Ground Biomass Accumulation Research Articles

Food and agricultural wastes-derived biochars in combination with mineral fertilizer as sustainable soil amendments to enhance soil microbiological activity, nutrient cycling and crop production

The ever-increasing human population associated with high rate of waste generation may pose serious threats to soil ecosystem. Nevertheless, conversion of agricultural and food wastes to biochar has been shown as a beneficial approach in sustainable soil management. However, our understanding on how integration of biochar obtained from different wastes and mineral fertilizers impact soil microbiological indicators is limited. Therefore, in the present study the effects of agricultural (AB) and food waste derived (FWB) biochars with and without mineral fertilizer (MF) on crop growth and soil health indicators were compared in a pot experiment. In particular, the impacts of applied amendments on soil microbiological health indicators those related to microbial extracellular (C, N and P acquiring) enzymes, soil basal as well as different substrate induced respirations along with crop’s agronomic performance were explored. The results showed that compared to the control, the amendment with AB combined with MF enhanced the crop growth as revealed by higher above and below ground biomass accumulation. Moreover, both the biochars (FWB and AB) modified soil chemical properties (pH and electric conductivity) in the presence or absence of MF as compared to control. However, with the sole application of MF was most influential strategy to improve soil basal and arginin-induced respiration as well as most of the soil extracellular enzymes, those related to C, N and P cycling. Use of FWB resulted in enhanced urease activity. This suggested the role of MF and FWB in nutrient cycling and plant nutrition. Thus, integration of biochar and mineral fertilizers is recommended as an efficient and climate smart package for sustainable soil management and crop production.

Performance of rice under different water regimes and plant nutrient sources

Field experiment was carried out at the Soil and Irrigation Research Centre, University of Ghana, Kpong in 2015 and 2016 cropping seasons to evaluate the effect of different soil water condition and plant nutrient sources on the growth and yield of rice. The experiment was laid out in a split plot design with three replications. Water regime and nutrient source were the main and sub-plot factors, respectively. Water regimes included; continuous flooding (CS), alternate wetting and drying (AWD) and moist soil condition between field capacity and permanent wilting point (MC) while the nutrient fertilizer treatments included no fertilizer (N0), 90 kg N/ha mainly from urea fertilizer (N1), 90 kg N/ha from 12.8 tons of compost (N2) and 45 kg N/ha from urea fertilizer + 45 kg N/ha from 6.4 tons of compost (N3). Results from the study revealed that keeping the soil periodically in aerobic and anaerobic condition through AWD method of water management recorded similar growth and grain yield of rice as with complete submergence of paddy field. Combination of inorganic fertilizer and compost for each to supply 45 kg N/ha under AWD produced the highest rice growth and grain yield. There was a positive and significant correlation between grain yield and growth parameters (plant height, chlorophyll content and above ground biomass accumulation).

Modelling above ground biomass accumulation of mangrove plantations in Vietnam

In many tropical nations, mangrove forests are essential ecosystems for climate change mitigation and adaptation in coastal regions as they provide important forest resources as well as a suite of other benefits to communities including carbon sequestration. Empirical growth and yield modelling methods derived from terrestrial forestry, which are often robust with respect to forestry forecasting and management, have not often been assessed in mangrove forests yet they are important for underpinning sustainable forest management. We surveyed 89 Rhizophora apiculata mangrove plantations with age ranges from 4 to 26 year old in Vietnam, destructively harvesting 25 trees for biomass measurements and 70 for stem analyses, to assess increments in biomass and standing timber. Systems of equations were developed to model site index, mean diameter, dominant height, stocking, biomass and timber volume. We found that conventional forest growth modelling methods fitted the observed data well. Similar to terrestrial forests, stand height is a good indicator of site productivity. Mean errors for stand volume and biomass estimated from yield tables were both less than 5.3%. The root mean square error (RMSE) of the biomass model was 12 and RMSE of the volume model was 10.8, suggesting that these methods are applicable to evenly aged monoculture mangrove plantations in Vietnam. Our research also indicated high variation in mean annual increment of biomass (MAI) in the surveyed plantations due to a wide range of age and site conditions. Some R. apiculata plantations in Vietnam can reach a peak aboveground biomass MAI of 22.7 Mg ha−1 year−1, which is among the highest of published values from plantations of the same species worldwide. Further studies addressing the application of terrestrial forest growth methods to mangrove systems are suggested in order to develop reliable and useful tools for sustainable management of this important ecosystem.

