Optimal Plant Research Articles

Agronomic advantage of bacterial biological nitrogen fixation on wheat plant growth under contrasting nitrogen and phosphorus regimes.

Given their remarkable capacity to convert atmospheric nitrogen into plant-accessible ammonia, nitrogen-fixing microbial species hold promise as a sustainable alternative to chemical nitrogen fertilizers, particularly in economically significant crops like wheat. This study aimed to identify strains with optimal attributes for promoting wheat growth sustainably, with a primary emphasis on reducing reliance on chemical nitrogen fertilizers. We isolated free nitrogen-fixing strains from diverse rhizospheric soils across Morocco. Subsequently, we conducted a rigorous screening process to evaluate their plant growth-promoting traits, including nitrogen fixation, phosphate solubilization, phytohormone production and their ability to enhance wheat plant growth under controlled conditions. Two specific strains, Rhodotorula mucilaginosa NF 516 and Arthrobacter sp. NF 528, were selected for in-depth evaluation, with the focus on their ability to reduce the need for chemical nitrogen supply, particularly when used in conjunction with TSP fertilizer and natural rock phosphate. These two sources of phosphate were chosen to assess their agricultural effectiveness on wheat plants. Twenty-two nitrogen-fixing strains (nif-H+) were isolated from various Moroccan rhizospheric soils, representing Bacillus sp., Pseudomonas sp., Arthrobacter sp., Burkholderia sp. and a yeast-like microorganism. These strains were carefully selected based on their potential to promote plant growth. The findings revealed that the application of Rhodotorula mucilaginosa NF 516 and Arthrobacter sp. NF 528 individually or in combination, significantly improved wheat plant growth and enhanced nutrients (N and P) uptake under reduced nitrogen regimes. Notably, their effectiveness was evident in response to both natural rock phosphate and TSP, demonstrating their important role in wheat production under conditions of low nitrogen and complex phosphorus inputs. This research underscores the significant role of nitrogen-fixing microorganisms, particularly Rhodotorula mucilaginosa NF 516 and Arthrobacter sp. NF 528, in wheat production under conditions of low nitrogen and complex phosphorus inputs. It showcases their potential to reduce chemical nitrogen fertilization requirements by up to 50% without compromising wheat plant yields. Our study emphasizes the importance of bacterial biological nitrogen fixation in meeting the remaining nitrogen requirements beyond this reduction. This underscores the vital role of microbial contributions in providing essential nitrogen for optimal plant growth and highlights the significance of biological nitrogen fixation in sustainable agriculture practices.

An optimal standalone wind-photovoltaic power plant system for green hydrogen generation: Case study for hydrogen refueling station

Sustainability goals include the utilization of renewable energy resources to supply the energy needs in addition to wastewater treatment to satisfy the water demand. Moreover, hydrogen has become a promising energy carrier and green fuel to decarbonize the industrial and transportation sectors. In this context, this research investigates a wind-photovoltaic power plant to produce green hydrogen for hydrogen refueling station and to operate an electrocoagulation water treatment unit in Ostrava, Czech Republic's northeast region. The study conducts a techno-economic analysis through HOMER Pro® software for optimal sizing of the power station components and to investigate the economic indices of the plant. The power station employs photovoltaic panels and wind turbines to supply the required electricity for electrolyzers and electrocoagulation reactors. As an off-grid system, lead acid batteries are utilized to store the surplus electricity. Wind speed and solar irradiation are the key role site dependent parameters that determine the cost of hydrogen, electricity, and wastewater treatment. The simulated model considers the capital, operating, and replacement costs for system components. In the proposed system, 240 kg of hydrogen as well as 720 kWh electrical energy are daily required for the hydrogen refueling station and the electrocoagulation unit, respectively. Accordingly, the power station annually generates 6,997,990 kWh of electrical energy in addition to 85595 kg of green hydrogen. Based on the economic analysis, the project's NPC is determined to be €5.49 M and the levelized cost of Hydrogen (LCH) is 2.89 €/kg excluding compressor unit costs. This value proves the effectiveness of this power system, which encourages the utilization of green hydrogen for fuel-cell electric vehicles (FCVs). Furthermore, emerging electrocoagulation studies produce hydrogen through wastewater treatment, increasing hydrogen production and lowering LCH. Therefore, this study is able to provide practicable methodology support for optimal sizing of the power station components, which is beneficial for industrialization and economic development as well as transition toward sustainability and autonomous energy systems.

