Grain yield and N uptake of maize in response to increased plant density under reduced water and nitrogen supply conditions

The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas.

Effects of Seeding Date and Density on Yield and Agronomic Traits of Millet : A Case Study of Wangu 098 Variety of Millet

[Objectives]To find out a suitable cultivation technique of Wangu 098 in Nanyang area,speed up the popularization,demonstration and application of Wangu 098,and provide a theoretical and practical basis for adjusting the planting structure and realizing the matching of improved varieties and methods.[Methods]The new self-bred millet variety Wangu 098 was used as the material,and the two-factor split zone experimental design was adopted.The effects of different sowing dates and densities on the yield,growth period and agronomic characters of millet were studied.[Results]The interaction of seeding date and density had a great effect on the yield and plant traits of millet.Millet yield was significantly and positively correlated with plant height,panicle length,single panicle weight,panicle grain weight and tiller number.[Conclusions]The reasonable combination of seeding date and density could give full play to the yield potential of millet.According to the experimental results and cultivation experience,the suitable seeding date of millet in Nanyang area is in the first and middle ten days of June,and the best density is about 750000 plants/ha.However,after June 30,the seeding millet did not tiller,so the density should be increased to more than 900000 plants/ha to obtain higher yield.In terms of cultivation and management,timely seeding,reasonable close planting,and coordination of vegetative growth and reproductive growth can make the plant tall and strong,panicle long and thick,and improve the yield of millet.

Adaptive Density-Based Spatial Clustering of Applications with Noise(ADBSCAN)for Clusters of Different Densities

Finding clusters based on density represents a significant class of clustering algorithms.These methods can discover clusters of various shapes and sizes.The most studied algorithm in this class is theDensity-Based Spatial Clustering of Applications with Noise(DBSCAN).It identifies clusters by grouping the densely connected objects into one group and discarding the noise objects.It requires two input parameters:epsilon(fixed neighborhood radius)and MinPts(the lowest number of objects in epsilon).However,it can’t handle clusters of various densities since it uses a global value for epsilon.This article proposes an adaptation of the DBSCAN method so it can discover clusters of varied densities besides reducing the required number of input parameters to only one.Only user input in the proposed method is the MinPts.Epsilon on the other hand,is computed automatically based on statistical information of the dataset.The proposed method finds the core distance for each object in the dataset,takes the average of these distances as the first value of epsilon,and finds the clusters satisfying this density level.The remaining unclustered objects will be clustered using a new value of epsilon that equals the average core distances of unclustered objects.This process continues until all objects have been clustered or the remaining unclustered objects are less than 0.006 of the dataset’s size.The proposed method requires MinPts only as an input parameter because epsilon is computed from data.Benchmark datasets were used to evaluate the effectiveness of the proposed method that produced promising results.Practical experiments demonstrate that the outstanding ability of the proposed method to detect clusters of different densities even if there is no separation between them.The accuracy of the method ranges from 92%to 100%for the experimented datasets.

Effects of paclobutrazol application on plant architecture,lodging resistance,photosynthetic characteristics,and peanut yield at different single-seed precise sowing densities

The key to high-yielding peanut cultivation is the optimization of agricultural production practices.Regulating single-seed precise sowing(SSPS)density and paclobutrazol(Pbz)application concentration are effective practices that increase peanut yield by improving plant architecture,lodging resistance,and photosynthetic characteristics.Therefore,we conducted a two-factor field optimization experiment for the sowing density(D1:1.95×10^(5)plants ha^(-1),D52:2.40×10plants ha^(-1),D3:2.85×10^(5)plants ha^(-1),and D4:3.30×10^(5)plants ha^(-1))and Pbzapplication concentration(P0:0 mg L^(-1)and P1:100 mg L^(-1)).The objective was to optimize agricultural production practices and provide a theoretical basis for highyielding peanut cultivation by evaluating the effects of sowing density and Pbzapplication on plant architecture,lodging resistance,photosynthetic characteristics,and yield.The results showed that at the same Pbzapplication concentration,increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity.At the same sowing density,Pbzapplication reduced lodging percentage by decreasing plant height(PH),improving lignin biosynthesis-related enzyme activities,and enhancing stem puncture strength(SPS)and breaking strength(SBS).The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata,resulting in the increase in relative chlorophyll content and net photosynthetic rate(Pn)of leaves.Furthermore,D3P1treatment had the highest peanut yield among all treatments.In summary,the production strategy combining the sowing density of 2.85×10^(5)plants ha^(-1)with the application of100 mg L^(-1)Pbzwas found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.

