Effects Of Different Application Rates Research Articles

Monitoring the effect of different application rates of plant growth regulators in altering the canopy of hybrid cotton (Gossypium hirsutum L.)

Monitoring the effect of different application rates of plant growth regulators in altering the canopy of hybrid cotton (Gossypium hirsutum L.)

Exploring the effect of different application rates of biochar on the accumulation of nutrients and growth of flue-cured tobacco (Nicotiana tabacum).

Biochar application has become one of the most potential tools to improve soil fertility and plant growth for sustainable and eco-friendly agriculture. However, both positive and negative effects of biochar application have been recorded on plant growth and soil fertility. This study investigated the impact of different application rates (0, 600, 900, 1200, and 1800 kg/ha) of biochar on the soil nutrient contents, accumulation of nutrients and dry matter in different plant parts, and growth of flue-cured tobacco plants under field conditions. Results demonstrated that soil organic carbon pool and carbon/nitrogen ratio were increased proportionally with the increasing dosage of biochar, 25.54 g/kg and 14.07 g/kg compared with control 17 g/kg and 10.13 g/kg, respectively. The contents of soil total nitrogen were also significantly increased after biochar application in the middle (1.77 g/kg) and late-growth (1.54 g/kg) stages of flue-cured tobacco than in control (1.60 g/kg and 1.41 g/kg, respectively). The contents of soil nitrate nitrogen were also higher under low (600 and 900 kg/ha) application rates of biochar and reduced when higher (1200 and 1800 kg/ha) dosages of biochar were applied. However, it was observed that varying application rates of biochar had no impact on soil ammonium nitrogen content during the growth period of flue-cured tobacco plants. The nutrient accumulation (N, P, K) in different parts of flue-cured tobacco plants was significantly increased under a low application rate of biochar, which enhanced the soil and plant analyzer development values, effective leaves number, growth, dry matter accumulation, and leaf yield of flue-cured tobacco. In contrast, the high biochar application rate (1200 and 1800 kg/ha) negatively impacted nutrient accumulation and growth of flue-cured tobacco. Conclusively, the optimum application of biochar (600 and 900 kg/ha) is beneficial for plant growth, soil fertility, accumulation of nutrients, and dry matter in different plant parts. However, excessive biochar application (> 900 kg/ha) could inhibit flue-cured tobacco plant growth. This study provides a theoretical foundation for biochar application in tobacco and other crop production to obtain agricultural sustainability and economic stability.

Effect of rate of biofertilizers on growth and development of spinach (Spinacia Oleracea L.)

This research delves into the utilization of biofertilizers as a sustainable substitute for conventional chemical fertilizers, offering multifaceted advantages for soil fertility, plant vitality, and ecological equilibrium. The study investigates the effects of different application rates of biofertilizers on various growth parameters, nutrient assimilation efficiency, yield components, and physiological responses in spinach cultivation. A series of experimental trials were conducted to evaluate the impacts of biofertilizer treatments, comprising vermicompost, Azotobacter, and phosphate-solubilizing bacteria (PSB), on spinach plants. The results indicate that combined application of biofertilizers significantly enhances key parameters including plant height, leaf area, shoot biomass, root biomass, nutrient assimilation efficiency, yield components, and physiological responses compared to conventional fertilizer practices and control groups. Correlation and regression analyses reveal strong positive relationships between levels of biofertilizer application and various growth metrics, nutrient assimilation efficiency, yield components, and physiological responses. Furthermore, ANOVA results confirm the statistical significance of differences among treatment groups, highlighting the efficacy of biofertilizers in promoting spinach growth and productivity. Economic evaluations suggest that despite higher initial costs, the use of biofertilizers results in increased spinach yields, making it a financially viable and environmentally sustainable alternative to traditional fertilization methods.

