Rate Of Dry Matter Accumulation Research Articles

Magnesium fertilizer application increases peanut growth and pod yield under reduced nitrogen application in southern China

This study investigated the effect of magnesium application on peanut growth and yield under two nitrogen (N) application rates in acidic soil in southern China. The chlorophyll content, net photosynthetic rate and dry matter accumulation of the N-sensitive cultivar decreased under reduced N treatments, whereas no effect was observed on the relevant indicators in the N-insensitive variety GH1026. Mg application increased the net photosynthetic rate by increasing the expression of genes involved in chlorophyll synthesis and Rubisco activity in the leaves during the pegging stage under 50%N treatment, while no effect on the net photosynthetic rate was observed under the 100%N treatment. The rate of dry matter accumulation at the early growth stage, total dry matter accumulation and pod yield at harvest increased after Mg application under 50%N treatment by increasing the transportation of assimilates from stems and leaves to pods in both peanut varieties, whereas no effect was found under 100%N treatment. Moreover, Mg application increased the NUE under 50%N treatment. No improvement of NUE in either peanut variety was found under 100%N treatment, while Mg application under the 50%N treatment can obtain a higher economic benefit than the 100%N treatment. In acidic soil, application of 307.5 kg ha−1 of Mg sulfate fertilizer under 50% reduced nitrogen application is a suitable fertilizer management measure for improving carbon assimilation, NUE and achieve high peanut yields in southern China.

Crossing latitude introduction delayed flowering and facilitated dry matter accumulation of soybean as a forage crop

Grain soybean [Glycine max (L.) Merr] shows potential as a forage crop following introduction from low to high due to the growth phenotype alteration. However, the application of this approach is impeded by the diverse ecological types of soybeans, their adaptability to the introduction, and the uncertainty surrounding the growth phenotype post-introduction. In this study, 24 grain soybean varieties from low-latitude regions (22-31°N) were introduced to the high-latitude northwestern Loess Plateau (39°N) between 2018 and 2019. The growth phenotypes were observed, and their forage productivity potential was assessed. All varieties displayed delayed flowering following cross-latitude introduction, with the vegetative growth phase of some varieties even exceeding their entire growth duration at their origin. Rapid dry matter accumulation rates were indicative of growth adaptation performance and formed the basis for soybean forage yield. Varieties from the tropical south China region exhibited significant yield advantages, with dry matter yields of 8.97-14.68 t ha-1 and crude protein yields of 1.44-2.51 t ha-1. Varieties HX3 and GX7, originating from this region, demonstrated optimal growth adaptability and productivity in the cross-latitude environment, achieving the highest dry matter yields of 14.68 and 13.86 t ha-1, respectively. As a result, HX3 and GX7 are recommended for local farming systems to provide high-quality forage. The cross-latitude introduction of soybean is proposed as a viable and efficient strategy for forage improvement and application.

Integrated application of fertilization and reduced irrigation improved maize (Zea mays L.) yield, crop water productivity and nitrogen use efficiency in a semi-arid region

Water scarcity as well as soil degradation and environmental problems potentially caused by excessive application of chemical fertilizers are major challenges to agricultural production in semi-arid areas. It is crucial to explore a suitable and eco-friendly strategy to achieve sustainable production of maize with high crop water productivity and nitrogen use efficiency. Here, a two-year field experiment with three irrigation levels of W1 (220 mm), W2 (140 mm) and W3 (60 mm), and five fertilization types of no fertilizer (CK), chemical fertilizer (CF), bio-fertilizer combined with CF (CFB), organic fertilizer combined with 70% CF (CFO) and bio-fertilizer combined with CFO (CFOB) was conducted to investigate the effect on dry matter, N uptake and remobilization, grain yield, crop water productivity, nitrogen use efficiency and economic benefits of maize in 2021 and 2022. The results showed that the W2 and W3 decreased in the leaf area index, photosynthetic rate, dry matter accumulation, the maximum dry matter accumulation rate and actual crop evapotranspiration. Under W1 condition, the CFB improved the growth of maize, increased the dry matter and nitrogen accumulation and yield, with 8.1% and 7.4% higher than CF in 2021 and 2022, respectively. Under deficit irrigation (W2 and W3), CFOB significantly increased the leaf area index, photosynthetic rate, dry matter accumulation at later growth stage, in addition, CFOB increased the post-silking N uptake and the percentage in total N content, finally improved the grain yield with 23.8% and 22.8% under W2, 22.5% and 25.7% under W3 higher than that of the CF in 2021 and 2022, respectively. Irrigation and fertilizer showed a coupling effect on grain yield, crop water productivity, agronomy efficiency and nitrogen use efficiency. Overall, the CFOB under moderate deficit (W2) exhibited the highest water productivity, nitrogen use efficiency and economic benefits, as well as maintained the high yield, could be a promising approach to sustainable development of local maize.

