg N ha-1 and PSB supplied 19 kg N ha-1
3. Unfertilised control.
4. PSB only, which supplied 88 kg N ha-1 at 4 sprays at 10-day intervals.
5. DAP+CAN. Where the DAP supplied 18 kg N ha-1 and CAN supplied 52 kg N ha-1.

Treatment 1 is designated as PO, treatment 2 as P1, treatment 3 as P2 and treatment 4 as P3 and treatment 5 as P4, AND ARE REFERRED THUS IN THE SUBSEQUENT RESULTS.

Data collection.
Soils were sampled with an auger within the soil profile at 0-20 cm, 20-40 cm, and 40-60 cm. Analysis were subsequently done at NARC Muguga laboratory for mineral nitrogen, C, P, K, Ph, Cu, and Zn. These were done according to standard methods described by Anderson and Ingram (1993). A water sample was also collected and analysed.

Data were also collected on plant heights 30,40 and 50, 60 days after transplanting. Flower numbers and fruits were also counted at 50 and 60 days after transplanting. At each sampling flower colour was also recorded. From 50 days after transplanting, flower numbers were recorded. The plants were harvested at 80 days after transplanting for determination of root and shoot dry weights.

The experiment was conducted from December 2002 to April,2003. Milraz and Ridomil were used to protect the plants from blight.

Results and Discussion

Total dry weights were taken for the roots and shoots at 80 days after transplanting. Treatments with the highest yields were PO and PI,where the former had Easy Gro and the latter PSB (Table 4). All fertilizer treatments performed better than the unfertilized control. The PSB performed better when combined with the mineral fertilizers, compared with singular application. This indicates that the PSB alone cannot solely supply the nutrients necessary for tomato production, which is a general observation with other foliar feeds. This is because PSB alone supplied possible about a third of the 88 kg N ha-1, the rest went to the empty spaces between plants and possible some N was also volatilized.

Table 4. Tomato dry weights (g) for 4 plants sampled at 80 days after transplanting

P0                  172.1+ 55.7             9.6+ 2.6                 181+ 72.3
P1                  175.7+ 75.2             13.8+ 4.0                180.6+ 62.5
P2                  74.8+ 16.6              6.4+ 0.6                 81.1+ 17.2
P3                  77.3+ 22.9              9.3+ 4.1                 86.6+ 27

Values are means + standard deviation

Data for plant heights followed similar patterns to those on dry matter yields with the combination of soil applied mineral fertilizer and the two foliar feeds performing better than the other treatments (Table 5)

Table 5. Plant heights at 30 40 ,50 and 60 days after transplanting

Days after transplanting

P0              6.5+ 2.8            17+ 0.3           33.5+ 0.9            41.7+ 3.2
P1              8.9+ 1.8            17.2+ 0.2            32.7+ 0.3          53.7+ 2.1?
P2              9.7+ 1.0            15.2+ 0.2            29.4+ 0.6            37.3+ 17.3
P3              9.0+1.4             14.9+ 0.3            29.8+ 1.0              42+ 3.6

Values are means + standard deviation

In addition, the flower, fruits and branch numbers followed the dry matter results, although PSB had higher numbers for flowers and fruits (Table 6), possible arising from the amino acids and organic acids, which it is said to contain.

Table 6. Flower and fruit number at 50 and 60 and braches at 60 days after transplanting
_______________________________________________________________________________

Days after transplanting

1.             60

P0         17.7+ 3.2          3              16+ 3            5.7+ 2.1        5+ 1
P1         18.1+1           4.3+0.6          22+ 2.7          8.7+ 2.1        5+ 1
P2         15.7+ 1.2        2.0+1.7          8.6+ 3.2         4.0+ 2          2+ 0
P3         13.1+ 1          2.3+1.5          14+ 7            7.7+ 4          2+ 1
P4         13.3+ 1.5        1.6+0.6          14.3+ 2.1        2.3+ 0.6       3.3+ 0.6

