The effect of environment on the radiation useefficiency of cotton was studied in 2006 and 2007 at Marianna, AR (Lon Mann Cotton Research Station, University of Ar- kansas) (34˚5'N, 90˚5'W) (Captina silt loam, Typical Fragiudult) and Fresno, CA (Campus Farm, California State University at Fresno) (36˚5'N, 119˚5'W) (Ramona sandy loam, Typical Haploxeralfa). The cotton cultivar DP444BGRR (Delta and Pine Land Company, Scott, MS) was used in both locations of the study. The fertilization program was determined according to preseason soil tests and recommended rates. Weed and insect control was performed according to state recommendations at each location. The studies were furrow irrigated according to the irrigation scheduler program based on soil moisture balance and evapotranpiration in Arkansas , and soil water potential in California .
Water useefficiency (WUE) is often considered an important determinant of yield under stress and even as a component of crop drought resistance (Blum 2009). WUE provides a simple means of assessing whether yield is limited by water supply or other factors. Roots have a crucial role in water uptake. However, roots can be damaged by diseases or mechanical pruning. It has been reported that both diseases and root pruning reduce root water uptake (Aldahadha et al. 2012; Amir and Sinclair, 1996). Therefore, water use or leaf transpiration will be affected substantially by root damage. A better understanding of the effects of root damage (either by disease or pruning) under drought conditions on the ability of the crop to use available water may lead to increased WUE.
Light useefficiency (LUE or photosynthetically active radiation useefficiency) in production of young spruce stands aboveground biomass was determined at the study sites Rájec (the Drahanská vrchovina Highland) and Bílý Kříž (the Moravian‑Silesian Beskids Mountains) in 2014 and 2015. The LUE value obtained for the investigated spruce stands were in the range of 0.45 – 0.65 g DW MJ –1 . The different
years, as well as the expertise to phenotype for phenology, architecture and nutrient useefficiency parameters. A typical trial of bi-parental wheat populations illustrates the diversity of form and the impact of nitrogen inputs (Figure 3). The critical challenge is having the right phenotypic screening strategies which can be applied with high throughput at the appropriate scale. The use of optical sensors  and crop indices such NDVI (normalised difference vegetation index)  to measure canopy development and canopy nutritional status have been widely employed, both with ground-based observa- tions using spectrometers and hand-held contact devices such as SPAD meters  or using aerial imagery [54,55]. The most recent developments include automated mobile  and fixed  platforms for high temporal and spatial analysis of such parameters.
When extrapolating leaf-level intrinsic WUE to the can- opy scale, Beer et al. (2009) assumed the difference between ambient and inner-leaf water vapor pressure to be the vapor pressure deficit (VPD). However, the method neglected to consider aerodynamic resistance through the leaf boundary layer, thus calculating inherent WUE (IWUE). Meanwhile, the slope of linear regression be- tween vegetation productivity and ET has been considered equal to WUE so that one can compare the differences among ecosystems (Brümmer et al. 2012; Shurpali et al. 2013). Notably, due to a lack of ET data at the regional scale, precipitation has frequently been used to replace ET as a proxy of WUE called rainfall useefficiency (RUE) (Yang et al. 2010; Zhang et al. 2013). The various defini- tions are summarized in Table 1. The different definitions of WUE represent different ecological processes or inher- ent mechanisms at different spatial scales (Table 1). For example, emphasis on hydrological processes increases from WUEt to WUE and RUE (Hu et al. 2009), and vice versa for biological process.
As well as the specific points listed above, some fundamental issues still need to be addressed. These include improved understanding of the relative roles of plants versus microbes in the cycling and the availability of soil phosphorus, to facilitate better management. Also, improvement and maintenance of soil structure will have significant impacts. Basic issues such as access to phosphorus fertilizers by farmers in terms of both affordability and availability are still fundamental issues, and likely to remain so in the future, but the development of novel fertilizers that are sourced locally could help remedy this. Of course, tackling these issues and developing more knowledge to enable this will require considerable investment in research, technology and sometimes infrastructure. Given the potentially imminent issue of phosphorus fertilizer availability in some parts of the world and the growing pressures on global food security, it is now important that a concerted effort to increase phosphorus useefficiency is prioritized.
Nitrogen useefficiency is defined as dry mass produced/unit of available nitrogen absorbed from the soil (Hirose, 2011). N useefficiency can be further split into Nitrogen uptake efficiency and Nitrogen utilisation efficiency, relating to the efficiency of N absorbed and efficiency to convert absorbed N to yield, respectively. Despite the high capacity of B. napus plants to obtain N from the soil, particularly before flowering, OSR has an innate low N UseEfficiency (Sylvester-Bradley and Kindred, 2009; Sieling and Kage, 2010), of less than 10 kg dry matter/kg N, compared to 69, 31, 27, 25 and 21 for sugar beet, triticale, winter oats, winter wheat and malting spring barley, respectively (Sylvester-Bradley and Kindred, 2009). As previously reported this is primarily due to confluence of two factors; an inadequate efficiency of N remobilisation from the vegetative tissues to the siliques as previously described (Malagoli et al., 2005a; Gombert et al., 2006; Koeslin-Findeklee and Horst, 2016) as well as low N uptake, in particular, post-flowering N uptake (Berry et al., 2010b). Interestingly, several field studies under limiting N fertiliser conditions have reported on an increased association between N uptake efficiency and N useefficiency compared to N utilisation efficiency (Berry et al., 2010b; Schulte auf‘m Erley et al., 2011; Kessel et al., 2012; Nyikako et al., 2014).
