Canopy Production Research Articles

Thermal imaging can reveal variation in stay-green functionality of wheat canopies under temperate conditions.

Canopy temperature (CT) is often interpreted as representing leaf activity traits such as photosynthetic rates, gas exchange rates, or stomatal conductance. This interpretation is based on the observation that leaf activity traits correlate with transpiration which affects leaf temperature. Accordingly, CT measurements may provide a basis for high throughput assessments of the productivity of wheat canopies during early grain filling, which would allow distinguishing functional from dysfunctional stay-green. However, whereas the usefulness of CT as a fast surrogate measure of sustained vigor under soil drying is well established, its potential to quantify leaf activity traits under high-yielding conditions is less clear. To better understand sensitivity limits of CT measurements under high yielding conditions, we generated within-genotype variability in stay-green functionality by means of differential short-term pre-anthesis canopy shading that modified the sink:source balance. We quantified the effects of these modifications on stay-green properties through a combination of gold standard physiological measurements of leaf activity and newly developed methods for organ-level senescence monitoring based on timeseries of high-resolution imagery and deep-learning-based semantic image segmentation. In parallel, we monitored CT by means of a pole-mounted thermal camera that delivered continuous, ultra-high temporal resolution CT data. Our results show that differences in stay-green functionality translate into measurable differences in CT in the absence of major confounding factors. Differences amounted to approximately 0.8°C and 1.5°C for a very high-yielding source-limited genotype, and a medium-yielding sink-limited genotype, respectively. The gradual nature of the effects of shading on CT during the stay-green phase underscore the importance of a high measurement frequency and a time-integrated analysis of CT, whilst modest effect sizes confirm the importance of restricting screenings to a limited range of morphological and phenological diversity.

Controls on use efficiency of plant nutrients along subtropical to alpine gradients on the Tibetan Plateau

AbstractQuestionKnowledge of how nutrient use strategies differ between forest trees and alpine shrubs/grasses is important to understand the mechanisms of vegetation changes from montane forests to alpine shrubs/grasslands along altitudinal gradients. We tested the hypothesis that, to maximize the nitrogen use efficiency (NUE) of canopy production, forest trees tend to have a higher mean residence time (MRT) of nitrogen in the plants through increased leaf life span, whereas alpine shrublands and grasslands tend to have higher nitrogen productivity through increased below‐ground biomass fraction. We further tested whether similar patterns are found in phosphorus use efficiency (PUE).LocationTwenty‐one sampling sites along Tibetan Alpine Vegetation Transects (TAVT) at altitudes from 1900 m to 4900 m.MethodsWe measured the maximum biomass of new canopy leaves and twigs and the concentrations of their nutrients N and P and associated ecosystem variables along the TAVT. NUE (PUE) was calculated as the product of nutrient productivity (dry matter production per unit N or P in new canopy leaves and twigs) and MRT (the ratio of foliage nutrient pool to annual nutrient uptake).ResultsWith increasing altitude, leaf life span increased in forest trees but decreased in shrublands and grasslands, while below‐ground fraction increased when vegetation changed from montane forests to alpine shrubs/grasslands. In forest trees, higher N‐MRT and P‐MRT and lower P productivity were associated with longer leaf life span and lower below‐ground fraction, while N productivity varied little. In alpine shrublands and grasslands, N‐MRT, P‐MRT and P productivity varied little with leaf life span and below‐ground fraction, while N productivity was positively correlated with below‐ground fraction.ConclusionsOur data supported the hypothesis, suggesting that NUE of canopy production would be a measure of changes in ecosystem functioning from montane forests to alpine shrublands and grasslands along altitudinal gradients. The findings provide an insight into the linkage between biogeochemistry and phytogeographic processes across ecosystems.

High canopy photosynthesis before anthesis explains the outstanding yield performance of rice cultivars with ideal plant architecture