Effect of Different Weed Management Practices on Growth Characters of Chickpea in Mid-hills of Himachal Pradesh, India

Chickpea (Cicer arietinum) is one of the most important pulse legumes in many parts of the world. India is largest producer of chickpea in the world, sharing 65 and 70 % of the total global area and production, respectively. Different weed control practices use of herbicides were followed for better management. Application of herbicide at critical growth stages followed by one or two hand weeding at proper time or manipulation of row spacing for improving the weed suppressing effect of crops gives marginal improvement in crop yield. A field experiment titled “Effects of Different Weed Management Practices on Growth Characters of Chickpea in Mid-hills of Himachal Pradesh” was conducted during rabi season of 2022 at Chamelti Agriculture Farm, MS Swaminathan School of Agriculture, Shoolini University of Biotechnology and Management Sciences, Solan. The soil of the experimental field was sandy loam in texture, slightly alkaline in reaction with EC in a safer range, medium in organic carbon, available nitrogen, potassium, and high in available phosphorus. The experiment was laid out in randomized block design with three replications comprising ten weed management treatments viz. (T1) One hand weeding at 20 DAS, (T2) Two hand weeding at 20 and 40 DAS, (T3) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE), (T4) Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS, (T5) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE) + One hand weeding at 30 DAS, (T6) Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS + One hand weeding at 40 DAS, (T7) Fenoxaprop-p-ethyl 9.3 EC @ 60 g ha-1 (PoE) at 25 DAS + One hand weeding at 40 DAS, (T8) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE) + Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS, (T9) Weed free and (T10) Weedy Check. The recommended dose of fertilizer (30:60:30 kg ha-1) was applied through Urea, SSP, and MOP at the time of sowing. PBG-7 variety of chickpea was used for sowing. Weed management practices were done as per treatment. Other crop management practices were followed as per the recommendation of the area. Application of (T8) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE) + Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS registered higher growth parameters viz. plant height, number of branches plant-1, dry matter accumulation and crop growth rate. Thus, study suggest that chickpea can successfully grown under Mid-hills of Himachal Pradesh on (T8) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE) + Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS.

Impact of foliar applied nano-urea on growth, productivity and profitability of hybrid rice (Oryza sativa L.)

In lowland rice cultivation, the application of conventional urea fertilizer provides low N to rice plants and exhibits low N use efficiency (~ 30%) due to greater loss of N. Hence the present study hypothesized that nano-urea spray could fulfil N requirement of rice plants and thereby produce high yields. So, a field experiment was conducted on hybrid rice (cv. Arize-6444 Gold) at Regional Research Sub-Station, BCKV, Chakdaha, Nadia under new alluvial zone (NAZ) of West Bengal during winter (rabi) season of 2021-22 to assess the effect of nano-urea on growth attributes, yield components, yield, nutrient uptake and economics of hybrid rice.The experiment was laid out in randomized complete block design with six treatments [T1:100% RDN i.e. 150 kg ha-1 through urea, T2:100% N(Urea) + 2 foliar spray of nano-urea, T3:75% N (Urea) + 2 foliar spray of nano-urea, T4:50% N(Urea) + 2 foliar spray of nano-urea, T5:125% N (Urea) + 2 foliar spray of nano-urea, T6:Control], each replicated four times. All the treatments were consisted of a uniform recommended dose of 100% P and K (each of 80 kg ha-1) supplied through SSP and MOP, respectively, except for T6 (control). In each treatment, foliar spray was done with IFFCO nano-urea @ 4ml litre-1 of water twice at active tillering stage and panicle initiation stage. Results of the present experiment revealed that growth parameters of tested hybrid rice namely plant height, LAI, dry matter accumulation and crop growth rate registered better result under treatment T2 than other treatments. As expected, the above-mentioned growth attributes were lowest on receiving T6 treatment at almost all dates of observation. Among yield attributes of hybrid rice, number of panicles m-2(392), panicle length (32.46 cm) and panicle weight (5.58 g) were highest with treatment T5, while filled grains panicle-1(194) and 1000-grain weight (24.18 g) were maximum for T2 treatment. Highest grain yield (7.15 t ha-1) and HI (50.71%) of hybrid rice were obtained with T2 treatment, while the highest straw yield (7.20 t ha-1) was obtained with T5 treatment. The treatment T2 resulted in highest grain N (1.48%) and K (0.21%) content. Total cost of cultivation was highest in T5 (Rs. 77712 ha-1), but net return (Rs. 43720 ha-1) as well as B:C ratio (1.57) was highest for T2 treatment. Hence, the application of 100% RDN in conjunction with nano-urea spray twice at 25 and 50 DAT has been effective for higher productivity and profitability of hybrid rice cultivation.

