Leaf Biomass Yield Research Articles

Assessment of yield loss due to fall armyworm in maize using high-resolution multispectral spaceborne remote sensing

ABSTRACT The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), invasion endangered the maize production worldwide, including India. The objective of this study was to quantify the FAW damage severity and its impact on leaf area index (LAI), biomass and grain yield of maize and to detect the field damage using high-resolution multispectral spaceborne remote sensing data. Maize growing fields in the Kurnool District of Andhra Pradesh and the Gadwal District of Telangana, India, were randomly surveyed to collect detailed ground-truth information. Foliar damage due to FAW was recorded, and the fields were categorized into various severity grades (healthy, low, medium and severe). FAW infestation caused significant change in LAI between the severity grades, which formed the basis for its damage detection using multispectral spaceborne remote sensing. Severe FAW infestation caused significant reduction in LAI, biomass and grain yield ranging between 36.9 and 39.9% compared to healthy grade. The infestation at the leaf collar (LC) stage caused significant yield loss of up to 26.5% compared to the tassel initiation (TI) and tasselling and silking (TS) stages. Canopy spectral reflectance from healthy and FAW-infested plants showed significant differences in the visible and near infrared (NIR) regions. A reflectance peak was observed in the NIR region of healthy plants compared to infested plants. Among various spaceborne vegetation indices, the Soil Adjusted Vegetation Index (SAVI) performed better in identifying the FAW infestation (R2 = 0.61**), biomass (R2 = 0.70**) and yield loss (R2 = 0.82**). These findings indicate the feasibility of utilizing multispectral remote sensing data for monitoring FAW infestation on a spatial scale, thus enabling the site-specific management.

Fodder trees: Identification, leaf biomass yield, nutritional quality and socioeconomic importance in Essera district, Dawuro zone, southwest Ethiopia

The scarcity of feed in terms of quantity and quality tremendously impacts livestock productivity in Ethiopia. Using fodder trees (FTs) as livestock feed could partially overcome this gap. Thus, the present study aimed to identify species, estimate leaf biomass yield (LBY), evaluate nutritional quality and assess the socioeconomic importance of FTs in the Essera district. The study sites and households (HHs) were selected using a multistage sampling procedure. Data on the socioeconomic importance of FTs were collected from 134 randomly selected HHs. Ten FT species were evaluated for LBY determination, and 15 FTs (including nine FT species) were evaluated for nutritional quality across three agroecologies (AEs). In total, 34 FTs were identified at the species level. The overall mean of LBY of the FTs ranged from 14.32 to 370.94 kg/tree, with the lowest and highest values of 10.85 and 430.27 kg/tree at mid- and low-altitudes, respectively. A significant difference (p < 0.05) in the chemical composition of the selected FTs was observed between AEs. The overall mean of dry matter (DM), ash, crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), and acid detergent lignin (ADL) contents of the FTs ranged from 90.03 to 93.55 %, 6.26–16.52 %, 13.05–25.50 %, 33.06–50.42 %, 25.58–34.52 %, and 4.19–8.38 %, respectively. Moreover, the in vitro dry matter digestibility (IVDMD) of the FTs ranged from 37.80 to 67.89 %. The results indicated that the overall mean tannin, phytate, and oxalate contents were 2.84 ± 0.12 %, 0.60 ± 0.05 %, and 1.66 ± 0.21 %, respectively. Antinutritional factors (ANFs) were significantly (p < 0.05) influenced by FT species. In addition to feed sources, FTs were used for air pollution reduction (52.2 %), income generation (44.0 %), and soil erosion prevention (34.3 %) in the studied areas. In conclusion, due to the high CP content, high digestibility potential, low to moderate fibre and lignin contents, and tolerable levels of ANFs in FTs, the use of FTs as supplementary feed to livestock in the study area is recommended. Further experimental studies should be conducted on the impact of FTs on livestock performance.