ContextThe majority of investigations on mechanisms underlying yield difference between superior and conventional cultivars has focused on the grain-filling stage after anthesis. However, the physiological process before anthesis has been less explored. ObjectiveWe aimed to quantify the contribution of canopy photosynthesis at pre-anthesis stage to grain yield formation and clarify the mechanism underlying the yield advantage of the superior cultivars. MethodsThis study selected representative cultivars of indica and japonica rice, each type having a pair of cultivars with ideal plant architecture (IPA) and conventional architecture. Field experiments over four years (2019–2022) were conducted to compare the relevance of canopy photosynthesis to yield formation between the phases before and after anthesis. ResultsThe two IPA cultivars, JYZK-6 and ZZY-1, produced higher grain yield than the two conventional cultivars, NJ-5055 and HHZ. JYZK-6 and ZZY-1 also had good distribution of light interception inside the canopy, with the middle and lower part receiving more light than NJ-5055 and HHZ. At leaf level, there was no significant difference in photosynthetic rate between the two types of cultivars. At canopy level, the IPA cultivars had stronger photosynthetic activities before anthesis, outperforming NJ-5055 by 35.56% in averaged canopy photosynthesis, and by 46.65% in averaged daily net photosynthetic accumulation in 2021–2022. By contrast, canopy photosynthesis after anthesis was not significantly different between the two types. The IPA cultivars stored heavier biomass in internodes and sheaths before anthesis and remobilized more reserves to the developing grains, with the remobilization rate being 16.42% (internodes) and 35.34% (sheaths) higher than NJ-5055 and HHZ. ConclusionThe higher canopy productivity before anthesis is one of the main reasons accounting for the superior IPA cultivars, suggesting the necessity of optimizing plant growth and development during the vegetative and reproductive phases.

Výchovný zásah v mladých smrkových porostech jako nástroj mitigace globální klimatické změny?

Although the ongoing global climate change elicits a shift in tree species composition along the vertical gradient, very extensive areas of pure Norway spruce [Picea abies (L.) Karst.] stands still occur out of their ecological optimum in the Czech Republic and Central Europe. Adaptive measures should be applied in these stands to promote productivity and stability. All measurements were performed in the 2018–2021 period on three permanent research plots located in the North-East part of Bohemia (Czech Republic). Based on the results, the most favourable way to increase solar radiation use efficiency expressed by canopy production index (CPI) and leaf area efficiency (LAE) is in-time heavy precommercial thinning application. The highest CPI and LAE values were observed in the Norway spruce stand after heavy pre-commercial thinning application (CPI = 2.00 and LAE = 1.59). In contrast, CPI = 1.26 and LAE = 0.99 were observed after the mild one, and CPI = 0.73 and LAE = 0.60 were reported in the control treatment with no silvicultural intervention. Overall, the presented results indicate a positive effect of heavy pre-commercial thinning on CPI and LAE in pure young Norway spruce stands. However, more effort should be devoted to studying the impact of different pre-commercial thinning intensities on solar radiation use efficacy across a broader gradient of site conditions, and future work should also be extended to other tree species.

Deficit irrigation combined with nitrogen application in the early growth stage of sugar beet increases the production capacity of canopy and avoids yield loss.

Properly reduced irrigation combined with nitrogen (N) application can be used to improve crop water use efficiency (WUE) in arid regions, but its effect on sugar beet is unknown at present. A two-year field experiment was conducted to evaluate the effects of N application (N0, 0; N1, 150; N2, 225 kg N ha-1 ) on the canopy production capacity (CPC), yield and WUE of sugar beet under normal irrigation (W1, 70% of field capacity (FC)) and deficit irrigation (DI) (W2, 50% FC) in the early growth stage (EGS). The results showed that the W2 treatment reduced the CPC by reducing gas exchange, leaf area index (LAI) and chlorophyll content (SPAD value) of sugar beet leaves compared to the W1 treatment. However, DI combined with N application increased these parameters. Specifically, N application increased the net photosynthetic rate by 40.7% by increased gas exchange, SPAD and LAI compared to the N0 treatment. In addition, N application increased WUE by 12.5% by increasing thickness of upper surface, stomatal aperture and cross-sectional area of petiole. This ultimately led to a significant increase in taproot yield (TY; 19.7%) and sugar yield (SY; 57.6%). Although the TY of the N2 treatment was higher than that of the N1 treatment, the SY and WUE did not increase significantly and the harvest index decreased significantly by 9.3%. DI combined with 150 kg N ha-1 in the EGS of sugar beet increases the WUE in arid areas while avoiding yield loss by improving the CPC. © 2023 Society of Chemical Industry.

Direct evidence for phosphorus limitation on Amazon forest productivity.