Application rate and hydraulic tips used in remotely piloted aircraft affect the phytosanitary products in coffee plant canopies

Most coffee (Coffea arabica) phytosanitary management techniques are performed using ground-based equipment, and remotely piloted aircraft are a recent alternative. Therefore, this study evaluates the effect of different application rates and hydraulic tips used for spreading phytosanitary products on coffee crops using a remotely piloted aircraft, assisted by artificial targets and dye tracing. The experiment was a 4 × 3 factorial randomized block design with four tips (XR 110-01, TT 110-01, AIXR 110-015, and TTJ60 110-02) and three application rates (8, 12, and 16 L ha-1). Hydrosensitive paper was used to analyze the droplet spectrum, and the Brilliant Blue tracer was used to detect spray deposition. The DJI Agras T20 remotely piloted aircraft was used to apply the phytosanitary product. Speed, flight height, and application range were maintained at 5.56 m s-1, 2 m, and 5 m, respectively. The flight direction was perpendicular to the crop planting lines. The application rate and hydraulic tip jointly controlled the accumulation of droplets on the target according to its position in the plant canopy. Therefore, remotely piloted aircraft can be used in coffee phytosanitary management, particularly to control targets that predominately occur in the upper third of the plant canopy.

Elucidating the impact of biochar with different carbon/nitrogen ratios on soil biochemical properties and rhizosphere bacterial communities of flue-cured tobacco plants.

In agriculture, biochar (BC) and nitrogen (N) fertilizers are commonly used for improving soil fertility and crop productivity. However, it remains unclear how different levels of BC and N fertilizer affect soil fertility and crop productivity. This study elucidates the impact of different application rates of BC (0, 600, and 1200 kg/ha) and N fertilizer (105 and 126 kg/ha) on biomass accumulation, soil microbial biomass of carbon (SMC) and nitrogen (SMN), and soil biochemical properties, including soil organic carbon (SOC), total nitrogen (TN), soil nitrate nitrogen (NO3--N), ammonium nitrogen (NH4+-N), urease (UE), acid phosphatase (ACP), catalase (CAT), and sucrase (SC) of tobacco plants. In addition, a high throughput amplicon sequencing technique was adopted to investigate the effect of different application rates of BC/N on rhizosphere bacterial communities of tobacco plants. The results confirm that high dosages of BC and N fertilizer (B1200N126) significantly enhance dry matter accumulation by 31.56% and 23.97% compared with control B0N105 and B0N126 under field conditions and 23.94% and 24.52% under pot experiment, respectively. The soil biochemical properties, SMC, and SMN significantly improved under the high application rate of BC and N fertilizer (B1200N126), while it negatively influenced the soil carbon/nitrogen ratio. Analysis of rhizosphere bacteriome through amplicon sequencing of 16S rRNA revealed that the structure, diversity, and composition of rhizosphere bacterial communities dramatically changed under different BC/N ratios. Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, and Acidobacteria were highly abundant bacterial phyla in the rhizosphere of tobacco plants under different treatments. Co-occurrence network analysis displayed fewer negative correlations among rhizosphere bacterial communities under high dosages of biochar and nitrogen (B1200N126) than other treatments, which showed less competition for resources among microbes. In addition, a redundancy analysis further proved a significant positive correlation among SMC, SMN, soil biochemical properties, and high dosage of biochar and nitrogen (B1200N126). Thus, we conclude that a high dosage of BC (1200 kg/ha) under a high application rate of N fertilizer (126 kg/ha) enhances the biomass accumulation of tobacco plants by improving the soil biochemical properties and activities of rhizosphere bacterial communities.

Effect of Attapulgite Application on Aggregate Formation and Carbon and Nitrogen Content in Sandy Soil