Exploring the Role of Active Photosynthetic Pigments in Tomato (Solanum lycopersicum) Crop Growth Process

Photosynthesis is a necessary process for plants during which light energy is absorbed via pigments present in leaves for essential processes and needs of the particular plant. This work identified and studied the active photosynthetic pigments in tomato crop (Solanum lycopersicum) at each growth stage and grown in an open field under Sahelian conditions. Phytochemical screening, UV-visible and Fourier transform infrared spectroscopy, and thin layer chromatography analyses were done on tomatoes leaves samples. The results, first, revealed the presence of phytoconstituents such as triterpenoids and carotenoids. Then, UV spectra combined with FTIR and thin layer chromatography showed that chlorophylls (a and b), xanthophyll (lutein) and carotene (mostly β) are being synthesized at different proportions during all growth stages. Besides, the photosynthetic pigments showed more activity during the flowering stage than at the other growth stages. The various action spectra showed intense absorption within the intervals 400 – 510 nm and 560 – 710 nm which seem to be vital radiation ranges for photosynthesis. Knowing these optimum plant’s needs can help in a choice of better outdoor and indoor cultivation conditions that can ensure necessary radiations for optimum plant growth.

Extremophiles in Space Exploration.

In the era of deep space exploration, extremophile research represents a key area of research w.r.t space survival. This review thus delves into the intriguing realm of 'Space and Astro Microbiology', providing insights into microbial survival, resilience, and behavioral adaptations in space-like environments. This discussion encompasses the modified behavior of extremophilic microorganisms, influencing virulence, stress resistance, and gene expression. It then shifts to recent studies on the International Space Station and simulated microgravity, revealing microbial responses that impact drug susceptibility, antibiotic resistance, and its commercial implications. The review then transitions into Astro microbiology, exploring the possibilities of interplanetary transit, lithopanspermia, and terraforming. Debates on life's origin and recent Martian meteorite discoveries are noted. We also discuss Proactive Inoculation Protocols for selecting adaptable microorganisms as terraforming pioneers. The discussion concludes with a note on microbes' role as bioengineers in bioregenerative life support systems, in recycling organic waste for sustainable space travel; and in promoting optimal plant growth to prepare Martian and lunar basalt. This piece emphasizes the transformative impact of microbes on the future of space exploration.

Mitigating Emerging and Reemerging Diseases of Fruit and Vegetable Crops in a Changing Climate.

Fruit and vegetable crops are important sources of nutrition and income globally. Producing these high-value crops requires significant investment of often scarce resources, and, therefore, the risks associated with climate change and accompanying disease pressures are especially important. Climate change influences the occurrence and pressure of plant diseases, enabling new pathogens to emerge and old enemies to reemerge. Specific environmental changes attributed to climate change, particularly temperature fluctuations and intense rainfall events, greatly alter fruit and vegetable disease incidence and severity. In turn, fruit and vegetable microbiomes, and subsequently overall plant health, are also affected by climate change. Changing disease pressures cause growers and researchers to reassess disease management and climate change adaptation strategies. Approaches such as climate smart integrated pest management, smart sprayer technology, protected culture cultivation, advanced diagnostics, and new soilborne disease management strategies are providing new tools for specialty crops growers. Researchers and educators need to work closely with growers to establish fruit and vegetable production systems that are resilient and responsive to changing climates. This review explores the effects of climate change on specialty food crops, pathogens, insect vectors, and pathosystems, as well as adaptations needed to ensure optimal plant health and environmental and economic sustainability.