The productivity of rainforests growing on highly weathered tropical soils is expected to be limited by phosphorus availability1. Yet, controlled fertilization experiments have been unable to demonstrate a dominant role for phosphorus in controlling tropical forest net primary productivity. Recent syntheses have demonstrated that responses to nitrogen addition are as large as to phosphorus2, and adaptations to low phosphorus availability appear to enable net primary productivity to be maintained across major soil phosphorus gradients3. Thus, the extent to which phosphorus availability limits tropical forest productivity is highly uncertain. The majority of the Amazonia, however, is characterized by soils that are more depleted in phosphorus than those in which most tropical fertilization experiments have taken place2. Thus, we established a phosphorus, nitrogen and base cation addition experiment in an old growth Amazon rainforest, with a low soil phosphorus content that is representative of approximately 60% of the Amazon basin. Here we show that net primary productivity increased exclusively with phosphorus addition. After 2 years, strong responses were observed in fine root (+29%) and canopy productivity (+19%), but not stem growth. The direct evidence of phosphorus limitation of net primary productivity suggests that phosphorus availability may restrict Amazon forest responses to CO2 fertilization4, with major implications for future carbon sequestration and forest resilience to climate change.

Interference of weeds in ruziziensis grass pastures

The aim of this study was to assess the effect of increasing periods of coexistence of weed plants with Urochloa ruziziensis on the canopy structure and productivity of a pasture already established with this forage species. The experiment was a randomized blocks design with four replications, and treatments consisted of seven increasing periods of coexistence of forage grass with weed plants: 0 (control), 15, 30, 45, 60, 75 and 90 days after regrowth (DAR). The main morpho-structural and productive characteristics of the forage plants were determined at the end of the experimental period (90 DAR). The ratio of the first green leaf height to the tiller height increases, while the leaf to stem ratio diminishes as the period of interaction with the infesting community increases. The number of green leaves per tiller and the tiller height diminishes as the period of coexistence with weed plants increases. The presence of weed plants interferes negatively with all parameters of the grass canopy structure and productivity of a grazing land already established with Urochloa ruziziensis, suggesting that measures of control of the infesting community should be adopted up to 17 days of regrowth of the forage plant.

Uncertainty in the evaluation of photosynthetic canopy traits using the green leaf area index

The green leaf area index (GLAI) has been widely used in agriculture, forestry, and environmental sciences for the analysis and modeling of many biophysical processes of vegetation, including the attenuation of light through the canopy, transpiration, photosynthesis, and carbon and nutrient cycles. Nevertheless, its usefulness is hampered by the uncertainty introduced through the lack of quantitative information on leaf biochemistry, particularly leaf chlorophyll content, in its computation. Thus far, this uncertainty has not been properly recognized nor quantified. The main goal of this study was to quantify the uncertainty of GLAI as used in the estimation of key photosynthetic canopy traits, namely canopy chlorophyll content (CCC). This uncertainty was assessed through the evaluation of the relationship between GLAI and CCC in structurally and functionally contrasting crop species (Zea mays L., Glycine max (L.) Merr., and Oryza sativa L). Results show that for the same GLAI value, CCC varied 2- to 3-fold due mainly to the variability of leaf chlorophyll content. Therefore, we suggest using the absorption coefficient in the red-edge region of the electromagnetic spectrum as an alternative to GLAI for the evaluation of CCC and other important photosynthetic canopy traits. The absorption coefficient in this spectral region is particularly suitable as it has been successfully related with the gross primary productivity of vegetation canopies, the quantum yield of photosynthesis, and is sensitive to the repositioning of chloroplasts within leaf cells in response to water stress.

A model-guided holistic review of exploiting natural variation of photosynthesis traits in crop improvement.

Breeding for improved leaf photosynthesis is considered as a viable approach to increase crop yield. Whether it should be improved in combination with other traits has not been assessed critically. Based on the quantitative crop model GECROS that interconnects various traits to crop productivity, we review natural variation in relevant traits, from biochemical aspects of leaf photosynthesis to morpho-physiological crop characteristics. While large phenotypic variations (sometimes >2-fold) for leaf photosynthesis and its underlying biochemical parameters were reported, few quantitative trait loci (QTL) were identified, accounting for a small percentage of phenotypic variation. More QTL were reported for sink size (that feeds back on photosynthesis) or morpho-physiological traits (that affect canopy productivity and duration), together explaining a much greater percentage of their phenotypic variation. Traits for both photosynthetic rate and sustaining it during grain filling were strongly related to nitrogen-related traits. Much of the molecular basis of known photosynthesis QTL thus resides in genes controlling photosynthesis indirectly. Simulation using GECROS demonstrated the overwhelming importance of electron transport parameters, compared with the maximum Rubisco activity that largely determines the commonly studied light-saturated photosynthetic rate. Exploiting photosynthetic natural variation might significantly improve crop yield if nitrogen uptake, sink capacity, and other morpho-physiological traits are co-selected synergistically.

