Effect Of Plant Density Research Articles

Planting density and mechanical site preparation effects on understory composition, functional diversity and planted black spruce growth in boreal forests

Mechanical site preparation (MSP) is used prior to planting to control competing vegetation and enhance soil conditions, particularly in areas prone to paludification. Tree planting density can be adapted to the management context and objectives, as it influences yield and wood quality. However, the combined effects of MSP and planting density on understory vegetation composition, functional traits, and diversity remain uncertain. We thus conducted a study in the Clay Belt region of northwestern Quebec, Canada. After careful logging, the study area was divided into nine sites, each receiving one of three treatments: plowing, disc trenching, or no preparation. Sites were further divided into two, with black spruce (Picea mariana [Mill.] Britton, Sterns & Poggenb.) seedlings planted at either a low planting density of 1100 seedlings ha-1 or a high planting density of 2500 seedlings ha-1. After nine years, we assessed understory composition, diversity, key functional traits, sapling density and growth of planted trees. Careful logging alone led to a higher density of naturally established conifers compared to plowing or disc trenching. The interaction between planting density and MSP significantly influenced understory diversity and composition in plowed plots. Understory composition was affected by the soil C/N ratio, coniferous species, and deciduous species density. The growth of black spruce was notably enhanced with higher planting density in the plow treatment only. Neither planting density nor MSP alone affected tree height and diameter. Our results suggest that combining plowing with high-density planting can enhance stand growth and improve forest productivity. These findings guide future research on paludified forests.

УРОЖАЙНОСТЬ И КАЧЕСТВО КЛУБНЕЙ КАРТОФЕЛЯ В ЗАВИСИМОСТИ ОТ ПРИЕМОВ АГРОТЕХНИКИ В УСЛОВИЯХ ЧЕЛЯБИНСКОЙ ОБЛАСТИ

The study investigated the effect of balanced mineral fertiliser rates, planting density and single irrigation on the yield and quality of tubers of locally bred potato cultivars. The study was conducted in the forest-steppe zone of Chelyabinsk region. It was established that in the arid conditions of 2021–2022 potato yields depended on mineral nutrition (40 % factor contribution), planting density (32 % factor contribution), irrigation (21 % factor contribution) and genotype (5 % factor contribution). The planned yield of tubers (40 t/ha) was obtained against single irrigation (300 m3 /ha) combined with a thick planting pattern (75 × 14 cm) and an appropriate fertiliser rate (N132P143K158): cultivar Kavaler (49.7 t/ha), cultivar Amulet (41.0 t/ha), cultivar Zakhar (40.5 t/ha), cultivar Kashtak (38.7 t/ha) (cultivar Kavaler had 41.0 t/ha in the planting pattern of 75 × 19 cm). The yield of 60 t/ha was obtained only in cultivar Kavaler (63.4 t/ha) and cultivar Amulet (58.4 t/ha) against fertilisation (N260P260K285) combined with a planting pattern of 75 × 14 cm and single irrigation of plants in the second ten-day interval of July. The tuber quality remained high in all variants of the experiment since the thick planting pattern increased dry matter and starch in tubers; the single irrigation in the second ten-day interval of July (300 m3 /ha) and the balanced rates of mineral fertilisers per a yield of 40 t/ha (N132P143K158) did not have a negative impact on the tuber quality. A slight decrease in dry matter (by 0.7–1.1 %) and starch (by 0.7–0.9 %) compared with the control (without fertilisers) was found in tubers of cultivars Amulet, Zakhar and Kavaler with fertilisers applied per 60 t/ha (N260P260K285). The quality of tubers did not change in cultivar Kashtak against the increased mineral nutrition.

Effect of Plant Density on the Physiological and Quality Trait for Different Varieties of Wheat (Triticum aesitivum L.)

Effect of Plant Density on the Physiological and Quality Trait for Different Varieties of Wheat (Triticum aesitivum L.)