Water use efficiency in perennial forage species: Interactions between nitrogen nutrition and water deficit

Interactions between nitrogen and water may vary between N2 fixing species and species that rely only mineral soil nitrogen. Here we compared above ground biomass accumulation (W), nitrogen uptake (N), evapotranspiration (ET) of alfalfa (Medicago sativa L.) and tall fescue (Festuca arundinacea Schreb.) during regrowth periods under contrasting supply of water (irrigated vs non-irrigated) and N (for non-fixing species). Using previously published data, we estimated the dynamics of the two components of ET, evaporation from soil (E) and transpiration (T), in order to analyse the impact of E/T, of the transpiration efficiency (TE = W/T) and the role of crop N nutrition on water use efficiency (WUE= W/ET). In tall fescue, limiting N supply reduced WUE by both increasing E/T ratio and decreasing TE. Water limitation in both alfalfa and tall fescue led to crop nitrogen deficit. This drought-induced N deficiency resulted in a proportional reduction in TE irrespective of the source of N for the plant. We propose that the ratio N/T, representing the apparent N concentration of water transpired by the crop, is relevant for analysing N-water interactions. Comparisons of dynamics of N/T ratio must be done at similar biomass or similar transpiration because N and T are related allometrically.

Defoliation management of kleingrass (Panicum coloratum L. var coloratum) cv Verde

The defoliation frequency determines above and below ground biomass accumulation, pasture structure and nutritive value. Two defoliation experiments with Panicum coloratum were performed, from September to March. One of them was conducted in pots under greenhouse conditions, and the other one in field plots for three growing seasons (EC) at the Faculty of Agronomy, La Pampa, Argentina (36˚ 46' S; 64˚ 16' W). Defoliation frequency treatments were four cutting intervals (IC; 3, 4, 6 and 8 weeks). In greenhouse experiment, live leaf blade accumulation rates (TAL), tiller appearance (TAM) and death (TMM) rates, live leaf blade length (LL) and above and below ground dry matter (MS) accumulation were determined. In field plots tiller height, weight and tiller, crude protein (PB) and dry matter accumulation were determined. TAL and the TAM were 1.28 (0.1024 vs 0.0798 cm/tiller/°Cd; P

Biomass Partitioning and Accumulation in Tectona grandis (Teak) at Young Stage

Forest biomass is considered to have a large potential for temporary and long-term carbon storage as biomass. Enhancement of biomass increase via forest plantation establishment can be considered as an effective method of mitigation of atmospheric carbon dioxide. However, due to the difficulty of measuring the below ground biomass accumulation, most of the tree and forest related biomass studies have been conducted on the above ground components of the trees. Therefore the present study was conducted to identify the biomass accumulation over the age and its partition in above and below ground segments of young teak trees by destructive sampling. Teak trees of 55, 67, 79, 91 and 103 months growing in a single plantation in Puttlam was selected for this reason. Three trees of each age were randomly selected and carefully uprooted with the minimum damage to the roots. Then each tree was separated into main stem, primary, secondary and tertiary branches and roots and the weights were measured. Representative samples of each segment of the tree were oven dried at 72° C for three days. Then the biomass of each segment was calculated. The average total tree biomass increased from 28.430 to 79.760 kg from 55 to 103 months. Comparatively, the highest biomass was recorded in the main stem (63.5%) followed by primary branches (15.7%). The third highest biomass was recorded from the roots (11.7%) and the lowest biomass was recorded in tertiary branches (3.6%). A strong exponential relationship was observed between the tree age and whole tree biomass increase with the R2 of 97.7%. It further revealed that the biomass increase of teak is rising with a rapid rate even at the age of 10 years. Keywords: Tree biomass, Biomass partition, Teak

Climate change and the potential spread of Sorghum halepense in the central area of Argentina based on growth, biomass allocation and eco-physiological traits