Analisis Pengendalian Kualitas Produk Kanopi di Bengkel Las Purnama Karya

The Purnama Karya weld workshop is individual business engaged in the welding industry that produces one of the products, namely the canopy. In the process of canopy production, there is no possibility if there are no results of products that have bad quality. This research uses Failure Mode and Effects Analysis method. The method contains steps for the identification failure mode against product or process by scoring each form of failure mode based on occurrence values, severity values and detection values. The purpose of this research is found out factors that cause canopy product defects, identify the types of potential defects that occur and identify the impacts that occur. The results show that there are defects that occur with the classification of 2 types of defects, welding and painting, where the most common types of defects are welding defects with a frequency of damage of 56.8% and there are also 16 causes of canopy product defects with details of 8 factors that cause weld defects and 8 factors that cause painting defects. The results of the provision of severity, occurrence, and detection are taken in the order of the 3 highest rankings taken from the results of RPN values.

Investigating the Rainforest Canopy Phenology Variation and Productivity Responses to Drought by Using Digital Camera Images

Among the natural disturbances, drought may cause significant change in forest ecosystems by shifting phenology and productivity. Digital cameras have been used in phenological observations for their high accuracy and the colour index values (digital-number of red, green and blue) derived from long-term continuous digital camera imagery are useful as proxies for investigating a forest canopy’s response to drought. Here, we examine the interaction between colour indices (the strength of red (Sred), the strength of green (Sgreen), green excess index (GEI)), productivity (gross primary productivity (GPP)) and drought (standardised precipitation evapotranspiration index (SPEI)) and climatic factors. We use forest canopy images derived from a digital camera and flux tower-based productivity from 2010 to 2016 to show the rainforest’s responses to drought in phenology and productivity. The SPEI indicated the occurrence of drought condition in 2014. The lowest values of the SPEI (-0.403 mmday-1), and total precipitation (1062 mmyr-1), and the highest values of average air temperature (21.3 C)”, need to be changed like that “the highest values of average air temperature (21.3°C)”, to put Degree symbol between the 21.3 and C, potential evapotranspiration (3.31 mmday-1) and rain use efficiency (2.26 gCL-1) were found in 2014. Leaf color variation period (CVP) become longer with an advance in foliage green-up after drought. The peak GEI values were found at the end of the CVPs. The GPP and the Sgreen had positive and the Sred had negative relationship with drought index. The GPP dropped during the drought and bounced back after the drought due to a longer leaf CVP. The Sgreen and GEI were significantly (p<0.05) related to GPP during the drought. During the CVP of the drought, the Sgreen and GEI were significantly correlated (p<0.05) with total P, PET and average Ta, meanwhile, there was only a significant relationship (p<0.05) between the GPP with PET and avg Ta. Among the variables, the GPP was more significant (p < 0.001) with avg Ta. There was also a relationship between the colour indices and GPP with climatic factors on a yearly time series. Our results indicate an understanding of the phenology and productivity response of rainforests to drought, which might be useful for ecologists when predicting the effects of future climatic change on rainforest phenology and productivity.

Habitat Adaptation Mediates the Influence of Leaf Traits on Canopy Productivity: Evidence from a Tropical Freshwater Swamp Forest

Functional traits offer generalizability to the prediction of ecosystem processes such as production, and community-weighted mean trait values are increasingly used for such predictions. However, the underlying causal direction between traits and ecosystem processes are often indirect and sometimes even tenuous. In this study, we aimed to uncover underlying causal mechanisms between traits, habitat adaptation and canopy productivity. We used canopy production data estimated from leaf litter traps, and trait and habitat association data obtained from 40 permanent vegetation plots in the Nee Soon catchment in Singapore, which contains a heterogeneous mix of freshwater swamp and dry-land tropical forests. Mean canopy production across the catchment was estimated to be 768 g m−2 year−1, which is similar to other tropical dry-land forests in the region. Biweekly per-basal-area canopy production was found to be consistently lower in swamp than non-swamp plots, and positively correlated with monthly mean temperature. Structural equation models fitted to data of canopy production, leaf traits, plot type (swamp versus non-swamp), basal areas and habitat adaptations of 69 tree species–plot combinations suggested that tree species possessing leaf traits associated with more conservative resource acquisition strategies, viz. low specific leaf area, high leaf C:N ratio, and thicker leaves, are better adapted to stressful, waterlogged swamp conditions, but that this adaptation also reduces canopy—and likely total—net primary productivity. These observations suggest that the stressful conditions of waterlogged, anoxic swamp habitats significantly reduce the rate at which nutrients are cycled by communities found in such environments.