Winter wheat yield improvement by genetic gain across different provinces in China

The replacement of winter wheat varieties has contributed significantly to yield improvement worldwide,with remarkable progress in China.Drawing on two sets of data,production yield from the National Bureau of Statistics of China and experimental yield from literature,this study aims to(1)illustrate the increasing patterns of production yield among different provinces from 1978 to 2018 in China,(2)explore the genetic gain in yield and yield relevant traits through the variety replacement based on experimental yield from 1937 to 2016 in China,and(3)compare the yield gap between experimental yield and production yield.The results show that both the production and experimental yields significantly increased along with the variety replacement.The national annual yield increase ratio for the production yield was 1.67%from 1978 to 2018,varying from 0.96%in Sichuan Province to 2.78%in Hebei Province;such ratio for the experimental yield was 1.13%from 1937 to 2016.The yield gap between experimental and production yields decreased from the 1970s to the 2010s.This study reveals significant increases in some yield components consequent to variety replacement,including thousand-grain weight,kernel number per spike,and grain number per square meter;however,no change is shown in spike number per square meter.The biomass and harvest index consistently and significantly increased,whereas the plant height decreased significantly.

Increasing the appropriate seedling density for higher yield in dry direct-seeded rice sown by a multifunctional seeder after wheatstraw return

Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient,relatively cheap,and environmentally friendly.However,this method of rice production may produce lower yields in a rice–wheat rotation system because of its poor seedling establishment.To address this problem,we performed field experiments to determine the rice yield at five seedling density levels(B1,B2,B3,B4,and B5=100,190,280,370,and 460 seedlings m-2,respectively) and clarify the physiological basis of yield formation.We selected a representative high-quality rice variety and a multifunctional seeder that used in a typical rice–wheat rotation area in 2016 and 2018.The proportion of main stem panicle increased with increasing seedling density.There was a parabolic relationship between yield and seedling density,and the maximum yield(9.34-9.47 t ha-1) was obtained under B3.The maximum yield was associated with a higher total spikelet number m-2 and greater biomass accumulation from heading to maturity.The higher total spikelet number m-2 under B3 was attributed to an increase in panicle number m-2 compared with B1 and B2.Although the panicle numbers also increased under B4 and B5,these increases were insufficient to compensate for the reduced spikelet numbers per panicle.Lower biomass,smaller leaf area,and lower N uptake per plant from the stem elongation stage to the heading stage were partially responsible for the smaller panicle size at higher seedling density levels such as B5.The higher biomass accumulation under B3 was ascribed to the increases in the photosynthetic rate of the top three leaves m-2 of land,crop growth rate,net assimilation rate,and leaf area index.Furthermore,the B3 rice population was marked by a higher grain–leaf ratio,as well as a lower export ratio and transport ratio of biomass per stem-sheath.A quadratic function predicted that 260-290 seedlings m-2 is the optimum seedling density for achieving maximum yield.Together,these results suggested that appropriately increasing the seedling density,and thereby increasing the proportion of panicles formed by the main stem,is an effective approach for obtaining a higher yield in DDR sown using a multifunctional seeder in a rice–wheat rotation system.

Effects of Variety and Planting Density on Mung Bean Eco-Physiology and Yield in the Southeastern US

Mung bean (Vigna radiata L. Wilczek.) is a warm-season, C3 pulse crop of the legume family that has been widely cultivated in Asian countries. As the demand for mung bean continues to increase in the United States, the ecophysiology, growth, and yield of mung bean varieties in the southeastern US need to be assessed. A field experiment was conducted at the Agricultural Research and Education Center of Tennessee State University to investigate the effects of four varieties (OK2000, Berken, TSU-1, AAMU-1) and three planting densities (5, 10, and 15 cm spacing) on the ecophysiology and yield of mung bean. Results showed that the relative chlorophyll content, plant height, pod dry biomass, pod number, crop yield, and harvest index significantly varied among the varieties. Density only influenced transpiration, relative chlorophyll content, and plant dry biomass. OK2000 had 101.0% more pods per plant and a 42.4% higher harvest index and produced a 45.3% higher yield than other varieties, but no significant difference in yield was found among the other three varieties. This study demonstrated that the mung bean variety OK2000 with a high yield would be ideal for commercial production in the southeastern US.