The effects of high temperature, drought, and their combined stresses on the photosynthesis and senescence of summer maize

Global climate change has significantly increased the frequency and intensity of high temperature and drought stresses. Additionally, the high temperature and drought are often concurred, which make the situation of maize production tougher. However, the influence of the combined stresses of high temperature and drought on summer maize production remains uncertain. The study aimed to investigate the effects of high temperature, drought, and their combined stress at different growth stages on photosynthetic and senescence characteristics of summer maize. Denghai 605 (DH605) was used as the experimental material. High temperature (T), drought (D), and their combined stress (T-D) for 6 days were set at the 3rd leaf stage, 12th leaf stage, and tasseling stage, respectively. The natural temperature and normal water management were used as the control (CK). The results showed that high temperature, drought, and their combined stress at different growth stages decreased the activities of antioxidant enzymes and soluble protein content in leaves, leading to increases in MDA content and damage to cell membranes, which accelerated the senescence of the plant. Accordingly, the activities of RuBPcase and PEPCase were decreased, indicating the abilities of plants to harvest and utilize light energy declined due to high temperature, drought, and combined stresses at different growth stages. As a result, the Pn and thus, the dry matter accumulation rate were decreased by these stresses. In addition, the translocation of dry matter to ears was impeded by stresses, especially by the high temperature at the VT stage. While, high temperatures concurred with drought aggravated the adverse effects on summer maize, compared with single stresses. Significantly, high temperature, drought, and their combined stresses at the VT stage decreased the yield mostly, followed by stresses at the V12 stage, and then by stresses at the V3 stage. Compared with CK, the yield of VT-T-D, V12-T-D, and V3-T-D were decreased by 61.6 %, 13.7 %, and 10.4 %, respectively. As global climate change is unstoppable, the superimposed changes of various meteorological factors make the growth conditions for crop production extreme. Studies to explore the combined effects of two or even more meteorological factors on crop growth are becoming more and more important. This study fulfilled the current knowledge gap of the combined stresses on maize production, however, the underlying mechanisms should be dug out in the future.

Effects of Combined Application of Organic Fertilizer on the Growth and Yield of Pakchoi under Different Irrigation Water Types

The long-term utilization of inorganic fertilizers in pakchoi cultivation can result in increased nitrate levels, potentially posing health risks to human consumers. For this study, we investigated the efficacy of organic fertilizers as a promising alternative for enhancing soil structure, improving fertility, and increasing the yield of pakchoi. A two-year field trial was conducted from 2022 to 2023 to examine the effects of the combined application of organic fertilizer on the growth and yield of pakchoi. Three types of irrigation water, namely fresh water (F), brackish water (B), and magnetized–ionized brackish water (MIB), were used in combination with five different organic fertilizer rates (0, 20, 40, 60, and 80 kg/ha, denoted as 0, 1, 2, 3, and 4). The results revealed that treatments F2, F3, B2, B3, and MIB3 significantly improved the growth indexes of pakchoi. Notably, treatments F3, B3, and MIB3 resulted in an earlier onset of the fast growth period for leaf area index and fresh weight. During this period, we observed the highest cumulative growing degree days (ΔCGDD) values, which were 628.36 °C for plant height (MIB4), 475.01 °C for leaf area index (B3), 259.73 °C for fresh weight (B3), and 416.82 °C for dry matter accumulation (B3). The logistic model indicated an increase in eigenvalue at an organic fertilizer application rate of 60 kg/ha, while excessive fertilization had inhibitory effects. Under brackish water irrigation, both plant height and leaf area index demonstrated significant positive effects on yield, with plant height having a particularly noteworthy direct effect at a coefficient of 0.935. MIB water irrigation demonstrated superior advantages for promoting pakchoi growth, leading to significantly higher rates of fresh weight and dry matter accumulation compared to traditional brackish water irrigation. The maximum value of each growth index exerted a significant direct influence on its respective growth parameter, whereas ΔCGDD demonstrated a relatively smaller or potentially negative effect. Applying organic fertilizer appropriately can assist in the production of pakchoi and provide a scientific basis for increasing yield.