Clay minerals are the main cementing substances for sandy soils to form aggregates. The clay mineral attapulgite clay is abundant in Northwest China, and its special colloidal properties and crystal structure make it excellent in improving soil physicochemical properties. Using attapulgite as soil conditioner, the effects of different application rates of attapulgite on the formation and stability of sandy soil aggregates were studied through field experiments for two consecutive years. The results showed that the application of 6000 kg·hm−2 attapulgite soil in sandy soil farmland for two consecutive years reduced the soil bulk density by 0–20 cm, from 1.55 g·cm−3 to 1.47 g·cm−3, a decrease of 3.6%; the soil pH was increased by 3.7% from 8.59 to 8.84. The soil organic carbon, inorganic carbon and total nitrogen in the whole soil increased by 4.52%, 5.23% and 6.22%, respectively. The mass fraction of macro-aggregates of 2–0.25 mm and micro-aggregates of 0.25–0.053 mm as well as the contents of organic carbon, inorganic carbon and total nitrogen increased by 3.5%, 5.2%, 8.7%, 5.6% and 6.7%, respectively, thus improving the stability of aggregates. However, low application rates (1500 kg·hm−2 and 3000 kg·hm−2) of attapulgite had no significant effect on soil physical and chemical properties. Attapulgite, as a kind of highly adsorptive clay mineral, can be directly applied to sandy soil to increase soil cementitious substances, promote the formation of soil aggregates and increase the carbon and nitrogen fixation capacity of sandy soil. The improvement effect on the formation and stability of aggregates will gradually accumulate with the years of application. Therefore, in the future, the effects of adding attapulgite on the growth of various crops under various types of soil and climatic conditions should be carried out to obtain more systematic conclusions.

Magnesium improved fruit quality by regulating photosynthetic nitrogen use efficiency, carbon-nitrogen metabolism, and anthocyanin biosynthesis in 'Red Fuji' apple.

Both nitrogen (N) and magnesium (Mg) play important roles in biochemical and physiological processes in plants. However, the application of excessive N and insufficient Mg may be the factor leading to low nitrogen utilization rate (NUE) and fruit quality degradation in apple production. In this study, we analyzed the effects of different application rates of Mg (0, 50, 100, 150, 200 kg/ha) on the photosynthetic nitrogen use efficiency (PNUE), the accumulation and distribution of carbon (C), N metabolism, anthocyanin biosynthesis and fruit quality of the 'Red Fuji' apple in 2018 and 2019. The results showed that the application of Mg significantly increased the 15NUE and increased the allocation rate of 15N in the leaves whereas the 15N allocation rate in the perennial organs and fruits was decreased. With the increase in Mg supply, the activities of N metabolism enzymes (NiR, GS, and GOGAT) were significantly promoted and the content of intermediate products in N metabolism ( , , and free amino acid) was significantly decreased. Furthermore, an appropriate rate of Mg significantly promoted the net photosynthetic rate (Pn) and photosynthetic nitrogen use efficiency (PNUE), enhanced the enzyme activities of C metabolism (SS, SPS, S6PDH), and increased the contents of sorbitol and sucrose in leaves. In addition, Mg upregulated the gene expression of sugar transporters (MdSOT1, MdSOT3, MdSUT1, and MdSUT4) in fruit stalk and fruit fresh; 13C isotope tracer technology also showed that Mg significantly increased the 13C allocation in the fruits. Mg also significantly increased the expression of anthocyanin biosynthesis genes (MdCHS and MdF3H) and transcription factors (MdMYB1 and MdbZIP44) and the content of anthocyanin in apple peel. The comprehensive analysis showed that the appropriate application of Mg (150 kg/ha) promoted PNUE, C-N metabolism, and anthocyanin biosynthesis in apple trees.

Dynamic and Migration Characteristics of Soil Free Amino Acids in Paddy Soil Applied with Milk Vetch

To explore the attribution factors and migration characteristics of free amino acids (FAAs) in paddy soils after green manure application during the entire growth period of rice. Amino acid analyzer, quantitative PCR, and high-throughput sequencing were used to analyze the effects of different application rates of milk vetch on FAAs in paddy soil under equal nitrogen, phosphorus, and potassium conditions. Soil FAAs concentration at different growth stages was highest at the seedling stage and lowest at the tillering stage. The concentration of threonine, alanine, valine, isoleucine, leucine, and phenylalanine was most abundant during the growth period, accounting for 59.42–76.46% of the respective FAAs pool. The application of milk vetch was shown to increase the soil FAAs concentration, especially glutamic acid, which increased by 368.17–680.78%, but the excessive application had an inhibitory effect. Soil bacteria were critical factors affecting soil FAAs dynamics, among which Bacteroidetes, Firmicutes, and Nitrospirae contributed 56.89% to the FAAs dynamics. FAAs displayed significant vertical profile characteristics, and the mobility of serine, glycine, and proline was high. Conclusively, the application of milk vetch was able to significantly change the concentration and composition of soil FAAs, which were affected by soil bacteria.

