Jointing Stage Research Articles

Foliar application of potassium and restricted irrigation improved the growth and yield of wheat under rainfed condition of Bhal region

Foliar application of potassium increases the drought tolerance in the wheat crop with restricted irrigation, keeping in the view, a field experiment effect of foliar K application for improving wheat yield and water productivity under restricted irrigation condition was conducted at Agricultural Research station, Anand Agricultural University, Dhandhuka, Bhal region of Gujarat under conserved soil moisture condition with restricted irrigation in the Rabi season of 2021-22 with the objective to reduce moisture stress and to enhance the yield potential of wheat by using potash sprays. Inadequate moisture during the sensitive stages will cause substantial reduction in yield. The experiment was laid out in three replication with nine treatments in split plot design. They are (A). Irrigation levels, I1­: One irrigation at CRI stage, I2: Two Irrigation at CRI and flowering stage, I3: Three irrigation at CRI, late jointing and milking stage. (B). Foliar K application, F1: Control (Water spray), F2: 2% K foliar application at tillering (40-45) and jointing (60-65 DAS), and K3: 4% K foliar application at tillering (40-45) and jointing. The result indicated that due to irrigation management plant height at harvest (70.56 cm), length of ear (7.12), biological yield (7751 kg/ha) and grain yield (3367 kg/ha) was found significant with I3 treatment rest of parameters found non- significant with irrigation levels. Further data indicate from K foliar application, the plant height at harvest (71.51 cm), no of ear head sq. m. (295.44), length of ear (7.17), no, of grain per ear (32.68), test weight (44.03), biological yield (7112 kg/ha) and grain yield (3244 kg/ha) were recorded superior with K3 Treatment (4% K foliar application at tillering (40-45) and jointing) whereas, plant height, no of ear head (sq. m) no, of grain per ear, biological yield and grain yield found at par with F2 treatments Overall, it was observed that the foliar potassium fertilization and restricted irrigation increased the growth, yield attributes and grain yield.

Drought and Waterlogging Status and Dominant Meteorological Factors Affecting Maize (Zea mays L.) in Different Growth and Development Stages in Northeast China

Drought and floods affect the growth and yield of maize, affecting food security. Therefore, it is crucial to assess maize’s drought and waterlogging status in various growth stages. We used phenological and daily meteorological data and spatial analysis to identify the drought and waterlogging conditions of spring maize in Northeast China in eight growth stages. We calculated the crop water surplus/deficit index and used the national standard for maize drought and waterlogging. The results indicate a significant decreasing trend of effective precipitation in Northeast China. The maize’s water requirements changed during the growing period. The ranking of the daily water requirements of maize from high to low in the different growth stages was the flowering stage to the silking stage (6.9 mm/d), the tasseling stage to the flowering stage (6.1 mm/d), the jointing stage to the tasseling stage (4.9 mm/d), the seven-leaf stage to the jointing stage (3.4 mm/d), the silking stage to the harvesting stage (2.0 mm/d), the emergence stage to the three-leaf stage (1.4 mm/d), the three-leaf stage to the seven-leaf stage (1.3 mm/d), and the sowing stage to the emergence stage (1.2 mm/d). Drought occurred primarily in the early growth and development stage, and the most severe drought conditions were observed in the sowing to emergence stages and the emergence to the three-leaf stages in most areas in Northeast China. Waterlogging occurred predominantly in the flowering to the silking stages and the silking to the maturity stages in southeast Liaoning and parts of Jilin. Inner Mongolia had the lowest soil moisture conditions and was unsuitable for maize growth, followed by Heilongjiang, Jilin, and Liaoning. The dominant meteorological factors affecting the drought and waterlogging status of maize in different growth stages were precipitation and wind speed, followed by the minimum temperature, relative humidity, sunshine hours, and maximum temperature. The average temperature did not influence the drought and waterlogging status. The results provide a basis for selecting drought-resistant varieties and preventing waterlogging.

Methane emission under straw return is mitigated by tillage types depending on crop growth stages in a wheat-rotated rice farming system