Spore Germination of Diplazium simplicivenium Holtt. (Athyriaceae) in Peninsular Malaysia

Diplazium simplicivenium Holtt. a species of fern in Peninsular Malaysia. This study reports an efficient method for D. simplicivenium spore sterilisation and the effect of plant growth regulators (PGRs) via green globular bodies (GGB). Sterilisation with 0.1% mercuric chloride effectively allowed spore germination. The result showed that the culture media supplemented with 0.5 mg/L gibberellin positively affects the weight of GGB and the number of shoots with significant differences (ANOVA, p < 0.05). The soaking technique established in this study for spore sterilisation is an efficient approach, and the optimal plant and concentration of plant hormones were identified. This procedure can be applied to other indigenous ferns and closely similar species.

Spatial and temporal distribution of optimal maize sowing dates in Nigeria.

Climate change and inter-annual variability cause variation in rainfall commencement and cessation which has consequences for the maize growing season length and thus impact yields. This study therefore sought to determine the spatially explicit optimum maize sowing dates to enable site specific recommendations in Nigeria. Gridded weather and soil data, crop management and cultivar were used to simulate maize yield from 1981-2019 at a scale of 0.5°. A total of 37 potential sowing dates between 1 March and 7 November at an interval of 7 days for each year were evaluated. The optimum sowing date was the date which maximizes yield at harvest, keeping all other management factors constant. The results show that optimum sowing dates significantly vary across the country with northern Nigeria having notably delayed sowing dates compared to southern Nigeria which has earlier planting dates. The long-term optimal sowing dates significantly (p<0.05), shifted between the 1980s (1981-1990), and current (2011-2019), for most of the country. The most optimum planting dates of southern Nigeria shifted to later sowing dates while most optimum sowing dates of central and northern Nigeria shifted to earlier sowing dates. There was more variation in optimum sowing dates in the wetter than the drier agro-ecologies. Changes in climate explain changes in sowing dates in wetter agro-ecologies compared to drier agro-ecologies. The study concludes that the optimum sowing dates derived from this study and the corresponding methodology used to generate them can be used to improve cropping calendars in maize farming in Nigeria.

ВЛИЯНИЕ ОТДЕЛЬНЫХ ЭЛЕМЕНТОВ ТЕХНОЛОГИИ ВОЗДЕЛЫВАНИЯ КАРТОФЕЛЯ СОРТА ГАЛА НА УРОЖАЙНОСТЬ КЛУБНЕЙ В УСЛОВИЯХ ЗАКАМЬЯ РЕСПУБЛИКИ ТАТАРСТАН

An assessment of the impact of various areas and food conditions on potato yields in the Kama region of the Republic of Tatarstan has been carried out. It was found that on leached chernozems, as the number of tubers planted on different nutrient backgrounds increased from 30 to 60 thousand pieces/ha, the yield of potato tubers of the Gala variety increased on average over 2 years from 25.2 to 29.2 t/ha in the control, against the background of the use of fertilizers from 31.0-34.8 and 32.4-38.7 tons/ha . However, the maximum yield minus the weight of the planting material of 25.2...31.1 and 35.1 t/ha had a clear, pronounced maximum at a certain optimal planting rate of 50 thousand tubers/ha. The effect of the nutrition background on the number of stems of one bush was insignificant, however, in terms of unit area, the number of stems against the background of N60P60K90 with a planting density of 50 thousand tubers exceeded the control (without fertilizers) by 3.41 thousand pieces, and against the background of N60P60K90 - by 100 thousand pieces. + When applying 60 tons of manure, this difference amounted to 4.38 thousand pieces, which ultimately affected the formation of the tuber harvest. The largest assimilation surface – 44.6...46.7 thousand m2/ha was noted in the fertilized variants of the experiment with a planting density of 60 thousand tubers per 1 ha. The excess compared to the control was 6.3...8.4 thousand m2/ha. The use of fertilizers in potato cultivation led to a slight decrease in the starch content in tubers by 1.4...2.1% with a planting density of 50 thousand tubers per 1 hectare. As the planting density increased, regardless of the nutritional background, the starch content increased by 1.1% on the control and by 0.8...0.9% on the fertilized backgrounds.

