Optimum Plant Density Research Articles

The Optimum Plant Density for Vigorous Seed Production in Safflower

Seed viability and vigor have been influenced by several factors including soil and climatic conditions, plant nutrition, fertilization, irrigation, plant population and post-harvest storages. The study was conducted to determine the appropriate plant density for vigorous seed production in safflower. The effects of row spacing (14 and 28 cm) and seeding rate (40, 80, 120, 160 and 200 seeds m-2) on yield, yield components and seed quality of safflower were detected in the study. The results showed that increased seeding rates resulted in enhanced seed yield and the highest seed yield was obtained from 14 cm and 200 seed m-2 with 3320 kg ha-1. The row spacing and seeding rate did not cause a significant difference in oil and protein contents. Laboratory emergence, germination after accelerated ageing (AA) and electrical conductivity tests were suitable for determining seed quality among the seed lots, while standard germination, cool and cold tests were not appropriate. The highest laboratory emergence percentage and germination after AA were determined in 80 seed m-2 but field emergence percentage in 120 seed m-2. It was concluded that the 14 cm row spacing and seeding rate of 120 seed m-2 should be advised for high yielding seed production regardless of seed vigor in safflower.

Optimum plant density of Digitaria eriantha for herbage accumulation and hydrological performance in a summer dominant rainfall zone

AbstractIn the frost‐prone, summer dominant rainfall zone of northern NSW and southern Queensland, sown tropical grass pastures commonly establish with plant densities >26 plants per m2, yet the optimum density for maximum herbage accumulation and hydrological performance is not known. A replicated, field study was established in northern NSW in November 2011, using five densities of Digitaria eriantha (digit grass): 0, 1, 4, 9 and 16 plants per m2 and a range of agronomic and hydrologic measures was assessed. The results showed that the largest differences between plant densities in herbage accumulation, root depth, soil water extraction and rainfall refill efficiency occurred during the first 2 years; after this time, digit grass pastures with densities of ≥4 plants per m2 responded similarly. Plant frequency increased with increasing plant density but the treatments did not converge. During the first two growing seasons, there was no effect of plant density on water use efficiency; however, by the third growing season, pastures with 4 plants per m2 were the most water efficient. Overall, the results indicated that 1 plant per m2 was too low to efficiently use resources, 16 plants per m2 utilized the resources quickly then tended to stall, while 4–9 plants per m2 was a good compromise between agronomic and hydrological response, achieving both herbage accumulation and sustainability goals. A practical management advantage of pastures with 4–9 plants per m2 is they allow soil water resources to be available for a longer period of time and potentially provide the opportunity to establish legumes in the ensuing 24‐month period.

Integrated model and field experiment to determine the optimum planting density in plastic film mulched rainfed agriculture

Ridge–furrow mulching with plastic film is widespread in northern China because it can significantly improve crop yields. Whether maize grain yield would further increase with higher plant density, due to the better soil moisture conditions under plastic mulch, is unknown. A process-based model (DeNitrification–DeComposition) coupled with a field experiment during the 2014–2015 growing seasons was used to evaluate the effect of plant density on yield. The field experiment included three treatment groups: soil fully covered with transparent polyethylene film (PM) with plant densities 35,000 (PM35), 45,000 (PM45), and 65,000 plants ha–1 (PM65) and bare soil with a maize planting density of 45,000 plants ha–1 as the control (CK). The DNDC simulated yield in PM and CK was well-matched with the measured values and maize growth pattern, and explained 64% of the yield variation and had an RMSE of 176 kg ha–1. At the same planting density (45,000 plants ha–1), individual plant weight, grain weight per plant, 100-seed weight, and grain yield in the non-mulched plots were 45, 28, 52, and 28% of the values for mulched plots, respectively. In the mulched plots, the individual plant size, grain weight, and seed size significantly decreased as planting density increased. The PM65 had 8% and 19% higher grain yield than PM45 and PM35, respectively. Increasing planting density above 45,000 plant ha–1 in the PM resulted in a small but non-significant increase in grain yield. We concluded that increasing plant density in PM will not necessarily increase maize yield, and the optimum planting density could be determined by combining the field experiment with the model.