Straw return (SR) is a recommended management practice to improve soil fertility, but often increases methane (CH4) emissions from rice paddies. Tillage type (before or after irrigation) will change the contact surface between soil and straw, as well as soil structure, but little is known about how tillage type affects CH4 emission under SR from rice fields. A field experiment using split-plot design (straw as main plot and tillage type as subplot) was conducted to quantify the interactive effects of SR and tillage type on CH4 emission from transplanting to jointing, jointing to booting, and booting to maturity stages of rice in 2018 and 2019 and its underlying mechanisms. The results showed that SR significantly increased CH4 emission throughout the rice growing season by 58.8% due to enhanced methanogenic activity compared with straw removal (S0). Cumulative CH4 emission from transplanting to booting stage accounts for 95% of that from the whole rice growth season. Dry tillage (tillage before irrigation, -W) mitigates CH4 emission under SR from transplanting to jointing stage due to lower mcrA abundance compared with wet tillage (tillage after irrigation, +W). However, +W mitigates CH4 emission from jointing to booting stage in the absence of significant interaction between straw and tillage type through improved soil aggregation and higher carbon accumulation compared with -W. Overall, S0 +W had lower CH4 emission by 18.3%− 36.5%, 42.9%− 52.7%, and 44.0%− 48.6% than S0-W, SR-W, and SR+W, respectively (P < 0.0.5). Our results emphasize the importance of adjusting paddy tillage method in mitigating CH4 emission boosted by straw incorporation.

Effects of Nitrogen Application Level on Growth and Yield Of Winter Wheat

In order to achieve higher crop yield and improve the utilization efficiency of nitrogen fertilizer resources. Effect of nitrogen on the tillering ability, the aboveground dry matter mass and yield of winter wheat (WW) during the growing period were analyzed in a field experimental plot of Qinling Field Monitoring Center Station in Baoji City, Shaanxi Province from 2020 to 2021. Results demonstrated that nitrogen use significantly improved the tillering ability of WW during the overwintering and turning green stage; however, the use of nitrogen &gt; 120 kg/hm2 did not have a significant impact on the tillering ability of WW. The growth stages were directly proportional to the extent of aboveground dry matter accumulation (DMA) of WW and were found to be maximum at maturity. Greater usage of nitrogen significantly enhanced aboveground DMA before the jointing stage, but nitrogen application as high as 270 kg/hm2 was not conducive to the aboveground DMA after the jointing stage. For WW, at first, the yield increased and then decreased with the increased concentration of nitrogen. When the nitrogen application level was 120 kg/hm2, the highest yield of WW was 7506 kg/ha. However, there was an insignificant increase in yield at nitrogen levels &gt; 120 kg/hm2. In the study area, at nitrogen &gt; 195 kg/hm2, a decrease in yield was observed. Therefore, the recommended nitrogen application level in this area was 120kg/hm2. Bangladesh J. Bot. 51(4): 937-941, 2022 (December) Special

Dynamic of Soil Porosity and Water Content under Tillage during Summer Fallow in the Dryland Wheat Fields of the Loess Plateau in China

The adoption of tillage during summer fallow can effectively store precipitation in summer and increase the soil water content in the dryland wheat fields of the eastern Loess Plateau; however, its influencing mechanism is still unknown. Three tillage measures were implemented in 2018, namely, no-tillage during summer fallow (NTF), subsoiling during summer fallow (STF), and plough tillage during summer fallow (PTF), to investigate the changes in soil porosity in different growth periods of winter wheat and their contribution to the soil water storage. The results showed that soil total porosity (Pt) at the 0.2–0.3 m soil depth under the PTF treatment increased significantly from 5.64% to 34.72% compared with that under the STF treatment from pre-seeding to anthesis and significantly increased from 8.67% to 11.56% compared with that under the NTF treatment from pre-seeding to the overwintering stage. In the overwintering period, aeration porosity (Pa) in the 0.1–0.3 m profile under the PTF treatment increased from 31.59% to 73.98% compared with that under the NTF treatment, and that of the 0.2–0.3 m soil layer under the STF treatment increased by 82.47% compared with that under the STF treatment. At the overwintering stage and jointing stage, capillary porosity (Pc) at 0.2–0.3 m soil depth under the NTF treatment increased significantly by 17.45–17.72% compared with that under the STF treatment. The Pt and Pa of the 0–0.1 m soil layer promoted soil water storage in the 0.1–1 m soil profile, while the Pc of the 0–0.3 m soil profile was significantly negatively correlated with the gravimetric water content of the 0.1–0.6 m soil profile. In summary, compared with the NTF treatment, the PTF and STF treatments increased the soil water content and soil water storage at a depth of 0–1 m by increasing Pt and Pa.

An Optimized Nitrogen Application Rate and Basal Topdressing Ratio Improves Yield, Quality, and Water- and N-use Efficiencies for Forage Maize (Zea mays L.)