Effect of Different Methods and Planting Density on the Growth and Yield of Spring Rice at Tikapur, Kailali

A field experiment was conducted at Agronomy farm, Far Western University, Tikapur-1 to study the effect of different planting methods and density on yield of spring rice variety (chaite-4), when sown a month earlier than normal time. The research was laid out in randomized complete block design (RCBD) with seven treatments and three replications during Feb-June, 2022. The treatments consisted of planting methods viz. early broadcasting (T1 ), early line sowing (T2 ) on the day of nursery bed (1st Feb), transplanting 20 hills m-2(T3 ), transplanting 30 hills m-2 (T4 ), transplanting 40 hills m-2 (T5 ), late broadcasting (T6 ) and late line sowing, (T7 ) on the day of transplanting (2nd Mar). The results showed that transplanting significantly outperformed broadcasting method of rice planting in terms of yield attributing traits and yield. Broadcasting method showed significant reduction in tiller number, biological yield and grain yield than line sowing. But performance of late line sown rice was better than early line sown rice. Similarly transplanting 30 hills m-2 showed significant effect in early tiller formation followed by 20 hills-2resulting in significant increase in grain yield of spring rice as compared to transplanting 40 hills m-2. There was no difference in tiller number between line sown rice either early or late. This study recommends sowing of 30 hills m-2 and suggests further research on line sowing of spring rice at different dates ranging from 1st February to 3rd March at same planting density to define appropriate time for preponing planting time under similar condition.

Effect of Plant Density and NPS Fertilizer Rates on Growth, Yield and Yield Components of Maize (Zea mays L.) in Central highland of Ethiopia

Maize is an important cereal crop in Ethiopia due to its use as a source of food security. However, its productivity is limited by insufficient application of the NPS fertilizer and inappropriate plant density. A field experiment was conducted during 2020 and 2021 cropping seasons at Liban Jawi and Toke Kutaye districts of West Shoa Zone, Ethiopia to study the effect of plant density and NPS fertilizer rates on growth, yield, and yield components of maize. The experiment consisted of three plant populations (53,300, 66,600 and 88,800 plants ha-1) and five NPS fertilizer rates (100, 150, 200, 250 and 300 kg NPS ha-1) laid out in a randomized complete block design with three replications. The results showed that plant height, ear height and biological yield increased with increasing plant density. On the contrary ear length, number of grains per row, grain yield and harvest index decreased with increasing plant density. Plant density of 53,300 plants ha-1 produced the higher grain yield (5969 kgha-1) compared to that of 88,800 plants ha-1 (5175 kg ha-1). However, grain yield at 53,300 plants ha-1 did not show a significant difference with that of 66,600 plants ha-1 (5746 kg ha-1). In case of NPS fertilizer rates the results showed that plant height, ear height, ear length, number of grains per row, 1000 seed weight, biological yield, grain yield and harvest index increased with increasing NPS fertilizer rates up to optimum rate. Fertilizer application of 200kg NPS ha-1 produced a higher grain yield (6710 kg ha-1). The highest economic (126,423 Birr ha-1) and a higher MRR (2630%) resulted from the application of 200 kg NPS ha-1 with a plant population of 53,300 plants ha-1. Therefore a Plant density of 53,300 plants ha-1 and a blended fertilizer application with 200 kg NPS ha-1 was the most appropriate for highland maize in the study area.

Effects of plant density on alfalfa (Medicago sativa L.) seed yield in western Heilongjiang areas.

Alfalfa (Medicago sativa L.) is known as the "king of forages". The aim of the current study is to determine the optimum planting density as the key cultivation technique for high yield of alfalfa seed. Alfalfa variety (Longmu 801) was planted in experimental fields from 2014 to 2017. In the planting density test, the row spacing was 65, 80, and 95 cm, and the plant spacing was 30, 45, 60, 75, and 90 cm. The seed yield and yield components in the row spacing and plant spacing tests were measured. On the basis of 3 years average of the experimental data, the highest seed yield of 225.49 kg ha-1 was obtained with row spacing vs plant spacing of 65 and 60 cm, respectively. Correlation analysis showed a significant positive correlation between the racemes per stem, pods per raceme, pods per stem, seeds per pod, and the seed yield. These results suggested that Longmu 801 should be cultivated with 65 cm row spacing and 60 cm plant spacing to maximize seed yields in western Heilongjiang areas.

