Opportunities and constraints for improved vegetable production technology in tropical Asia

A description of the characteristics of vegetable production in tropical Asia is presented. The description is followed by a discussion of the opportunities and constraints of improved non-seed vegetable production technologies. Sowing of seeds and seedling emergence, transplant production, irrigation, mulching, fertiliser use, crop protection and weed control methods, protected cultivation and harvest date planning are discussed in relation to their use and impact. Conditions for successful introduction of new technologies and the role of outside actors are discussed. It is argued that in order to increase the success of adoption of improved technologies, farmers and public and private institutions should work together. With increasing prosperity, the demand for vegetables, especially in the expanding urban areas, will increase, leading to the intensification of production and higher profitability. With better profitability, the application of mulch, drip irrigation, fertigation and protected cultivation will become more common. With increasing production, harvest date planning as related to year-round city market demand, will become essential to improve profitability. It is recommended that, next to the development and introduction of improved production technologies, research and extension on vegetables in tropical Asia, should also focus on methods to improve harvest date planning and year-round suppl

Gewassaldo van Kouseband en Sopropo in drie Surinaamse tuinbouwgebieden : verslag van een survey in Commewijne, Saramacca en Wanica

In september 2010 is een survey uitgevoerd in de tuinbouwgebieden Commewijne, Saramacca en Wanica. In Saramacca en Wanica werden elk 5 telers van sopropo en kouseband geïnterviewd en in Commewijne werden 5 kouseband en 5 sopropo telers geïnterviewd. De telers werden met behulp van een vragenformulier bevraagd naar de kosten en opbrengsten van een kouseband of sopropo teelt. Ook werd gevraagd naar de benodigde arbeid voor de diverse teelthandelingen. Uit dit onderzoek kwam naar voren dat over het algemeen er weinig teeltregistratie door de telers zelf wordt gedaan. De meeste gegevens zijn afkomstig op basis van herinnering. Voor het opstellen van de gewassaldo’s moesten aannames gemaakt worden op het gebied van teeltduur, oogstperiode en gewasbeschermingsmiddel gebruik. Op basis van de opgestelde gewassaldo’s blijken tussen de drie onderzochte regio’s verschillen aanwezig te zijn in bemestingsstrategieën, opbrengsten en benodigde arbeid

Onderzoek naar cavity spot in peen

De proef werd in de kas te Lelystad uitgevoerd. Hiervoor werd eerst uit drie regio’s grond van verschillende percelen verzameld. Vervolgens werd hierin peen gezaaid en onder vochtige omstandigheden opgekweekt. Wanneer de peen redelijk van formaat was werd per pot aantal peen met cavity spot vastgesteld en werd getracht uit de symptomen de ziekteverwekker te isoleren en te determineren

Witlof in MA-verpakking leidt tot verbluffende resultaten

In 1997 werd door het PAV al aangetoond dat het verpakken van witlof in zogenaamde foliezakken leidt tot een beter kwaliteitsbehoud. In 1998 zijn verdere proeven gedaan met de foliezakken die in 1997 de beste resultaten gaven. Ook is de invloed van de temperatuur op de kwaliteit van het lof tijdens bewaring onderzoch

Learning on electrical circuits while playing 'E&E electrical endeavours' : design research on a serious game optimizing for conceptual understanding

In a two year design research project, a serious game was developed in a close collaboration of educational researchers, game-designers and secondary school teachers. In a first round, the game was used in classroom employing an open-inquiry format. It was found that the game had a strong impact on the student’s conceptual development but that it provoked the construction of misconceptions. The game was then adapted and partially redesigned on the basis of the evaluation outcomes and additional expert-review. Also the way of using the game in classroom was redesigned and written down in a teachers’ guide. In a second round this pedagogical approach to using the game in classroom alternating open inquiry type gaming-episodes with guided reflection and internalisation episodes, was used. Again a strong impact on students’ conceptual understanding of electrical circuits was found. Significantly less misconceptions occurred. The results indicate that the close collaboration of school teachers, educational experts and game designers was fruitful for improving the serious game and its use in school practice. Moreover it became clear that serious games have a potential to strongly contribute to students’ conceptual understanding, in particular by the mental model implicitly represented in the game´s layout and structure

Hollow stem in cauliflower

The occurrence of, sometimes large, cavities in the stem of cauliflower formed a serious quality problem for Dutch cauliflower growers in recent years. The cause of the problem under the local conditions was not clear. In field experiments, the application of boron and variation in the growth rate of the crop, were studied for effects on the occurrence and degree of seriousness of hollow stem. Broadcast application of boron at 1 and 2 kg per hectare at planting had no effect on the percentage of affected plants nor on the length of the cavities. There was no causal relation between the boron content of the stem at harvest and the occurrence or the length of the cavities. However, a positive relation between the average growth rate of the stem and the percentage of affected plants was observe

Snelle groei leidt tot meer holle stronken bij bloemkool

Een te hoge groeisnelheid van de stronk bij bloemkool kan worden afgeremd door dichter te planten. Per plant komt dan minder minerale stikstof beschikbaa