Growth rates and nutrient accumulation in aerial biomass of sunn hemp juncea and spectabilis sown in spring

Crotalaria juncea and spectabilis have been widely used in green manuring, mainly due to the fact that they incorporate large amounts of N into the soil, through biological fixation of atmospheric N2, and also because they have a vigorous and branched root system, characteristics that help to recycle nutrients from the deeper layers of the soil. The present work was carried out in the municipality of Mercês, in the Mata Mineira area. Growth rates and nutrient accumulation were evaluated in the aerial part of sunn hemp and sunn hemp, grown in soil with good nutrient availability. The soil in the chosen area had good fertility, with no exchangeable aluminum in the 0 to 20 cm layer. Soon after the first spring rains, the soil was subsoiled, plowed, and harrowed, and the study was then installed, conducted in an experimental design in randomized blocks with five replications. The plots consisted of six furrows of five meters in length with 0.50 meters of spacing. Sowing was carried out in the first week of October. Evaluations of dry matter accumulation and plant height were carried out in the four central furrows of the plots, at 30; 45; 60; 75; 90 and 105 days after emergence (D.A.E.), with a sample area of 1.0 m of furrow (0.5 m2). In the biomass collected at 105 D.A.E, phenological stage of grain filling, the contents of nitrogen, phosphorus, potassium, calcium, magnesium and sulfur were determined, with the objective of quantifying the accumulation of these elements in the aerial part of sunn hemp. The results obtained in this edaphoclimatic environment led to the conclusion that sunn hemp juncea had faster vegetative development than sunn hemp spectabilis, therefore, a plant with greater soil protection potential against the impact of raindrops than sunn hemp spectabilis. Although they have very different growth rates, both for sunn hemp and sunn hemp, the highest rates of growth and dry matter accumulation in the shoots occurred in the periods from 45 to 60 D.A.E., with mean values, respectively, of 406, 7 and 140.0 kg per hectare per day. The accumulation of dry matter in the aerial part, as a function of the age of the plants, can be described by the quadratic equation, y = 0.0024 x2 + 0.5267x -11.8086 (R2= 0.9888), for sunn hemp, and y = 0.0008 x2 + 0.2003x -4.4657 (R2= 0.9928), for sunn hemp spectabilis. For the adopted production system, and in this climatic environment, sunn hemp was a better recycled/fixing plant than sunn hemp spectabilis, thus, green manuring with sunn hemp was more advantageous than with sunn hemp spectabilis.

Optimized N application improves N absorption, population dynamics, and ear fruiting traits of wheat.

Optimizing the N application amount and topdressing ratio can increase crop yield and decrease N loss, but its internal mechanisms have not been well studied, especially from the aspects of population dynamics and structure, ear fruiting traits. Here, field experiments, with three N rates 120 (N1), 180 (N2), and 240 (N3) kg N ha-1 and three N topdressing ratios T1 (7:3), T2 (6:4), and T3 (5:5) were conducted. At the same N level, results showed that the N accumulation amounts in the leaf, grain, and plant in T2 were higher than in T3 and T1, and increasing 60 kg N ha-1 (N3 compared to N2, N2 compared to N1) significantly enhanced N accumulation amounts. The effect of the N topdressing ratio on partial factor productivity of applied N was consistently T2 > T3 > T1, but T1 was more conducive to improving N utilization efficiency for grain and biomass production. After the jointing stage, compared to T1 and T3, T2 was more conducive to increasing the population growth rate of plant height, leaf area index, leaf area growth rate, dry matter weight, dry matter accumulation rate, light interception rate, and spikelets of population, and the above-mentioned indexes of population could be significantly enhanced by increasing 120 kg N ha-1. T2 increased the fruiting spikelets per ear, grains per ear, grain weight per ear, fruiting rate per ear, grain filling rate per ear, and yield but decreased the sterile spikelets at the top and bottom and imperfect grains per ear. Increasing N from 120 kg ha-1 to 180 kg ha-1 or from 180 kg ha-1 to 240 kg ha-1 significantly enhanced yield. The N accumulation amount in the grain, leaf, plant, leaf area growth rate, dry matter accumulation rate, light interception rate, population spikelets, fruiting spikelets per ear, grain filling rate, and yield were significantly positively correlated with each other. This study demonstrates a suitable N application rate with a N topdressing ratio 6:4 would more effectively improve N efficiency, population dynamics, structure, ear fruiting traits, and yield, but the effect of the N topdressing ratio is not as significant as that of increasing 60 kg N ha-1.