The underlying mechanism of variety–water–nitrogen–stubble damage interactions on yield formation in ratoon rice with low stubble height under mechanized harvesting

Agronomic measures are the key to promote the sustainable development of ratoon rice by reducing the damage from mechanical crushing to the residual stubble of the main crop, thereby mitigating the impact on axillary bud sprouting and yield formation in ratoon rice. This study used widely recommended conventional rice Jiafuzhan and hybrid rice Yongyou 2640 as the test materials to conduct a four-factor block design field experiment in a greenhouse of the experimental farm of Fujian Agricultural and Forestry University, China from 2018 to 2019.The treatments included fertilization and no fertilization, alternate wetting and drying irrigation and continuous water flooding irrigation, and plots with and without artificial crushing damage on the rice stubble. At the same time, a 13C stable isotope in-situ detection technology was used to fertilize the pot experiment. The results showed significant interactions among varieties, water management, nitrogen application and stubble status.Relative to the long-term water flooding treatment, the treatment with sequential application of nitrogen fertilizer coupled with moderate field drought for root-vigor and tiller promotion before and after harvesting of the main crop, significantly improved the effective tillers from low position nodes. This in turn increased the effective panicles per plant and grains per panicle by reducing the influence of artificial crushing damage on rice stubble and achieving a high yield of the regenerated rice. Furthermore, the partitioning of 13C assimilates to the residual stubble and its axillary buds were significantly improved at the mature stage of the main crop, while the translocation rate to roots and rhizosphere soil was reduced at the later growth stage of ratooning season rice. This was triggered by the metabolism of hormones and polyamines at the stem base regulated by the interaction of water and fertilizer at this time. We therefore suggest that to achieve a high yield of ratoon rice with low stubble height under mechanized harvesting, the timely application of nitrogen fertilizer is fundamental,coupled with moderate field drying for root-vigor preservation and tiller promotion before and after the mechanical harvesting of the main crop.

Calculation of microscopic nuclear level densities based on covariant density functional theory

In this study,a microscopic method for calculating the nuclear level density(NLD)based on the covariant density functional theory(CDFT)is developed.The particle-hole state density is calculated by a combinatorial method using single-particle level schemes obtained from the CDFT,and the level densities are then obtained by considering collective effects such as vibration and rotation.Our results are compared with those of other NLD models,including phenomenological,microstatisti-cal and nonrelativistic Hartree–Fock–Bogoliubov combinatorial models.This comparison suggests that the general trends among these models are essentially the same,except for some deviations among the different NLD models.In addition,the NLDs obtained using the CDFT combinatorial method with normalization are compared with experimental data,including the observed cumulative number of levels at low excitation energies and the measured NLDs.The CDFT combinatorial method yields results that are in reasonable agreement with the existing experimental data.

The Probability Density Function Related to Shallow Cumulus Entrainment Rate and Its Influencing Factors in a Large-Eddy Simulation

The process of entrainment-mixing between cumulus clouds and the ambient air is important for the development of cumulus clouds.Accurately obtaining the entrainment rate(λ)is particularly important for its parameterization within the overall cumulus parameterization scheme.In this study,an improved bulk-plume method is proposed by solving the equations of two conserved variables simultaneously to calculateλof cumulus clouds in a large-eddy simulation.The results demonstrate that the improved bulk-plume method is more reliable than the traditional bulk-plume method,becauseλ,as calculated from the improved method,falls within the range ofλvalues obtained from the traditional method using different conserved variables.The probability density functions ofλfor all data,different times,and different heights can be well-fitted by a log-normal distribution,which supports the assumed stochastic entrainment process in previous studies.Further analysis demonstrate that the relationship betweenλand the vertical velocity is better than other thermodynamic/dynamical properties;thus,the vertical velocity is recommended as the primary influencing factor for the parameterization ofλin the future.The results of this study enhance the theoretical understanding ofλand its influencing factors and shed new light on the development ofλparameterization.