Applying nitrogen (N) fertilizer at irrational rates and basal topdressing ratios typically leads to high resource wastage and serious environmental pollution and is a global problem. A pot experiment was conducted between 2020 and 2021 to investigate the effects of different N application rates and basal topdressing ratios on the growth, yield, quality, and water- and N- use efficiencies of forage maize. Four N treatments were used, with the following levels: 0 kg/ha (N0), 70 kg/ha (N70), 140 kg/ha (N140), and 210 kg/ha (N210); and two basal topdressing ratios of N fertilizer were tested, namely: 2:8 and 4:6. An increased N application rate, from 0 to 200 kg/ha, increased whole fresh and dry yields. N fertilization increased the crude protein (CP) content of different plant parts (stems, leaves, and ears), as well as at the whole plant level, but decreased neutral and acid detergent fiber content. The dry matter water use efficiency (WUEDM) increased, while the partial-factor productivity of applied N decreased with an increasing N application rate. Compared with N0, the 2-year average dry matter yield under N70, N140, and N210 increased by 21.8%, 27.6%, and 38.2%, respectively, while WUEDM increased by 19.1%, 28.7%, and 45.0%, respectively. At the 2:8 basal topdressing ratio, the dry matter yield, CP content, and N recovery efficiency under all N application rates were higher at harvest compared to the 4:6 ratio during normal rainfall years, while dry matter yield and WUEDM were both lower compared to the 4:6 ratio during dry years. In conclusion, during a normal rainfall year, a N application rate of 210 kg/ha, with a basal topdressing ratio of 2:8 between the sowing and jointing stages, is considered the optimal N fertilizer application strategy to improve forage maize production in the semi-arid areas of the Chinese Loess Plateau.

Root pruning improves maize water-use efficiency by root water absorption.

Root systems are an important component of plants that impact crop water-use efficiency (WUE) and yield. This study examined the effects of root pruning on maize yield, WUE, and water uptake under pot and hydroponic conditions. The pot experiment showed that root pruning significantly decreased root/shoot ratio. Both small root pruning (cut off about 1/5 of the root system, RP1) and large root pruning (cut off about 1/3 of the root system, RP2) improved WUE and root hydraulic conductivity (Lpr) in the residual root system. Compared with that in the un-cut control, at the jointing stage, RP1 and RP2 increased Lpr by 43.9% and 31.5% under well-watered conditions and 27.4% and 19.8% under drought stress, respectively. RP1 increased grain yield by 12.9% compared with that in the control under well-watered conditions, whereas both pruning treatments did not exhibit a significant effect on yield under drought stress. The hydroponic experiment demonstrated that root pruning did not reduce leaf water potential but increased residual root hydraulic conductivity by 26.2% at 48 h after root pruning under well-watered conditions. The foregoing responses may be explained by the upregulation of plasma membrane intrinsic protein gene and increases in abscisic acid and jasmonic acid in roots. Increased auxin and salicylic acid contributed to the compensated lateral root growth. In conclusion, root pruning improved WUE in maize by root water uptake.

Effect of Sowing Methods and Irrigation Levels on wheat (Triticum aestivum L.)

The field experiment was carried out at agricultural research farm of IFTM University Moradabad (U.P.), India during rabi season 2018-19 to study the effect of sowing methods and irrigation levels on wheat. Sowing method and irrigation being a major constraint to reduces the potential of wheat yield. The treatments were arranged in split plot design in three replications, sowing methods in main plots and irrigation levels in sub-plots. The experiment treatments included two sowing methods, i.e. [S1 – conventional sowing method and S2 - furrow irrigated raised bed (FIRB) system] in main plots and six irrigation levels [I0 – (control), I1 – (one irrigation at CRI stage), I2 – (two irrigation at CRI and tillering stage), I3 – (three irrigations at CRI, tillering and late jointing stage), I4 – (four irrigations at CRI, tillering, late jointing and milking stage) and I5 – (five irrigations at CRI, tillering, late jointing, milking and dough stage). Wheat crop was sown by traditional method and furrow irrigated raised beds (FIRB) method. Raised beds were accommodating 3 rows of wheat at 20 cm wide. Furrows that are in between the beds are used for irrigation. This system permits adequate saving of irrigation water. Results indicated that sowing of wheat on FIRB system surpassed the conventional method of sowing for plant height, number of tillers plant-1, dry weight (g plant-1), number of effective tillers plant-1, spike length, number of grain spike-1, 1000 grain weight, grain yield, straw yield and biological yield followed by conventional sowing method. On the other hand irrigation levels I5 - (five irrigations at CRI, tillering, late jointing, milking and doughing stage) recorded the highest values for most of growth, yield components and yield of wheat. In FIRB system beds gave the opportunity for mechanical weeding and fertilizer placement and also improved the fertilizer and water use efficiencies. The role of sowing methods and level of irrigation in plant health and growth has been investigated in crop and it seemed significantly affecting with treatment.

