Influence of NPK-application to seed-potato crops on the productivity of the progeny
SummaryThe amount of P- and K-application to the seed-potato crop did not show any influence on the chemical composition of the immature harvested tubers, nor on the productivity if used as seed. Nitrogen had a marked influence on the chemical composition of the tubers.Seed from plots with high nitrogen dressing showed a tendency to give fewer main stems. Concerning the productivity of the seed the experiments showed contradictory results. It is concluded that the amount of fertilizer applied to the seed-potato crop is of little importance for the productivity of the progeny.
The physiological degeneration of potato seed tubers and its control
Summary1.After starting independent life, the potato tuber exhibits its own growth characteristics according to each stage in the life cycle. The term “proper age” denotes the stage at which the seed tuber performs the highest function. When the seed tuber is planted before or after the proper age degeneration is proportionate to the time interval. This is known as physiological degeneration.2.Degeneration that occurs before the proper age is reached, is termed juvenile degeneration and senile degeneration that occurring after the proper age (Figs. 2 and 3).3.The age is calculated in months. Taking into consideration varieties, cultural practices, type of crop season, etc. (Table 1), the proper age is considered to be 4–6 months.4.In most areas the time of year selected for potato growing often proves unfavourable for the use of seed tubers at the proper age (Fig. 1 andTable 2). This is because physiological degeneration is extremely widely distributed and the loss is also large, and special measures have to be taken to obtain seed tubers of the proper age.5.In order to control physiological degeneration it is advisable to grow seed tubers that can be lifted 4–6 months before planting, or the seed tubers should be obtained from areas in which seed is grown during the appropriate crop season (Fig. 4).Zusammenfassung1.Nachdem sie ihr selbständiges Leben begonnen hat, zeigt die Kartoffelknolle ihre eigene Wachstumscharakteristik entsprechend den einzelnen Stadien des Lebenszyklus. Die Bezeichnung “geeignetes Alter” (“proper age”) bedeutet das Stadium, in welchem die Saatknolle am leistungsfähigsten ist. Wird die Knolle vor oder nach dem geeigneten Alter ausgepflanzt, so tritt Degeneration entsprechend der Zeitdifferenz ein. Dies ist die physiologische Degeneration.2.Die vor dem geeigneten Alter eintretende Degeneration ist die “juvenile Degeneration”; die nach diesem Alter eintretende die “senile Degeneration” (Abb. 2 und 3).3.Das Alter wird in Monaten ausgedrückt. Als geeignetes Alter wird normalerweise 4 bis 6 Monate angenommen; je nach Sorte, Anbauweise, Anbauzeit usw. (Tabelle 1).4.In den meisten Gegenden erweist sich die für den Kartoffelbau gegebene Jahreszeit häufig als ungünstig für die Verwendung von Saatkartoffeln im geeigneten Alter (Fig. 1 undTabelle 2). Die physiologische Degeneration erstreckt sich dadurch schr weit und der Verlust ist ebenfalls beträchtlich; es sind daher Vorkehrungen nötig, um Saatkartoffeln von geeignetem Alter zu erhalten.5.Um der physiologischen Degeneration entgegenzuwirken, empfiehlt es sich daher, Saatkartoffeln zu züchten, die 4 bis 6 Monate vor dem Auspflanzen gerodet werden können, oder die Saatkartoffeln aus Gegenden zu beziehen, wo die Pflanzguterzeugung in der geeigneten Anbauzeit betrieben wird (Fig. 4).Résumé1.Après avoir commencé son existence indépendante, le tubercule de pomme de terre présente ses propres caractéristiques de croissance correspondant à chaque phase du cycle vital. Le terme “âge approprié” (“proper age”) désigne la phase où les fonctions du plant sont à leur maximum. Lorsque le tubercule de semence est planté avant ou après l’âge approprié, il se manifeste une dégérescence correspondant à la différence avec l’âge approprié. C’est ce qu’on nomme la dégérescence physiologique.2.La dégénérescence provoquée par la plantation avant l’âge approprié se nomme “dégénérescence juvénile”. Celle qui résulte de la plantation retatdés s’appelle “dégénérescence sénile” (Fig.) 2 et 3).3.L’âge est exprimé en mois. On situe l’âge approprié à 4–6 mois, selon la variété, les techniques de culture, le type de saison de culture, etc. (Tableau 1).4.Dans la plupart des régions, la saison de l’année consacrée à la culture de la pomme de terre se révèle défavorable à l’emploi de tubercules d’un âge approprié (Fig. 1 etTableau 2). C’est pourquoi la dégénérescence physiologique est très répandue et les pertes sont également importantes. Il faut donc chercher à se procurer des plants de pomme de terre d’un âge approprié.5.Pour la lutte contre la dégénérescence physiologique, il est recommandable de cultiver des plants de pomme de terre pouvant être arrachés 4 à 6 mois avant l’époque de la plantation ou de se procurer des plants provenant de régions où la culture des plants est effectuée dans la saison appropriée (Fig. 4).
Comparison between Two Chemicals for Reducing Scale Formation in Reverse Osmosis Systems
In this present research was transacted with the calcium carbonate scale inhibition on the membrane surface of the reverse osmosis desalination system. Influence of changing feed solution flow rate (10-25)l/h, pH of the feed solution (6-10) on the recovery ,penetrate flow rate and total dissolved solid in (RO) system by using solution of calcium carbonate as feed solution was investigated, furthermore the effect of adding two types of scale inhibitor ,zinc chloride and polyamino polyether methylene phosphonate with difference concentration (2-8)mg/l for zinc chloride and (8-15) mg/l for polyamino polyether methylene phosphonate was calculated. The results showed that the permeate rate increases as the feed flow rate augmentation ,while it reducing with time, the total dissolved solids decreases as the feed flow rate increases while it increases with time and recovery rate decreases as the feed flow rate increases and it also decreases with time. It was concluded that the permeate rate decreases as the feed solution pH value increases and it cause high scale forming thus decrease the permeate TDS.By adding the scale inhibitor, it was found that the permeate rate and recovery rates increases as the concentration of inhibitor increases while the total dissolved solids decreases in the permeate with increasing the concentration of both inhibitors .It was discovered that Polyamino polyether methylene phosphonate more sturdy than zinc chloride as scale inhibitor for reverse osmosis desalination system in all concentrations was studied in this article.