جستجوی مقالات مرتبط با کلیدواژه « biomass production » در نشریات گروه « زراعت »

Development of saffron corm resources with higher ability to acquire nutrients and produce more dry matter may offer one solution to mitigate the yield loss problem in growing areas. In the present study, variability in growth, nutrition, and biomass production among saffron ecotypes grown for a two-year field experiment was investigated at Kerman, a semi-arid region of Iran, during the 2015-2016 and 2016-2017 growing seasons. The results indicated that the studied ecotypes significantly differed in the mentioned parameters and responded differently to growing seasons. High-agronomic performance (yield) and nutrient-efficient ecotypes, e.g. Ferdows, Sarayan, and Bajestan, accumulated more nutrients as a result of increased Relative Growth Rate (RGR) and Net Assimilation Rate (NAR) before the critical stage, resulting in higher dry matter production. In contrast, ecotypes with lower potential to acquire nutrients, e.g. Zarand and Torbat, had lower growth and dry matter. Further, the results showed that variation in nitrogen (N) concentration in corms and leaves was not significant, although significant variation existed in N uptake, N uptake efficiency, and N use efficiency. This can be due to variation observed in the ability of corms to utilize nutrients for dry matter production. Cluster analysis revealed the presence of highly efficient, moderately efficient, and inefficient ecotypes. Generally, the results indicated that ecotypes with higher growth rate before critical stage showed more potential to uptake and utilize nutrients to produce more dry matter, and exhibited more nutrients use efficiencies. Overall, this study suggested that the nutrient acquisition capacity of ecotypes, a desired feature associated with higher biomass production, can be an important factor in selection programs.

Despite tropical grasses being the main feed source for major part of ruminant livestock, information about nutritional quality changes under climate changes scenario are still scarce. The novelty of this work was to determine the effects of season and elevated CO2 under field conditions upon biomass production and nutritional value of Brachiaria decumbens during 2 years. The Free-Air Carbon Dioxide Enrichment was established in twelve rings: six of them being the control (current atmosphere) and others six fumigated with pure CO2 to achieve a higher concentration (e[CO2]). In each ring, two 0.25 m2 plots have been established with B. decumbens and after standardization cut, green forage yield was evaluated frequently. Plant samples were collected at 20 cm height and evaluated for determining the biomass production, nutritive value and in vitro enteric methane (CH4) production. Season and year had significant effect (P < 0.01) upon all the studied variables. Biomass production, acid detergent fibre and cellulose contents of samples from e[CO2] were statistically greater (P < 0.05). Carbon, nitrogen and crude protein content were within the normal range and as well as CH4 production were not altered by e[CO2] (P > 0.05). Overall, e[CO2] and rainfall seasons significantly increased forage production, contributing to sequester carbon in plant biomass, but this C4 tropical grass must be grazed at its best protein and fermentable carbohydrate ratio for advantages in the rumen microbial synthesis and lowering CH4 production intensity of the production system.

Grafting of Cucurbitaceae species to some rootstocks seems to be especially beneficial for the nitrogen nutrition of these plants. Moreover, melons (Cucumis melo L.) have been considered among those plants that could benefit from the addition of Silicon (Si) in the Nutrient Solution (NS). Thus, two experiments were carried out in the following order: (i) it was investigated how grafting affects nitrate absorption (following the disappearance of nitrates from NS), leaf water relations, leaf gas exchange, chlorophyll parameters and antioxidant activity, and (ii) it was also assayed which of the aforementioned physiological factors could be associated with Si supply in melon plants at early developmental stage when metabolism is intense. Results revealed that grafting and Si supply could improve photosynthesis, nitrate absorption, and biomass production in melon plants with respect to non-grafted or plants not receiving extra Si. Grafting melon on Cucurbita rootstock improved photosynthetic performance associated with higher antioxidant activity in melon leaves. Silicon supplementation results lend support to an active role of Si in biochemical processes at chloroplast level in melons. Increased assimilation rates in grafted and Si treated plants (20 to 35%), resulted in higher nitrate depletion from the medium (17 to 18%), which boosted shoot biomass production (23 to 26%) compared to the control plants. Our results suggest that grafting and Si supply in melon plants may lead to a better crop performance and a lower environmental impact of greenhouse fertigation effluents with respect to nitrate leaching, in some instances.

mprovement of N2 fixation might be an effective strategy in peanut breeding for high yield under drought stress conditions. However, under water limited conditions peanut varieties having high water-use efficiency (WUE) are favorable. A pot experiment was conducted under greenhouse conditions at Khon Kaen University, Thailand during December 2002 to May 2003, and repeated during June 2003 to November 2003. Twelve peanut genotypes were tested under three water regimes to estimate the relationships between N2 fixed with biomass production, WUE and pod yield under drought stress conditions. N2 fixed biomass production; pod yield and WUE were reduced by drought stress. At 2/3 AW, Tifton-8 and KK 60-3 were the best genotypes for high N2 fixed and high WUE. ICGV 98324 and ICGV 98300 had high pod yield, whereas Tifton-8 had low pod yield. N2 fixed was positively correlated with biomass and WUE under mild drought conditions but negatively correlated with pod yield. Tifton-8 was the best genotype for N2 fixed and WUE, but it was a poor performer for pod yield under drought conditions. ICGV 98324 and ICGV 98300 had higher pod yield with lower N2 fixed and WUE than did Tifton-8. Results indicated that N2 fixed under drought conditions contributed to vegetative growth and water use efficiency rather than to pod yield. Improvement for high N2 fixed in peanut could lead to high biomass production and WUE but may not necessarily improve pod yield under drought stress conditions.