Stichting Proefboerderijen Noordelijke Akkerbouw                                                                      (Northern Experimental Crop Growing Farms Foundation)

This report was drawn up after testing in collaboration with Holland Green B.V. BioAktiv Distibutor in Holland.

KW 0014

Author: Ing. H.W.G. Floot

A. untreated - -                                                                                                                                                                          L BioActive Powder                                           1 kg/ha                                              

1* prior to row cultivation

*) pesticide

Seed potatoes of the variety Asterix, size 35/50, were well chitted in trays and hardened in a greenhouse.           Two thirds of fertilizer were given on May 15, followed by additional fertilization with KAS on June 23. Furrows were tilled by rotary cultivator on May 15, after spraying location L with BAP.                                                                

Emergence around May 26 was good and uniform, with approx. 41,400 plants per ha.                                                   Soil coverage was 71% on June 21, 95% on June 29, and 99% on July 6.                                                               Spraying was carried out on these days:                                                                                                                              Slight colour differences were found.

On Aug. 16, the untreated location (A) showed serious Mn deficiency, which was less in the other locations.

After the entire field had been defoliated with Reglone, the potatoes were lifted on Oct. 4.They were dried and graded, followed by underwater weighing of the 50/60 mm sizes. A mixed sample was also sent to ALF for tuber analysis.

Analytical findings for leaf stalks are given in Table 1. Table 2 lists analytical results for the dry matter of leaves, Table 3 for the dry matter of tubers, and Table 4 yields per variety, underwater weight and leaf colour as found on Sept. 1.

Table 1: Elements (mg/l) found in leaf stalks on Aug. 1

A       5647   213  50  12      81      54    10      6      343     0.2     0. 4     0.3      1.3      0.3

L       5552    215 62   26     84      77    18      5      368       0      0.4       0.3     1.1       0.3

Table 2: Elements (mg/100 g) found in dry matter of leaves on Aug. 1, 2000

Loc   . Mn       Ds   Tot- N      P        K       Ca       Mg     Fe     B      Zn     Na    Cu    Mo

A        1.21  11.21  5970    442   4524    1156  402.4   10   3 .6   3. 1    24    1.9   0.16                               

L         1.2  12.69   5660    453   4672    1164  387.6    11   3.3    3.2    21    1.7  0.25 

Location A (untreated) showed high values for most elements

Table 3: Elements (mg/100 g dry matter) found in leaves on Nov. 3, 2000

Loc   . Ds       Tot-N      P        K       Ca      Mg      Fe    Mn        B       Zn      Na     Cu      Mo                                         

A       20.35    1,730    262   2312    95    113 5.   9     0.41     0.63  2.28    9.3   0.81   0.02                                      

Location A (untreated) had the highest readings for TotN, P, K, Mn and B.

Table 4: Yields per variety (kg/Ar), underwater wt. (UWW) and leaf color on Sept. 1

Loc.   <40      40/50       50/60      60/70       >70      total      >50 %     >50      UWW    Color                                          

A         53        111         160          106           11       441        278          62       378         7                                                 

L         46           94         177          143           33       492        353          71       376        7                                           

1sd     8           16            31            52           21         77         88             8          9          0.4

Locations L (BAP) and N had the highest percentages > 50.

Yields were low for location A (untreated).

„N“ was a test using other means. No BioAktiv was used on location A, „L“ was the treated location.

There was a total of 4 locations using no Bioktive, and 4 locations treated with BioAktiv