Optimizing maize production through sowing date, nitrogen levels, and cultivar selection in northwest region of India

Maize is the third largest growing cereal crop in Northwest India (Punjab) after wheat and rice, faces significant challenges posed by increasing temperature, changing rainfall patterns and nutrient deficiency. These challenges can be addressed and maize production can be improved by optimizing management practices, such as sowing date, nitrogen level and cultivar selection. The primary objective of this study was to evaluate the effects of sowing date, nitrogen levels and cultivar dynamics on the phenology, plant growth, biomass yield, grain yield, and associated yield-related characteristics of maize in Northwest India (Punjab). A field experiment was conducted in a split–split plot design (SSPD) with three replications, comprising twenty-four treatment combinations of sowing dates (SD1: May 25, SD2: June 4, SD3: June 14 and SD4: June 24), cultivars (PMH1 and PMH2) and nitrogen levels (NL1: recommended −25 kg, NL2: recommended and NL3: recommended +25 kg). The results showed that plant height, leaf area index, dry matter, biomass yield, grain yield and yield attributing characters were highest in sowing date SD1, cultivar PMH1 and nitrogen level NL3. The postponed sowing date from SD1 to SD4 resulted in a reduction of 14.18% in grain yield in 2020 and 13.66% in 2021. Compared to cultivar PMH2, the cultivar PMH1 produced higher grain yield of 5343.6 kg ha−1 in 2020 and 5615.8 kg ha−1 in 2021. Among the nitrogen levels, treatments with an additional 25 kg nitrogen (NL3) resulted in a significantly higher grain yield of 428.4 kg ha−1 in 2020 and 331.8 kg ha−1 in 2021, surpassing those observed under NL2; however, it reduced the grain yield in NL1 by 616.5 kg ha−1 in 2020 and 579.7 kg ha−1 in 2021 compared NL2. The finding suggests that early sowing (SD1), cultivar PMH1 and an additional 25 kg nitrogen (NL3) can lead to higher grain yield, while postponed sowing (SD4) and lower nitrogen level (NL1) can result in reduced grain yield.

Effect of Elevated CO2 and Temperature on Chlorophyll Content and Growth Attributes of Rice-wheat Cropping System in Central India

Rice-wheat is a major cropping system in India and it is predicted that the productivity of both crops will decline due to climate change factors including elevated CO2 and temperature. To define the mechanisms, a field experiment was carried out to evaluate the effect of elevated CO2 and temperature on growth attributes of rice and wheat crops using a Free Air CO2 Enrichment (FACE) system. The treatments were ambient CO2+ambient temperature, elevatedCO2of 600ppm+ambient temperature, ambient CO2 + elevated temperature (+2°C), ambient CO2+elevated temperature (+3°C), elevated CO2 600 ppm +elevated temperature (+2°C) and elevated CO2 600ppm +elevated temperature (+3°C). Elevated CO2 and elevated temperature (+2°C or +3°C) strongly affected the crop growth. Elevated CO2 stimulated leaf chlorophyll content, root-shoot length and biomass yield. However, elevated temperature inhibited chlorophyll content in both the crops. Elevated CO2enhanced chlorophyll content by 12.9–19% in rice and 8.8–16.5%in wheat. Elevated temperature reduced chlorophyll content by a range of 20.5-27.3% in rice and 6.3-11.5% in wheat. Combined effect of elevated CO2and elevated temperature decreased the leaf total chlorophyll and plant biomass in both crops. Study highlights that elevated CO2 concentration and rising temperature may affect the photosynthesis and productivity of rice and wheat crop in central India.

Effect of Molybdenum on Leaf Chlorophyll and Biomass Yield of Cowpea (Vigna unguiculata)

Molybdenum (Mo) is an essential micronutrient for plant. It is plays an important key role in chlorophyll synthesis. The Experiment was conducted in Pot house at Department of Soil Science and Agricultural Chemistry, College of Agriculture, JNKVV, Jabalpur during Kharif season 2014.The soil of experimental site belongs to Kheri-series and taxonomically comes under the order Vertisols, sub order Sterts, great group Haplusterts, sub group TypicHaplusterts. In all total 14 number of treatment combinations were tried under factorial randomized block design replicated thrice. The result revealed that variations in observation were found with treatment of Rhizobium inoculation. Seed treatment of Mo @ 0.5 g ammonium molybdate kg-1 seed (StM1) responded better, followed by soil application of Mo @ 1.0 kg Mo ha-1 soil (SaM1) as main effects. With higher dose of Mo as seed treatment (StM2) exerted significantly negative effect. Whereas higher dose of soil application of Mo (SaM2) was merginally higher over no application of Mo which was seemed to be the buffer action of soil to nulify adverse effect of the micronutrient.