Values are means + standard deviation

PSB has been shown to increase yields of 58 different crop plants and in different soils in China. In cereals increase in yields have been reported (15%) and an increase of between 30 and 60% has been reported for economic crops. The work in Asia also SHOWED AN IMPROVED QUALITY OF SEEDS AND FRUITS.INCREASED PEST RESISTANCE OF THE CROPS. SUBSEQUENTLY, SOME WORK WAS CARRIED OUT IN Kenya at KARI Muguga in 1999. In that glasshouse experiment, PSB increased tomato fruit yields by 36.5% and dry matter yields by 11%. It is generally recommended to spray between 12 and 3 pm in a fine day without rain. If it trains within 6 hours after spraying the foliar fertilizer is not effective.

According to our results the PSB works best when combined with mineral fertilizers. The manufactures also contend that PSB contain amino acids such as lysine and aspartic acid. Some of these amino acids can stimulate the absorption of nutrient elements. For instance, glycine can stimulate the absorption of N and P, while aspartic acid can increase the absorption of P and K.

Plant and root tissue analysis

Analysis for plant and root tissues for N, P, K , Mg and Cu are shown in Table 7. The results indicate that PSB promoted a higher uptake of N, P and K compared with Easy Gro and the other soil-applied mineral fertilizer. This suggests that PSB application may promote a better crop performance, possibly a higher photosynthetic rate caused by the higher levels of N and P. This in turn may also result in earlier plant development, hence the higher numbers of flowers and fruits under the PSB treatment. The root tissue analysis showed relatively lower levels of N, P and K for the PSB treated plants. This in turn suggests that PSB caused a more efficient partitioning of assimilates between roots and shoots, possibly arising from the higher levels of growth regulators that are said to be in PSB.

Shots tissue analysis
TRT          %N        %P      %K           %Mg          %Ca        %Cu
P0           3.36     0.14    4.12         0.15        0.40       Trace
P1           3.92     0.19    4.47         0.12        0.28       Trace
P2           3.42     0.14    3.52         0.14        0.28       Trace
P3           3.42     0.14    3.76         0.14        0.30       Trace
P4           3.52     0.12    3.82         0.14        0.32       Trace

Root tissue analysis
TRT         %N       %P        %K         %Mg        %Ca        %Cu
P0         2.17     0.09      3.27         0.03      0.16      Trace
P1         1.61     0.11      2.81         0.01      0.16      Trace
P2         2.10     0.08      2.65         0.02      0.19      Trace
P3         2.25     0.09      2.55         0.02      0.19      Trace

Values are means of three replicates

Soil analysis

The data on analysis of the soils sampled from the field are shown in Table 8.
Analysis was done for the soils in the experimental site to determine mineral nitrogen, as shown by nitrate and ammonium N, P, Fe, Mn, Cu, Zn and exchangeable K, Ca, and Mg. The soils have an inherently high ability to mineralize. For the surface soil, 0-20 cm depth, treatments where fertilizers were applied, including PSB only (treatment P3) the mineral N levels were high compared with the unfertilized control (P2). The surface soils indicate a higher retention of mineral N where PSB was applied compared with the other treatments. However, lower soil profile 20-40 cm depth showed a relatively higher accumulation of nitrates for the treatments where mineral fertilizers were applied compared with the control. Where the foliar feeds were applied, the soils contained less mineral N, indicating that the foliar feeds promoted a higher nitrate and ammonium uptake. Where both PSB and Easy Gro were applied, the mineral N levels were lower than the control.
At 40-60 cm depth, the mineral N levels followed similar trends to the 20-40 cm depth.

Exchangeable Ca and K values showed a possible higher uptake for the treatments where the foliar feeds were applied, with a possibly higher uptake of K under PSB compared with Easy Gro.

The lower P levels measured under treatments where both the foliar feeds were applied suggest that the foliar sprays may have promoted higher P uptake.