Short-term warming and water stress affect Panicum maximum Jacq. stoichiometric homeostasis and biomass production

Organic amendments may improve the quality of acidic tropical agricultural soils with low organic carbon contents under conventional management (mineral fertilization and irrigation) in Southeast Asia. We investigated the effect of biochar, compost and their combination on maize growth and yield, soil physical, biological and chemical properties at harvesting time at four sites in three countries: Thailand, Vietnam and Laos. Treatments consisted of 10 t·ha−1 cow manure compost and 7 t·ha−1 of Bamboo biochar and their combination. Maize biomass production and cop yields were recorded for two seasons. Elemental content, pH and nutrient availability of soils were analyzed after the first growing season. We also characterized macrofauna abundance and water infiltration. Few changes were noted for maize biomass production and maize cop yield. Soil chemical parameters showed contrasting, site-specific results. Compost and biochar amendments increased soil organic carbon, pH, total K and N, P and K availability especially for sandy soils in Thailand. The combination of both amendments could reduce nutrient availability as compared to compost only treatments. Physical and biological parameters showed no treatment response. We conclude that the addition of compost, biochar and their mixture to tropical soils have site-specific short-term effects on chemical soil parameters. Their short-term effect on plants is thus mainly related to nutrient input. The site-dependent results despite similar crops, fertilization and irrigation practices suggest that inherent soil parameters and optimization of organic amendment application to specific pedoclimatic conditions need future attention.

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Physiological and morphological responses to water stress in Aegilops biuncialis and Triticum aestivum genotypes with differing tolerance to drought

Functional Plant Biology ◽

10.1071/fp03143 ◽

2004 ◽

Vol 31 (12) ◽

pp. 1149 ◽

Cited By ~ 66

Author(s):

István Molnár ◽

László Gáspár ◽

Éva Sárvári ◽

Sándor Dulai ◽

Borbála Hoffmann ◽

...

Keyword(s):

Growth Rate ◽

Triticum Aestivum ◽

Water Stress ◽

Drought Tolerance ◽

Osmotic Stress ◽

Biomass Production ◽

Water Loss ◽

Stomatal Closure ◽

Co2 Assimilation ◽

Wheat Genotypes

The physiological and morphological responses to water stress induced by polyethylene glycol (PEG) or by withholding water were investigated in Aegilops biuncialis Vis. genotypes differing in the annual rainfall of their habitat (1050, 550 and 225 mm year–1) and in Triticum aestivum L. wheat genotypes differing in drought tolerance. A decrease in the osmotic pressure of the nutrient solution from –0.027 to –1.8 MPa resulted in significant water loss, a low degree of stomatal closure and a decrease in the intercellular CO2 concentration (Ci) in Aegilops genotypes originating from dry habitats, while in wheat genotypes high osmotic stress increased stomatal closure, resulting in a low level of water loss and high Ci. Nevertheless, under saturating light at normal atmospheric CO2 levels, the rate of CO2 assimilation was higher for the Aegilops accessions, under high osmotic stress, than for the wheat genotypes. Moreover, in the wheat genotypes CO2 assimilation exhibited less or no O2 sensitivity. These physiological responses were manifested in changes in the growth rate and biomass production, since Aegilops (Ae550, Ae225) genotypes retained a higher growth rate (especially in the roots), biomass production and yield formation after drought stress than wheat. These results indicate that Aegilops genotypes, originating from a dry habitat have better drought tolerance than wheat, making them good candidates for improving the drought tolerance of wheat through intergeneric crossing.

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Adaptation to Water Stress of the Leaf Water Relations of Four Tropical Forage Species

Functional Plant Biology ◽

10.1071/pp9800207 ◽

1980 ◽

Vol 7 (2) ◽

pp. 207 ◽

Cited By ~ 49

Author(s):

JR Wilson ◽

MM Ludlow ◽

MJ Fisher ◽

E Schulze

Keyword(s):

