Search results for "Agronomy"
showing 10 items of 2540 documents
Sensibilité des rendements agricoles potentiels aux paramètres climatiques et environnementaux dans la région du mont Kenya en Afrique de l’Est.
2013
7 pages; International audience; Comprendre les interactions existantes entre le climat et les rendements céréaliers est un objectif important pour l'actuelleproduction agricole et la sécurité alimentaire future des populations résidant dans des régions à agriculture pluviale. Lesrendements potentiels de sorgho simulés par le modèle SARRAH montrent une sensibilité aux paramètres climatiques etenvironnementaux le long des pentes orientales du Mont Kenya. Si le cumul et la durée de saison expliquent une part importante dela variabilité des rendements, d’autres variables comme l’intensité quotidienne, les Tmax ou encore le rayonnement global jouentun rôle non négligeable. La date de semis modu…
Special Issue: Water Management Strategies in Irrigated Areas
2016
The 2015 edition of the United Nations World Water Development Report highlighted that ‘water is at the core of sustainable development’. Water has upgraded the quality of human life, and any progress to achieve a more sustainable world will deal with the maintenance and/or the improvement of water management. Water demand has grown at more than twice the population rate in the XX century. By 2025, it is estimated that about 1.8 billion people will live in countries or regions with absolute water scarcity, and two-thirds of the world population could be under stress conditions.
Nutrient removal by rice–wheat cropping system as influenced by crop establishment techniques and fertilization options in conjunction with microbial…
2020
AbstractNutrient uptake by the rice–wheat cropping system (RWCS) is an important indicator of soil fertility and plant nutrient status. The hypothesis of this investigation was that the rate and sources of nutrient application can differentially influence nutrient removal and soil nutrient status in different crop establishment techniques (CETs). Cropping system yield was on par in all the CETs evaluated, however, there were significant changes in soil nutrient availability and microbiological aspects. The system nitrogen (N), phosphorus (P), potassium (K) and zinc (Zn) uptake in aerobic rice system followed by zero tillage wheat (ARS-ZTW) was 15.7–17.6 kg ha−1, 0.7–0.9 kg ha−1, 7–9.8 kg ha…
Effects of tilling methods on soil penetration resistance, organic carbon and water stable aggregates in a vineyard of semiarid Mediterranean environ…
2018
Tillage, especially in semiarid Mediterranean environment, enhances the mineralization process of soil organic matter (SOM) and, in turn, decreases aggregate stability. Furthermore, continuous tillage leads to the formation of plough pan beneath the tilled layer. In the present study, we investigated the effect of an innovative self-propelled machine (spading machine, SM) for shallow tillage on SOM, water stable aggregates (WSA) and soil penetration resistance (PR). Such effects were compared to those of chisel plough (CP), rotary tiller (RT) and no tillage (NT). Each tilling method was applied up to a depth of 15 cm, whereas in NT only a brush cutter was used for weed control. Soil analyse…
Differential toxicity of simazine and diuron to Torilis arvensis and Lolium rigidum
1990
Summary: In a soil application, Torilis arvensis was nearly as susceptible as Lolium rigidum to simazine but was 18-fold more tolerant to diuron. Treat ment with diuron inhibited photosynthesis in L. rigidum but had only a limited effect in T. arvensis although chloroplasts isolated from both species displayed similar susceptibility. 14C-diuron degradation in plants was limited, with the formation of conjugates of mono-methyl-diuron in T. arvensis and N-dealkylated derivatives of diuron in L. rigidum. 14C-diuron entered the roots and was translocated throughout the leaves of L. rigidum but was restricted to stems, leaf petioles and leaf veins of T. arvensis. This difference in transport pat…
Influence of plant traits, soil microbial properties, and abiotic parameters on nitrogen turnover of grassland ecosystems
2016
International audience; Although it is known that multiple interactions among plant functional traits, microbial properties , and abiotic soil parameters influence the nutrient turnover, the relative contribution of each of these groups of variables is poorly understood. We manipulated grassland plant functional composition and soil nitrogen (N) availability in a multisite mesocosm experiment to quantify their relative effects on soil N turnover. Overall, root traits, arbuscular mycorrhizal colonization, denitrification potential, as well as N availability and water availability, best explained the variation in measured ecosystem properties, especially the trade-off between nutrient sequest…
Galerucella nymphaeae (Col., Chrysomelidae) grazing increases Nuphar leaf production and affects carbon and nitrogen dynamics in ponds.
1990
The grazing effects of the waterlily beetle Galerucella nymphaeae on Nuphar lutea stands were studied in three ponds in Central Finland. Production of floating leaves of N. lutea and growth in the G. nymphaeae population were investigated in the ponds and bioenergetics of the beetle larvae in the laboratory. Combination of field and laboratory data enabled estimation of the effect of the beetle on the production of floating leaves of N. lutea and the consequences of grazing for the input of detritus from Nuphar into the ponds. Adults and larvae of G. nymphaeae consumed 3.0–6.1% of the net annual floating leaf production during the growing period. In addition to consumption losses, feeding a…
Airborne birch pollen in Poland and Latvia in the light of data obtained from aerobiological monitoring and tauber traps in relation to mean air temp…
2012
Birch pollen contains allergens belonging to those with the strongest allergenic properties. In order to trace pollen season patterns of this taxon and pollen annual sums at a wider regional scale, cooperation was established with the University of Latvia in Riga (Latvia). A comparison of the results obtained in the years 2003-2008 in Lublin and in Riga, using volumetric samplers, shows that there was a similar trend in the abundance of birch pollen. The highest sums were noted at both sites in 2003. In all the study years, more birch pollen grains were recorded in Lublin than in Riga, on the average by 7110. The birch pollen seasons started earlier in Lublin than in Riga, on the average by…
Leaf starch and nutrient responses to stem girdling and drought stress with respect to understanding HLB (greening) symptoms in citrus
2016
The most important problem in world citrus production is the bacterial disease Huanglongbing (HLB; greening) which is caused by a phloem-limited bacterium that is vectored by a phloem-feeding psyllid. The earliest visible symptoms of HLB in leaves are an asymmetrical chlorosis referred to as "blotchy mottle", thought to be from starch accumulation from a phloem dysfunction and a decline in root health. We tested the hypothesis that such visible symptoms are not unique to HLB by stemgirdling two year-old seedling trees of 'Cleopatra' mandarin and 'Swingle' citrumelo rootstocks in the greenhouse. Girdling induced a 4-fold greater starch concentration in leaves on well-watered trees while star…
Les phénols de la lignine et le 13C, traceurs de l'origine des matières organiques du sol
2001
Abstract In spodosols of Gascony (France), conversion of maritime pine stands into maize cropping leads to an incorporation of maize organic matter, which changed the isotopic (δ13C) and phenolic signature in A and L horizons of soil. Hydrolysis of phenol lignin in forests and cultivated soils showed the predominance of vanillic units under forest and the early but moderate incorporation of cinnamic acids. Incorporation of syringic units appeared higher, related to a large maize production of stable syringic phenols. Syringic units represented a long-term marker of maize inputs in soils, whereas vanillic units revealed the degradation of forest organic matter.