Construction of a high-density SSR genetic linkage map and identification of QTL for storage-root yield and dry-matter content in sweetpotato

Sweetpotato(Ipomoea batatas(L.)Lam.)is a widely grown food crop especially in developing countries.Increasing storage-root yield and dry-matter content has been the main breeding objective of the crop,and DNA marker-assisted breeding is needed for this purpose.In this study,using a mapping population of 500 F1 individuals from a cross between Xushu 18(female)and Xu 781(male),we constructed a highdensity genetic linkage map of sweetpotato using 601 simple-sequence repeat(SSR)primer pairs.The Xushu 18 map contained 90 linkage groups with 5547 SSR markers and spanned 18,263.5 cM,and the Xu 781 map contained 90 linkage groups with 4599 SSR markers and spanned 18,043.7 cM,representing the highest genome coverage yet reported for sweetpotato.We identified 33 QTL for storage-root yield and 16 QTL for dry-matter content,explaining respectively 6.5%–47.5%and 3.2%–18.9%of variation.These results provide a foundation for fine-mapping and cloning of QTL and for marker-assisted breeding in sweetpotato.

Identification of tolerance to high density and lodging in short petiolate germplasm M657 and the effect of density on yield-related phenotypes of soybean

Soybean yield has traditionally been increased through high planting density,but investigating plant height and petiole traits to select for compact architecture,lodging resistance,and high yield varieties is an underexplored option for further improving yield.We compared the relationships between yield-related traits,lodging resistance,and petioleassociated phenotypes in the short petiole germplasm M657 with three control accessions during 2017–2018 in four locations in the Huang–Huai region,China.The results showed that M657 exhibited stable and high tolerance to high planting density and resistance to lodging,especially at the highest density(8×105 plants ha–1).The regression analysis indicated that a shorter petiole length was significantly associated with increased lodging resistance.The yield analysis showed that M657 achieved higher yields under higher densities,especially in the northern part of the Huang–Huai region.Among the varieties,there were markedly different responses to intra-and inter-row spacing designs with respect to both lodging and yield that were related to location and density.Lodging was positively correlated with planting density,plant height,petiole length,and number of effective branches,but negatively correlated with stem diameter,seed number per plant,and seed weight per plant.The yield of soybean was increased by appropriately increasing the planting density on the basis of the current soybean varieties in the Huang–Huai region.This study provides a valuable new germplasm resource for the introgression of compact architecture traits that are amenable to providing a high yield in high density planting systems,and it establishes a high-yield model of soybean in the Huang–Huai region.

Effect of Inorganic and Organic Fertilizers on Growth and Yield of Two Industrial Potato Varieties (Asterix and Courage) in Bangladesh

Potato is one of the most important vegetable crops, which contributes more than half of the total vegetable production in Bangladesh. Four field experiments were conducted in two different locations in Bangladesh to develop integrated nutrient management practices to produce quality potato seed in industrial processing varieties Asterix and Courage. For the inorganic trial, Factorial Randomized Complete Block Design (RCBD) including 2 potato varieties, 5 treatments with 4 replications, and in the organic fertilizer trial, Factorial RCBD including 2 potato varieties, 6 treatments with 4 replications were used. In the inorganic fertilizer trail, the highest yield was obtained in the variety Asterix due to Nitrogen, Phosphorus, Potassium, and Sulfur (NPKS) plus Magnesium treated plot in Domar BADC farm and due to NPKS plus Boron, Zinc, and Magnesium treated plots in Kashimpur Farm. In the case of variety Courage, the highest yield was found in the treatment of NPKS plus Zinc in Domar BADC farm while in Kashimpur farm, NPKS plus Mg treated plots had the highest yield of potato variety-Courage. In the organic fertilizer trail, the highest tuber yield per hill was obtained by applying the government-approved commercial brand Northern organic fertilizer in variety Asterix and by organic fertilizer brand Chook Chook in variety Courage. Parameters such as days to tuber initiation, number of stems per hill, plant height, and number of tubers per hill were found statistically different among the treatments and between the two varieties. Treatments namely Northern organic fertilizer and Cowdung combined with mustard oil cake performed better considering standard grade tuber yield (grade A and B) compared to other treatments. Hence, the combination of NPKS MgZn and either Northern organic or Chook Chook or Cowdung plus mustard oil cake could be used to grow the varieties Asterix and Courage.