Water Stress ◽

Water Content ◽

Water Relations ◽

Bound Water ◽

Leaf Tissue ◽

Dry Weight ◽

Panicum Maximum ◽

Soil Drying ◽

Buffel Grass ◽

Heteropogon Contortus

Three tropical grasses, green panic (Panicum maximum var, trichoglume), spear grass (Heteropogon contortus) and buffel grass (Cenchrus ciliaris) and the tropical legume siratro (Macroptilium atropurpureum), were grown in plots in a semi-arid field environment. The water relations characteristics of leaves from plants subjected to a soil drying cycle were compared with those of unstressed leaves from plants in irrigated plots. Minimum water potentials attained in the stressed leaves were c. -44, - 38, - 33 and - 13 bar for the four species, respectively. The grass leaves adjusted osmotically to water stress, apparently through accumulation of solutes, so that there was a decrease in osmotic potential at full turgor (Ψπ100) of 5.5, 3.9 and 7.1 bar, and in water potential at zero turgor (Ψ0) of 8.6, 6.5 and 8.6 bar for green panic, spear grass and buffel respectively. Water stress appeared to increase slightly the proportion of bound water (B) and the bulk modulus of elasticity (ε) of the grass leaves, but it did not alter the relative water content at zero turgor (RWC0) or the ratio of turgid water content to dry weight of the tissue. The Ψπ100 and Ψ0 of stressed siratro leaves decreased by 2.5-4 bar and 3-5 bar respectively when subjected to soil drying cycles. These changes could be explained by the marked decrease in the ratio of turgid water content to dry weight of the leaf tissue rather than by accumulation of solutes. The values of RWC0 and ε for siratro leaves were not altered by stress but, in contrast to the grasses, B was apparently decreased although the data exhibited high variability. Adjustments in Ψπ100 and Ψ0 of stressed leaves of buffel grass and siratro were largely lost within 10 days of rewatering.

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Phosphorus as a mitigator of the effects of water stress on the growth and photosynthetic capacity of tropical C4 grasses

Acta Scientiarum Agronomy ◽

10.4025/actasciagron.v38i3.28454 ◽

2016 ◽

Vol 38 (3) ◽

pp. 363 ◽

Cited By ~ 2

Author(s):

Frank Akiyoshi Kuwahara ◽

Gustavo Maia Souza ◽

Kezia Aparecida Guidorizi ◽

Ciniro Costa ◽

Paulo Roberto de Lima Meirelles

Keyword(s):

Water Stress ◽

Crop Production ◽

Photosynthetic Capacity ◽

Panicum Maximum ◽

P Deficiency ◽

Tropical Grasses ◽

Tropical Forage ◽

Productive Potential ◽

Urochloa Decumbens ◽

Urochloa Brizantha

Water deficiency during the dry seasons influences the relationship between water and gas exchange in tropical grasses, reducing their productive potential. In addition, the phosphorus (P) deficiency Brazilian soils adds to the set of factors limiting crop production. In this context, the objective of this study was to evaluate the responses of different tropical forage species to phosphorus supplementation as mitigating the damage caused by water stress. Seeds of Urochloa brizantha cv. MG-4, Urochloa decumbens cv. Basilisk, Panicum maximum cv. Áries, Panicum maximum cv. Tanzânia and Paspalum atratum cv. Pojuca were germinated in pots containing 10 liters of red-yellow Acrisol type soil. Experiments were conducted by combining levels of phosphorus, 8,0 and 100,0 mg of P dm-3, with two irrigation regimes, 100 and 40% replacement of transpired water. The biometric parameters, photosynthetic capacity, leaf water potential and soil chemical characteristics were evaluated, and the data was submitted to analysis of variance (ANOVA, p < 0.05), and subsequently the means were compared using a Tukey test (p < 0.05). The results showed for tropical grasses grown under water stress, there is a clear mitigating effect of phosphorus supplementation, especially on the maintenance of biomass growth.