Potential of indigenous legume fodder tree and shrubs to animal feed and mitigation of methane emission in the semi‐humid condition of southern Ethiopia

AbstractThe study was conducted to investigate the in vitro gas production characteristics and methane (CH4) emission potential of indigenous legume fodder trees and shrubs (ILFTS). The most predominant 11 ILFTS species were selected, and leaves and fruit/pod samples were collected, oven dried, and ground. The potential leaf biomass yield (PBY), dry matter (DM), ether extract, digestible crude protein, carbohydrate (CHO), acid detergent lignin, ash, total phenol, condensed tannin, gross energy, digestible energy, metabolizable energy (ME), gas production characteristics, CH4 emissions, organic matter digestibility (OMD), and short‐chain fatty acids (SCFA) were determined. ANOVA and independent t test were used to examine variation among species in plants nature and between fruits and pods within agroecosystems, respectively. Correlation analysis was used to determine relationships among parameters. The study indicated that only DM and CHO showed substantial variation in nutritional quality parameters among trees, shrubs, and fruit/pods in the lowlands. Fruits/pods and trees displayed significant differences in gas production characteristics in the lowlands, unlike shrubs, which had non‐substantial variations. Moreover, the PBY, CH4 emission, OMD, and ME of ILFTS revealed substantial variation (P &lt; .05) with species and among trees, shrubs, and fruits/pods in both agroecosystems. Besides, CH4 production showed a positive significant correlation with gas volume and (b) substantiating the effect of rate and degree of fiber fermentation on CH4 emission. It was discovered that there was a positive significant correlation between the 6 and 24 h incubation period, (c) which substantiated the need for optimal microbial density and substrate for high rate constant gas production of b (c). In conclusion, ILFTS produce considerable biomass rich in nutrients but vary in the degradability of CHO with plant nature, species, and forage origin. This elicits differences in gas production characteristics and CH4 emission with in vitro fermentation, resulting in differences in the corresponding OMD, ME, and SCFA values.

Living Mulch as Sustainable Tool to Improve Leaf Biomass and Phytochemical Yield of Cynara cardunculus var. altilis

Living mulch (LM) provides many beneficial agro-ecological services by reducing soil evaporation, conserving moisture, controlling soil temperature, reducing weed growth, increasing organic matter and nutrient availability, and improving microbial activities. Legumes, commonly used as living mulches, can affect the yield and quality of main crops. We hypothesized that Egyptian clover co-cultivated with Cynara cardunculus var. altilis (cultivated cardoon) can positively affect both leaf biomass and phytochemical yield. The study was performed on two growing seasons of field experiments to evaluate the potential variation in biomass and phytochemical yields of cardoon leaves. In addition, the leaves were collected at 90, 120, and 150 days after transplanting to evaluate the possible effect of the harvest time. LM improved the fresh and air-dried leaves biomass yields, total phenolic, and dry matter content, while it had no effect on the content of crude fibre, total sugars, L-ascorbic acid, total chlorophylls, and antioxidant activity. Except for luteolin-7-O-glucoside content, no negative effect of LM was observed on the polyphenol profile. Behind the cultivation system, the parameters were also affected by both the harvest time and growing season. According to our data, the proposed intercropping of cultivated cardoon with LM could represent an innovative cultivation system to increase both leaf biomass and the health-promoting compounds of cultivated cardoon leaves by sustainable soil management.