Increasing planting density can improve the yield of Tartary buckwheat.

Planting densities and nitrogen fertilizer application rates determine the yield of crops. Tartary buckwheat is a pseudocereal crop with great health care and development values. However, little is known about application of nitrogen fertilizer and planting density on the physiological characteristics of Tartary buckwheat. This study aims to clarify the effect of planting density on the senescence and yield of Tartary buckwheat under low nitrogen conditions. A 2-year field experiment was conducted on Tartary buckwheat (Jinqiao 2) to study the effects of different planting densities (8 × 105, 10 × 105, 12 × 105, 14 × 105, and 16 × 105 plants·ha-1) on the root morphology and activity, chlorophyll and malondialdehyde (MDA) contents, antioxidant enzyme activity, photosynthetic characteristics, agronomic traits, and yield of Tartary buckwheat in the absence of nitrogen fertilizer treatment. With the increase in planting density, the root morphological indices and activities; chlorophyll a, chlorophyll b, and carotenoid contents; superoxide dismutase and peroxidase activities; net photosynthetic rate; transpiration rate; intercellular CO2 concentration and transpiration rate; main stem node, branch, and leaf numbers; grain number and weight per plant; and 1000-grain weight of Jinqiao 2 decreased continuously, whereas plant height and leaf MDA content increased continuously. The yield of Tartary buckwheat first increased and then decreased with the increase in planting density. The yield under 14 × 105 plants·ha-1 treatment increased by 68.61%, 44.82%, 11.00%, and 22.36%, respectively, relative to that under 8 × 105, 10 × 105, 12 × 105, and 16 × 105 plants·ha-1treatments. In summary, planting at an appropriately high density (14 × 105 plants·ha-1) can promote the increase in the yield of Tartary buckwheat populations under low nitrogen conditions and is recommended for use in production to achieve the high-yielding and nitrogen saving cultivation of Tartary buckwheat. This research can serve as a theoretical basis to jointly achieve the high yield and nitrogen saving of Tartary buckwheat.

Effects of NPK Fertilizer application and plant density on forage yield and chemical composition of wild sunflower (Tithonia diversifolia)

A study was conducted in 2017 and 2018, in the Forest Zone of southwestern Nigeria, to evaluate the yield and chemical composition of wild sunflower (Tithonia diversifolia) fertilized with compound fertilizer (20N:10P2O5:10K2O), under different planting densities. Seedlings of 20-day old Tithonia diversifolia were transplanted on a site, in a split plot arrangement, with fertilizer application at 0, 50, 100, 200 and 400kg/ha, using a planting density of 83.3 ×103, 166.7 ×103, 222 ×103, 333 ×103, 500 ×103, and 1000 ×103 plants/ha. After 114-116 days of growth, the plants were harvested and analyzed for proximate composition. The highest whole plant DM yield occurred at 400 kg/ha fertilizer level and a population density of 333×103 plants/ha. Leaf and inflorescence DM yields peaked at 400 kg/ha fertilizer application while the best leaf yield and inflorescence response to density resulted from 333 ×103 plants/ha, regardless of year under investigation. Overall fertilizer treatments and across densities, the leaf and inflorescence fractions recorded 16.88-22.92 % and 14.38-15.10% CP, 12.09-13.24 % and 21.25-23.60 % CF, 4.89-5.60 % and 3.67-4.72 % EE and 13.42-14.84 % and 6.27-7.53 % ash, respectively. Results obtained suggest that the high biomass yield of Tithonia diversifolia combined with its satisfactory nutrient levels, qualifies the plant as a potential suitable feed supplement source for ruminant livestock.
 
