17.05.12

Phnom Penh, Cambodia (PRWEB) December 25, 2011

Besides his Curriculum vitae, a number of presentations developed during his employment for scientific, commercial and rural-development companies, and several packages of cultivation practices for different crops, the Tropical Agriculture Website of Dr. agr. Volker Kleinhenz covers his scientific publications. Two of these publications address the impacts of seasonally fluctuating soil moisture on soil contents of plant-available soil nitrogen. The paper on "Soil moisture, soil and crop nitrogen, and yield of vegetables in a seasonally wet-dry tropical lowland" was published in the journal "Plant Research and Development" while the article on "Crop and N management to improve environmentally sound vegetable production in tropical lowlands" was published in the "Thammasat International Journal of Science and Technology".

The agronomic article "Soil moisture, soil and crop nitrogen, and yield of vegetables in a seasonally wet-dry tropical lowland" published in "Plant Research and Development" covers agricultural research on soil moisture tension, soil and plant sap nitrogen, root length density distribution, and yield in four vegetables year-round in rice-based tropical southern Taiwan. Vegetables included vegetable soybean, Chinese cabbage, chili, and carrot. Soil nitrate accumulated during the dry season when evaporation exceeded precipitation. This could not be explained by release of nitrogen from the low soil organic matter alone. Release of nitrogen from clay-fixed or other soil fractions may be significant in soil environments which are kept under anaerobic (submerged) conditions during paddy rice cultivation. Fertilizer rates can be reduced and vegetables with a high capacity to absorb nitrogen should be grown during the dry season to protect nitrate from being lost with the onset of rainfall in the wet season. Soil moisture was high and soil nitrate low during the wet season. Nitrification of ammonium fertilizer was slower than in the dry season and nitrate disappeared quickly after rainfall. Overall, stresses caused by excessive soil moisture in the wet season and deficient soil moisture in the dry season limited vegetable growth apparently more than limited availability of soil nitrogen.

Source: DigitalJournal.com (press release)