Effects of Seed Tuber Size and Plant Population on Seed Tuber Yield of Potato (Solanum Tuberosum L.) in Central Ethiopia

Optimizing plant density and seed tuber sizes are the most important agronomic management practices in seed production of potato due to their effects on seed cost and seed tuber yields. A field experiment was conducted under irrigation during in 2014 at Holetta, Ethiopia with the objective of elucidating the effect of varied plant spacing and seed tuber sizes on seed tuber yield production. The results of analysis of variance (ANOVA) indicated that seed tuber size and plant spacing significantly (P< 0.05) influenced on average tuber weight, number of tubers and tuber yield in each seed size categories, seed tuber costs. Highest tuber yield were obtained at closer plant spacing and from medium and large seed tuber sizes whereas the lowest tuber yield were obtained at wider plant spacing and from small seed tuber sizes. The highest numbers of tubers were obtained from large seed tuber sizes and plants grown at closer plant spacing of 50 x 20, 50 x 30 and 60 x 20cm produced highest tuber number. Plant spacing 60 x 20 cm and medium-sized tubers (35-45mm) led to the production of the highest seed tuber yield and appropriate for seed tuber yield production by considering better income, seed saving and intercultural operations. Keywords: Seed tuber size, Plant population, Seed tuber yield, Seed cost DOI : 10.7176/JNSR/9-3-08

Integrated agronomic practice increases maize grain yield and nitrogen use efficiency under various soil fertility conditions

Crop yield potential can be increased through the use of appropriate agronomic practices. Integrated agronomic practice (IAP) is an effective way to increase maize (Zea mays L.) grain yield and nitrogen use efficiency (NUE); however, the physiological processes associated with gains in yield potential obtained from IAP, particularly the different under various soil fertility conditions, remain poorly understood. An IAP strategy including optimal planting density, split fertilizer application, and subsoiling tillage was evaluated over two growing seasons to determine whether the effects of IAP on maize yield and NUE differ under different levels of soil fertility. Compared to farmers' practices (FP), IAP increased maize grain yield in 2013 and 2014 by 25% and 28%, respectively, in low soil fertility (LSF) fields and by 36% and 37%, respectively, in high soil fertility (HSF) fields. The large yield gap was attributed mainly to greater dry matter (DM) and N accumulation with IAP than with FP owing to increased leaf area index (LAI) and DM accumulation rate, which were promoted by greater soil mineral N content (Nmin) and root length. Post-silking DM and N accumulation were also greater with IAP than with FP under HSF conditions, accounting for 60% and 43%, respectively, of total biomass and N accumulation; however, no significant differences were found for post-silking DM and N accumulation between IAP and FP under LSF conditions. Thus, the increase in grain yield with IAP was greater under HSF than under LSF. Because of greater grain yield and N uptake, IAP significantly increased N partial factor productivity, agronomic N efficiency, N recovery efficiency, and physiological efficiency of applied N compared to FP, particularly in the HSF fields. These results indicate that considerable further increases in yield and NUE can be obtained by increasing effective soil N content and maize root length to promote post-silking N and DM accumulation in maize planted at high plant density, especially in fields with low soil fertility.

Agronomic Optimal Plant Density by Yield Environment in Soybean

Agronomic Optimal Plant Density by Yield Environment in Soybean

Exploiting genotype x environment x management interactions to enhance maize productivity in Ethiopia

Maize is the main staple food crop grown by smallholder farmers in Ethiopia. High variability in inter-seasonal rainfall presents the biggest risk for farmers to invest in best management practices in maize crop grown in Ethiopia. Optimising genotype (G) and management (M) of maize for different growing environments (E) could alleviate risks associated with seasonal rainfall variability and enhance reliability of yield of this crop. The objectives of this study were to quantify G x E x M interactions and identify best combinations of G and M for target maize production environments in Ethiopia. Ten genotypes, five each from early and medium maturity classes were evaluated at five planting densities, 2, 5, 6, 7 and 9 plants m−2, across seven environments in 2013 and 2014 cropping seasons. Our study explored a range of morphological, phenological and physiological traits underpinning the yield of maize. Our results revealed that combining the appropriate G and M is more effective than relying on the choice of genotypes. The optimum plant densities identified in this study are higher than the plant densities currently used by farmers. Planting BH-546 and TH13321 at 7 plants m−2 substantially increased yield compared with other genotypes. For instance, yield for TH13321 was higher by 48% (3.7 t ha-1) at 7 plants m−2 in high yielding environments compared with BH-540, the most widely grown hybrid by farmers. This indicates the need for optimising G and M and using versatile genotypes to exploit variability in weather and input-use in the country. The genotypes substantially varied for their response to radiation use efficiency, rainwater productivity and leaf orientation value at high plant density. The least response to these traits observed for BH-540 highlights the need for a reassessment of current varietal and agronomic options for maize production in Ethiopia. Information from this study could be extended to sub-Saharan African countries that are similarly using low plant density.