 
 
 
 Une étude a été menée en 2017 et 2018, dans la zone forestière du sud-ouest du Nigéria, pour évaluer le rendement et la composition chimique du tournesol sauvage (Tithonia diversifolia) fertilisé avec un engrais composé (20N:10P2O5:10K2O), sous différentes densités de plantation. Des semis de Tithonia diversifolia âgés de 20 jours ont été transplantés sur un site, dans une disposition en parcelles divisées, avec une application d'engrais à 0, 50, 100, 200 et 400 kg/ha, en utilisant une densité de plantation de 83,3 × 103, 166,7 × 103, 222. ×103, 333 ×103, 500 ×103 et 1 000 ×103 plants/ha. Après 114 à 116 jours de croissance, les plantes ont été récoltées et analysées pour déterminer leur composition immédiate. Le rendement le plus élevé en matière sèche de plante entière a été obtenu avec un niveau d'engrais de 400 kg/ha et une densité de population de 333 × 103 plantes/ha. Les rendements en matière sèche des feuilles et des inflorescences ont culminé à 400 kg/ha d'application d'engrais, tandis que le meilleur rendement foliaire et la meilleure réponse de l'inflorescence à la densité résultaient de 333 × 103 plantes/ha,quelle que soit l'année étudiée. Dans l'ensemble des traitements d'engrais et selon les densités, les fractions de feuilles et d'inflorescences ont enregistré 16,88-22,92 % et 14,38-15,10 % CP, 12,09 13,24 % et 21,25-23,60 % CF, 4,89-5,60 % et 3,67-4,72 % EE et 13,42-14,84 %. et 6,27 à 7,53 % de cendres, respectivement. Les résultats obtenus suggèrent que le rendement élevé en biomasse de Tithonia diversifolia, combiné à ses niveaux de nutriments satisfaisants, qualifie la plante comme une source potentielle de complément alimentaire appropriée pour le bétail des ruminants.

Matching light and nitrogen distributions in the maize canopy to achieve high yield and high radiation use efficiency

Light and nitrogen distribution within a plant's canopy reflect growth adaptation of crop to the environment and are conducive to improving the carbon assimilation ability. So is it possible to rationalize regulation in crop production to maximize yield by improving light and nitrogen distribution without adding additional inputs? In this study, the effects of different nitrogen application rates and planting densities on canopy light and nitrogen distribution of two high-yielding maize cultivars (i.e., XY335 and DH618) and the regulation of canopy physiological characteristics on radiation use efficiency (RUE) and yield were studied based on high yield field experiments in Qitai, China, during 2019 and 2020. The results showed that the distribution of photosynthetically active photon flux density (PPFD) in the maize canopy has been decreasing from top to bottom, while the vertical distribution of specific leaf nitrogen (SLN) initially increased and then decreased from top to bottom in the canopy. When SLN began to decrease, the PPDF of XY335 and DH618 were 0.5 and 0.3, corresponding to 40.6 and 49.3% of the total leaf area index (LAI). The KN/KL in the middle and lower canopy of the XY335 (0.32) was 0.08 higher than that of DH618 (0.24). Yield and RUE of the XY335 (17.2 t ha-1, 1.8 g MJ-1) were 7.0% (1.1 t ha-1) and 13.7% (0.2 g MJ-1) higher than that of DH618 (16.1 t ha-1, 1.6 g MJ-1). Therefore, better light conditions (the proportion of LAI in the upper and middle canopy is small) improved the light distribution when SLN started to decrease, thus helping to mobilize nitrogen distribution and maintain a high nitrogen extinction coefficient (KN) and KN/light extinction coefficient (KL). And KN/KL was a key parameter for yield improvement when maize nutrient requirements were met at 360 kg ha-1. At this time, an appropriately optimized high planting density could promote nitrogen utilization and produce higher yield and higher efficiency. This study will be important for maize high yield and high efficiency cultivation and breeding in the future.