Influence of Poultry Manure Application Rates on Red and Yellow Varieties of Watermelon (Citrullus lanatus) in the Marginal Mineral Soil of Bukit Kor (Marang)

Increased crop yields and higher soil quality can be achieved by using the appropriate amount of fertiliser at the right time. A study on optimal poultry fertiliser rates for watermelon development on nutrient deficient soil, contributes to the current knowledge base. Thus, this paper intends to ascertain the effect of different application rates of poultry fertilizer on growth and yield properties of two cultivars of watermelon (Citrullus lanatus) on soil with marginal nutrients. Accordingly, an experiment was conducted at Universiti Malaysia Terengganu's research farm at Bukit Kor (Marang) to compare the effects of various application rates (T1: 0T/Ha, T2: 10T/Ha, T3: 20T/Ha, T4: 30T/Ha) of poultry manure on the performance of two watermelon varieties (V1:yellow variety (golden delight) and V2:red variety (new dragon)). Several growth and yield parameters were determined, of which the treatments on the red variety at 20THa^-1 and 30THa^-1 produced the significant higher results for vine length (189.38 & 189.43cm), number of leaves (61 & 63), number of lateral branches (2.5 & 2.33), leaf area index (0.12 & 0.13), chlorophyll content SPAD (36.32 & 37.03), fruit weight (10.23 & 9.84THa^-1) and number of flowers (8.33 & 11.7). The present research, therefore, contributes to a growing body of evidence suggesting that the red variety of watermelon treated with 20THa^-1 or 30THa^-1 presented the best results.

Nitrous oxide and carbon dioxide emissions from two types of soil amended with manure compost at different ammonium nitrogen rates

ABSTRACT Ammonium nitrogen (NH4 +-N) content in soil is a key factor affecting nitrous oxide (N2O) emissions due to its role as a primary substrate of nitrification. This study aimed at investigating the effects of different application rates of NH4 +-N on N2O and CO2 emissions from two different types of manure compost-amended soil, along with analysis of relative abundances of narG and nosZ genes under aerobic conditions. Laboratory experiments were conducted using Kochi and Ushimado soils amended with mixed compost (MC: mixture of cattle, poultry, and swine manure) or cattle manure compost (CC) at 3% (dry weight basis). In no compost- and compost-amended soils, (NH4)2SO4 was added as a solution equivalent to 160, 200, and 400 mg-N kg−1 of soil. Soil samples were aerobically incubated at 70% water-holding capacity (WHC) and 25°C. Emissions of N2O and CO2 were measured on days 0, 3, 7, 15, 21, 28, and 42. The abundances of narG and nosZ genes in Kochi (day 7) and Ushimado (day 21) soils were estimated using qPCR tests. Emissions of N2O and CO2 were higher in MC-amended soil because of higher mineral N content and lower C/N ratio of MC than those of CC, regardless of NH4 +-N rates. Emissions of N2O and CO2 were higher in compost-amended Kochi soil due to higher mineral N, total N and C, and clay contents, and possibly because of higher water-filled pore spaces than those in Ushimado soil at the same WHC. In both soils with CC and no compost, raising NH4 +-N rate from 160 to 200 increased N2O emissions due to stimulation of nitrification. In contrast, increasing NH4 +-N rate from 200 to 400 decreased N2O and CO2 emissions except for N2O emissions in MC- and CO2 emissions in CC- and no compost-amended Ushimado soil possibly due to osmotic stress on microorganisms and limited C availability. Emissions of N2O were positively related to narG gene copy numbers in Kochi soil (R 2 = 0.78) due to high N and C contents. Our study revealed that NH4 +-N rate 400 suppresses N2O and CO2 emissions from manure compost-amended soil under aerobic conditions.