Despite the research dedicated to understand the potential climate change impacts on cropping systems, little attention has been given to potential effects on the geographic range of agricultural weeds. This paper reviews some biological and eco-physiological features of Sorghum halepense populations and their current and potential spread in a central eco-region of Argentina. Above ground biomass accumulation of the weed shows very high accumulation rates, which in the case of rhizomes is boosted as the available resources in propagule increases. An increase in temperature by 15 % may increase the relative growth rate (RGR) by 50 % in a 20–90 days growth period. Not only biomass output but also biomass allocation is directly related to adaptation in changing environments. Populations adapted to limited water conditions are able to maintain a higher RGR under water restriction as compared to those adapted to more humid conditions. Regarding the temperature, climate models are coincident: a range of increase from 0.9 °C in the south to 1.4 °C in the north of Argentina is predicted for 2020–2040, as compared to the period 1961–1990. Concerning the rainfall, not yet a prediction but a real fact is the displacement of isohyets from east to south. The average frequency of the weed in the pool of fields recently surveyed in the central region was 37 %, which increased to 42 % in the field borders. We consider that this frequency is high, since all crop fields are managed with high technology level and herbicides have been applied not only during the crop cycles, but also in previous fallows. The high RGR and other physiological features of weed populations at low water availability, which is more frequent in the west of the surveyed region where the frontier of extensive crops have recently displaced, may explain higher frequencies found. Well-adapted S. halepense populations invading rainfed crops in this eco-region will likely to take advantage under the forthcoming forecasted climatic conditions. Since temperatures increase from east to west as shown in climograms, S. halepense populations will likely perform even better under the new climate conditions. Coupling the actual management to physiological traits, it is envisaged an increase of the weed frequency in the surveyed eco-regions.

Biomass accumulation in tropical lands with different disturbance histories: Contrasts within one landscape and across regions

Large areas of tropical forests have been converted to agricultural land and subsequently abandoned. If restoration can occur on these abandoned lands, it offers great potential for biodiversity recovery, carbon sequestration, and enhanced ecosystem services. To understand the interaction between different forms of anthropogenic degradation and restoration strategies we examined biomass accumulation at two different scales. First, using small scale comparisons where the tree species pool, climate, and dispersers were similar, we quantified regeneration in degraded sites in Kibale National Park, Uganda subjected to different restoration strategies. Second, we contrasted biomass accumulation for 57 tropical studies where the nature and time since disturbance differed. The above ground biomass of 10–32year old forest in Kibale ranged from 15,675 to 34,294kg/ha and was a function of the type of the management strategy used to promote regeneration. The above ground biomass accumulation from other tropical sites ranged extensively; from 470kg/ha in an 8year old abandoned pasture in Brazil to 272,000kg/ha in a 16year old abandoned agricultural field in Mexico. Overall, the time since abandonment was a good predictor of biomass accumulation. This review demonstrates that once left to regenerate, secondary forests accumulate above ground biomass in a very positive manner; however, the speed of biomass accumulation can be facilitated by site-specific restoration strategies. Both the cost and efficiency of different restoration strategies vary dramatically and our research in Kibale suggests that making larger financial investments does not necessarily result in more positive biomass accumulation.

Disturbance Regime Mediates Riparian Forest Dynamics and Physiological Performance, Arkansas River, CO

Tamarix ramosissima has caused dramatic morphological changes to riparian ecosystems and their bank structures over the last century throughout the southwestern United States. Growing as either small trees or dense stands of shoots, Tamarix species displace or actively outcompete native species of willow (Salix exigua) and cottonwood (Populus deltoides) on the Arkansas River in Colorado. Under normal conditions for colonization by native species, Tamarix seedlings are at a great competitive disadvantage due to slow above ground biomass accumulation. However, damming and the resulting altered disturbance regime may give Tamarix an advantage over native species. Damming on the Arkansas River, Colorado, dramatically reduces the intensity and recurrence interval of downstream flooding. Using two dams in eastern Colorado as proxies for flood control, we assessed physiological, demographic and abiotic factors in order to understand how flooding and damming might influence riparian community dynamics. Our study demonstrates that drought and salinity stress may influence native species recruitment and survival in areas with reduced flooding. Moreover, Tamarix water-use may be quite plastic in drought conditions, suggesting that it conserves water at below dam sites.

<b>EFISIENSI PENGGUNAAN RADIASI SURYA DAN SEBAGAI DASAR DALAM MODEL JARAK PAGAR</b><br>(RADIATION USE EFFICIENCY AS BASIS THE CROPS MODELING OF JATROPHA)

Plant growth interpretation in term of accumulated intercepted solar radiation and the radiation use efficiency (RUE) was used to study the growth and analysis of Jatropha (Jatropha curcas L.). A number of crop growth simulation models have been developed using the RUE concept to predict crop growth and yield in various environments. These models generally calculate daily biomass production as the product of the quantity of radiation intercepted and RUE. This research was carried out to quantify the RUE, biomass and leaf area index on Jatropha under rainfall condition, four levels of nitrogen fertilizer (N) and three population densities (P) planted twice. The experiments used a systematic Nelder fan design with 9 spokes and 4 – 5 rings were conducted at SEAMEO-BIOTROP field experiment in 2007. Data from the first experiment were used for parameterization and calibration and the second experiment data for model validation. Values of RUE were determined by nitrogen fertilizer and plant density. Based on parameterization, we found that RUE for prediction above ground biomass accumulation of Jatropha were 0.94 (r=0.83) g MJ-1 to 1.3 (r=0.75) g MJ-1. Validation between model prediction and field experimental data showed that model can simulate crop growth and development of Jatropha.