Potassium Increases Nitrogen and Potassium Utilization Efficiency and Yield in Foxtail Millet

Field experiments were conducted to investigate the effects of K application on the nitrogen and potassium utilization efficiency and yield of foxtail millet (Setaria italica L.). The experiment was performed with a completely randomized design with two millet cultivars (Jingu 21 and Zhangza 10) and five K2O rates (0, 60, 120, 180, and 240 kg/hm2) in 2020 and 2021. We found that K promoted K and N absorption; significantly increased dry matter (DM), N, and K accumulation in millet organs; caused dry matter accumulation to peak earlier; and increased the DM accumulation rate. In addition, K accumulation preceded that of DM or N. Relative to the crop cycle, most K (61.07%) accumulated at booting, whereas N accumulated mostly (33.86%) during grain filling. N absorption efficiency increased by 31.87%, and the apparent and agronomic utilization rate of K fertilizer remained high, increasing millet yield, which peaked at a K rate of 180 kg/hm2 for both cultivars, by 29.91% and 31.51% in Jingu 21 and Zhangza 10, respectively, relative to untreated controls. Stepwise regression and path analysis showed that the leaf and spike K accumulation, stem N accumulation, and stem DM were the main factors affecting yield, with DM having the greatest direct effect, followed by leaf K accumulation. The K concentration (0.77–3.04%) in Zhangza 10 was higher than that in Jingu 21 (0.69–2.91%) in untreated plants. Under the same K application rate, N and K accumulation and the harvest index were higher for Zhangza 10 than those for Jingu 21, and the nutrient utilization ability was greater for Zhangza 10. The results demonstrated that rational K fertilizer application can increase K concentration and accumulation in leaves, promote N metabolism and accumulation, increase N and K utilization efficiency, and improve DM accumulation and millet yield.

Relationship between Seed Properties and Outcome Components for Selection Criteria of Corn (Zea Mays L.) Products at Various Dosages of Popostium Fertilizer

This research was conducted to determine the relationship between seed developmental characteristics and yield components in a population of maize (Zea mays L.) grown at different potassium fertilizer rates. The information could be utilized as alternative selection criteria for maize genotypes with high-yielding potential. This research was conducted at the Experimental field of the Horticulture Seed Agency, Pekanbaru. Seven maize genotypes with four potassium fertilizer rates were grown in a 350 cm x 200 cm experimental plot with three replications. The genotypes used were Bisi 228. Pertiwi 3. Bisi 2. Decoral, Bisi 18. Betras 4. and Srikandi. Potassium fertilizer rates included 30 kg, 50 kg, 70 kg, and 90 kg per ha, respectively. Traits observed were plant height, tesseling flowering date, silking date, seed dry accumulation rate, effective seed filling period, cob length, cob weight, number of seed rows, number of seeds per cob, seed weight per cob, the weight of 100 seeds and seed yield per m2. Analysis of variance was performed to the data using SAS and further tested by honesty significant difference at 5% level. Variance component, heritability, genetic correlation coefficient, and selection response were calculated for all characters and effective seed filling duration. The results indicated that the genetic variance component was significant for all characters except for the dry matter accumulation rate. All characters' heritability values were quite high except for effective seed-filling duration and the number of seeds per cob. Phenotypic correlation coefficients were positively significant between seed yield per m2 and plant height, seed development rate, cob length, ear weight, number of seeds per ear, seed weight per ear, and weight of 100 seeds. The genetic correlations was significant between seed yield per m2 and plant height, seed development rate, number of seeds per ear, and seed weight per ear. All characters' direct selection response value is higher than the indirect selection response value.

Plant Photosynthesis and Dry Matter Accumulation Response of Sweet Pepper to Water–Nitrogen Coupling in Cold and Arid Environment

In order to optimize the water and nitrogen management mode and realize the efficient scale production of sweet pepper, from 2021 to 2022, field experiments on sweet pepper cultivation with different water and nitrogen coupling modes were conducted in the Hexi Oasis irrigation areas. The regulation effects of the water–nitrogen coupling mode on the dry matter accumulation characteristics, photosynthesis, yield, and water–nitrogen utilization efficiency of sweet pepper were further discussed. Irrigation was set for full irrigation (W1, 75–85% FC [field capacity]), mild (W2, 65–75% FC), and moderate (W3, 55–65% FC) water deficit levels. Three levels of nitrogen were applied, high (N1, 300 kg·ha−1), medium (N2, 225 kg·ha−1) and low (N3, 150 kg·ha−1), with full irrigation and no nitrogen application used as the control (CK). The results showed that the appropriate water–nitrogen coupling mode could enhance the photosynthetic rate, increase dry matter accumulation and the accumulation rate, advance the days of a maximum rate of dry matter accumulation, and improve yield and water–nitrogen utilization efficiency. N1W1 had the greatest dry matter accumulation, the mean rate and the maximum increase rate of dry matter accumulation in sweet pepper, which was not a significant difference from N2W2, but significantly increased by 19.61%, 19.67%, and 23.45%, respectively, compared with CK. Water deficit significantly advanced the days of a maximum rate of dry matter accumulation. The days of a maximum rate of dry matter accumulation appeared 1.18–5.79 days earlier at W3 than at W2 and W1, and the maximum rate appeared gradually later with increasing irrigation. The net photosynthetic rate, the transpiration rate, and stomatal conductance of N2W2 sweet pepper showed the best performance at all growth stages, significantly increasing by 23.87%, 27.71%, and 27.39%, respectively, compared with CK. Moreover, the Intercellular CO2 concentration was significantly reduced by 14.77% in N2W2 compared to CK. The N2W2 had the highest yield, water use efficiency, and irrigation water use efficiency of sweet pepper, significantly increasing 26.89%, 33.74%, and 31.22% compared to CK. Excessive water and nitrogen dosage reduced nitrogen partial factor productivity, while an appropriate increase in irrigation under reduced nitrogen conditions facilitated the water nitrogen potential. Passage path analysis further showed that water–nitrogen coupling promotes plant biomass formation and distribution by increasing photosynthetic assimilation capacity, ultimately increasing yield. Therefore, the N2W2 treatment (65–75% FC, 225 kg·ha−1) is the ideal water and nitrogen mode for obtaining higher yields and water and nitrogen use efficiency of sweet pepper in a cold and arid environment.