Biotic and climatic controls on the interannual variation in canopy litterfall of a deciduous broad-leaved forest

Canopy litterfall is an important component of net primary productivity (NPP) in forests, but the climatic and biotic controls on its interannual fluctuation remain poorly understood. In this study, we quantified the interannual variation in and the influencing factors of the canopy litterfall with 45 litter traps in nine plots for 12 years (2008 − 2019) in a temperate deciduous broad-leaved forest in Northeast China. The coefficients of interannual variation in the total (7.3%) and leaf (5.6%) litterfall were substantially lower than those in the basal area (BA) increment (21.0%) and gross primary productivity (10.2%). Climatic (i.e., air temperature, thermal time, precipitation, and radiation) and biotic (i.e., BA and species richness) factors jointly controlled the annual production of litterfall for individual plots and species. Significant climate legacy effects were detected in all components of the litterfall, with the strongest in woody tissue component that contributed to 58.9% of the total litterfall variability. The most important factor driving the variability of the total litterfall and its non-leaf components was climate legacy effect (67.2% to 86.6%), while those for the leaf litterfall were BA (40.4%) and species richness (38.3%). We conclude that high species richness of the deciduous forest increases the temporal stability of canopy productivity, and leaf productivity is much more stable than wood productivity as indicated by BA increament. These findings provide insight into spatiotemporal dynamics in the litterfall and canopy NPP in temperate deciduous forests.

Interactions between nitrogen nutrition, canopy architecture and photosynthesis in rice, assessed using high-resolution 3D reconstruction

AbstractIncreasing nitrogen use efficiency is a key target for yield improvement programs. Here we identify features of rice canopy architecture during altered N availability and link them to photosynthetic productivity. Empirical mathematical modelling, high-resolution 3-dimensional (3D) reconstruction and gas exchange measurements were employed to investigate the effect of a mild N deficiency vs. surplus N application on canopy architecture, light and photosynthesis distribution throughout development. Three contrasting rice lines: two Malaysian rice varieties (MR219 and MR253) and a high-yielding indica cultivar (IR64) were cultivated. 3D reconstruction indicated key N-dependent differences in plant architecture and canopy light distribution including changes to leaf area index (LAI), tiller number, leaf angle and modelled light extinction coefficients. Measured leaf photosynthetic capacity did not differ substantially between the high and reduced N treatments; however, modelled canopy photosynthesis rate indicated a higher carbon gain per unit leaf area for the reduced N treatment but a higher carbon gain per unit ground area for the high N treatment. This is a result of altered canopy structure leading to increased light distribution under reduced N which partially offsets the reduced LAI. Within rice, altered N availability results in the development of full photosynthetically functional leaves, but leads to altered canopy architecture, light distribution and overall productivity suggested that N availability can be fine-tuned to optimize biomass production. We propose wider use of 3D reconstruction to assess canopy architecture and productivity under differing N availabilities for a range of species.

Phenology and litter production in the mangrove genus Xylocarpus along rainfall and temperature gradients in tropical Australia

We investigated how variation in climate influences the timing and intensity of phenological events in two species of the mangrove genus Xylocarpus. Leaf fall in Xylocarpus granatum was continuous in high rainfall sites but was seasonal at sites with long dry seasons. Xylocarpus moluccensis is deciduous, and leaf shedding occurred over 1–2 months at different times in dry season months. Budding and flowering were tightly coupled in X. granatum and occurred in the wet season. At the highest rainfall site, flower fall in X. moluccensis occurred in the mid-wet season, but occurred 9 months later at other sites with protracted dry seasons. For X. moluccensis, the quantities of leaves, buds, flowers and total litter fall were negatively related to annual rainfall, whereas bud fall was negatively related to air temperature. Variations in the quantity of litter produced by X. granatum were not explained by the environmental variables considered. Mean litter production was significantly greater for X. moluccensis than X. granatum (5.16 v. 3.37Mgh–1 year–1 respectively). Mixed forest litter production was greater in forests containing X. moluccensis than X. granatum (7.86 v. 5.95Mgh–1 year–1 respectively). X. granatum has a more plastic response to environmental drivers of canopy production than X. moluccensis.