Response of sunflowers (Helianthus annuus L.) to varying seeding rates and nitrogen fertilizer rates in a no-till cropping system in Saskatchewan

In the past, most sunflower research was conducted in tilled cropping systems and was based on wide row configurations established using precision planters. Little agronomic information is available for the no-till systems predominant in Saskatchewan, where crops are typically seeded in narrow rows using an air drill. Two studies were conducted in Saskatchewan to determine the optimum seeding and nitrogen (N) rates for short-season sunflowers in a no-till cropping system. The N rate study used 5 N rates (10, 30, 50, 70, and 90 kg N ha−1) with the hybrid 63A21. The seeding rate study used 7 seeding rates (37 000, 49 000, 61 000, 74 000, 86 000, 98 000, and 111 000 seeds ha−1) with two cultivars, AC Sierra (open pollinated) and 63A21 (hybrid). There was a linear yield increase as the N rate increased from 10 to 90 kg N ha−1. Based on the N rates tested in this study and current N fertilizer costs below $1 kg−1, sunflower yields and gross returns were most favorable at 90 kg N ha−1. Future N response research with a wider range of N rates is warranted to best determine the optimum N rate. The optimum seeding rate was between 98 000 and 111 000 seeds ha−1 for AC Sierra and between 74 000 and 86 000 seeds ha−1 for 63A21. The optimum plant density, approximately 70 000 to 75 000 plants ha−1, was similar for both cultivars. These results are higher than the current recommended seeding rates for wide-row precision planting systems in areas with a longer growing season.

Crop Yield and the Quality of Sunflower Seeds in the Use of Fertilizers and Growth Regulation Substances

AbstractIn the Russian Federation the most favorable area for high and stable yields of sunflower crop is the Northern zone of Krasnodar region. The research was conducted in multivariate experience of long-term stationary monitoring. We researched the effect of doses of mineral fertilizers and furolan on sunflower yield and seed quality. It was found that it is expedient and cost-effective to use small doses of nitrogen fertilizers for sunflower. The expediency of application of plant growth regulator (Furolan) during vegetation is shown. We found that the use of mineral fertilizers and the use of furolan contributed to the activation of growth processes of sunflower plants which led to the formation of optimal plant density. Improving the nutritional status of plants has provided an increase in the leaf area unit. The treatment of sunflower crops on the background of fertilizers N20P30 and the furolan has had a positive impact on the value of photosynthetic potential. Under the influence of mineral fertilizers there was an increase in the dissemination of the sunflower head, weight of seeds and weight of 1000 seeds, which has a positive impact on productivity. With the increase of fertilizer doses, the oil content of seeds increased when compared to the unfertilized variant. The treatment of plants with furolan has not violated the process of accumulation of protein and fat.

Density resistance evaluation of maize varieties through new \u201cDensity\u2013Yield Model\u201d and quantification of varietal response to gradual planting density pressure