Optimal Planting Density and Nutrient Application of Soybeans: A Case Study in Northeastern China

In the context of the Chinese government’s policy guidance, there is black soil protection and ecological environment protection. The purpose of this paper is to solve the problem that the soil ecology of the black soil in Northeast China is changing year by year, and it is necessary to explore the sowing and fertilization strategy under the new situation; most Chinese growers rely excessively on their personal experience in the process of soybean sowing and fertilization. In this study, we used “Heihe 43” soybeans and used regression experimental design methods to analyze the effects of planting density, nitrogen, phosphorus, and potassium fertilizer application on soybean yield and to determine the optimal planting density and fertilizer ratios. The study reveals that the optimal soybean planting density in Northeast China is 45.37 × 104 plants/ha, with nitrogen at 98.4 kg/ha, phosphorus at 218.96 kg/ha, and potash at 47.62 kg/ha. Under these conditions, soybean yields can reach 3816.67 kg/ha. This study can provide a theoretical method for decision-making to obtain the optimal planting density and fertilizer ratio for different regions of the farming system.

Quantifying the effects of plant density on soybean lodging resistance and growth dynamics in maize-soybean strip intercropping

Shading-induced soybean stem lodging is a prevalent concern in the maize (Zea mays L.)-soybean (Glycine max L. Merr.) strip intercropping system, leading to a substantial decline in yield. Nevertheless, the associations between soybean growth, stem lodging, and yield formation in this scenario remain unclear. To investigate this, the logistic and beta growth models were utilized to analyze the growth process of soybean organs (stems, leaves, branches, and pods) and the accumulation of carbohydrates (lignin, cellulose, and sucrose) at three planting densities (8.5, 10, and 12.5 plants m−2) in both strip intercropping and skip strip monoculture systems. The results indicate that shading stress caused by maize in the intercropping system reduced lignin and cellulose accumulation in soybean stems, thus decelerating soybean organ growth compared to monoculture. Furthermore, intercropped soybean at higher planting density (PD3) exhibited a 28% reduction in the maximum dry matter growth rate (cm) and a 11% decrease in the time taken to reach the maximum dry matter growth rate (te) compared to the lower planting density (PD1). Additionally, a 29% decrease in the maximum accumulation rate (cmax) of sucrose, lignin, and cellulose was observed, along with a 13% decrease in the continuous accumulation time (tc) of these carbohydrates in intercropped soybean at PD3. Interspecific and intraspecific shading stress led to a preferential allocation of assimilates into soybean stems, enhancing plant height during the initial stage, while at later stages, a greater proportion of sucrose was allocated to leaves. Consequently, this hindered the conversion of sucrose into lignin and cellulose within the stems, ultimately resulting in a reduction in the lodging resistance index (LRI). Overall, this study provides valuable insights into the effects of shading stress on soybean growth and yield. It also emphasizes how optimizing planting density in intercropping systems can effectively alleviate shading stress and enhance crop productivity.

Effect of planting density and micronutrient application on growth, physiological parameters and yield of rice (Oryza sativa)

The field experiments were conducted during the rainy (kharif) seasons of 2019 and 2020 at crop research centre (CRC) of Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, Uttar Pradesh to study the effect of seedling density and micronutrient application on growth, physiological parameters and yield of basmati rice (Oryza sativa L). Three planting densities, viz. 1 seedling per hill, 2 seedlings per hill and 3 seedlings per hill and 5 foliar application of micronutrient [MN0-control; MN1, B @0.04% and Fe @0.1% at maximum tillering (MT) stage; MN2, B @0.04% and Fe @0.1% at panicle initiation (PI) stage; MN3, Fe @0.1% at maximum tillering stage (MT) and B @0.04% at panicle initiation (PI) stage and MN4, B @0.04% and Fe @0.1% at maximum tillering (MT) and panicle initiation (PI) stages] were tested in a split plot design, keeping as main plots and sub plots, respectively with 3 replications. The growth, physiological traits and yield of basmati rice were significantly influenced by varying planting density and micronutrients application through leaves, as indicated by the outcomes of the experiments. Growth and physiological parameters such as dry matter accumulation, leaf area index, plant height, chlorophyll content, crop growth rate and relative growth rate increased through the application of boron and iron, being highest in foliar spray of 0.04% B and 0.1% Fe at both the stages (MT and PI). Of the different seedling densities, 3 seedlings per hill resulted in significantly higher grain yield (5.0 and 5.1 t/ha) during 1st and 2nd year, respectively. In both the years, the highest grain and straw yield were observed by using 3 seedlings per hill along with a foliar application of 0.04% B and 0.1% Fe during the MT and PI stages.