Transcriptome analysis reveals potential genes associated with plant height in rice

Plant height (PH) is a complex trait regulated by the environment and multiple genes. PH directly affects crop yield, harvest index, and lodging resistance. From plant dwarf mutants, many genes related to PH have been identified and described. Nonetheless, the molecular mechanism of height regulation in high-culm rice mutants has not been well studied. By using transcriptome and weighted gene co-expression network analysis (WGCNA), we identified the differentially expressed genes (DEGs) between high-culm rice mutants (MUT) and wild-type (WT) and explored the key pathways and potential candidate genes involved in PH regulation. Transcriptome analysis identified a total of 2,184 DEGs, of which 1,317 were identified at the jointing stage and 1,512 were identified at the heading stage. Kyoto Encyclopedia of Genes and Genomes enrichment showed that the enrichment pathways were mainly involved in plant hormone signal transduction, ABC transportation, and steroid hormone biosynthesis. Among these metabolic pathways, LOC_Os05g43910 and LOC_Os01g35030 were auxin (IAA)-related genes, up-regulated in MUT and LOC_Os02g08500 (LEPTO1), LOC_Os11g04720, and LOC_Os12g04500 were cytokinin (CK)-related genes, down-regulated in MUT. The WGCNA identified four modules (light cyan, dark grey, grey, and pale turquoise) closely related to PH, and seven key genes were screened from these modules, of which two were up-regulated cell wall-related genes (LOC_Os01g26174 (OsWAK5), LOC_Os06g05050) in MUT, and one gibberellic acid (GA) gene (LOC_Os06g37364, OsKO2) was also up-regulated. These genes might be closely related to PH regulation. These findings help us better understand the transcriptional regulation of rice plant growth and development and provide a theoretical basis for mapping and cloning the PH regulatory genes.

臭氧胁迫冬小麦叶片高光谱特征和叶绿素含量估算

PDF HTML阅读 XML下载 导出引用 引用提醒 臭氧胁迫冬小麦叶片高光谱特征和叶绿素含量估算 DOI: 10.5846/stxb202201200196 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(42130714) Hyperspectral characteristics and chlorophyll content estimation of winter wheat under ozone stress Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为无损、快速监测臭氧胁迫下冬小麦叶片叶绿素含量,建立叶绿素含量与光谱指标的定量关系,基于自由式臭氧浓度增加系统平台观测了臭氧浓度升高下拔节期、开花期及灌浆期冬小麦叶片的叶绿素含量和光谱特征。通过线性回归、人工神经网络(ANN)以及偏最小二乘回归(PLSR)模型对臭氧胁迫下叶片高光谱特征进行了叶绿素含量的估算。结果表明:臭氧胁迫冬小麦叶片的光谱曲线特征出现绿峰"红移"和红边位置"蓝移"现象。相比于拔节期和开花期,小麦叶片在灌浆期受到臭氧的影响更大。臭氧胁迫下叶绿素含量与部分光谱特征参数及遥感植被指数存在显著相关关系,所有模型均取得了较高的估算精度(R2>0.8),其中以光谱特征参数为建模参量的偏最小二乘回归模型精度最高。该方法可用于臭氧胁迫下冬小麦叶片叶绿素含量的估测,动态监测作物的臭氧胁迫。 Abstract:To quantify the O3-induced damage non-destructively and rapidly, it is important to build up the relationship between the chlorophyll content and spectral characteristics. In this study, the winter wheat leaves under ozone stress were measured at the jointing, flowering and grain filling stages, respectively. The field experiment was conducted through the free-air ozone concentration elevation system (O3-FACE) platform located at Jiangdu, Yangzhou, Jiangsu Province. Hyperspectral estimation of chlorophyll content under ozone stress was made using linear regression model, artificial neural network (ANN) model and partial least squares regression (PLSR) model, respectively. The results showed that the green peak of the leaf spectrum under ozone stress showed a "red shift", while the red edge of the leaves spectrum showed a "blue shift". Elevated ozone affected wheat leaves more at grain filling stage than jointing and flowering stages. There was a significant correlation between chlorophyll content and most spectral characteristics or vegetation spectral indexes under ozone stress with high estimation accuracy (R2>0.8). Among all models, the highest accuracy was achieved by the PLSR model based on spectral characteristics. The PLSR model can be used to estimate the chlorophyll content of winter wheat exposed to high ozone concentration and thus quantify the damage induced by ozone stress. 参考文献 相似文献 引证文献

Effects of nitrogen application rate on the accumulation of 13C assimilates after flowering and water-nitrogen use efficiency of wheat under supplemental irrigation based on soil moisture.