Leaf photosynthesis traits and associations with biomass and drought tolerance in amphidiploid and ancestral wheat genotypes

Future progress in wheat grain yield will depend on increasing photosynthesis capacity and biomass. Wheat wild relatives represent sources of novel genetic variation for photosynthesis traits. Our objective was to quantify variation in leaf photosynthesis traits, biomass and grain yield in a panel of diverse germplasm comprising: i) elite winter bread wheat (Triticum aestivum L.) lines, ii) wheat amphidiploid lines and iii) accessions of two wheat wild relatives Thinopyrum bessarabicum and Aegilops speltoides under well watered and drought conditions. A field experiment was carried out in one season examining 94 bread winter wheat Savannah × Rialto (S × R) doubled-haploid (DH) lines under irrigated and unirrigated conditions; and two glasshouse experiments were carried out examining: i) six bread wheat S × R DH lines, ii) seven amphidiploid lines (durum wheat (Triticum turgidum subsp. Durum) × Thinopyrum bessarabicum crosses) and iii) three accessions each of Th. bessarabicum and Aegilops speltoides under well-watered and drought conditions. In the field experiment, drought reduced grain yield by 22% (P < 0.001). Flag-leaf photosynthetic rate (Amax), stomatal conductance (gs) and grain ∆13 C were each positively associated with grain yield in the unirrigated treatment (P < 0.05). In the glasshouse experiments, biomass plant−1 was higher in Ae. speltoides accessions (54.7 g plant−1) and the amphidiploid lines (50.8 g plant−1) than the bread wheat S × R lines (40.9 g plant−1) (P < 0.001) under drought. Flag-leaf Amax was higher in the Th. bessarabicum accessions and the amphidiploid lines than the bread wheat S × R lines under both irrigation and drought conditions (P < 0.05). There was a positive association between flag-leaf specific weight (FLSW) and flag-leaf Amax across the 19 genotypes in both irrigated and unirrigated conditions; there was no association between flag-leaf area and flag-leaf specific weight. Our results indicated that Th. bessarabicum accessions and amphidiploid lines (durum wheat × Th. bessarabicum) offer novel variation for high expression of leaf photosynthesis rate for introgression into bread wheat genotypes to support genetic gains in biomass.

Decreasing photosystem antenna size by inhibiting chlorophyll synthesis: A double-edged sword for photosynthetic efficiency

Improving photosynthetic efficiency has long been considered as an important strategy to increase crop yield. Optimization of antenna size of photosynthetic systems is one strategy to increase plant photosynthetic efficiency. However, applying this strategy to improve photosynthesis received conflicting results, and the reasons behind these conflicts are unclear. In this study, we constructed transgenic rice with amiRNA targeting to YGL1, which encodes a key enzyme of chlorophyll a/b synthesis in chlorophyll biosynthesis pathway, to generate different lines with different leaf chlorophyll contents and antenna sizes to test under what conditions reduction of antenna size can improve photosynthesis. We found that leaf photosynthesis, canopy photosynthesis (Ac), biomass and grain yield of the heterozygote were not significantly different from those of wild type (WT) while the Ac, biomass and yield of the homozygote were lower than those of WT. Further, when the maximal quantum yield of photosystem II (Fv/Fm) was larger than 0.8, decreasing antenna size by reducing chlorophyll biosynthesis didn't affect leaf photosynthesis. In view of this phenomenon, we proposed that the accumulation of protoporphyrin and the reduced photoprotection capacity might be the cause of the decrease in Fv/Fm and Ac. Therefore, this study shows that reduction of antenna size by inhibiting chlorophyll synthesis can lead to improved light distribution and photosystem efficiency, as long as photodamage and photobleaching can be avoided to maintain the photosystem II efficiency. The double-edged sword effect of inhibiting chlorophyll synthesis on photosynthetic efficiency should be considered when the antenna size is manipulated to gain higher photosynthesis.

ANÁLISIS DE CRECIMIENTO, RENDIMIENTO DE FRIJOL AYOCOTE (Phaseolus coccineus L.) EN UN SISTEMA DE FERTILIZACIÓN NITROGENADA