Responses of an ethnobotanically important wetland species, Gunnera perpensa L. to soil waterlogging

Gunnera perpensa L., a wetland herb, is extensively harvested and used as traditional medicine. In many areas of KwaZulu-Natal, South Africa, populations are under threat of overexploitation from the herb. Successful cultivation would reduce harvesting of natural populations and could help conserve the species. To provide information for cultivation, we assessed the effects of various flooding regimes on plant growth and biomass accumulation, as well as on morphological and physiological adaptations of this species to waterlogging stress. Plant rhizomes collected from the field were cultivated for three weeks, and then subjected to drained, 20%, 40%, and 80% flooded treatments for 12 weeks. Plant height, total dry biomass accumulation, and carbon dioxide exchange increased significantly with increase in level of flooding from the drained to the 40% flooded treatments, and thereafter decreased as level of flooding increased to 80%. Soil Eh and root specific gravity decreased with increases in flooding. In rhizotron experiments, in which plants were subjected to 40%, 80%, and 100% flooding, root growth as well as biomass accumulation decreased as flooding increased. Photosynthetic performance, monitored along a natural soil moisture gradient in the field, indicated that carbon dioxide exchange, quantum yield of photosystem II (PS II), and electron transport rate (ETR) through PS II were higher at a soil moisture of 45% than at 25% or 60%. This study demonstrated that G. perpensa grows best in moderately reduced soils that are moist but not waterlogged. Adaptations to waterlogging include increased aerenchyma in roots and petioles, and decreased below ground biomass accumulation.

Temperature dependence of growth, development, and photosynthesis in maize under elevated CO 2

Global atmospheric carbon dioxide concentrations ( C a) are rising. As a consequence, recent climate models have projected that global surface air temperature may increase 1.4–5.8 °C with the doubling of C a by the end of the century. Because, changes in C a and temperature are likely to occur concomitantly, it is important to evaluate how the temperature dependence of key physiological processes are affected by rising C a in major crop plants including maize ( Zea mays L.), a globally important grain crop with C 4 photosynthetic pathway. We investigated the temperature responses of photosynthesis, growth, and development of maize plants grown at five temperature regimes ranging from 19/13 to 38.5/32.5 °C under current (370 μmol mol −1) and doubled (750 μmol mol −1) C a throughout the vegetative stages using sunlit controlled environmental chambers in order to test if the temperature dependence of these processes was altered by elevated C a. Leaf and canopy photosynthetic rates, C 4 enzyme activities, leaf appearance rates, above ground biomass accumulation and leaf area were measured. We then applied temperature response functions (e.g., Arrhenius and Beta distribution models) to fit the measured data in order to provide parameter estimates of the temperature dependence for modeling photosynthesis and development at current and elevated C a in maize. Biomass, leaf area, leaf appearance rate, and photosynthesis measured at growth C a was not changed in response to CO 2 enrichment. Carboxylation efficiency and the activities of C 4 enzymes were reduced with CO 2 enrichment indicating possible photosynthetic acclimation of the C 4 cycle. All measured parameters responded to growth temperatures. Leaf appearance rate and leaf photosynthesis showed curvilinear response with optimal temperatures near 32 and 34 °C, respectively. Total above ground biomass and leaf area were negatively correlated with growth temperature. The dependence of leaf appearance rate, biomass, leaf area, leaf and canopy photosynthesis, and C 4 enzyme activities on growth temperatures was comparable between current and elevated C a. The results of this study suggest that the temperature effects on growth, development, and photosynthesis may remain unchanged in elevated C a compared with current C a in maize.

Podophyllotoxin content in Podophyllum hexandrum Royle plants of known age of seed origin and grown at a lower altitude

Podophyllum hexandrum Royle, an important alpine herb, and a source of the highly valued aryltetralin-type lignan, podophyllotoxin, has been subjected to heavy collection from the wild due to ever increasing demand. The present study deals with an attempt to bring this plant under cultivation at a relatively lower altitude and to evaluate (1) various growth parameters including above and below ground biomass accumulation, net assimilation rate and relative growth rate, etc., and (2) podophyllotoxin content from the resulting above and below ground biomass in seed raised plants of a known age series of 1–5 years. The podophyllotoxin content was estimated on the basis of HPLC analyses. The levels were found to increase with the plant age and the maximum amount was found in 5-year old plants. This study demonstrates that (1) seeds can be conveniently used for raising healthy propagules in easily approachable locations at a relatively lower altitude, and that the plants can be maintained in such sites over long periods, and (2) this approach of “conservation through cultivation” can be suggested as an effective tool for the management of this “critically endangered status” species.