Some of the dynamic aspects of water useefficiency are more difficult to predict. For example, soil-water is conventionally thought to be completely ‘unavailable’ until it reaches a state of gravitational equilibrium, called “field capacity” by agronomists (e.g. Gardner 1968) and the “drained upper limit” by horticulturalists (Harden 1988). This concept is completely arbitrary though, because plants under water stress do not wait to absorb water until the energy status of the irrigation water reaches ‘field capacity’ - they immediately start taking up water in response to the ambient vapour pressure deficit. Nevertheless, excessively large hydraulic conductivities do remove a considerable amount of water before plants can extract it. This explains the link between the availability of soil- water and an arbitrary matric head describing its energy status, even though this varies from 5 to 33 kPa depending on circumstance. Similarly, at the dry end, excessively low hydraulic conductivity limits the rate at which water can move toward plant roots. We know from experience (and limited experimental evidence – e.g. Gardner 1965) that unsaturated hydraulic conductivity declines precipitously with increasing matric head, and that this varies with soil type. We don’t, however, understand how to manage irrigation water efficiently to prevent leaching of nitrogen and other soluble compounds in horticultural operations, even using trickle- or drip-irrigation (Thorburn et al 2003; Mmolawa and Or 2000). Our understanding of the way in which hydraulic properties of Australian soils change as they drain and dry out is also limited (Cresswell & Paydar 1996). Research is therefore needed to link our understanding of how soil hydraulic properties change during drying with irrigation management so that we minimize leaching, even with drip-irrigation.
Ameri and Nasiri (2008) with effects of nitrogen application and plant densities on flower yield, essential oils, and radiation useefficiency of Marigold (Calendula officinalis L.) revealed significant effects of nitrogen on flower dry matter production and radiation useefficiency of Marigold. Tahmasebi Sarvestani and Mostafavi Rad (2011) in a study by application of nitrogen sources including 50% Azocompost, 50% Azocompost +50% urea and urea on varieties of oilseed rape (Brassica napus L.), they reported increased quality of oilseed rape seeds oil treated with Azocompost. Yousefzadeh et al. (2013) by using nitrogen sources of 100% urea, 75% urea +25% Azocompost, 50% urea + 50% Azocompost, 25% urea +75% Azocompost and 100% Azocompost on dragonhead (Dracocephalum moldavica L.), they reported that optimum yield and essential oil was achieved by treatment with 50% Azocompost +50% urea. Given the different effects of different nitrogen sources on growth and yield of medicinal plants are grown. Comparison of different levels of urea and azocompost fertilizers on yield, NUE and RUE of wild marjoram is necessary to reach.
A higher instantaneous water useefficiency, observed in the wild genotype (S. pennellii), about the other treatments, is related to its low transpiration (E). Among the evaluated genotypes, UFU22/F 2 BC 1 #2 highlighted, being the one that most resembled the wild accession. On the other hand, S. pennellii was 2.2 more efficient in water use than the cv. Santa Clara, which is possible the main result, proving its resistance to water stress. Similar results were found by Machado et al. (2010), correlating the amount of transpiration water with the dry matter production.
Figure 5. Effect of maintenance respiration (R maintenance ) on C-useefficiency (CUE). Theoretical relations between CUE and the ratio of maintenance respiration to C uptake rate under two different assumptions: (a) priority to growth respiration and (b) priority to maintenance respiration for three values of growth yield (i.e. (C uptake – growth respiration) / C uptake). The central panels show decreasing CUE when (c) the C substrate is consumed (moving right to left along the abscissa) during 12-day (glucose) and 71-day (cellulose) incubations (Öquist et al., 2017) or (d) resource availability (as the ratio of salicylic acid C to biomass C) is low (Collado et al., 2014). (e) Reduction in CUE through time as plants end their growth phase and set seeds (Yamaguchi, 1978). (f) Significantly higher (p<0.05) GGE of managed, and thus more nutrient-rich, forests and grasslands (Campioli et al., 2015). In (c) to (e), CUE or GGE decrease as costs for maintenance respiration increase relative to growth respiration; in (f), GGE decreases when costs for symbiotic associations are higher (natural systems). Curves in (c) and (d) are least-square linear and hyperbolic regressions drawn to guide the eye; error bars indicate standard errors of the mean.