Evaluation of biomass production of CO-3 fodder grass under coconut and its effect on nut yield of intermediate zone coconut plantations in Sri Lanka

Six CO-3 fodder grass planting systems under coconut palms were evaluated for six years concerning biomass production and coconut yield. This study was carried out at Potthukulama (PRS) Research Station of the Coconut Research Institute, in the Low Country Dry Zone of the Northwestern province of Sri Lanka, where the soil series is Ambakele. According to the experiment results, the highest CO-3 biomass was produced when five CO-3 rows were planted between coconut rows and harvested in 30 days lopping interval. There was no significant effect of CO-3 planting densities and lopping intervals on the yield of coconut.

Optimizing the Growth of Silage Maize by Adjusting Planting Density and Nitrogen Application Rate Based on Farmers’ Conventional Planting Habits

Silage maize is cultivated due to its high nutritional value as a forage. China’s recent agricultural policy promotes the popularization and cultivation of silage maize. The production of silage maize is affected by planting density and nitrogen application. Based on investigating the planting habits of local farmers, we adjusted the planting density and nitrogen application rate to optimize the growth of silage maize. This study was conducted to investigate the effects of planting density (65,000 plant ha−1 (D1), 80,000 plant ha−1 (D2), and 95,000 plant ha−1 (D3)) and nitrogen rate (150 kg ha−1 (N1), 230 kg ha−1 (N2), and 310 kg ha−1 (N3)) on growth, yield, and quality of silage maize using a two-factor random block design. Planting density and nitrogen fertilizer significantly affected plant height, stem diameter, leaf area index, crude protein, neutral detergent fiber, acid detergent fiber, and starch of silage maize. In summary, the combination of a planting density of 80,000 plants ha−1 and a nitrogen application rate of 310 kg ha−1 produced a higher crude protein and starch yield and better palatability and quality; this result can aid silage maize growth.

Investigating the Effects of Planting Density on Yield and Yield Components of Chickpea Under Spring Cultivation Conditions in Takhar Province, Afghanistan

A factorial experiment was conducted as randomized complete blocks in three replications at the Agriculture Faculty research farm, Takhar University to quantify the effect of planting density and planting arrangement on some morphological traits. Experimental treatments included 15, 30, 45, and 60 cm row spacing. The harvest was done by hand when all the pods were yellow, and seeds were hard. At the time of the final harvest, ten bushes were randomly selected from each plot and used to determine the performance components (elevation of the bush, the number of pods per plant, the number of seeds per pod, the weight of 100 seeds, and the biological yield). The results showed that the effect of density on performance was not significant. The maximum yield of seeds in the planting arrangement of 30 to 45 cm row distance has been obtained at the rate of 935.76, and 996.15 kg per hectare. The maximum height of the plant was observed at the distance between the rows of 30 cm. The density decreased with increasing the distance between the planting rows from 30 to 45 cm. The number of pods increased from 14.44 to 16.33 pods per plant, i.e., 11.57 percent.