Sugarcane leaf litter biomass and its effects on increasing sugarcane drought stress tolerance and reducing CO₂ emissions

Burning biomass on sugarcane plantations can lead to pollution (CO₂ emissions) and degradation in soil properties. Adopting non-burning technology can increase the value of biomass by applying it directly to the soil, although this may result in nutrient immobilization, which can hinder optimal plant growth due to high lignin and cellulose content or high CN ratio. On the contrary, composting waste with a decomposer will boost plant nutrient availability and enhance other soil characteristics. This research was aimed to assess the effect of several types of sugarcane organic matter on improving soil characteristics, growth of sugarcane and the CO₂ emissions. The study was conducted using a Completely Randomized Factorial Design with two factors: type of organic matter (control, fresh litter and compost of sugarcane biomass) and level of drought stress (100, 75, 50 and 25%). Incubation occurred over 16 weeks, divided into two phases of 8 weeks each. The results showed that the application of organic materials in the form of compost could reduce water loss caused by environmental heat and sugarcane growing process. Furthermore, compost application improved soil chemical and biological properties by increasing soil pH, total nitrogen (N), total phosphate (P), total potassium (K), and the total microbial population, although differences were not significant compared to the control. Additionally, applying organic matter in the form of compost or litter helped suppress or reduce emissions, with compost treatment proving more effective than litter in reducing CO₂ emissions.

The effect of planting distance on the growth and yield of sweet potato clone Arf-03 on alluvial soil

Sweet potato (Ipomoea batatas L) is one of the alternative foods for food diversity. The need for sweet potatoes is increasing as consumption of materials and industrial raw materials have bright prospects, so various efforts are needed to increase production. One of the efforts to improve cultivation techniques to increase sweet potato production is by setting optimal planting spacing so that plant needs are met. Spacing is very closely related to nutrient absorption and photosynthesis processes, so plant growth increases. The purpose of this study was to determine the effect of planting distance on the growth and yield of ARF-03 clone sweet potatoes on alluvial soils and obtain optimal planting spacing for the growth and yield of sweet potatoes. The planting distance treatment given in this study was P1 = 20 cm × 100 cm, P2 = 30 cm × 100 cm, and P3 = 40 cm × 100 cm, using RAK as a reference for the placement of experimental units. The results of the growth of ARF-03 sweet potato plants on planting distance treatment showed that planting spacing had a significant effect on the length of the main tendrils, the number of branches, the fresh weight of the plant header, the dry weight of the plant header, the weight of tubers per plant, and the weight of tubers per bed. However, it has no real effect on the variables of the number of tubers, the length of the tubers, or the diameter of the tubers. The plant reaches its highest growth rate at a distance of 40 cm × 100 cm and its highest yield at a distance of 30 cm × 100 cm, with a bulb weight of 425.75 g per plant.

Variation and interrelationships in the growth, yield, and lodging of oat under different planting densities.

