Potato late blight - fatal threat in organic potato production

Improved potato late blight management is crucial for the continuity of organic potato production. Two major changes in cultural practises are necessary: more diverse crop rotation with at least 4 years between consecutive potato crops and optimising nitrogen fertilisation according to the needs of the crop

Nitrogen forms affect root structure and water uptake in the hybrid poplar

The study analyses the effects of two different forms of nitrogen fertilisation (nitrate and ammonium) on root structure and water uptake of two hybrid poplar (Populus maximowiczii x P. balsamifera) clones in a field experiment. Water uptake was studied using sap flow gauges on individual proximal roots and coarse root structure was examined by excavating 18 whole-root systems. Finer roots were scanned and analyzed for architecture. Nitrogen forms did not affect coarse-root system development, but had a significant effect on fine-root development. Nitrate-treated trees presented higher fine:coarse root ratios and higher specific root lengths than control or ammonium treated trees. These allocation differences affected the water uptake capacity of the plants as reflected by the higher sapflow rate in the nitrate treatment. The diameter of proximal roots at the tree base predicted well the total root biomass and length. The diameter of smaller lateral roots also predicted the lateral root mass, length, surface area and the number of tips. The effect of nitrogen fertilisation on the fine root structure translated into an effect on the functioning of the fine roots forming a link between form (architecture) and function (water uptake)

Role of White Clover in the Improvement of Economical Efficiency of Feeds from Grasslands

The aim of the research was to analyse the role played by white clover in the improvement of economical efficiency of feeds obtained from permanent grasslands. The influence of the proportion of white clover in the pasture sward on unit production costs of yield, energy and crude protein and the profit threshold in milk production was analysed taking into account three white clover cultivars, nitrogen fertilisation, irrigation and overdrilling. The investigation procedures employed the author’s own calculation models elaborated in optimisation programs based on production conditions found in dairy farms in the region of Wielkopolska. It was proved that the role of different cultivars of white clover in reducing unit production costs of DM, NEL and CP as well as of profit threshold in milk production is greater in conditions of the absence or low level of nitrogen fertilisation and without irrigation. Among the examined cultivars, Astra was found to be the most beneficial. Overdrilling of pastures with white clover increased fodder economical efficiency more in conditions of lack of nitrogen fertilisation

Effect of nitrogen on safflower physiology and productivity

Safflower (Carthamus tinctorius L.) is an oil-crop suitable for semi-arid agriculture, but its physiological response to agronomic inputs has yet to be fully evaluated. The effect of fertiliser on the physiology and production of safflower grown in pots filled with standard grade perlite inside a semi-controlled glass house was studied. Plants were initially irrigated with 20-100 ml standard hydroponic solution and then one month after germination plants were irrigated using 50-200 ml complete Hoagland’s solution, supplemented with one of eight levels of nitrogen (0, 25, 50, 75, 100, 125, 150, 175 kg N ha-1) in the form of ammonium nitrate. Elevating nitrogen to 100 kg N ha-1 significantly increased the assimilation rate by about 42 %, transpiration rate by 32%, stomatal conductance by 52% and LAI by 42% compared with the control. The above ground dry weight, seed yield and Water Use Efficiency (WUE) increased incrementally with increases in nitrogen rate. Above ground dry weight increased by an average of 42%, seed yield by 76% and WUE by 41% at harvest compared with the control. This study clearly demonstrates how nitrogen fertilisation can affect physiology of safflower leading to improvement in seed yield

The Effects of Nitrogen Fertilisation on Plant Species Richness in European Permanent Grasslands: A Systematic Review and Meta-Analysis

Nitrogen fertilisation is a common form of agricultural intensification, aimed at increasing biomass, which can affect plant species diversity and ecosystem functioning. Using a systematic review and meta-analysis of nitrogen fertilisation studies in European permanent grasslands, we asked: (i) what relationship form exists between nitrogen application rate and change in plant diversity, compared to zero fertilisation controls; and (ii) how grassland, management and study characteristics affect this relationship. Meta-analysis of 34 control-treatment effects from 14 studies conducted across nine European countries revealed a negative linear relationship between nitrogen fertilisation rate and change in plant species richness, equivalent to approximately 1.5 species/m(2) lost for every 100 Kg ha(-1) yr(-1) of nitrogen added. Fertilisation induced reductions in plant species richness were greater when defoliation rates were lower. We found some evidence that grasslands with a higher baseline plant diversity lost more species when fertilised compared to more species poor grasslands, although uncertainty was high. Due to the diverse grassland types included in the analysis, the variability in fertilisation-driven changes in plant diversity was high. We identified several remaining limitations to our understanding, including uncertainty about non-linear effects, which could aid efforts to optimise the trade-off of plant diversity and increasing grassland yields