The effect of epiphytic algae on the growth and production of Potamogeton perfoliatus L. in two light conditions

Direct evidence of epiphytic algal effects on the growth and production of freshwater submerged macrophytes is scarce. To obtain more reliable, quantitative data about this phenomenon, a laboratory experiment was carried out over 84 days in controlled conditions with the submerged macrophyte, Potamogeton perfoliatus. It was based on a 2×2 factorial design with two epiphytic conditions (with epiphytic algae and without) and two light conditions (high and low). Growth and production was investigated by measuring biomass, chlorophyll a concentration of leaves and net photosynthesis of the plants on Days 14, 28, 42, 70 and 84. The chlorophyll a concentration of epiphytic algae was also measured on these days. Morphological parameters of the plants were measured on Days 14, 30, 70 and 84. The chlorophyll a concentration of epiphytic algae increased significantly over the experimental period in both HLE (high light with epiphytic algae) and LLE (low light with epiphytic algae) treatments. Plants showed significant morphological changes in total shoot length, number of newly recruited shoots and expansion or contraction of the leaf surface area due to the epiphytic algal load and low light condition. The biomass (both above and below ground) and net photosynthesis rate was higher in high light than in the low light condition, but the chlorophyll a concentration was always higher in the low light condition than in the high light condition. In the plants without epiphytic algae, the chlorophyll a concentration, above ground biomass accumulation and net photosynthesis was significantly higher than in plants with epiphytic algae in both light conditions. The dead leaf dry matter was greater in the plants with epiphytic algae than in those without epiphytic algae in both light conditions. Therefore, epiphytic algae and low light phenomena both reduce growth and production. In general, plants tend to optimize low light-created shade by changing their physiology and morphology, but they could not respond to the same when epiphytic algae-created shade occurred on the leaf surface in the present experiment.

Allocation of photoassimilates to biomass, resin and carbohydrates in Grindelia chiloensis as affected by light intensity

Grindelia chiloensis (Asteraceae) is a shrub native to Patagonia, Argentina, and can accumulate as much as 25% resin (on a dry weight basis) in leaves. The resin can be used in applications similar to those of pine resins. Reductions in available radiation are thought to decrease both the plant C:N ratio and resin production. The objective of this study was to assess the effect of light availability on the allocation of photoassimilates to biomass, resin (terpenes) and carbohydrates in G. chiloensis. To examine this, three radiation treatments were applied to field grown plants: (i) 100% radiation (full-sun), (ii) 50% radiation and (iii) 25% photon flux density radiation. Changes in available radiation resulted in significant changes in above ground biomass accumulation, carbon based secondary metabolites (resin), non-structural carbohydrate (TNC) content, and relative growth rate (RGR). At low radiation levels, above ground biomass accumulation, RGR, resin, TNC content and CO 2 assimilation rate were highly reduced (from 150 to 80 g per plant, from 16 to 7%, and from 30.2 to 8.6 g per plant, for biomass, resin content, and resin production, respectively). The responses to low radiation found in G. chiloensis would limit productivity and the distribution of this species when grown under cultivation.

Enhanced UV-B radiation increases the reproductive effort in the Mediterranean shrub Cistus creticus under field conditions

Seedlings of the Mediterranean shrub Cistus creticus L. were grown in the field under ambient or ambient plus supplemental UV-B radiation (simulating a 15% ozone depletion over Patras, 38.3°W, 29.1°E) for 20 months. During this period, measurements of photosynthetic capacity, photochemical efficiency of PS II, chlorophylls and carotenoids were performed once per season. Supplemental UV-B radiation had no significant effect on these parameters nor on the total, above ground biomass accumulation, plant height and leaf specific mass measured at plant harvest. It was observed, however, that UV-B supplementation increased the number of seeds per fruit as well as mean individual seed mass. As a result, seed number and total seed mass per plant were considerably increased. Germination rates of produced seeds were not affected. We may conclude that C. creticus is a UV-B resistant plant whose competitive ability may be improved by enhanced UV-B radiation through an increase in its reproductive effort and a higher contribution to the seed bank.