Effect of indaziflam on microbial activity and nitrogen cycling processes in an orchard soil

Indaziflam is a preemergent herbicide widely used for the control of weeds in pecan ( Carya illinoinensis ) orchards in the US southwestern region. Given the paucity of data regarding indaziflam's impact on the biochemical properties of soils supporting pecan production, this study was conducted to evaluate the effect of different application rates of indaziflam on soil microbial activity, diversity and biochemical processes related to nitrogen cycling. During 2 consecutive growing seasons (2015 and 2016), soil samples were obtained from experimental mesocosms consisting of soil-filled pots where pecan saplings were grown, and that were treated with indaziflam applied at 2 different rates (25 and 50 g ai ha -1 ). Soil samples were collected one week before and one week after herbicide application, and used for determination of soil microbial biomass, microbial diversity, nitrogen (N) mineralization and β-glucosaminidase enzyme activity. Soil samples collected from control mesocosms were treated in the laboratory with 2 rates of indaziflam (75 and 150 g ai ha -1 ) to determine immediate impact on microbial activity. No significant effect of herbicide treatment on soil respiration and microbial biomass was detected. Results showed a slight to moderate decrease in microbial diversity (7 % in 2015, 44 % in 2016). However, decreased β-glucosaminidase activity with herbicide treatment was observed with soils from the mesocosms (33% decline) and soils treated with indaziflam in the laboratory (45 % decline). The mineral N pool was generally dominated by NH 4 + after indaziflam application, an observation consistent with the drastic decrease (75 %) in nitrification activity measured in the laboratory experiment. This study results indicate that indaziflam, even when applied at higher than recommended rates, has limited effects on total soil microbial activity but could affect N cycling processes.

Nitrogen application alleviates salt stress by enhancing osmotic balance, ROS scavenging, and photosynthesis of rapeseed seedlings (Brassica napus)

ABSTRACT Nitrogen application could alleviate salt stress on crops, but the specific physiological mechanism is still unclear. Therefore, in this study, a pot experiment was conducted to explore the effects of different application rates of nitrogen (0, 0.15, 0.30, and 0.45 g·kg−1) on the growth parameters, osmotic adjustment, reactive oxygen species scavenging, and photosynthesis of rapeseed seedlings planted in the soils with different concentrations of sodium chloride (1.5, 3.5, 5.5, and 7.5 g·kg−1). The results showed that nitrogen could alleviate the inhibition of salt on rapeseed growth, and improve the antioxidant enzyme activities and the contents of non-enzymatic substances, K+, soluble protein (SP), soluble sugar (SS), and proline. Besides, there was a significant correlation between the indexes of active oxygen scavenging system, osmoregulation system, and photosynthesis. Therefore, applying appropriate amount of nitrogen can promote the growth and development of rapeseed seedlings under salt stress, accelerate the scavenging of reactive oxygen species, maintain osmotic balance, and promote photosynthesis. This study will improve our understanding on the mechanism by which nitrogen application alleviates salt stress to crops.

Effect of uniconazole and nitrogen level on lodging resistance and yield potential of maize under medium and high plant density.

Lodging in maize results in grain yield reduction. This experiment investigated the effects of different application rates of the growth retardant, uniconazole (UCZ), and nitrogen (N) on medium and high maize population densities on lodging resistance and yield. UCZ was applied to maize seeds at concentrations of 0 (U0 ) and 25 (U25 ) mg kg-1 , and three different N application rates, 0 (N0 ), 150 (N150 ) and 225 (N225 ) kg ha-1 , at plant densities of 75,000 (D1 ) and 105,000 plants ha-1 (D2 ). UCZ application, different N rates and plant population density affected the lodging resistance and yield attributes of maize. The diameter, plumpness, cortex penetration and bending strengths of the internodes were enhanced with UCZ and N application at medium and high plant density, where maximum values were obtained with U25 N150 D1 . Internode length increased in the high-density population and higher N rate, whereas UCZ reduced internode length, where maximum internode length was obtained with U0 N225 D2 . Plant height, centre of gravity height, ear and height above ear-bearing node were higher with the high N rate, while UCZ reduced it significantly. UCZ, N rate and plant density enhanced lignin accumulation in the third internode and ear-bearing internode, where maximum values were obtained with U25 N150 D1 . Yield and yield attributes were also improved by UCZ, N rate and population density. Treatment with U25 N150 D2 significantly improved grain yield of maize compared with the other treatments.

