Black rot of cabbage in The Netherlands : studies on spatial and temporal development

Black rot in cabbage is caused by the bacterium Xanthomonas campestris pv. campestris . An exploratory survey at farm level suggested that major aspects contributing to black rot development are cultivar, initial inoculum, refuse management, origin of transplants, and seed quality. Black rot development was far more intensive with fresh than with old refuse piles, infected with X.c. pv. campestris . Increased levels of field resistance reduced the development of black rot in time and space.Field resistance to black rot is thought to be composed of several mechanisms. Black rot is hypothesised to be a potentially polycyclic disease. Fast disease development was related to the number of rain days. Secondary foci may appear at short distances from the initial focus but they usually merge with the expanding initial focus.Fast spatio-temporal development was related to high initial inoculum levels. Disease proceeds faster in plots with multi-focal inoculation than in those with uni-focal inoculation. Serious epidemics in Dutch cabbage fields originate from large numbers of foci. Temperatures≥5°C stimulated decomposition of plant debris and subsequently hastened the decline of X.c. pv. campestris . Infestation foci of X.c. pv. campestris in soil dwindled away during winters and became extinct in spring of the successive year. Polyetic development of black rot was not found. Geostatistics was successfully applied to reduce field sampling needed to obtain insight in disease patterns.</p

In-Situ Nuclear Magnetic Resonance Investigation of Strain, Temperature, and Strain-Rate Variations of Deformation-Induced Vacancy Concentration in Aluminum

Critical strain to serrated flow in solid solution alloys exhibiting dynamic strain aging (DSA) or Portevin–LeChatelier effect is due to the strain-induced vacancy production. Nuclear magnetic resonance (NMR) techniques can be used to monitor in situ the dynamical behavior of point and line defects in materials during deformation, and these techniques are nondestructive and noninvasive. The new CUT-sequence pulse method allowed an accurate evaluation of the strain-enhanced vacancy diffusion and, thus, the excess vacancy concentration during deformation as a function of strain, strain rate, and temperature. Due to skin effect problems in metals at high frequencies, thin foils of Al were used and experimental results correlated with models based on vacancy production through mechanical work (vs thermal jogs), while in situ annealing of excess vacancies is noted at high temperatures. These correlations made it feasible to obtain explicit dependencies of the strain-induced vacancy concentration on test variables such as the strain, strain rate, and temperature. These studies clearly reveal the power and utility of these NMR techniques in the determination of deformation-induced vacancies in situ in a noninvasive fashion.

Van precisielandbouw naar smart farming technology

Tijdens deze inaugurele rede wordt toegelicht hoe precisielandbouw wordt uitgevoerd en in de toekomst uitgevoerd gaat worden en hoe de 2 lectoren met het lectoraat daar een bijdrage aan willen leveren. Zij focussen zich op precisielandbouw in akkerbouwmatige teelten en in melkveehouderij

Van precisielandbouw naar Smart Farming Technology

Door de voortdurend stijgende kosten voor o.a. brandstof, grondstoffen en personeel is precisielandbouw feitelijk voorwaardelijk aan het worden voor elk type landbouwer en elke bedrijfsgrootte. Daarnaast is er vanuit de samenleving een sterk groeiende vraag naar meer en kwalitatief hoogwaardig voedsel, in combinatie met een minimale milieubelasting en een maximale zorg voor veiligheid en welzijn. Op lange termijn dient precisielandbouw de landbouw naar the next level te brengen. Dan wordt het Smart Farming Technology waarbij een integrale benadering van alle bedrijfsmatige facetten gecombineerd wordt tot een duurzame precisie bedrijfsvoering