Increasing planting density is the main method and key management to enhance the grain yield. Preventing lodging and premature senescence in high planting density, and screening and enhancing the density-tolerance of maize variety is the main goal of agronomy. Differential response of maize hybrids to high plant density greatly affect the dry matter accumulation and its allocation to maize kernel, depending upon various traits responsible for crowding stress tolerance, of which ear characteristics are pivotal. Density resistance as a quality appraisal of certain variety permits the construction of a simple and accurate method to determine this value, useful for plant breeding. Therefore, we created a new quantitative method, which tested several maize varieties planted populary in China (e.g. Zhengdan 958, Xianyu 335, and Denghai 661) to quantify their response to crowding stress through model. We established 13 planting densities (ranging 1.67–16.67 plants m−2) by adopting fixed line spacing (80 × 40 cm) and then gradually increasing row spacing from 1 m to increasing planting density. A conventional standard plot was also established for verification and evaluation of the plant morphologic characteristics, ear traits, and the yield of maize at various standard densities during 5-year study period. By studying the density–yield relationship, a quantitative model was constructed to identify the density resistance of maize. Grain yield of maize varieties under varying planting densities were simulated, and models of population yield and yield per plant that fitted the data well with high biological significance were produced. From the models, the optimal density of the popular main maize varieties planted in China and the morphological characteristics of each variety at that density were identified. The density-resistance of each variety was referred to as the ear-sensitivity classification. With the highest yield at the optimal density, the plant height of each variety reached 98% to that of tallest plant. The ear/plant ratio was about 0.45, and the ratio between the stem diameter and the largest stem diameter was 0.65–0.80. During the harvest period, the ratio between average single-plant yield and the highest single-plant yield was 0.40–0.50. By gradually increasing planting density, the density resistance of the maize and the changes in yield with density were quantified. Present study provides a convenient tool for the effective selection of varieties by plant breeders through this method and model will help to rapidly identify the density resistance for a new variety and accurate confirmation to optimal planting density, it could be optimized to enable practical production at reasonable planting densities.

Effect of organic manure and plant population on growth and yield of Vicia faba L.

A field experiment was conducted at Alwardea farms in Babylon governorate during winter season i. e. 2014–15. The experiments were conducted in silty clay soil to investigate the effect of population density and organic manure on growth and yield of broad bean-Spanish cultivar (Barcelona). Three poultry residue levels (0, 2 and 4 t/ha) and three levels of plant population (180.000, 240.000 and 300.000 plants/ha) were used. RCBD factorial experiment method was followed with three replicates. The results showed that there was a significant difference in organic residue levels. From the results, it was inferred that addition with 4 t/ha was the best choice for optimum plant height, number of branches, chlorophyll content, weight of 100 grains, and total yield when compared to control samples which resulted in low means of the studied parameters. On the other hand, the results revealed a significant difference between the planting density in all growth and yield indicators. The optimum planting density was 180.000 plants/ha in which the number of branches, chlorophyll content in leaves, weight of 100 seeds and total yield (2710 kg/ha) were achieved. The interaction treatment (4 t/ha and 180.000 plants/ha) was significant in all the interactions.

Response of canopy structure, light interception and grain yield to plant density in maize

AbstractGood canopy structure is essential for optimal maize (Zea maysL.) production. However, creating appropriate maize canopy structure can be difficult, because the characteristics of individual plants are altered by changes in plant age, density and interactions with neighbouring plants. The objective of the current study was to find a reliable method for building good maize canopy structure by analysing changes in canopy structure, light distribution and grain yield (GY). A modern maize cultivar (ZhengDan958) was planted at 12 densities ranging from 1.5 to 18 plants/m2at two field locations in Xinjiang, China. At the silking stage (R1), plant and ear height increased with plant density as well as leaf area index (LAI), whereas leaf area per plant decreased logarithmically. The fraction of light intercepted by the plant (F) increased with increasing plant density, but the light extinction coefficient (K) decreased linearly from 0.61 to 0.39. Taking the optimum value ofF(95%) as an example, and using measured values ofKfor each plant density at R1 and the equation from Beer's law, the corresponding (theoretical) LAI for each plant density was calculated and optimum plant density (9.72 plants/m2) obtained by calculating the difference between theoretical LAIs and actual observations. Further analysis showed that plant density ranging from 10.64 to 11.55 plants/m2yielded a stable GY range. Therefore, taking into account the persistence time for maximum LAI, the plant density required to obtain an ideal GY maize canopy structure should be increased by 10–18% from 9.72 plants/m2.

Plant density and peanut crop yield (Arachis hypogaea) in the peanut growing region of Córdoba (Argentina)