Light, Not Age, Underlies the Maladaptation of Maize and Miscanthus Photosynthesis to Self-Shading.

Zea mays and Miscanthus × giganteus use NADP-ME subtype C4 photosynthesis and are important food and biomass crops, respectively. Both crops are grown in dense stands where shaded leaves can contribute a significant proportion of overall canopy productivity. This is because shaded leaves, despite intercepting little light, typically process light energy very efficiently for photosynthesis, when compared to light-saturated leaves at the top of the canopy. However, an apparently maladaptive loss in photosynthetic light-use efficiency as leaves become shaded has been shown to reduce productivity in these two species. It is unclear whether this is due to leaf aging or progressive shading from leaves forming above. This was resolved here by analysing photosynthesis in leaves of the same chronological age in the centre and exposed southern edge of field plots of these crops. Photosynthetic light-response curves were used to assess maximum quantum yield of photosynthesis; the key measure of photosynthetic capacity of a leaf in shade. Compared to the upper canopy, maximum quantum yield of photosynthesis of lower canopy leaves was significantly reduced in the plot centre; but increased slightly at the plot edge. This indicates loss of efficiency of shaded leaves is due not to aging, but to the altered light environment of the lower canopy, i.e., reduced light intensity and/or altered spectral composition. This work expands knowledge of the cause of this maladaptive shade response, which limits productivity of some of the world’s most important crops.

Ecosystem respiration of old and young irrigated citrus orchards in a semiarid climate

Both biotic and abiotic factors are involved in the seasonal variability of ecosystem respiration (Re) and its aboveground (Rag) and belowground (Rs) components. Knowledge of these factors is crutial to predict the respiration processes of structurally-distinct orchards under varying environmental conditions. This paper aims to characterize those factors in and across adult (AO) and young (YO) drip-irrigated citrus orchards over a 2-year period. Two methods for estimating Re were used and compared. In the first one (C-method) Re was calculated as the sum of Rag and Rs components, with each being estimated using organ-specific and soil respiration models previously validated and calibrated from chamber-based respiration and biometric canopy measurements. The second method was based on the determination of nighttime Re from data of early morning Net Ecosystem Exchange (NEE-method) provided by eddy covariance sensors located above the canopy. Estimates of Re by the two methods compared reasonably well. The C-method indicated that Rs was the predominant component of Re in both orchards, with a main peak in early spring (ratio Rs/Re ∼0.75 and 0.65 in AO and YO, respectively) during the period with no fruit load and minimum Rag. Data obtained with the NEE-method were used to test the performance of functional relationships between Re and abiotic factors (i.e., temperature through a Q10 function, and soil water content). It was found that a model only based on abiotic factors was unable to explain the differences in Re across sites; whereas accounting for canopy productivity and structure by introducing the leaf area index (LAI) as an additional driving variable notably increased the predictive power of the models in describing changes in Re, both seasonally and across sites. The study suggested that biotic factors explained a large part of the differences in Re between orchards, and that LAI could be an appropriate driving variable for predicting the impact of tree age and structural heterogeneity on Re.

Using soundscapes to assess biodiversity in Neotropical oil palm landscapes

Expanding oil palm plantations have caused widespread deforestation and biodiversity loss in Southeast Asia, stigmatizing the industry around the world regardless of regional context. In Latin America, oil palm plantations are primarily replacing other agroindustrial land uses with uncertain implications for local biodiversity. Our aim was to create empirical baseline data to help guide development of future plantations into areas where biodiversity impacts are minimized. We used soundscapes to assess fauna in oil palm landscapes of Colombia, the world’s 4th largest palm oil producer. Soundscapes capture daily patterns of acoustic activity that can be used to measure differences between biotic communities between habitats. Using remnant forest fragments as reference sites, we sampled land use classes that are commonly replaced by commercial oil palm including cattle pastures, rice fields, and banana plantations. Soundscape analysis showed that even highly degraded forests have a unique soundscape compared to production systems. Similarities were found among closed canopy production sites (oil palm, banana) and open production habitat (pastures, rice), suggesting the importance of habitat structure for acoustic communities. Oil palm also showed notable overlap with pastures, but had soundscapes that were more similar to forest than the other production types. Future oil palm development in Latin America can replace cattle pastures and other commodity plantation agriculture with minimal impacts on acoustic communities. New supply chain governance approaches such as the zero-deforestation agreements being implemented in the Colombian oil palm and cattle sectors may help guide the industry toward more sustainable development by continuing to target previously cleared lands.