This study aimed to explore nitrogen fertilizer management measures to synergistically improve wheat yields and water and nitrogen use efficiency under supplemental irrigation based on soil moisture in the Huang Huai winter wheat area. Wheat variety "Yannong 1212" was used as the test material. There were three nitrogen application levels, 150 kg·hm-2 (N1), 210 kg·hm-2 (N2), and 270 kg·hm-2 (the conventional nitrogen application rate in the Huang Huai winter wheat area, N3), with the relative soil water content of 0-40 cm of each treatment was supplemented to 70% at the jointing and flowering stages. We investigated the effects of nitrogen rates on photosynthetic characteristics of flag leaves after flowering, 13C assimilate accumulation and transport, and water and nitrogen use efficiency after flowering of wheat. The results showed that photosynthetic capacity of flag leaves in the N2 and N3 was significantly higher than that in N1 14-35 days after flowering, and that there was no significant diffe-rence between N2 and N3 treatments. The 13C isotope tracing results showed that the translocation amount of 13C assimilates in vegetative organs in N2 was 12.1% and 7.1% higher than that in N1 and N3, respectively. The distribution amount of 13C assimilates in grains at maturity was 10.1% and 5.3% higher than that of N1 and N3, respectively. The amount of nitrogen fertilizer affected water consumption, water consumption proportion, and total water consumption in different growth stages of wheat. Water consumption during the whole growth period showed no difference between N2 and N3 treatments, but both were significantly higher than that for N1. Water consumption and water consumption proportion of N2 were higher from the jointing to maturity stages, water use efficiency of N2 was 7.5% and 4.8%, and grain yield was 4.7% and 10.9% higher than that of N3 and N1 treatments, respectively. The partial productivity of nitrogen fertilizer was 34.6% higher in the N2 than that of N3. Considering wheat grain yield and water and nitrogen use efficiency, 210 kg·hm-2 nitrogen application was the best rate under water-saving condition of supplementary irrigation after soil moisture measurement in the study area.

Response of Physiological Growth Characteristics of Rice to Different Biodegradable Mulching and Irrigation Methods in Cold Region of Northeast China

Highlights The tested biodegradable mulch film can be rapidly degraded in rice fields in cold regions and has good applicability. The degradation rate of white mulch film is faster than that of black film before the induction period, and the degradation law after the induction period is opposite. The combination of mulching film and water-saving irrigation can effectively enhance the photosynthetic capacity and dry matter transport of rice in cold regions. Through comprehensive evaluation, we found that the combination of ridge irrigation and mulching FC plastic film has the best effect on environmental protection and rice growth. Abstract. To reveal the mechanism of influence of different types of biodegradable plastic film mulching and irrigation combinations on the physiological growth characteristics of rice in cold regions, eight types of film mulching irrigation methods were designed, which combined four types of plastic film mulching and two types of irrigation methods for a total of nine treatments. The study analyzed the degradation law of degradable plastic film in rice fields in cold regions, and the effects of film-mulching irrigation methods on rice photosynthetic characteristics, dry matter transport, and rice yield. The results showed that the three biodegradable plastic films were suitable for the rice fields in the northeast cold region. Except for the jointing stage, mulching irrigation treatments could increase the chlorophyll content and net photosynthetic rate of rice, and the improvement degree showed a downward trend with the growth of rice. The film mulching irrigation treatments improved rice stems and leaves dry matter transport and grain contribution. The comprehensive evaluation based on the comprehensive index method showed that the combination of ridge irrigation and thin black biodegradable mulch is the best combination of biodegradable plastic film mulching and irrigation in the study area. Keywords: Biodegradable mulching, Comprehensive index method, Dry matter transportation, Irrigation method, Photosynthetic character.

A study on the physiological parameters of corn during the jointing stage of growth under soil water stress based on the PSII light quantum yield (QY)

Water stress is a major factor limiting corn production in the semi-arid and semi-humid regions of the world. Well-scheduled irrigation is necessary to increase seed yield and ensure yield stability in these regions. A reasonable and intelligent irrigation system is generally based on the measurement of soil water content or the monitoring of corn water demand. Therefore, it is vital to be able to quickly and accurately determine the optimal threshold of the physiological parameters of corn.In this paper, in order to find the optimal threshold of the physiological parameters of corn, experiments in the open fields were conducted from February to June by measuring the corn growth under different degrees of water stress using remote sensing instruments. In this experiment, sweet corn 18# was chosen as the experimental subject, and several parameters of remote sensing spectral index such as leaf water potentia, Normalized difference vegetation index (NDVI), photochemical vegetation index (PRI), and PSII light quantum yield (QY) were measured at the same time every day-along with the varying moisture status—for the duration of the experiment. For this experiment, it was very important to set the varying moisture statuses as the moisture controlling standard. Leaf water potential and QY were selected as indexes to check the different moisture statuses. The QY proved to be sensitive to the water stress of corn and was chosen as the indicator. Furthermore, the effects on the corn under differing levels of water stress were explored by analyzing the variation trend of different remote sensing spectral indices. The main results and conclusions are as follows:(1) Differing degrees of water stress at the jointing stage of corn growth will cause the inhibition (in varying degrees) of leaf water potential, QY, NDVI, and PRI; and will also inhibit the processes of transpiration and photosynthesis. (2) After halting the water stress, with the different levels of water replenishment, the leaf water potential, QY, NDVI, and PRI will display the characteristics of the compensation phenomena. The compensation levels will depend on the degree of water stress. When the water stress is mild, all of the leaf water potential indexes, QY, NDVI, PRI will recover to normal levels or even succeed normal levels in a very short period of time-known as the super compensation effect. Meanwhile, for moderate levels of water stress, the compensation phenomena is also present; however, the replenishment of water cannot reach normal levels. Further, the water replenishment effect does not appear under conditions of severe water stress. This indicates that it is beneficial in maize growth for the corn to be under conditions of mild water stress.(3) Lastly, from the significance of the QY, water potential, PRI, and NDVI to water stress, it is apparent that the QY is the most reliable. Therefore, QY is the most reasonable choice to guide the water-saving irrigation in irrigated farming areas.