Effect of Planting Date on Yield and Yield Components of Grain Sorghum Hybrids

In Kansas, productivity of grain sorghum [Sorghum bicolor (L.) Moench] is affected by weather conditions at planting and during pollination. Planting date management and selection of hybrid maturity group can help to avoid severe environmental stresses during these sensitive stages. The hypothesis of the study was that late May planting improves grain sorghum yield and yield components compared with late June planting. The objectives of this research were to investigate the influence of planting dates yield and yield components of different grain sorghum hybrids, and to determine the optimal planting date and hybrid combination for maximum biomass and grains production. Three sorghum hybrids (early, medium, and late maturing) were planted in late May and late June without irrigation in Kansas at Manhattan/Ashland Bottom Research Station, and Hutchinson in 2010;and at Manhattan/North Farm and Hutchinson in 2011. Data on dry matter production, yield and yield components were collected. Grain yield and yield components were influenced by planting date depending on environmental conditions. At Manhattan (2010), greater grain yield, number of heads per plant, were obtained with late-June planting compared with late May planting, while at Hutchinson (2010) greater yield was obtained with late May planting for all hybrids. The yield component most affected at Hutchinson was the number of kernels∙panicle−1 and plant density. Late-May planting was favorable for late maturing hybrid (P84G62) in all locations. However, the yield of early maturing hybrid (DKS 28-05) and medium maturing hybrid (DKS 37-07) was less affected by delayed planting. The effects of planting dates on yield and yield components of grain sorghum hybrids were found to be variable among hybrid maturity groups and locations.

Effect of Different Mulch Materials on Yield and Nutrition Profile of Common Capsicum (Capsicum annuum) Cultivars in Bangladesh

Capsicum is a nutritious vegetable and its cultivation in farms is getting popular in Bangladesh. Although many efforts have lain to explore better yielding and nutritionally rich cultivars with suitable modern cultivation techniques but still have to find the desired outcome. Thus, it’s necessary to conduct further research to identify the high-yielding and nutritious capsicum cultivars in Bangladesh. An experiment was conducted from July 2021 to June 2022 at the Bangladesh Institute of Research and Training on Applied Nutrition (BIRTAN) research field with three cultivars of capsicum: B0 = California Wonder, B1 = BARI Misti Morich-1 and B2 = BARI Misti Morich-2 and three mulching: T0 = No mulching, T1 = Water hyacinth, T2 = Poly Mulching in randomized complete block design with three replications to identify better quality capsicum cultivar and suitable mulching material. Among cultivars the BARI Misti Morich-2 (B2) showed increased agronomic parameters like number of branches and effective branches per plant, leaves length and width, consequently yield and yield contributing traits were also enhanced like fruits per plant, fruit length, fruit diameter and yield per plant (25.97%, 4.54%, 3.64% and 21.43%, respectively). Poly Mulching (T2) increased agronomic traits, yield traits and yield (0.61 kg) than BARI Misti Morich-1 (T1). The combined effect of B2T2 increased the number of branches per plant, effective branches per plant, leaves length and breadth by 40%, 90%, 15.57% and 26.22%, respectively, hence resulting in an increased yield of 20%. BARI Misti Morich-2 cultivar showed an increase in Fe, Zn and Vitamin-C content of 26.24% and 23.10%, 8.82% and 5.14%, and 6.03% and 5.74% than B0 and B1 cultivars, respectively. Therefore, BARI Misti Morich-2 exhibited the improved agronomic, yield and nutritional traits of capsicum under poly mulching among other cultivars in Bangladesh.

Genetic and Agronomic Parameter Estimates of Growth, Yield and Related Traits of Maize (Zea mays L.) under Different Rates of Nitrogen Fertilization

This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha−1) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha−1 plots exhibiting the lowest and highest grain yields of 1238 kg∙ha−1 and 2098 kg∙ha−1, respectively. Variety and nitrogen effects on partial factor productivity (PFPN), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFPN (41.3 kg grain kg−1∙N) and AEN (29.4 kg grain kg−1∙N) were obtained in the 30 kg∙N∙ha−1 plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL−1 spent on N) were obtained in the 180 kg∙N∙ha−1. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.