Effect of elevated CO(2) and nitrogen levels on lentil growth and nodulation

Global carbon dioxide levels are rising, and could reach levels of 815 $\mu$mol mol$^{-1}$ by the year 2100. Since photosynthetic rate in C$_{3}$ species under the current levels of ambient CO$_{2}$ is still below physiological saturation levels, it is anticipated that photosynthesis and consequently productivity for most crops should be stimulated by the higher levels of atmospheric CO$_{2}$. A stronger response is expected in legumes as nitrogen is not considered as a limiting factor for growth. This study investigates the effect of elevated CO$_{2}$ and different nitrogen fertilizer levels on the growth and nodulation of lentils. Syrian lentil was grown under ambient CO$_{2}$ concentration of 400 $\mu$mol mol$^{-1}$, and under elevated CO$_{2}$ concentration of 700 $\mu$mol mol$^{-1}$, at five nitrogen levels equivalent to 5, 25, 50, 75 and 100 kg N ha$^{-1}$. Five harvests were conducted over the growth period and measurements of leaf area index (LAI), biomass dry weight, nodule number, and seed yield at the final harvest were recorded. The results showed that, compared to the ambient control, elevated CO$_{2}$ led to a significant increase in LAI after flowering (+20–30%), biomass dry weight (+35%) and seed yield (+60%) from 1292.74 kg ha$^{-1}$ to 2639.55 kg ha$^{-1}$ at the lowest and highest N levels respectively. Moreover these values increased with increasing levels of nitrogen. Nodule number also increased under elevated CO$_{2}$ and the highest nodule number was observed at the nitrogen level equivalent to 50 kg N ha$^{-1}$ under ambient and 75 kg N ha$^{-1}$ under elevated CO$_{2}$. The average increase of nodule number for all treatments under elevated CO$_{2}$ was +52%. Examination of total nitrogen and phosphorus concentrations in the dry matter showed that the total uptake was higher under elevated CO$_{2}$ but due to the increases in biomass concentration levels were slightly lower. For all parameters, no significant interaction between CO$_{2}$ and nitrogen treatment was recorded

Effect of elevated CO(2) and nitrogen levels on lentil growth and nodulation

Global carbon dioxide levels are rising, and could reach levels of 815 $\mu$mol mol$^{-1}$ by the year 2100. Since photosynthetic rate in C$_{3}$ species under the current levels of ambient CO$_{2}$ is still below physiological saturation levels, it is anticipated that photosynthesis and consequently productivity for most crops should be stimulated by the higher levels of atmospheric CO$_{2}$. A stronger response is expected in legumes as nitrogen is not considered as a limiting factor for growth. This study investigates the effect of elevated CO$_{2}$ and different nitrogen fertilizer levels on the growth and nodulation of lentils. Syrian lentil was grown under ambient CO$_{2}$ concentration of 400 $\mu$mol mol$^{-1}$, and under elevated CO$_{2}$ concentration of 700 $\mu$mol mol$^{-1}$, at five nitrogen levels equivalent to 5, 25, 50, 75 and 100 kg N ha$^{-1}$. Five harvests were conducted over the growth period and measurements of leaf area index (LAI), biomass dry weight, nodule number, and seed yield at the final harvest were recorded. The results showed that, compared to the ambient control, elevated CO$_{2}$ led to a significant increase in LAI after flowering (+20–30%), biomass dry weight (+35%) and seed yield (+60%) from 1292.74 kg ha$^{-1}$ to 2639.55 kg ha$^{-1}$ at the lowest and highest N levels respectively. Moreover these values increased with increasing levels of nitrogen. Nodule number also increased under elevated CO$_{2}$ and the highest nodule number was observed at the nitrogen level equivalent to 50 kg N ha$^{-1}$ under ambient and 75 kg N ha$^{-1}$ under elevated CO$_{2}$. The average increase of nodule number for all treatments under elevated CO$_{2}$ was +52%. Examination of total nitrogen and phosphorus concentrations in the dry matter showed that the total uptake was higher under elevated CO$_{2}$ but due to the increases in biomass concentration levels were slightly lower. For all parameters, no significant interaction between CO$_{2}$ and nitrogen treatment was recorded

Integrated and ecological nutrient management

This VEGINECO method manual is one of a series of publications resulting from the VEGINECO project. VEGINECO specialises in producing tested and improved multi-objective farming methods for key farming practices – e.g. crop rotation, fertilisation and crop protection – to facilitate the integration of potentially conflicting objectives like economy and ecology. This report describes a methodology for developing nutrient management strategies. In addition, examples of its application under different conditions in Europe are presented

Effect van stikstofverlaging op productie van grasland en rundvee

This report describes the effect of reducing the nitrogen fertilisation on production and botanic composition of grassland, grassland use, uptake of roughage and the production of dairy cattl

Influence of management practices on quality and biodiversity of tomatoes in Germany

Four old and endangered tomato cultivars were cultivated under greenhouse conditions with different levels of organic N-fertilisation and harvest at different maturity stages in order to develop a conclusive concept to preserve the diversity of old, endangered and multicolour cultivars. First results of several physio-chemical and sensory parameters were analysed to describe product quality. In order to assess consumer acceptance, 550 consumers were interviewed. The individual attributes of the cultivars, which differ in size, shape, colour, taste and health-related, beneficial physio-chemicals, are promoted by optimal harvest time. A combination of these cultivars distributed in regional markets is considered as a suitable concept for saving these endangered cultivars