Effect of irrigation regime, Pusa hydrogel and vermicompost on growth, productivity and soil-nutrient status in late-sown wheat (Triticum aestivum)

A field experiment was conducted during the winter (rabi) season of 2015–16 and 2016–17 at Crop Research Centre of the Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, Uttar Pradesh, India to study the effect of Pusa hydrogel and vermicompost on crop productivity and soil nutrient status in late-sown wheat (Triticum aestivum L.). Three irrigation levels, viz., I1 [at crown-root initiation (CRI) stage], I2 (at CRI, booting and milking) and I3 (at CRI, late tillering, late jointing, flowering and milking stage), and 4 moisture-conservation practices, viz. application of Pusa hydrogel @ 5 kg/ha, vermicompost @ 1 t/ha, Pusa hydrogel @ 5 kg/ha + vermicompost @ 1 t/ha and no application, were tested in split-plot design, with 3 replications. Results revealed that, the growth parameters, viz. of plant height (106.6 and 103.8 cm), tillers/m, dry-matter accumulation (184.5 and 195.0 g/m), leaf-area index (3.15 and 3.23) and harvest index, of wheat were significantly higher under 5 irrigation levels than 3 and 1, being the lowest under 1 irrigation during 2015–16 and 2016–17, respectively. The wheat received 5 irrigations outyielded wheat received 3 and 1 irrigations during the first and second years by 7.6, 68.8% and 8.1 and 69.4% respectively. Similarly, wheat grown with 3 and 5 irrigations recorded 5.98 and 5.84 q/ ha and 28.88 and 26.65 q/ha higher straw yield during 2015–16 and 2016–17 respectively. The highest available nitrogen (229.9 and 232.2 kg/ha) and potassium (177.2 and 179.1 kg/ha) were recorded with 5 irrigations, followed by 3 irrigations during the first and second years, respectively. The combined application of Pusa hydrogel @ 5 kg + vermicompost @ 1 t/ha over no application at harvesting resulted in 33.2 and 31.0% more dry-matter production/ m and 34.6 and 38.4% higher grain yield/ha, besides 231.0 and 233.3 kg N, 14.6 and 15.1 kg P and 175.5 and 177.8 kg K/ha with 0.494 and 0.512% organic carbon after harvesting during 2015–16 and 2016–17, respectively

The wheat leaf delayed virescence of mutant dv4 is associated with the abnormal photosynthetic and antioxidant systems

Chlorophyll (Chl) is a key pigment for wheat (Triticum aestivum L.) photosynthesis, consequently impacts grain yield. A wheat mutant named as delayed virescence 4 (dv4) was obtained from cultivar Guomai 301 (wild type, WT) treated with ethyl methane sulfonate (EMS). The seedling leaves of dv4 were shallow yellow, apparently were chlorophyll deficient. They started to turn green at the jointing stage and returned to almost ordinary green at the heading stage. Leaf transcriptome comparison of Guomai 301 and dv4 at the jointing stage showed that most differentially expressed genes (DEGs) of transcription and translation were highly expressed in dv4, one key gene nicotianamine aminotransferase A (NAAT-A) involved in the synthesis and metabolism pathways of tyrosine, methionine and phenylalanine was significantly lowly expressed. The expression levels of the most photosynthesis related genes, such as photosystem I (PS I), ATPase and light-harvesting chlorophyll protein complex-related homeotypic genes, and protochlorophyllide reductase A (PORA) were lower; but macromolecule degradation and hypersensitivity response (HR) related gene heat shock protein 82 (HSP82) was highly expressed. Compared to WT, the contents of macromolecules such as proteins and sugars were reduced; the contents of Chl a, Chl b, total Chl, and carotenoids in leaves of dv4 were significantly less at the jointing stage, while the ratio of Chl a / Chl b was the same as that of WT. The net photosynthetic rate, stomatal conductance and transpiration rate of dv4 were significantly lower. The H2O2 content were higher, while the contents of total phenol and malondialdehyde (MDA), antioxidant enzyme activities were lower in leaves of dv4. In conclusion, the reduced contents of macromolecules and photosynthetic pigments, the abnormal photosynthetic and antioxidant systems were closely related to the phenotype of dv4.