Oat is a dual-purpose cereal used for grain and forage. The demand of oat has been increasing as the understanding of the nutritional, ecological, and economic values of oat increased. However, the frequent lodging during the growing period severely affect the high yielding potential and the quality of the grain and forage of oat. Therefore, we used the lodging-resistant variety LENA and the lodging-sensitive variety QY2 as materials, implementing four different planting densities: 2.25×106 plants/ha (D1), 4.5×106 plants/ha (D2), 6.75×106 plants/ha (D3), and 9×106 plants/ha (D4). At the appropriate growth and development stages, we assessed agronomic traits, mechanical characteristics, biochemical compositions, yield and its components. The study investigated the impact of planting density on the growth, lodging, and yield of oat, as well as their interrelationships. Additionally, we identified the optimal planting density to establish a robust crop structure. The research aims to contribute to the high-yield and high-quality cultivation of oat. We observed that with increasing planting density, plant height, grass and grain yields of both varieties first increased and then decreased; root fresh weight, stem diameter, stem wall thickness, stem puncture strength, breaking strength, compressive strength, lignin and crude fiber contents, and yield components decreased; whereas the lodging rate and lodging coefficient increased. Planting density affects lodging by regulating plant height, height of center of gravity, stem wall thickness, internode length, and root fresh weight of oat. Additionally, it can impact stem mechanical strength by modulating the synthesis of lignin and crude fiber, which in turn affecting lodging resistance. Plant height, height of center of gravity, stem wall thickness, internode length, root fresh weight, breaking strength, compressive strength, lignin and crude fiber content, single-plant weight, grain yield and 1,000-grain weight can serve as important indicators for evaluating oat stem lodging resistance. We also noted that planting density affected grain yield both directly and indirectly (by affecting lodging); high density increased lodging rate and decreased grain yield, mainly by reducing 1,000-grain weight. Nonetheless, there was no significant relationship between lodging and grass yield. As appropriate planting density can increase the yield while maintaining good lodging resistance, in this study, 4.5×106 plants/ha (D2) was found to be the best planting density for oat in terms of lodging resistance and grass and grain yield. These findings can be used as a reference for oat planting.

Resources and potential for utilization of low-exergy heat from mung bean sprouts cultivation – case study

Poland is a significant producer of vegetable sprouts, which, due to the high content of nutrients, are produced for food purposes. The cultivation cycle of these plants, especially the mung beans (Vigna radiata), is associated with significant exploitation of natural resources (as much as 275 dm3 of water per 1 kg of dry seeds) and requires appropriate temperature conditions. However, since producing of vegetable sprouts is an exothermic process, there are reasons to organize the growth conditions of these plants in a quasi-autonomous manner. Estimated preliminary studies show that during the entire period of sprout growth, as much as 2.86 MJ of heat from 1 kg of dry seeds can be used, which, taking into account the scale of production of these plants, places them among the significant sources of low-temperature waste heat. The paper presents the results of temperature measurements carried out in a growth chamber used for the industrial production of the mung bean vegetable sprouts. Based on the prepared energy balance, the total amount of heat generated (4.9 GJ) and recovered (3.3 GJ) in the seed germination process was determined. The amount of energy lost in the process of imbibition and the amount of heat needed to ensure optimal plant growth conditions were determined. The study shows that the use of low-temperature heat generated by plants allows for a significant reduction in the energy consumption of the production process.

Uniform Lighting of High-Power LEDs at a Short Distance to Plants for Energy-Saving and High-Density Indoor Farming

A tunable LED panel with multiple types of LEDs on a panel can provide various spectra for optimal plant growth. However, it is difficult for a lighting panel with multiple types of high-power LEDs to achieve uniform lighting. We demonstrated that by using optical reflectors at the sides of an LED panel to trap photons of LED arrays or using both the above-mentioned reflectors and optical lenses on each LED, high lighting uniformity can be achieved at a short distance to plants. The ray tracing simulation results show that the LED panel equipped with reflectors and optical lenses can achieve a high uniformity of &gt;0.80 when the LED-plant distance is at half of the LED array’s pitch. We further verified that an LED panel (at a size of 88 cm × 54 cm) installed with reflectors can achieve light uniformities around 0.90 at a 15 cm LED-plant distance for the 6 types of LEDs (4 color LEDs and 2 white LEDs) on the panel. Compared with a branded tunable LED panel, our LED panel saves &gt;25 cm vertical distance for each tier of plants and has 92.5% higher photon efficacy for 660 nm LEDs that exist on both panels.