ABSTRACT Plant density is one of the most important management factors affecting the peanut growth, modifying the capacity to capture radiation, water and nutrients. Peanut yield response to increased plant density changes according to environmental conditions, the genotype used, and planting date. Therefore, the optimum plant density (OPD) may vary with location. The aim of this project was (i) to fit the Mitscherlich's equation of diminishing productivities to the yield response of runner-type peanuts to increasing plant density under different growing conditions in the peanut growing region of Cordoba Argentina; and (ii) validate this model with independent experimental data. The first stage was based on the analysis of data from different projects of plant densities carried out in the peanut growing area of Córdoba. This information was adjusted to the decreasing yield equation and the OPD was calculated. For validation, a field experiment was conducted during the 2013/14 and 2014/15 growing seasons under irrigated and rain-fed conditions where pod yield was evaluated for 5, 12, 18, 25 and 36 plants/m2. No interaction was detected between soil moisture conditions and plant density. Yield response to plant density had a high degree of fitness for a wide range of environmental and crop conditions. In field experiments, the peanut yield decreased only at the lowest plant density (5 plants/m2). Yield response to density adjusted to the Mitscherlich equation indicated that OPD ranged from 10.5 to 24.8 plants/m2. Using a single adjustment equation y = 1(1 – e−0.1784x), OPD was estimated to be 16.8 plants/m2 at harvest (11.7 plants per linear meter in 0.7 m between rows) for the peanut growing region of Cordoba. This approach can be a valuable input, along with other variables to analyze, when choosing peanut sowing density.

Corn (Zea mays L.) yield and yield components as affected by light properties in response to plant parameters and N fertilization

Abstract Light absorption and light extinction can importantly affect crop growth and yield production. Accordingly, two field (split plot) experiments were conducted to investigate: 1) the most optimum plant spacing (S) and density (D), which result in the highest rate of corn yield and yield components as affected by light absorption (L) and extinction (K), 2) the most efficient corn genotype (G) and the most optimum N fertilization rate (N), which effectively increase corn yield and yield components by affecting corn light properties. D and N were devoted to the main plots and S and G were used as the sub treatments. Light absorption was measured using a light meter and the coefficients of light extinction (K) were calculated. D, N and G as well as their interactions were the most effective factors on corn light properties, growth and yield. The crop density of 10–12 significantly affected corn growth and yield production. D12 resulted in the highest LAI (4.40), L (16.00%), and biological yields (20,623.8 kg/ha). However, the highest K (0.79), grain yield (2398.8 kg/ha), and harvest index (14.36) were related to D6. Although plant height increased up to S60 (234.8 cm) (P = 0.05), the highest and significantly different LAI was resulted by S50 (4.20). S60 also resulted in the highest L (20.91%). Increasing S also increased K according to the following: S50 (0.69), S60 (0.80), and S75 (0.93). Elevating N significantly increased (P = 0.05) cob length and LAI at N100 (15.39 cm, 6.574) and N150 (15.72 cm, 6.512). The highest L, (28.58%, P = 0.1), K (0.51), biological (16,230.1) and grain (3623 kg/ha) yields as well as harvest index (22.33) were resulted by N100. Genotype SC704 resulted in the highest LAI (6.381), L (22.80%), K (0.49), and grain yield (3501 kg/ha). Although with increasing D, corn leaf area index (LAI) and L increased, K decreased, which may be used as an indicator of light efficiency utilized by crop. Such results indicate that measurement of K is also essential for the proper determination of corn plant response to light. The most optimum N treatment was 100 kg/ha and the most efficient G was SC704. D, N and G are among the most important factors affecting corn light properties, growth and yield, compared with S. It is strongly suggested that such experiments be conducted under different climatic conditions to indicate the significance of the experimental treatments on corn light properties, growth and yield. The results of these experiments can be used for the proper designing of corn plantation resulting in the highest rate of efficiency with respect to the available resources and the present climatic conditions.

High density orcharding and canopy management in guava

High density planting (hdp) is a highly efficient and advanced production system of fruit cultivation. High yield and good fruit quality can be achieved with a high density orchard in guava when the orchard has good light distribution throughout the tree canopy and there is a balance between vegetative growth and cropping. Guava bears on the current season emerging shoots. Regular pruning of shoots after fruit harvest encourages development of lateral shoots from which flowering occurs. Researchers from major guava growing countries like India, Mexico, Cuba, Venezuela, Australia, etc. have worked out the optimum plant density and canopy management techniques for higher yield and quality guava production. The techniques for ultra-high density (5000 plants ha-1) planting and rejuvenation of old, unproductive or senile orchards by canopy management have also been standardized in India. This paper reviewed the prospects of hdp and canopy management in guava.