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;. The ayocote bean (&lt;em&gt;Phaseolus coccineus &lt;/em&gt;L.) is a leguminous native of the temperate zones of the Mexican territory, with great potential for use and exploitation by the population. However, information on its growth and mineral nutrition for its production is scarce. &lt;strong&gt;Objective.&lt;/strong&gt; Determine the dynamics of growth, biomass production, grain yield and its components in the cultivation of runner beans in a cultivation system with nitrogen fertilization. &lt;strong&gt;Methodology&lt;/strong&gt;. The trial was carried out under field conditions, under a rainfall regime during 2014 in Montecillo, State of México, México; with temperate clime. The purple runner bean cultivar was sown with applications of 0, 75 and 150 kg ha&lt;sup&gt;-1 &lt;/sup&gt;of nitrogen fertilization. Variables were recorded as number of green leaves, leaf area index, total biomass and grain yield with its components. The study was developed using an experimental design that was randomized complete blocks with four replications. &lt;strong&gt;Results&lt;/strong&gt;. With the treatment of 150 kg ha&lt;sup&gt;-1 &lt;/sup&gt;of nitrogen, the highest values were obtained, such as the number of green leaves, 240 m&lt;sup&gt;2&lt;/sup&gt;; leaf area index, 7.75; leaf area length, 277 days; total biomass, 566 g m&lt;sup&gt;2&lt;/sup&gt; and grain yield 363 g m&lt;sup&gt;2&lt;/sup&gt; with respect to the control. With the same treatment, the organs with the highest accumulation of dry matter were: grain and stem with 39%. &lt;strong&gt;Implications&lt;/strong&gt;. Whit the supply of nitrogen, the biomass and the yield of the runner bean can be increased. This contribution can help the producers of this crop. &lt;strong&gt;Conclusions&lt;/strong&gt;. The application of nitrogen to the soil increases the leaf area index, its duration, growth rate, biomass and crop yield. The highest profitability in runner beans is achieved with the application of 150 kg ha&lt;sup&gt;-1&lt;/sup&gt; of nitrogen.&lt;/p&gt;

Genotype performance and relationship between leaf traits, biomass yield and wood quality on interspecific hybrids of Jatropha

Genotype performance and relationship between leaf traits, biomass yield and wood quality on interspecific hybrids of Jatropha

Comparison of Heat-Treated and Unheated Vermicompost on Biological Properties of Calcareous Soil and Aloe Vera Growth under Greenhouse Conditions in a Mediterranean Climate

Determining how intermittently applied heat treatment during the preparation of vermicompost changes the effectiveness of the fertilizer is a challenge. In this study, organic Aloe vera was grown using heat-treated cattle manure vermicompost (IVC) and unheated cattle manure vermicompost (VC). Additionally, these two vermicomposts were combined with vermiwash (LV) and applied to the soil. Thus, the cumulative effect of vermicompost on soil biological properties (number of bacteria, dehydrogenase, urease, alkaline phosphatase, β-glycosidase) and plant growth (plant height, number of leaves, leaf biomass yield, number of suckers, fresh gel weight) was investigated. According to the results obtained, it was understood that HVC-30+LV, HVC-60+LV, and VC-60+LV applications were more effective on soil biological properties. On the other hand, HVC-30+LV and HVC-60+LV applications were found to be effective on plant growth. In addition, increases of 140% in soil bacterial number, 170% in dehydrogenase activity, 125% in urease activity, 122% in alkaline phosphatase activity, 123% in β-glycosidase activity, 65% in plant height, and 45% in leaf biomass yield and wet gel weight were observed. Accordingly, it can be stated that heat-treated cattle manure vermicompost applied to the soil at a rate of 30 t ha−1 together with vermiwash is beneficial for improving the biological properties of calcareous soil and for organic Aloe vera cultivation.

Selenium Application in Improving Chicory (Cichorium intybus) Productivity and Quality

Selenium (Se) is an essential mineral element needed by livestock and human. The amount of Se intake is largely determined by the Se content in the plants (food and feed) consumed. This study aimed to analyze the effect of Se fertilizer on the morphological characters, biomass yield, nutrient content, and in vitro nutrient digestibility of Cichorium intybus . This study was conducted for four months, starting from May to August 2019, located at the Faculty of Animal Science, Universitas Gadjah Mada. The seeds of Cichorium intybus var. Chico was sown in 24 plots and the plots were arranged in a completely randomized block design. Three levels of Se fertilization treatments (0, 3.5, and 7.5 mg/m2) were applied with 8 replicates. Plant defoliation on every 45 days: namely the first defoliation (from sowing to 45 days), the second defoliation (regrowth 1 up to 45 days), and the third defoliation (regrowth 2 up to 45 days). In all studied parameters, the results showed that chicory with Se fertilizer (3.5 and 7.5 mg/m2) was higher (p<0.05) than chicory without Se fertilization. The chicory with Se fertilizer at the level of 7.5 mg/m2 had higher (p<0.05) leaf width, biomass yield, crude protein, and Se content, and in vitro nutrient digestibility (dry matter, organic matter, crude protein) compared to that with Se fertilizer at the level of 3.5 mg/m2. Chicory at the third defoliation had a higher biomass yield and Se content than at the second defoliation. In conclusion, the best combination from this study was the third defoliation, with Se fertilizer level of 7.5 mg/m2.