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Short-term and seasonal dynamics of bacterial biomass production and amino acid turnover in the water column of an intertidal ecosystem, the Wadden Sea

Aquatic Microbial Ecology ◽

10.3354/ame01453 ◽

2010 ◽

Vol 61 (2) ◽

pp. 205-218 ◽

Cited By ~ 5

Author(s):

A Lemke ◽

M Lunau ◽

TH Badewien ◽

M Simon

Keyword(s):

Amino Acid ◽

Water Column ◽

Biomass Production ◽

Seasonal Dynamics ◽

Wadden Sea ◽

Bacterial Biomass ◽

Short Term ◽

Intertidal Ecosystem ◽

Amino Acid Turnover

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Assimilation of Sentinel-2 Estimated LAI into a Crop Model: Influence of Timing and Frequency of Acquisitions on Simulation of Water Stress and Biomass Production of Winter Wheat

Agronomy ◽

10.3390/agronomy10111813 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1813

Author(s):

Andreas Tewes ◽

Carsten Montzka ◽

Manuel Nolte ◽

Gunther Krauss ◽

Holger Hoffmann ◽

...

Keyword(s):

Water Stress ◽

Winter Wheat ◽

Biomass Production ◽

Aboveground Biomass ◽

Stem Elongation ◽

Simulation Models ◽

Development Stage ◽

Crop Model ◽

Area Index ◽

Sentinel 2

The Sentinel-2 (S2) Toolbox permits for the automated retrieval of leaf area index (LAI). LAI assimilation into crop simulation models could aid to improve the prediction accuracy for biomass at field level. We investigated if the combined effects of assimilation date and corresponding growth stage plus observational frequency have an impact on the crop model-based simulation of water stress and biomass production. We simulated winter wheat growth in nine fields in Germany over two years. S2 LAI estimations for each field were categorized into three phases, depending on the development stage of the crop at acquisition date (tillering, stem elongation, booting to flowering). LAI was assimilated in every possible combinational setup using the ensemble Kalman filter (EnKF). We evaluated the performance of the simulations based on the comparison of measured and simulated aboveground biomass at harvest. The results showed that the effects on water stress remained largely limited, because it mostly occurred after we stopped LAI assimilation. With regard to aboveground biomass, we found that the assimilation of only one LAI estimate from either the tillering or the booting to flowering stage resulted in simulated biomass values similar or closer to measured values than in those where more than one LAI estimate from the stem elongation phase were assimilated. LAI assimilation after the tillering phase might therefore be not necessarily required, as it may not lead to the desired improvement effect.

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Short-term effects of herbage allowance on milk production, milk composition and grazing time of cows grazing nitrogen-fertilized tropical grass pasture

Australian Journal of Experimental Agriculture ◽

10.1071/ea9770892 ◽

1977 ◽

Vol 17 (89) ◽

pp. 892 ◽

Cited By ~ 10

Author(s):

TH Stobbs

Keyword(s):

Milk Production ◽

Milk Fat ◽

Latin Square ◽

Ground Level ◽

Short Chain Fatty Acids ◽

Lower Percentage ◽

Panicum Maximum ◽

Fat Percentage ◽

Short Term ◽

Short Term Effects

The short-term effects of varying the quantities of herbage allocated (15, 25, 35, 55 kg DM cow-1, day-1) to lactating Jersey cows strip grazing 3-week regrowths of nitrogen-fertilized Panicum maximum cv. Gatton panic pastures, upon the diet selected, milk production, milk and milk fat composition and grazing time, were measured. Sixteen cows were used in a latin-square design with experimental periods of 1 4 days. With increasing herbage allowance milk yields rose, averaging 8.9, 9.9, 10.4 and 10.6 kg milk cow-1, day-1 respectively. A lower solids-not-fat percentage in milk from cows receiving 15 kg DM cow-1, day-1 and a lower percentage protein from cows receiving 15 and 25 kg DM cow-1 day-1 indicated a lower intake of digestible energy by cows at these lower herbage allowances. Molar percentages of short-chain fatty acids in milkfat (C6, C8, C10, C14) increased linearly and oleic acid (C18:1) decreased linearly as herbage allowance increased, showing that a higher proportion of the milk fat was coming from energy in the feed and a smaller proportion from body reserves. Cows selectively grazed leaf from the uppermost layers of the swards. As herbage allowance was restricted, a higher proportion of pasture was eaten and this came mainly from pasture growing 10 cm or more above ground level. Total time spent grazing was similar for all herbage allowances but the proportion of night grazing was consistently lower at the higher intensities of grazing.

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