Differences in Dry Matter Accumulation and Distribution Patterns between Pre-Elite Seed and Certified Seed of Virus-Free Potato

Virus-free seed potatoes are generally divided into pre-elite seeds and certified seeds. To study the differences in dry matter accumulation and distribution between pre-elite seeds and certified seeds through a field randomized block two-factor experiment, pre-elite seeds and certified seeds of four varieties were selected to explore the differences in growth characteristics between the two levels of virus-free potatoes and to find a way to improve potato seed expansion efficiency. The results showed that the growth process of pre-elite seeds was slower and the growth period was longer than certified seeds. The dry matter accumulation of pre-elite seeds in various organs was lower than in certified seeds, and the distribution ratio in the roots and stems of each variety was also lower than the certified seed, while there was no significant difference in the leaf and tuber distribution ratio. The average dry matter accumulation rate in both pre-elite and certified seeds was sorted by size of tubers > leaves > stems > roots; however, it was significantly lower in pre-elite seeds than in certified seeds. Tuber fresh weight, tuber volume, tuber number, and the theoretical yield of certified seeds were higher than those of pre-elite seeds. Experiments have shown that appropriately prolonging the harvest time of virus-free potatoes, especially pre-elite seeds, and increasing the proportion of dry matter allocated to roots and stems by pre-elite seeds in the early growth stages can effectively increase yield.

Crop weather relationship in oilseed rape (Brassica napus) for north-west foothills of Himalayas, India

Agrometeorological indices have a strong correlation with growth, yield attributes and yield of crop and can be effectively used to select suitable cultivar for specific environmental conditions. Therefore, to study the cumulative effect of weather variables in terms of agrometeorological indices on cultivars of oilseed rape (Brassica napus L.) sown under different sowing environments, field experiments were conducted at the research farm of Agrometeorology section, Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu, Jammu and Kashmir during winter (rabi) season of 2018–19 and 2019–20. The treatments were comprised of 3 sowing environments, viz. 42nd SMW (standard meteorological week), 44th SMW and 46th SMW along with 3 cultivars (GSL-1, ONK-1 and DGS-1) of oilseed rape in factorial randomized block design with 3 replications. The pooled data of 2 years revealed that allthe cultivars of oilseed rape sown in 42nd SMW accumulated higher growing degree days (GDD), photothermal units (PTU) and heliothermal units (HTU) with higher rate of dry matter accumulation in comparison to 44th SMW and 46th SMW sown crop. The agrometeorological indices, viz. GDD, PTU and HTU were significantly positively correlated with growth parameters, yield attributes and yield at vegetative stage, while, PTU and HTU were negatively correlated at reproductive stage of the crop. Due to the significant impact of weather variables, the seed yield of all the oilseed rape cultivars decreased when the sowing was delayed from 42nd SMW to 46th SMW during both the years. Among cultivars, GSL-1 recorded significantly higher seed yield followed by ONK-1 and DGS-1.

Effects of Spraying KH2PO4 on Flag Leaf Physiological Characteristics and Grain Yield and Quality under Heat Stress during the Filling Period in Winter Wheat.