Modeling response of spring wheat yield to soil water and salt contents and its application in scheduling brackish water irrigation

Fresh water shortage and soil salinization are two key factors restricting agricultural development in arid areas. Brackish water is a possible alternative resource for crop irrigation, but brackish water irrigation should be properly scheduled to balance crop yield increment and soil salinization control. To determine suitable water amounts for crop irrigation under different water salinities, an agro-hydrological model, LAWSTAC, was used to simulate soil water and salt dynamics and crop growth in salinized croplands in an arid region of Northwest China. Model calibration and validation results of soil water content, salt concentration, groundwater table depth, leaf area index, biomass, and crop yield agreed well with the field measurements of spring wheat (Triticum aestivum L.) under both fresh and brackish water irrigations with the Nash and Sutcliffe efficiency of 0.50–0.96 and the coefficient of determination of 0.55–0.98. The model was further used to simulate crop yields for 432 combinations of six irrigation levels, six irrigation water salinity levels, four initial groundwater table depths, and three initial soil salt concentrations. Based on the simulation results, a function of relative crop yield response to soil water content and salt concentration was developed, which is expressed as the product of a hyperbolic function for water stress and a sigmoid function for salt stress. For known initial soil water content and salt concentration, a procedure was proposed to determine suitable water amounts applied to the cropland under different irrigation water salinities for expected crop yields using the developed crop-water-salinity production function. With the procedure, the minimum amount of applied water with known salinity can be obtained for an expected relative crop yield. The results are helpful to the amount control in fresh or brackish water irrigations for sustainable crop production in salinized croplands.

Effect of spacing on growth performance and leaf biomass yield of Moringa stenopetala tree plantations

Moringa stenopetala is a multipurpose tree distributed naturally in the lowland dry lands of the southern part of Ethiopia. The tree has vital nutritional, industrial, and medicinal applications and is thus good for large scale and/or commercial plantations. However, its cultivation is limited to traditional practices by small holder farmers for food, fodder, shade, windbreak and medicinal value around homesteads and on farmlands. The aim of this study was to determine the effect of plant spacing on plant growth parameters and leaf biomass production of M. stenopetala. The study was conducted in Arbaminch zuria woreda of Southern Nation Nationalities and Peoples Region (SNNPR). Three planting spacings (0.5 × 0.5 m; 1 × 1 m and 2 × 2 m) were arranged in a randomized complete block design (RCBD) and the treatments were replicated three times. Survival%, root-collar diameter (RCD), height and stem diameter of the trees in each plot were recorded at three monthly intervals from the 3rd to 15 months. Data for leaf biomass were collected at the age of 27, 32 and 48 months. The harvested leaves were then oven dried to determine the dry leaf biomass. Individual Moringa trees showed better growth performance at the wider spacing of 2 × 2 m. The mean RCD, plant height and stem diameter were 7.45 ± 0.20 cm, 1.69 ± 0.06 cm and 3.19 + 0.11 cm for the wider spacing, while 3.12 ± 0.16 cm, 1.02 ± 0.07 cm and 2.12 ± 0.14 cm for the narrow spacing at the age of 15 months. The wider spacing produced the largest quantity of dry leaf biomass per individual plant (119.28 ± 9.02, 143.85 ± 10.29 and 249.8 ± 24.220 g/tree, but the least quantity on hectare bases 298.20 ± 22.54, 359.62 ± 25.73 and 624.49± 60.59 kg/ha) while the narrow spacing produced the smallest quantity per individual plant (48.36 ± 5.10, 44.74 ± 3.19 and 88.15 ± 30.28 g/tree), but the largest quantity on hectare bases (1934.40 ± 203.89, 1789.56 ± 127.78 and 3526.01± 1211.2 kg/ha) at the first, second and third harvest, respectively. This indicates that an increase in the plant spacing led to higher dry leaf biomass production per tree due to better plant growth, but the lesser the leaf biomass yields per hectare due to the lower planting density. The performance of M. stenopetala is promising and hence it can be considered for large scale and commercial plantation .