Optimization of CO2 capture plants with surrogate model uncertainties

CO2 capture plants can help reduce the cost of deploying capture systems across the globe. However, the CO2 variability and model uncertainty represent operational challenges to capture CO2 from different sources. This work proposes a framework for analyzing the optimal plant design considering different flue gas sources. We show a methodology to generate large data sets from optimization runs using rigorous models in Aspen Plus®. The efficiency of the approach allows its application to large-scale optimization problems, with an average CPU time per run of 176 s.We additionally build surrogate models (SMs) for the capital and operating costs of the capture plants, employing an iterative procedure to generate SMs using ALAMO. We systematically reject SMs with high uncertainty in the estimated parameters. This approach results in SMs with favorable bias-variance tradeoffs, enabling their effective application to optimization problems under uncertainty, as demonstrated with a pooling problem of CO2 streams.

Smart Farming Robot for Detecting Environmental Conditions in a Green House

At a high level, the Smart Farming Robot for detecting environmental conditions in a greenhouse embodies a pioneering solution merging robotics and agricultural technology. This innovative system integrates advanced sensors to meticulously monitor vital parameters within the greenhouse environment, including temperature, humidity, soil moisture, light intensity, and air quality. Through seamless data collection and analysis facilitated by Raspberry Pi microcontroller technology, the robot autonomously navigates the greenhouse, continuously assessing conditions crucial for optimal plant growth. At an intermediate level, the system orchestrates a symphony of sensor data acquisition, processing algorithms, and navigational control mechanisms, all orchestrated to ensure real-time detection and response to deviations from ideal environmental conditions. Delving deeper, the system architecture encompasses intricacies of sensor interfacing, data processing, and algorithmic decision-making, harmonizing to deliver actionable insights for precision agriculture practices. Keywords- Raspberry Pico

Effects of mulching and nutritional strategies on the growth and yield of sweet basil (Ocimum basilicum L.)

The effect of mulching and nutrition on the growth and yield of sweet basil was examined by experimenting with four mulch treatments, viz., without mulch, black plastic, silver plastic, and organic mulch combined with four different nutrient compositions, viz., a 100% recommended dose of fertilizer (RDF), a combination of 75% RDF with humic acid, 75% RDF with microbial consortia and 75% RDF, and humic acid and microbial consortia, which served as sixteen treatment combinations with 100% RDF without mulch as a control. Among the different treatments, mulch had a significant effect on growth and yield parameters, with black plastic mulch having the maximum plant height (88.20 cm), number of branches (14.95), plant spread (5415 cm2), stem diameter (12.64 mm), fresh herbage yield (24.55 t/ha) and dry herbage yield (8.72 t/ha). Thus, the study revealed that among the various mulch treatments, black plastic mulch significantly enhanced the growth and yield parameters of sweet basil, demonstrating its efficacy in promoting optimal plant development and productivity.

Control of vapor pressure deficit (VPD) in micro-plant factory (McPF) to enhanced spinach microgreens growth

Harnessing the power of Vapor Pressure Deficit (VPD) control, this novel research illuminates a pathway to enhanced plant growth and yield within Micro-Plant Factory (McPF) and Urban Mini-Plant Factory (UMPF) environments. The research focused on the growth parameters of spinach microgreens, with the experimental data originating from each system's upper, central, and lower shelves. Results indicated significantly enhanced plant height and dry weight on the central shelves, attributed to optimal VPD control. Growth analysis also revealed higher relative growth rates (RGR) under tightly managed VPD conditions on the central shelves, even amidst varying environmental parameters. Most notably, effective VPD control translated these growth metrics into increased yields. For instance, a 71 % and 66 % increase in final plant dry weight over the lower and upper shelves was noted. These advances were mirrored in the plant height, which also saw 57 % and 103 % growth. Overall, the findings underscore the critical role of VPD control in plant growth and yield enhancement within structured environments like McPF and UMPF, offering significant insights for future research in manipulating VPD for optimal plant growth and productivity.