Given these increases in understanding, there are two approaches that can be proposed for the improvement of soil testing in order to make better phosphorus application rate recommendations. (1) Redesign soil tests to use extractants that are appropriate, e.g., re ﬂ ect what is happening in the root zone (organic acids) and utilize them for speci ﬁ c soil types and crop types. (2) Develop a more dynamic method of understanding and considering the phosphorus requirements of plants, considering both organic and inorganic phosphorus availability to plants, and universal incorporation of important metrics such as PBI. Achieving these aims will require considerable investment in a long-term program of practical ﬁ eld and laboratory studies that accounts for soil, crop, fertilizer and climatic variability along with different soil tests. These need to be accompanied by the development of faster, simpler and more reliable ﬁ eld tests for measuring soil phosphorus status, to enable farmers themselves to carry out frequent testing, rather than relying on sending samples to laboratories.
IT03K-351-1, IT 00K-901-5, IT93K-452-1 and IT98K- 1263 genotypes were more P efficient than IT97K-819- 118 and Soronko. According to Sanginga et al. (2000), genotypes which increased in shoot dry weight with increasing levels of P, as observed in this study, are distinguished as P-responders. Genotype 48 (Soronko) was identified as low efficiency under PEI, but was very responsive to P application. For instance, it had the highest leaf area when P was applied at 40 kg ha -1 and produced the highest percentage increase when P was
agricultural productivity by several orders of magnitude. Nutrient deficiencies are one particular threat to food security that can have a negative impact on crop yield and quality. Currently the standard agricultural approach to prevention is to supply an excess macronutrient fertiliser, such as nitrate or phosphate, during crop production. However, the efficiency of this approach is poor as deficiencies of specific nutrients, such as Ca, are not prevented in this circumstance, and fertiliser use is associated with a host of adverse environmental impacts. Herein, we describe a novel method to detect Ca deficiency using synchrotron radiation-based Fourier-transform infrared (FTIR)
for carboxylation while clones such as Et 228, Et 268, Et 007 were highly inferior in terms of their poor carboxylation efficiency. The correlation matrix showed an inverse relationship between intrinsic carboxylation efficiency and gs (r=-0.331) similarly with Ci (r=-0.764). This clearly indicates that a higher Ci and/ gs limit the carboxylation efficiency in the clones of Eucalyptus tereticornis and it has been reported by Sheshshayee (1996). Clones Et 130, Et 242, Et 008 and Et 027 were identified as superior clones as they had efficient stomatal regulatory capacity combined with carboxylation efficiency and are ideal planting stock especially for drier areas. Intrinsic mesophyll efficiency, the ratio of Ci to gs, ranged from 0.2861µl l -1 mol -1 m -2 s -1 in Et 12-11 to 1.2833µl l -1 mol -1 m -2 s -1 in Et 228 (Fig 4). Correlation matrix (Table 3) showed an inverse relation between intrinsic mesophyll efficiency and Pn (r=-0.503) indicating that higher Ci/gs was accompanied by reduced Pn. According to Sheshshayee (1996), lower Ci indicates better mesophyll efficiency due to rapid uptake of CO 2 from the intercellular spaces for
IMPORTANCE Soil microbes respond to environmental change by altering how they allocate carbon to growth versus respiration— or carbon use efﬁciency (CUE). Ecosys- tem and Earth System models, used to project how global soil C stocks will continue to respond to the climate crisis, often assume that microbes respond homoge- neously to changes in the environment. In this study, we quantiﬁed how CUE varies with changes in temperature and substrate quality in soil bacteria and evaluated why CUE characteristics may differ between bacterial isolates and in response to altered growth conditions. We found that bacterial taxa capable of rapid growth were more efﬁ- cient than those limited to slow growth and that taxa with high CUE were more likely to become less efﬁcient at higher temperatures than those that were less efﬁcient to be- gin with. Together, our results support the idea that the CUE temperature response is constrained by both growth rate and CUE and that this partly explains how bacteria ac- climate to a warming world.
requirements for nonrenewable energy resources; its fertilizer requirement was high and consumes relatively high amount of herbicides. It’s evident that most farmers in the study area lack adequate knowledge on efficient input use and there is a common belief that productivity increase with increase use of energy resources. Findings from this research demonstrate how energy useefficiency in sesame production may be improved by application of operational management tools to assess farmers’ performance. Averagely, considerable savings in energy inputs may be obtained by adopting best practices of better-performing farmers in crop production process. Adoption of energy- efficient cultivation systems will help in energy conservation and better resource allocation. Strategies such as providing better extension and training programs for farmers, and use of advanced technologies should be developed in order to increase energy efficiency of agricultural crop productions in the study area. Moreover, farmers should be trained with respect to optimal use of inputs, especially fertilizers and herbicides application, as well as employing the new production technologies. Also, based on these findings agricultural institutes in the study area are advised to establish energy-efficient and environmentally healthy sesame production systems in the study area.