As one of the most important wheat-producing areas in China, wheat is prone to heat stress during the grain filling period in the Huang-Huai-Hai Plain (3HP), which lowers yields and degrades the grain quality of wheat. To assess the effects of spraying potassium dihydrogen phosphate (KH2PO4) on the physiological traits in flag leaves and grain yield (GY) and quality under heat stress during the filling period, we conducted a two-year field experiment in the winter wheat growing seasons of 2020-2022. In this study, spraying water combined with heat stress (HT), 0.3% KH2PO4 (KDP), and 0.3% KH2PO4 combined with heat stress (PHT) were designed, and spraying water alone was used as a control (CK). The dates for the spraying were the third and eleventh day after anthesis, and a plastic film shed was used to impose heat stress on the wheat plants during the grain filling period. The results showed that spraying KH2PO4 significantly improved the chlorophyll content and net photosynthesis rate (Pn) in flag leaves compared with the non-sprayed treatments. Compared with CK, the Pn in HT decreased by 8.97% after heat stress, while Pn in PHT decreased by 7.44% compared to that of KDP. The activities of superoxide dismutase, catalase, and peroxidase in flag leaves were significantly reduced when the wheat was subjected to heat stress, while malonaldehyde content increased, and the enzyme activities were significantly enhanced when KH2PO4 was sprayed. Heat stress significantly decreased the contribution rate of dry matter accumulation (DM) after anthesis of wheat to grain (CRAA), whereas spraying KH2PO4 significantly increased the CRAA and harvest index. At maturity, the DM in CK was significantly higher than that in HT, KDP was significantly higher than PHT, and KDP had the highest DM. Compared with CK, the GY in KDP significantly increased by 9.85% over the two years, while the GY in HT decreased by 11.44% compared with that of CK, and the GY in PHT decreased by 6.31% compared to that of KDP. Spraying KH2PO4 after anthesis primarily helped GY by maintaining a high thousand grain weight to lessen the negative effects of heat stress on wheat. Moreover, heat stress significantly reduced protein concentration, wet gluten content, dough development time, and hardness index in grains of mature, while spraying KH2PO4 maintained a sufficient grain quality under the conditions of achieving higher yields. Overall, spraying KH2PO4 after anthesis could enhance the heat stress resistance of wheat and maintain the photosynthetic capacity of flag leaves, ensuring the dry matter production and reducing the negative effects on grain yield and quality in the 3HP.

Photosynthesis Product Allocation and Yield in Sweet Potato in Response to Different Late-Season Irrigation Levels.

Soil water deficit is an important factor affecting the source-sink balance of sweet potato during its late-season growth, but water regulation during this period has not been well studied. Therefore, the aim of this study was to determine the appropriate irrigation level in late-season sweet potato, and the effect of irrigation level on accumulation and allocation of photosynthetic products. In this study, two yield-based field trials (2021-2022) were conducted in which five late-season irrigation levels set according to the crop evapotranspiration rate were tested (T0: non-irrigation, T1: 33% ETc, T2: 75% ETc, T3: 100% ETc, T4: 125% ETc). The effects of the different irrigation levels on photosynthetic physiological indexes, 13C transfer allocation, water use efficiency (WUE), water productivity (WP), and the yield and economic benefit of sweet potato were studied. The results showed that late-season irrigation significantly increased the total chlorophyll content and net photosynthetic rate of functional leaves, in addition to promoting the accumulation of above-ground-source organic biomass (p < 0.05). The rate of 13C allocation, maximum accumulation rate (Vmax), and average accumulation rate (Vmean) of dry matter in storage root were significantly higher under T2 irrigation than under the other treatments (p < 0.05). This suggests that both non-irrigation (T0) and over-irrigation (T4) were not conducive to the transfer and allocation of photosynthetic products to storage roots in late-season sweet potato. However, moderate irrigation (T2) effectively promoted the source-sink balance, enhanced the source photosynthetic rate and stimulated the sink activity, such that more photosynthate was allocated to the storage sink. The results also showed that T2 irrigation treatments significantly increased yield, WUE and WP compared to T0 and T4 (p < 0.05), suggesting that moderate irrigation (T2) can significantly promote the potential of storage root production and field productivity. There was a close relationship between economic benefit and marketable sweet potato yield, and both were highest under T2 (p < 0.05), increasing by 36.1% and 59.9% compared with T0 over the two-year study period. In conclusion, irrigation of late-season sweet potato with 75% evapotranspiration (T2) can improve both the yield and production potential. Together, these results support the use of late-season water management in the production of sweet potato.

Allelopathy of Ricinus communis and light spectrum variation decrease emergence and growth of Cyperus rotundus

Weeds negatively influence agricultural production. However, those losses depend on weed specie, its time of emergence, and period of interference on agricultural crops. Synthetic herbicides are commonly used to control these plants species; however, they may cause damage to the environment, human beings and animals health, and this problem justify the need to develop alternative bioherbicides. To evaluate the allelopathic potential of Ricinus communis (Castor bean) and light spectrum variation on the emergence and growth of Cyperus rotundus L., a trial was carried out in a protected environment with 15% of brightness reduction at the Center for Agricultural and Environmental Sciences at the Paraíba State University. Four aqueous extract concentrations of R. communis leaves were tested (0, 5, 10, and 15%) and four light spectrums variations (white, purple, blue, and red lights). Variables such as emergence, length, dry matter accumulation and growth rates of shoots and root of C. rotundus seedlings were assessed. Data were analyzed by normality test, analysis of variance, polynomial regression, and averages test. Soot and root emergence, length, and dry matter accumulation of C. rotundus seedlings were reduced due to the allelopathy caused by R. communis aqueous extract leaves (15% concentration) and under purple or red light spectrum radiation.