Effect of plant density in long-cane blackberry winter production

Effect of plant density in long-cane blackberry winter production

Effects of tree species and planting density on the total yield of an agroforestry system in the Brazilian Cerrado

ABSTRACT This study aimed to evaluate the effects of spacing and population density of three tree species on the primary yield of an agroforestry system in the Cerrado. The experiment was conducted in the experimental area of the State University of Goiás, São Luís de Montes Belos, Brazil. The experiment was designed to assess the effects of tree species, density, and spacing in a factorial scheme of 3 × 2 × 3, totaling 18 treatments with two tree rows each. The tree species assessed were Corymbia citriodora (seedlings), Eucalyptus cloeziana (seedlings), and an Eucalyptus urophylla clone. The trees were planted in single and triple rows (Trees planted in single and triple rows, varying density). In the first year of the experiment, maize (Zea mays) and Crotalaria juncea were sown, maize and Marandu palisadegrass (Uroclhoa brizantha cv. Marandu) in the second year, and a monoculture of Marandu palisadegrass during the third and fourth years. Due to the larger tree-covered area, the arrangement in triple rows reduced maize yield by 36% in the first year, silage yield by 40% in the second year, and pasture yield by approximately 30%. Reducing tree density is crucial to ensure the functionality of the agroforestry system.

Coupling Effects of Optimized Planting Density and Variety Selection in Improving the Yield, Nutrient Accumulation, and Remobilization of Sweet Maize in Southeast China

Low planting density and lack of density-tolerant varieties are the critical factors limiting the yield of sweet maize in Southeast China. However, there is relatively limited information about the interaction effects of plant density and variety on sweet maize in Southeast China. A two-year (2021–2022) field experiment was conducted with two sweet maize varieties (MT6855 and XMT10) and three plant densities (D1: 45,000 plants ha−1, D2: 60,000 plants ha−1, and D3: 75,000 plants ha−1). The results showed that plant density and variety had significant interaction effects on sweet maize yield and most traits. Increasing plant density significantly increased the fresh ear yield of MT6855, while it did not affect the XMT10 variety. The increase in fresh ear yield for MT6855 under D2 treatment was 14.9% and 14.0% higher than that under D1 treatment in 2021 and 2022, respectively. Meanwhile, increasing plant density significantly increased the bare plant rate and decreased the number of grains per ear of XMT10, while no sustainable changes were observed in MT6855. Moreover, we observed significantly increased pre-silking dry matter, N, P, and K accumulation across different densities in both varieties. In contrast, during the post-silking stage, the increasing plant density significantly improved the accumulation of dry matter, N, P, and K, only in MT6855 but not in XMT10. Meanwhile, harvest index, dry matter remobilization, and leaf N, P, and K remobilization of MT6855 were significantly higher than those of XMT10. Increasing plant density significantly increased N, P, and K partial factor productivity of MT6855 but did not remarkably affect those of XMT10. In addition, fresh ear yield of sweet maize was significantly and positively correlated with pre-silking, post-silking, and total N and P accumulation but had no significant relationship with leaf K remobilization across the two varieties. These results suggest that MT6855 is a density-tolerant variety of sweet maize, and optimizing planting density with a density-tolerant variety can improve the accumulation and remobilization of dry matter and nutrients, thereby improving the fresh ear yield and nutrient use efficiency of sweet maize.

Earthen pond-based floating beds for rice-fish co-culture as a novel concept for climate adaptation, water efficiency improvement, nitrogen and phosphorus management