Estimating the yield stress of soft materials via laser-induced breakdown spectroscopy

Taking three typical soft samples prepared respectively by loose packings of 77-,95-,and 109-μm copper grains as examples,we perform an experiment to investigate the energy-dependent laser-induced breakdown spectroscopy(LIBS)of soft materials.We discovered a reversal phenomenon in the trend of energy dependence of plasma emission intensity:increasing initially and then decreasing separated by a well-defined critical energy.The trend reversal is attributed to the laser-induced recoil pressure at the critical energy just matching the sample's yield strength.As a result,a one-to-one correspondence can be well established between the samples'yield stress and the critical energy that is easily obtainable from LIBS measurements.This allows us to propose an innovative method for estimating the yield stress of soft materials via LIBS with attractive advantages including in-situ remote detection,real-time data collection,and minimal destructive to sample.

Effect of Variety and Plant Spacing on Growth and Yield of Groundnuts (Arachis hypogaea L.)

A field experiment was carried out to determine the effect of variety and plant spacing on yield and growth of groundnuts. The field experiment was laid in a 3 × 3 factorial experiment in a Randomized Complete Block Design (RCBD) with three (3) replications. The factor A included three (3) groundnut varieties (Nkatie Sari, Sum Nutt 22 and Yenyawoso) and Factor B was the three (3) spacing of 30 cm × 15 cm, 30 cm × 30 cm and 30 cm × 40 cm. All recommended agronomic practices were followed. Data was collected from eight (8) tagged plants. Growth data were recorded on plant height, number of branches, number of leaves, and the number of flowers while yield data were collected on the number of flowers, number of pods per plant, 100 seeds weight and the pod yield (kg/ha). The plant spacing significantly influenced (P < 0.05) the growth and yield parameters. Groundnut grown at a spacing of 30 cm × 15 cm produced the maximum plant height, whereas the maximum number of leaves, number of branches and number of flowers were produced from 30 cm × 40 cm. Yenyawoso variety with a wider plant spacing performed better vegetatively among all the varieties. The Yenyawoso variety produced the highest number of pods, 100 seeds weight and pod yield as compared to the other varieties. Also, Yenyawoso at 30 cm × 40 cm spacing and Nkatie Sari at 30 cm × 15 cm spacing produced the maximum pod yield.

Manure substitution improves maize yield by promoting soil fertility and mediating the microbial community in lime concretion black soil

Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidification,groundwater contamination and biodiversity reduction.Meanwhile,organic substitution has received increasing attention for its ecologically and environmentally friendly and productivity benefits.However,the linkages between manure substitution,crop yield and the underlying microbial mechanisms remain uncertain.To bridge this gap,a three-year field experiment was conducted with five fertilization regimes:i)Control,non-fertilization;CF,conventional synthetic fertilizer application;CF_(1/2)M_(1/2),1/2 N input via synthetic fertilizer and 1/2 N input via manure;CF_(1/4)M_(3/4),1/4 N input synthetic fertilizer and 3/4 N input via manure;M,manure application.All fertilization treatments were designed to have equal N input.Our results showed that all manure substituted treatments achieved high soil fertility indexes(SFI)and productivities by increasing the soil organic carbon(SOC),total N(TN)and available phosphorus(AP)concentrations,and by altering the bacterial community diversity and composition compared with CF.SOC,AP,and the soil C:N ratio were mainly responsible for microbial community variations.The co-occurrence network revealed that SOC and AP had strong positive associations with Rhodospirillales and Burkholderiales,while TN and C:N ratio had positive and negative associations with Micromonosporaceae,respectively.These specific taxa are implicated in soil macroelement turnover.Random Forest analysis predicted that both biotic(bacterial composition and Micromonosporaceae)and abiotic(AP,SOC,SFI,and TN)factors had significant effects on crop yield.The present work strengthens our understanding of the effects of manure substitution on crop yield and provides theoretical support for optimizing fertilization strategies.

Molecular Mechanism of Rice Necrotic Lesion for Optimized Yield and Disease Resistance

How to balance rice resistance and yield is an important issue in rice breeding.Plants with mutated necrotic lesion genes often have persistent broad-spectrum resistance,but this broad-spectrum resistance usually comes at the expense of yield.Currently,many necrotic lesion mutants in rice have been identified,and these genes are involved in disease resistance pathways.This review provides a detailed introduction to the characteristics,classification,and molecular mechanisms of necrotic lesion formation.Additionally,we review the molecular regulatory pathways of genes involved in rice disease resistance.Concurrently,we summarize the relationship between resistance and yield in rice using newly developed gene editing methods.We discuss a rational and precise breeding strategy to better utilize molecular design technology for breeding disease-resistant and high-yield rice varieties.