Corn Yield Response to Plant Density and Nitrogen: Spatial Models and Yield Distribution

Core Ideas Corn yield response to plant density and N rate were dependent on yield environment.Agronomic optimal plant density and N rate were positively correlated to yield level.Yield to density within a yield environment was independent on year, country, and hybrid.Similarity in yield frequency data distributions lead to similar yield–factor responses. Understanding the relationship of corn (Zea mays L.) yield responses to plant density and nitrogen (N) fertilization is critical to production decisions. The main objectives of this study were to (i) evaluate yield responses to plant density and fertilizer N rate at varying yields adjusting models considering a spatial component, (ii) perform a validation for the fitted models with an independent dataset, and (iii) identify key statistical parameters for the yield data distribution governing response models. Analyses were conducted with information from seven fields with 21 studies (one study per yield environment, with three environments per field) conducted from 2009 to 2017 in southern Brazil with geospatial data collected to evaluate yield response to plant density and fertilizer N rates (28911 data points) and one additional database with 12 field studies conducted from 2012 to 2015 in the US Midwest (1773 data points). Databases were divided into training and validation datasets. Field experiments evaluating both plant density and N rate were selected as training dataset. Key research findings were (i) yield–factor response models were dependent on yield environment and within a yield environment those models remained constant regardless the year, country, and hybrid for all evaluated fields, (ii) statistical models considering spatial correlation of the random errors outperformed those considering errors independent and identically distributed and, (iii) yield distribution with comparable 50% interquartile range and mode portrayed similar yield–factor relationship. In summary, fitting spatial yield–density models considering yield data distribution is critical to upscale site‐specific models to larger spatial domains.

Integrated soil-cotton system management enhances triacylglycerol yield and favourable fatty acid profile

Enhancement of triacylglycerol (TAG) and oleic acid accumulation in cottonseed is desirable as it is world’s sixth largest source of plant oil in addition to its potential application in biofuel industry and material industry. In this two years study, economic N management technology, optimal plant density and simplified seedling raising technology were integrated to investigate the systematic advantage of integrated soil-cotton system management (ISSM1 and ISSM2) over conventional management practice (CM) on lipid and fatty acid profiles of cottonseed embryos under different soil available nutrition conditions. In cottonseed embryos, TAG constituted for 94.7% to 97.8% of the total lipids and the integrated soil-cotton system management resulted in the TAG yield and oleic acid increased by 32.5% and 4.5% in ISSM1 embryos, and by 19.8% and 3.8% in ISSM2 embryos. A high embryo weight compensates decreased TAG content resulted from increased N rate. Moreover, TAG yield was positively related to TAG accumulation rate, and the rapid TAG accumulation stage from 24 days to 35 days contributed the highest to the increased TAG accumulation rate (0.15 g–0.18 g per 100 embryos per day). Increased activities of glucose-6-phosphate and phosphatidate phosphatase were observed under ISSM1 and ISSM2, which reflect a quantity increase in carbon flux and energy production required for lipid biosynthesis. Moreover, increased phosphoenolpyruvate carboxylase not only regulates carbon partitioning but also enhances seed filling period and embryo weight. Taken our results suggest that the combination of simplified seedling raising technology, economic N management schedule and optimal plant density was capable of increasing carbon flux and energy production required for lipid biosynthesis and thus generate high levels of embryo TAG and oleic acid at different soil available nutrition conditions. Targeted improvement of cottonseed yield should not focus on TAG content alone but also embryo weight and seed filling period.

Analysis of Long Term Study Indicates Both Agronomic Optimal Plant Density and Increase Maize Yield per Plant Contributed to Yield Gain

Concurrent to yield, maize (Zea Mays L.) plant density has significantly increased over the years. Unlike yield, however, the rate of change in plant density and its contribution to maize yield gain are rarely reported. The main objectives of this study were to examine the trend in the agronomic optimum plant density (AOPD) and quantify the contribution of plant density to yield gain. Maize hybrid by seeding rate trials were conducted from 1987–2016 across North America (187,662 data points). Mixed model, response surface, and simple linear regression analyses were applied on the meta-data. New outcomes from this analysis are: (i) an increase in the AOPD at rate of 700 plant ha−1 yr−1, (ii) increase in the AOPD of 1386, 580 and 404 plants ha−1 yr−1 for very high yielding (VHY, > 13 Mg ha−1), high yielding (HY, 10–13 Mg ha−1) and medium yielding (MY, 7–10 Mg ha−1), respectively, with a lack of change for the low yielding (LY, < 7 Mg ha−1) environment; (iii) plant density contribution to maize yield gain ranged from 8.5% to 17%, and (iv) yield improvement was partially explained by changes in the AOPD but we also identified positive impacts on yield components as other sources for yield gain.