The current study was carried out to evaluate and investigate a unique rice/fish-polyculture as Integrated Aquaculture-Agriculture Systems (IAAS) model established in Egypt, using Earthen Pond-based Floating Bed (EPFB). This novel idea is intended to improve Water, Nitrogen, and Phosphorus Use Efficiency (WUE, NUE, and PUE, respectively). Three experiments were carried out in this investigation. The first and second experiments investigated the effects of rice planting density (20, 25, and 30 plant m2) and rice seed germination methods (Styrofoam Trays Technique, SFT; Directly Outside Germination method, DOG, and Outside Germination for 24 h, 24 h-OG) on rice characteristics, N-contents, P-contents, N-retention, and P-retention of different rice parts. While the third trial, which lasted 90 days, assessed the impact of the EPFB on rice production characteristics, fish growth performances, and nutrient utilization efficiency (N-, P-contents, and retentions) in comparison to Traditional Rice Cultivation (TRC). In terms of rice production characteristics, 30 plants m−2 had the highest significant (p ˂ 0.05) yield values. A density of 20 plants m−2 produced the highest N-contents and total dietary P-content values in rice stem and leaf, whereas a density of 30 plant m−2 produced the highest total dietary N-retention and P-content values. The SFT approach produced the most significant results in terms of rice production variables and total yield, with the EPFB surpassing the TRC in terms of rice production characteristics. TRC produced slightly more (4412.32 kg Fadden −1, 2.5%) than EPFB (4295.58 kg Fadden −1). The EPFB system demonstrated a cumulative improvement in apparent FCR values (1.15) when compared to the apparent average FCR (1.80) of the polyculture system (catfish and tilapia). In terms of nutrient utilization efficiency (N-content and retention), the EPFB exceeded the TRC with values of 41.49%, 61.16%, 32.39%, and 28.01%, respectively, in root N-content and retention, kernel N-retention, and total N-retention. TRC achieved higher P-contents and P-retentions contents (%) in all rice parts than the EPFB system. EPFB had a total N-retention gain of 70.22% (15.83% in Nile tilapia, 12.15% in catfish, and 42.23% in rice), and a total P-retention gain of 30.68% (7.48% in Nile tilapia, 7.38% in catfish, and 15.82% in rice). FBPS's net income, on the other hand, was 5.45 times that of TCR. In conclusion, fish culture coupled with rice has a low environmental impact since it avoids contaminated streams and recycles wastewater ponds after biological treatment with rice. By producing rice without the use of agrochemical fertilizers, the present unique EPFB idea as an integrated system model can positively boost biomass production, improve WUE, NUE, and PUE, and decrease climate impact.

Productivity of soybean varieties of different maturity groups depending on plant density under drip irrigation in the South of Ukraine

Soybeans are a leading leguminous crop for universal use, therefore, measures aimed at increasing their productivity, including the reasonable selection of varietal resources and optimisation of planting density, will make a significant contribution to the creation of sustainable food production systems. The research aims to determine the effect of plant density on the productivity of soybean varieties of different maturity groups. Field laboratory and statistical (correlation and regression analysis) methods were used in the study. The field experiments were conducted during 2018-2020 on dark chestnut soil of a private agricultural enterprise of the agricultural company “Syvash” in Novotroitsk district of Kherson region. Its maximum values for the cultivation of early ripening varieties were ensured by a plant density of 700 thousand/ha, medium early varieties – 500-700 thousand/ha, and medium ripening varieties – 500 thousand/ha. A strong and very strong correlation between yield and soybean yield index was established. Increasing the length of the growing season contributed to the growth of yields. In the group of early maturing soybean varieties, the Monarch variety was determined to be the most productive. There was no significant difference in the level of yield of varieties within other maturity groups. For each variety, the optimum planting density was determined, at which the maximum grain yield was formed. Longer vegetation contributed to a greater accumulation of protein and fat in the grain. In terms of protein content, the difference between varieties of the same maturity group did not exceed 0.2%, but varieties differed in terms of conditional protein yield per hectare of crops. There was no difference in the fat content of mid-season soybean varieties. Among the early-ripening varieties, the Monarch variety was distinguished by higher oil content, and among the mediumearly varieties – by Aratta. The maximum conditional fat yield per hectare of crops was also determined for these varieties. A very strong and strong correlation was found between soybean grain yield and protein and fat content, respectively. A very strong correlation was also found between the protein and fat content of the grain. To ensure sustainable production and efficient use of soybeans and soybean by-products, it is advisable to take the results of the study into account in production conditions