Effects of nitrogen and water stress on the rehydration, endogenous hormonal regulation and yield of maize

AbstractWater scarcity is known to be a strong limiting factor affecting maize grown and yield in cold semi‐arid regions. Numerous studies have shown that rehydration improves maize growth. Our study aimed to explore the effects of rehydration treatments on maize growth and yield under water and nitrogen stress during different growth stages. We selected the drought‐tolerant maize variety Nendan 19 (ND19) and subjected it to water stress during the V6 (sixth‐leaf), R2 (filling) and R6 (maturity) growth stages and a rehydration treatment after each stress stage. Our results indicated that N1 (N100 kg N ha−1) and N3 (N300 kg N ha−1) treatments significantly increased the leaf moisture status relative to water content (RWC), bound water content (BWC), free water content (FWC) and water potential (WP)) at different growth stages. Similar trends were observed in the accumulation of plant leaf and root hormones (zeatin+zeatin riboside, indole‐3‐acetic acid, abscisic acid and gibberellic acid), photosynthetic pigments and chlorophyll fluorescence. However, under the same water stress conditions, they decreased as the N rate increased and reached a minimum value in the S3 (water stress for N3) treatments. In addition, with growth stage advancement and extension of the rehydration time, both showed a gradual upward trend. The results showed that to save water resources in the cold semi‐arid region, rehydration treatments (R2S1 and R2S3) significantly increased the photosynthetic pigments and chlorophyll fluorescence parameters, leaf moisture status, biomass, 100‐grain weight, hormone content, ear characteristics and grain yield of maize.

Nutrient uptake, physiological responses and growth of tobacco (Nicotiana tabacum L.) in soil under composite salt stress

Higher soil salinity imposes osmotic stress and ion toxicity in plants, leading to substantial crop yield loss worldwide. Understanding of the quantitative and dynamic physiological responses to composite soil salinity (CSS) is limited and needs to be expanded. In this study, physiological, nutritional, and biomass yield parameters of tobacco ( Nicotiana tabacum L.) grown in soil with five levels of CSS, basal CSS level (untreated control, CK) and 3 (T 1 ), 6 (T 2 ), 9 (T 3 ), and 12 (T 4 ) times the basal CSS level, grown under greenhouse were determined and studied at 30-, 60-, and 90-d growth periods. Leaf dry biomass was significantly ( P < 0.05) increased by the low salinity levels applied (T 1 and T 2 ) at all three time points, whereas it progressively declined as the CSS level further increased. The leaf physiological and photosynthetic responses were more adversely affected by CSS at the early growth stage (day 30). A path-coefficient analysis demonstrated that leaf proline concentration had the largest direct effect (–0.66), and leaf Cu content had the most significant indirect effect (0.49) on leaf dry biomass of plants. The results suggest that lower CSS levels (T 1 and T 2 ) could stimulate tobacco growth (leaf biomass yield, in particular), and higher leaf proline and Cu levels at the early growth stage may potentially increase the ability of tobacco plants to withstand the adverse effects of salinity, which could be considered for future research and development of salinity management strategies.

Effects of Different Nitrogen Forms and Competitive Treatments on the Growth and Antioxidant System of Wedelia trilobata and Wedelia chinensis Under High Nitrogen Concentrations.