Extraction of Winter Wheat Planting Area Based on Multi-Scale Fusion

It is difficult to accurately identify the winter wheat acreage in the Jianghuai region of China, and the fusion of high-resolution images and medium-resolution image data can improve the image quality and facilitate the identification and acreage extraction of winter wheat. Therefore, the objective of this study is to improve the accuracy of China’s medium-spatial resolution image data (environment and disaster monitoring and forecasting satellite data, HJ-1/CCD) in extracting the large area of winter wheat planted. The fusion and object-oriented classification of the 30 m × 30 m HJ-1/CCD multispectral image and 2 m × 2 m GF-1 panchromatic image (GF-1/PMS) of winter wheat at the jointing stage in the study area were studied. The GF-1/PMS panchromatic images were resampled at 8 m, 16 m and 24 m to produce panchromatic images with four spatial resolutions, including 2 m. They were fused with HJ-1/CCD multispectral images by Gram Schmidt (GS). The quality of the fused images was evaluated to pick adequate scale images for the field pattern of winter wheat cultivation in the study area. The HJ-1/CCD multispectral image was resampled to obtain an image with the same scale as the suitable scale fused image. In the two images, the training samples SFI (samples of fused image) and SRI (samples of resampled image) containing spectral and texture information were selected. The fused image (FI) and resampled image (RI) were used for winter wheat acreage extraction using an object-oriented classification method. The results indicated that the fusion effect of 16 m × 16 m fused image was better than 2 m × 2 m, 8 m × 8 m and 24 m × 24 m fused images, with mean, standard deviation, average gradient and correlation coefficient values of 161.15, 83.01, 4.55 and 0.97, respectively. After object-oriented classification, the overall accuracy of SFI for the classification of resampled image RI16m was 92.22%, and the Kappa coefficient was 0.90. The overall accuracy of SFI for the classification of fused image FI16m was 94.44%, and the Kappa coefficient was 0.93. The overall accuracy of SRI for the classification of resampled image RI16m was 84.44%, and the Kappa coefficient was 0.80. The classification effect of SFI for the fused image FI16m was the best, indicating that the object-oriented classification method combined with the fused image and the extraction samples of the fused image (SFI) could extract the winter wheat planting area with precision. In addition, the object-oriented classification method combining resampled images and the extraction samples of fused images (SFI) could extract the winter wheat planting area more effectively. These results indicated that the combination of medium spatial resolution HJ-1/CCD images and high spatial resolution GF-1 satellite images could effectively extract the planting area information of winter wheat in large regions.

Management of bacterial leaf blight disease of rice in farmer's field condition at Bhaktapur district of Nepal

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae is considered as one of the major threats to rice production in Nepal. To identify the effective control measures, an experiment was done in a randomized complete block design with three replications in a farmer's rice field at Bhaktapur, during the summer seasons of 2018 and 2019. Three plants extracts; 1% Neem extract, 2% Asuro leaf extract, and 2% Titepati leaf extract along with two fungicides viz. 0.1% Agricin and 0.2% Blitox 50, and one bio-control agent 1%Kisan Pseudomonas were used as treatments. The first spray was given as a prophylactic spray at the jointing stage, and they were applied 3 times at 50, 60 and 70 days interval. All the treatments significantly reduced disease and improved test weight higher than control. Among the tested treatments, 0.1% Agricin performed as the best with 65.70% disease control and increase in yield over control by 28.13%. Among the tested botanicals, 2% stock solution of Titepati performed as the best with 50.59% disease control and increase in yield by 13.51%. Therefore, three times application of 0.1% Agricinat 10 day interval starting from jointing stage can be used to control BLB disease for higher rice production.

Starch Physicochemical Properties of Normal Maize under Different Fertilization Modes