Effects of long-term phosphorus fertilizer applications on soil carbon and CO2 flux

ABSTRACT Long-term agricultural research with annual and perennial cropping systems provides significant insight into the carbon sequestration potential of agriculture in the East Mediterranean region of Anatolia. This study explored the effect of different application rates of phosphorus (P) fertilizer on the storage and quality of soil organic carbon (SOC) and soil CO2 flux to assess the relationship between SOC and P application. The study was based on the hypothesis that long-term P fertilization can affect carbon sequestration in soil and impact soil CO2 flux. The objectives of the present study were to: (i) analyze the effect of long-term inorganic chemical P fertilization on SOC content and (ii) estimate the effect of long-term P fertilization on CO2 flux. Under crop rotation, corn (Zea mays L.) and wheat (Triticum aestivum L.) (CW system) were exposed to four fertilizer doses (0, 50, 100, and 200 kg ha−1), which were repeated annually over 20 years. During plant growth, bare soil and treated soil CO2 fluxes were determined several times. The results demonstrated that P fertilizer did not have a direct impact on the SOC of the summer-maize growing season and had a positive impact on SOC during the winter-wheat growing season. P fertilization levels have positive impact on atmospheric CO2 capture and increased SOC content.

Effects of Different Application Rates of Organic Compound Fertilizer on Young Squash Growth and Soil Chemical Properties under Plastic Film House

To determine the replacement ratio of organic compound (OC) for basal application of inorganic fertilizers, the effects of different rate of OC on young squash (Cucurbita moschata) plant growth and soil chemical properties of plastic film house were investigated. The OC were applied at 50% (OC50+N50), 100% (OC100), and 150% (OC150) as the basal amount of inorganic nitrogen fertilizer recommended by soil fertility test, and the treatment were compared with inorganic NPK and PK treatment. The yield of young squash in OC150 treatment was similar to NPK treatment and higher than PK. In OC50+N50, OC100, and OC150 treatments, nitrate concentration and electrical conductivity (EC) were similar to NPK treatment. Relative nitrogen use efficiency of young squash ranged 17~37%. These results suggest that OC application as the basal dressing at the 150% level could be best rate to minimize nutrient accumulation of soil and to ensure the yield of young squash. Further study is required to evaluate effect of long-term application of OC on soil sustainability and young squash productivity. Changes of young squash yield according to replacement ratio of basal amount of nitrogen fertilizer with organic compound (OC) fertilizer. N, P, K, and OC mean nitrogen, phosphate, potash fertilizer, and organic compound, respectively. Treatment Fresh fruit weight Relative yield index† kg/10a % PK 8,607b† 96.0 NPK 8,960ab 100.0 OC50+N50 8,980ab 100.2 OC100 9,013ab 100.7 OC150 9,350a 104.5 †DMRT (p < 0.05). †Relative yield of other treatments to NPK treatment.