FAO AquaCrop Model Performance: in Green Canopy Cover, Soil Moisture and Production of Maize at Middle and Lower Reaches Plain of Yangtze River of China

Crop water productivity models are valuable tools for investigate the crop responses to the water-management strategies and ameliorate the efficiency of water use in agriculture. The objective of this study was to evaluate the performance of AquaCrop model for maize crop (Zea mays L.) under full, excessive and deficit applications of drip irrigation in semi-humid region of China. The evaluation results emphasized the model accuracy in simulations CC, SWC, B*, Y and WUE with satisfactory performance in full irrigation, and moderate water stressed treatment T2 of 75% of full irrigation. This accuracy declines in circumstances of excessive irrigation T1 of 125% of full irrigation, and high water stressed T3 of 50% of full irrigation. The RMSEs and NRMSEs in simulated CC, and SWC for full irrigation, T1, T2 and T3 treatments were 7.3–8.6, 6.3–7.2, 5.4–6.3 and 4.9–5.6% CC, respectively, and 9.4–4.8, 16.1–8.1, 16.4–9.3 and 20.9–13.4% SWC, respectively. Whereas, the D-index and R2 of CC varied between 0.72 to 0.89 and 0.99 to 1.0, while in the SWC varied between 0.54 to 0.83 and 0.48 to 0.96 for the four irrigation treatments. The differences (S.D) in final biomass and grain yield were within the range of 0.23 to 4.45% and 0.30 to 1.46% between the measurement and simulation. Simulated WUEs of biomass and yield under different irrigation treatments ranged between 6.07 to 6.52 kg/m3 and 3.07 to 3.16 kg/m3, AquaCrop’s performance trends to underestimate the WUEs of biomass and yield, and emphasizes that the yield WUE increased linearly with water stress condition increased.

Exploring the Sensitivity of Subtropical Stand Aboveground Productivity to Local and Regional Climate Signals in South China

Subtropical forest productivity is significantly affected by both natural disturbances (local and regional climate changes) and anthropogenic activities (harvesting and planting). Monthly measures of forest aboveground productivity from natural forests (primary and secondary forests) and plantations (mixed and single-species forests) were developed to explore the sensitivity of subtropical mountain productivity to the fluctuating characteristics of climate change in South China, spanning the 35-year period from 1981 to 2015. Statistical analysis showed that climate regulation differed across different forest types. The monthly average maximum temperature, precipitation, and streamflow were positively correlated with primary and mixed-forest aboveground net primary productivity (ANPP) and its components: Wood productivity (WP) and canopy productivity (CP). However, the monthly average maximum temperature, precipitation, and streamflow were negatively correlated with secondary and single-species forest ANPP and its components. The number of dry days and minimum temperature were positively associated with secondary and single-species forest productivity, but inversely associated with primary and mixed forest productivity. The multivariate ENSO (EI Niño-Southern Oscillation) index (MEI), computed based on sea level pressure, surface temperature, surface air temperature, and cloudiness over the tropical Pacific Ocean, was significantly correlated with local monthly maximum and minimum temperatures (Tmax and Tmin), precipitation (PRE), streamflow (FLO), and the number of dry days (DD), as well as the monthly means of primary and mixed forest aboveground productivity. In particular, the mean maximum temperature increased by 2.5, 0.9, 6.5, and 0.9 °C, and the total forest aboveground productivity decreased by an average of 5.7%, 3.0%, 2.4%, and 7.8% in response to the increased extreme high temperatures and drought events during the 1986/1988, 1997/1998, 2006/2007, and 2009/2010 EI Niño periods, respectively. Subsequently, the total aboveground productivity values increased by an average of 1.1%, 3.0%, 0.3%, and 8.6% because of lagged effects after the wet La Niña periods. The main conclusions of this study demonstrated that the influence of local and regional climatic fluctuations on subtropical forest productivity significantly differed across different forests, and community position and plant diversity differences among different forest types may prevent the uniform response of subtropical mountain aboveground productivity to regional climate anomalies. Therefore, these findings may be useful for forecasting climate-induced variation in forest aboveground productivity as well as for selecting tree species for planting in reforestation practices.