Improving the quality with desired functions of natural starch through agronomic practice will meet the increasing need of people for natural, functional foods. A one-off application of slow-release fertilizer is a simple and efficient practice in maize production, though its influence on the starch quality is scarce. In the present study, the structural and functional properties of the starch of normal maize under two fertilization modes (one-off application of slow-release fertilizer at the sowing time (SF), and three applications of conventional fertilizer at the sowing time, and topdressing at the jointing and flowering stages (CF)) under the same fertilization level (N/P2O5/K2O = 405/135/135 kg/ha) were studied using Jiangyu877 (JY877) and Suyu30 (SY30) as materials. The observed results indicate that the size of starch granules was enlarged by fertilization and the size was the largest under CF in both hybrids. The amylose content was unaffected by CF and reduced by SF in both hybrids. In comparison to no fertilizer (0F), the peak 1/peak 2 ratio was decreased by CF in both hybrids, whereas the ratio under SF was unaffected in JY877 and decreased in SY30. The amylopectin average chain-length was reduced by fertilization and the reduction was higher under CF in JY877. The relative crystallinity was increased by CF in both hybrids and the value under SF was unaffected in SY30 and increased in JY877. The peak, trough, and final viscosities of starch were increased by fertilization in both hybrids. The starch thermal characteristics in response to fertilization modes were dependent on hybrids. The retrogradation enthalpy and percentage were increased by CF in both hybrids, whereas those two parameters under SF were increased in SY30 and decreased in JY877. In conclusion, starch with similar granule size, higher peak 1/peak 2 ratio, and lower relative crystallinity was obtained under SF than under CF for both hybrids. Longer amylopectin chain-length was observed in JY877, which induced lower pasting viscosities in SY30 and lower retrogradation characteristics in JY877.

Impact of Irrigation Scheduling, Moisture Conservation Practices and Nutrient Management on Performance of Wheat (Triticum aestivum L.)

A field experiment was conducted during two consecutive Rabi seasons 2020-21 and 2021-22 at Students’ Instructional Farm of Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh, India, situated at 125.9 meter altitude, 26.491220 North latitude, 80.3070120 East longitude, to study “Impact of irrigation scheduling, moisture conservation practices and nutrient management on performance of wheat (Triticum aestivum L.)”. The experiment consisted three irrigation scheduling viz: I1: two irrigations at CRI and Jointing stage, I2: three irrigations at CRI, Jointing and Booting stage and I3: Four irrigations at CRI, Tillering, Booting and Milking stage, two moisture conservation practices viz: M0: without mulching and M1: Organic mulch @ 10 t ha-1 + Kaolin 6% spray and three nutrient management practices viz: N1: 100% RDF (150:60:40 kg ha-1 NPK), N2: 85% RDF + FYM @ 5.0 t ha-1 and N3: 75% RDF + FYM @ 10.0 t ha-1. The experiment was laid out in double split plot design with three replications. On pooled basis of two years experimentation the results indicated that, four irrigations at CRI, Tillering, Booting and Milking stage (I3) recorded highest value of grain yield (4381.60 kg ha-1), straw yield (6651.15 kg ha-1) and harvest index (39.70 %) with profitability in terms of net return (Rs. 83908.79 ha-1), under moisture conservation practices, organic mulch @ 10 t ha-1 + Kaolin 6% spray (M1) recorded significantly highest grain yield (4230.40 kg ha-1) and straw yield (6578.57 kg ha-1). Among the nutrient management treatments, 85% RDF + FYM @ 5.0 t ha-1 (N2) also recorded maximum grain yield (4117.60 kg ha-1) and straw yield (6338.71 kg ha-1) and net return (Rs. 77770.83 ha-1) compared to other treatments.

Soil respiration may be reduced by wind via the suppressing of root respiration: Field observation in maize farmland in the agro-pastoral transitional zone, northeastern China

Soil respiration is a major source of atmospheric carbon dioxide (CO2). Intensive exploring on soil respiration in farmland may provide important information for controlling CO2 emissions. However, some important meteorological factors, especially for the wind, have been neglected previously. In this two-season field observation, we measured soil total respiration (Rt) in maize farmland in an agro-pastoral transitional zone in northeastern China, including autotrophic (root) respiration (Ra) and heterotrophic respiration (Rh), using the root-exclusion method. The mean Rt was 4.0 ± 0.8 and 6.1 ± 1.4 μmol·m−2·s−1 in the two growing seasons. The root contribution to the total soil respiration rate (Rc) was 55.5 and 44.1 %, respectively, and both followed an approximately unimodal curve as a function of day of year. Ra and Rh were both positively correlated with the soil temperature. Ra decreased with increasing wind speed, but Rh was not significantly affected; thus, Rc was negatively correlated with the wind speed. The decrease of Rc caused by increased wind speed differed among the growth stages. Significant suppression of Rc was detected at the jointing stage and at maturity. Responses of Rt and its components to meteorological factors differed significantly in magnitude between the day and night. However, Rc decreased with increasing wind speed both during the day and at night. In summary, the decrease of farmland soil respiration by the wind resulted from decreased root respiration and could be regulated by the modifying of artificial windbreaks or by the expanding of row space of the maize planting, thereby reducing carbon dioxide emission. Indeed, this study is only the observation and analysis of some traditional factors, more intensive observations, especially evidence from physiological traits, morphological anatomy and other perspectives are required to confirm this relationship in further studies.