Nitrogen (N) is one of the essential nutrients for plant growth. Appropriate application of N can improve the N use efficiency (NUE) and significantly promote plants’ growth. However, under N toxic conditions, the relationship between the growth and antioxidant system of invasive plants under different N forms and competitive treatments is not fully understood. Therefore, in this study, the performance of invasive species Wedelia trilobata and its native species Wedelia chinensis was evaluated under two sets of N forms and ratios, namely, NH4+-N(AN)/NO3–-N(NN) = 2:1 and NH4+-N(AN)/NO3–-N(NN) = 1:2 along with two intraspecific and interspecific competitions under without N and high N level of 15 g N⋅m–2 year–1, respectively. Data regarding the growth indices, antioxidant enzyme activities, including peroxidase (POD) and catalase (CAT), malondialdehyde (MDA), and proline contents were determined. Results showed that for competitive treatments, growth status was better for interspecific competition than intraspecific competition. The plant biomass of W. trilobata was significantly higher than that of W. chinensis. N significantly promoted the plants’ growth in terms of leaf area and biomass yield, and the antioxidant enzyme activities were significantly increased under a high N treatment than that of the control. Among N forms/ratios, ammonium N (AN)/nitrate N (NN) = 2:1 significantly enhanced the enzyme activity, particularly in W. trilobata. Furthermore, for intraspecific competition, MDA contents of W. trilobata were significantly decreased compared to that of W. chinensis. In conclusion, our results showed that W. trilobata adapted well under competitive conditions through better growth and antioxidant defense system.

Response and contribution of shallow groundwater to soil water/salt budget and crop growth in layered soils

Shallow groundwater affects crop growth and yield by altering the root zone water and salt budgets, with the process being more complicated in layered soils. To gain insights into the role of shallow groundwater in layered soils, LAWSTAC, a physically-based agro-hydrological model, was employed to simulate soil water, salt, and groundwater fluxes and crop yield in three soil profiles: loam (L), loam with a sand interlayer (LSL), and loam with a clay interlayer (LCL). The model was verified using data collected in 2007 and 2008 from a spring wheat field with shallow groundwater tables. The model predictions matched well with the measured soil water content, salt concentration, groundwater table depth (GWD), leaf area index, biomass, and crop yield. Further simulations were conducted for the L, LSL, and LCL profiles with varying GWDs in the crop growth seasons and initial values specified at 130, 150, 170, 190, 210, 230, and 250 cm. The groundwater table showed greater fluctuations in LCL, with smaller fluctuations in LSL in comparison to L. When starting with smaller initial GWDs (of 130, 150, 170, and 190 cm), the coarse-textured soil under the root zone facilitated water and salt fluxes at the bottom of the root zone, resulting in larger averages for root zone water storage and more salt content during the crop growth seasons and lower crop yield due to salt stress. Meanwhile, in cases with an initial GWD larger than 210 cm, the coarse-textured soil inhibited the fluxes and improved crop yield due to the reduced salt stress. Fine-textured soil under the root zone inhibited water and salt fluxes, reducing root zone salt content and favoring crop yield; however, the effect decreased with larger initial GWDs. Thus, the groundwater table should be lowered to a level where coarse-textured soil acts as a capillary barrier for salt control and crop growth in soil profiles similar to LSL. Keeping a high groundwater table to sustain water for crop growth is acceptable in soil profiles similar to LCL, while keeping a lower groundwater table could be an effective practice to control salt and improve crop production in salinized croplands.

Effect of organic manures and inorganic fertilizers on dry matter yield, soil and plant nutrient content in onion (Allium cepa)

An experiment was conducted to study the effect of different sources of organic manures [Farmyard manure (FYM),Vermicompost (VC) and Jeevamrut] and inorganic fertilizers (Urea, SSP and MOP) on soil and plant nutrient content in onion (Allium cepa L.) during 2017–18 and 2018–19 at Dr Y S Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh. The experiment was laid out in randomized block design with nine treatments replicated thrice. Soil samples from all the treatments during both the years were collected from 0–15 cm depth. At the end of the experiment, significantly high post-harvest fertility status of macronutrients (NPK), viz. 386, 1566 and 384.1 kg/ha, respectively, were recorded under recommended nutrient management practice (RDF) i.e. 125 N: 75 P: 60 K kg/ha + FYM @250 q/ha. Similarly, significantly highest concentration of bulb and leaf macronutrients and biomass yield of bulbs and leaves were recorded under RDF. The purely organic module besides excelling at par with RDF in build-up of macronutrients in soil also registered maximum organic carbon content in soil. From the study, it can be inferred that RDF + FYM @250 q/ha can be used for maintaining the soil fertility.