PERFORMANS COVER CROPS HIJAUAN PAKAN TERHADAP LEVEL PUPUK BOKASHI DAN KEPADATAN POPULASI

RESPONS OF FORAGES COVER CROPS ON LEVEL OF ORGANIC FERTILIZER BOKASHI AND PLANT POPULATION DENSITY. The objectives of this research was to asses the interaction of bokashi levels and plant population density on vegetative growth of sorghum Brown Midrib (BMR) and Leucaena leucocephala legume trees. Level bokashi were LB1 = 0 G; LB2 = 200 G; LB3 = 400 G and LB4 = 800 G pot-1 interact with plant population density of KP1 = 2 plants; KP2 = 4 plants and KPB3 = 6 plants pot-1 of BMR, and for Lamtoro plant density were KP1= 1 plat, KP2= 2 plant, KP3= 3 plant and KP4 = 4 plant pot-1. Treatments were arranged in a 4 x 3 factorial with 3 replications based on a Completely Randomized Design. Variable measured were leaf length of leaf, number of leafes and plant height. The results showed that the interaction of both treatment had significant effect on leaf length (P&lt;0.05), but did not have significant effect (P&gt;0,05) on number of leafs and plant height of BMR. On the otherhand the optimum plant density was 3 plant per pot. Based on this results can be concluded that to get optimal vegetative growth of sorghum BMR needs bokashi fertilizer by 400 G/polybag at density of 2 plants/polybag, but up to 3 plant per pot for lamtoro.Keywords:Bokashi level of chicken manure, plant population density level, growth sorghum, growth.

Light interception and radiation use efficiency response to tridimensional uniform sowing in winter wheat

Improving radiation use efficiency (RUE) of the canopy is necessary to increase wheat (Triticum aestivum) production. Tridimensional uniform sowing (U) technology has previously been used to construct a uniformly distributed population structure that increases RUE. In this study, we used tridimensional uniform sowing to create a wheat canopy within which light was spread evenly to increase RUE. This study was done during 2014–2016 in the Shunyi District, Beijing, China. The soil type was sandy loam. Wheat was grown in two sowing patterns: (1) tridimensional uniform sowing (U); (2) conventional drilling (D). Four planting densities were used: 1.8, 2.7, 3.6, and 4.5 million plants ha−1. Several indices were measured to compare the wheat canopies: photosynthetic active radiation intercepted by the canopy (IPAR), leaf area index (LAI), leaf mass per unit area (LMA), canopy extinction coefficient (K), and RUE. In two sowing patterns, the K values decreased with increasing planting density, but the K values of U were lower than that of D. LMA and IPAR were higher for U than for D, whereas LAI was nearly the same for both sowing patterns. IPAR and LAI increased with increasing density under the same sowing pattern. However, the difference in IPAR and LAI between the 3.6 and 4.5 million plants ha−1 treatments was not significant for both sowing patterns. Therefore, LAI within the same planting density was not affected by sowing pattern. RUE was the largest for the U mode with a planting density of 3.6 million plants ha−1 treatment. For the D sowing pattern, the lowest planting density (1.8 million plants ha−1) resulted in the highest yield. Light radiation interception was minimal for the D mode with a planting density of 1.8 million plants ha−1 treatment, but the highest RUE and highest yield were observed under this condition. For the U sowing pattern, IPAR increased with increasing planting density, but yield and RUE were the highest with a planting density of 3.6 million plants ha−1. These results indicated that the optimal planting density for improving the canopy light environment differed between the sowing patterns. The effect of sowing pattern×planting density interaction on grain yield, yield components, RUE, IPAR, and LMA was significant (P<0.05). Correlation analysis indicated that there is a positive significant correlation between grain yield and RUE (r=0.880, P<0.01), LMA (r=0.613, P<0.05), and spike number (r=0.624, P<0.05). These results demonstrated that the tridimensional uniform sowing technique, particularly at a planting density of 3.6 million plants ha−1, can effectively increase light interception and utilization and unit leaf area. This leads to the production of more photosynthetic products that in turn lead to significantly increased spike number (P<0.05), kernel number, grain weight, and an overall increase in yield.