Combining Controlled-Release Urea and Normal Urea to Improve the Yield, Nitrogen Use Efficiency, and Grain Quality of Single Season Late japonica Rice

Controlled-release urea (CRU) is widely adopted to improve yields and nitrogen use efficiencies (NUEs) in rice. However, there are few studies on the effects of the mixed application of CRU and normal urea (at different N ratios) on rice yield, nitrogen efficiency, and grain quality. A series of simplified fertilization modes (SFMs) were set up in 2018–2019. CRU with release periods of 80 days and 120 days were mixed with urea at N ratios of 7:3, 6:4, 5:5, 4:6, and 3:7 and applied during the rice-growing season. We determined the rice yield, dry matter accumulation, NUEs, and grain quality. The yields of SFM_80_6/4 (CRU with release periods of 80 days were mixed with urea at N ratios of 6:4) and SFM_120_5/5 (CRU with release periods of 120 days were mixed with urea at N ratios of 5:5) were 3.69% and 4.39% higher than that of fractionated urea (FU), respectively, across 2018 and 2019. Combining the application of controlled-release urea and normal urea improved the dry matter accumulation, nitrogen accumulation, and nitrogen uptake rate when compared with FU. SFMs improved the processing quality and appearance quality of rice grains and did not reduce the cooking and eating quality. SFM_80_6/4 and SFM_120_5/5 are a one-time fertilization mode with high yield, high efficiency, and good grain quality, which is worthy of further promotion and application.

Variabilidade entre linhagens de feijão comum para máximo acúmulo de matéria seca nos grãos

Abstract The objective of this work was to verify if there is variability in the dry matter accumulation rate of grains of the carioca-type common bean, as well as to identify the success of selection for this trait and the best time for harvest. Sixteen lines with carioca-type grains were evaluated in three sowing seasons through samples of five plants obtained at regular intervals. A quadratic equation was used to estimate the number of days to obtain the maximum dry matter in the grains. A low variability was observed among the lines, discouraging selection for this trait. The ideal moment for harvesting is when 100% of the grains present the typical stripes of carioca common bean, which may vary among and within pods of the same plant. If the harvest is carried out before complete physiological maturation is reached, the dry matter in the grains decreases, on average, 2.75% per day.

Effect of the Rate of Nitrogen Application on Dry Matter Accumulation and Yield Formation of Densely Planted Maize

Planting maize (Zea mays L.) reasonably densely and adding amounts of appropriate nitrogen fertilizer are essential measures to improve the efficiency of maize yield and nitrogen use. In this study, two planting densities of 7.5 × 104 plants ha−1 and 12.0 × 104 plants ha−1 were established with the maize varieties DengHai 618 (DH618) and XianYu 335 (XY335). Simultaneously, 18 levels of nitrogen application were established, including a lack of nitrogen (N0) and increments of 45 kg ha−1 nitrogen up to 765 (N765) kg ha−1. The variables studied included the effects of the rate of nitrogen application on the characteristics of dry matter accumulation and the yield under drip irrigation, and they were integrated into water–fertilizer integration. The results indicated that the yield, harvest index, and dry matter accumulation of maize displayed a trend of increasing and then tending to be flat as the amount of nitrogen applied increased. The use of linear plus platform equation fitting indicated that the change in yield with nitrogen administered had the lowest turning point at N = 279 and N = 319, respectively. The next parameter that was measured was the harvest index. When highly dense maize was grown before silking, the rate of nitrogen applied was more obviously impacted by the accumulation of dry matter. The harvest index contributed 22.9–27.2% of the yield, and the total dry matter accumulation before and after silking contributed more than 70% of the production. Increasing the amount of nitrogen fertilizer is beneficial to prolonging the dry matter accumulation time and increasing the dry matter accumulation rate. The accumulation amount of dry matter was positively correlated with accumulation time and rate, and the correlation between dry matter and accumulation rate was greater. In conclusion, applying the right amount of nitrogen can dramatically increase the harvest index, accumulation of materials, and yield, with dry matter accumulation having the greatest influence on yield. The creation of dry matter is influenced by the time and rate of its accumulation, with its rate serving as the primary controlling factor.