Assessing the environmental contribution of clustered regularly interspaced short palindromic repeats (CRISPR) rice in the presence of insect pest uncertainty

AbstractAdopting genome editing with the trait of pest resistance contributes to sustainable development by reducing pesticide use. Developed by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology, CRISPR rice is resistant to two of its most destructive insect pests. However, there exists a trade-off between pest resistance and lower potential yield. In the presence of uncertainty of pest severity, adopting CRISPR rice demonstrates positive environmental benefits at its optimal planting ratio, estimated based on a microeconomic model extended with environmental externalities of rice cultivation. We estimate the optimal planting ratio to be 37%, with the environmental benefit of co-planting CRISPR rice to be 560 million US dollars annually in China. The environmental benefit accounts for 4–22% of the total value of co-planting CRISPR rice in the Monte Carlo simulations. Regional heterogeneity regarding optimal planting ratio and environmental benefit is studied for 12 major rice-cultivating provinces in China. We conclude with policy implications that policymakers need to consider the vast environmental benefit of CRISPR rice adoption to have a more comprehensive view of its economic and environmental market potential, contributing to the heated debate on regulating CRISPR technology in China and worldwide.

Yields, growth and water use under chemical topping in relations to row configuration and plant density in drip-irrigated cotton

BackgroundWater deficit is an important problem in agricultural production in arid regions. With the advent of wholly mechanized technology for cotton planting in Xinjiang, it is important to determine which planting mode could achieve high yield, fiber quality and water use efficiency (WUE). This study aimed to explore if chemical topping affected cotton yield, quality and water use in relation to row configuration and plant densities.ResultsExperiments were carried out in Xinjiang China, in 2020 and 2021 with two topping method, manual topping and chemical topping, two plant densities, low and high, and two row configurations, i.e., 76 cm equal rows and 10+66 cm narrow-wide rows, which were commonly applied in matching harvest machine. Chemical topping increased seed cotton yield, but did not affect cotton fiber quality comparing to traditional manual topping. Under equal row spacing, the WUE in higher density was 62.4% higher than in the lower one. However, under narrow-wide row spacing, the WUE in lower density was 53.3% higher than in higher one (farmers’ practice). For machine-harvest cotton in Xinjiang, the optimal row configuration and plant density for chemical topping was narrow-wide rows with 15 plants m-2 or equal rows with 18 plants m-2.ConclusionThe plant density recommended in narrow-wide rows was less than farmers’ practice and the density in equal rows was moderate with local practice. Our results provide new knowledge on optimizing agronomic managements of machine-harvested cotton for both high yield and water efficient.

Optimum Transplanting Date for Rape Forage and Grain Yields in the Ridge Culture Place Planting System on the Yangtze River Delta

The ridge culture place planting system (RCPPS) is a promising technique for planting rapeseed that can promote the growth of rapeseed by late rice stubble, which has been widely adopted in the Yangtze River delta. To determine the optimum planting date for rape (Brassica napus L.) forage and grain yield in an intensive rice–rape rotation system, a field experiment was conducted with five transplantation dates (from 20 October to 30 November at 10 day intervals) in RCPPS. The forage/grain yield, nutrition, and growth parameters were analyzed. At podding, rape biomass yield was highest, and no significant differences were found among treatments. It was around 12.0% crude protein, 11.4% ether extract, 38.8% neutral detergent fiber, and 34.9% acid detergent fiber. In the treatments of 20 and 30 November, crude protein content increased and acid detergent fiber content decreased significantly. Compared with 20 October, the grain yield of rape transplanted in November decreased significantly by 17.2% to 22.5%. The grain yield was significantly correlated with the number of secondary branches, pods, and seeds. At the final flowering stage, rape transplanted in November had noticeably reduced leaf growth, rhizome width, and yield than 20 and 30 October. Overall, for multiple uses of rapeseed in the Yangtze River delta belt with RCPPS, it is optimal to plant in mid to late November for forage use with higher nutritional value, being coordinated with the previous rice crop, whereas late October is the appropriate planting time to obtain a higher grain yield.