Response of Head Cabbage (&amp;lt;i&amp;gt;Brassica olearacea L.&amp;lt;/i&amp;gt;) Yield to Application of Different Rates of Inorganic Nitrogen and Phosphorus Fertilizers at Bore, Southern Ethiopia

The field trial was conducted during 2017 and 2018 main cropping season at the Bore Agricultural Research Centre which is located in Gudji Zones, of Southern Ethiopia to determine the effect of different application rates of nitrogen and phosphorus fertilizers on growth, yield and yield components of head cabbage and to identify their economically appropriate rates that maximize yield of head cabbage. The experiment was carried out to study cabbage variety Olsen to added N and P nutrients in respect to growth, yield and yield related parameters of the crop. The longest head initiation (90 days) and longest (140) days to maturity was attained in 294 kg ha^-1 Nitrogen and 138 kg ha^-1 phosphorus treatment, while shortest head initiation (64.33 days) was obtained in control treatment. The maximum plant height (26.4 cm) was recorded for the treatment T3P4 (235 +138 kag ha^-1), while the lowest (16.9 cm) plant height was recorded from the T1P1 (control) treatment. Nutrient levels markedly influenced the diameter, height, head mass and yield of head cabbage. The maximum average head diameter (25.44 cm) and average height (27.33 cm) was recorded in treatment receiving 235 kg N and 82 kg P ha^-1. Combined application of 235 kg N ha^-1 with the 82 kg P ha^-1 produced the highest (2356.67 g) untrimmed head weight of cabbage followed by second maximum (2133.33 g) untrimmed head weight with the rate of 235 kg N ha^-1 with the 110 kg P ha^-1 while the least (1120.67 g) untrimmed head weight was recorded for the control treatment. Combined application of 235 kg nitrogen and 82 kg phosphorus ha^-1 (N3P2) recorded maximum (69.00 t) head yield without wrapper ha^-1 and the lowest (27.66 t ha^-1) was recorded by control treatment. The marginal rate of returns, which determines the acceptability of any treatments shows that treatments that received 235 kg N ha^-1 in combination with 82 kg ha^-1 of P yielded 43498% marginal revenue. Therefore, this combined nutrient application rates can be recommended in the research area and similar agro-ecologies since it is the most feasible rates for the producers because of its low cost of production and higher benefits.

Eucalyptus biochar application enhances Ca uptake of upland rice, soil available P, exchangeable K, yield, and N use efficiency of sugarcane in a crop rotation system

AbstractIt was hypothesized that the application of eucalyptus biochar enhances nutrient use efficiencies of simultaneously supplied fertilizer, as well as provides additional nutrients (i.e., Ca, P, and K), to support crop performance and residual effects on subsequent crops in a degraded sandy soil. To test this hypothesis, we conducted an on‐farm field experiment in the Khon Kaen province of Northeastern Thailand to assess the effects of different application rates of eucalyptus biochar in combination with mineral fertilizers to upland rice and a succeeding crop of sugarcane on a sandy soil. The field experiment consisted of three treatments: (1) no biochar; (2) 3.1 Mg ha−1 biochar (10.4 kg N ha−1, 3.1 kg P ha−1, 11.0 kg K ha−1, and 17.7 kg Ca ha−1); (3) 6.2 Mg ha−1 biochar (20.8 kg N ha−1, 6.2 kg P ha−1, 22.0 kg K ha−1, and 35.4 kg Ca ha−1). All treatments received the same recommended fertilizer rate (32 kg N ha−1, 14 kg P ha−1, and 16 kg K ha−1 for upland rice; 119 kg N ha−1, 21 kg P ha−1, and 39 kg K ha−1 for sugarcane). At crop harvests, yield and nutrient contents and nitrogen (N) use efficiency were determined, and soil chemical properties and pH0 monitored. The eucalyptus biochar material increased soil Ca availability (117 ± 28 and 116 ± 7 mg kg−1 with 3.1 and 6.2 Mg ha−1 biochar application, respectively) compared to 71 ± 13 mg kg−1 without biochar application, thus promoting Ca uptake and total plant biomass in upland rice. Moreover, the higher rate of eucalyptus biochar improved CEC, organic matter, available P, and exchangeable K at succeeding sugarcane harvest. Additionally, 6.2 Mg ha−1 biochar significantly increased sugarcane yield (41%) and N uptake (70%), thus enhancing N use efficiency (118%) by higher P (96%) and K (128%) uptake, although the sugar content was not increased. Hence, the application rate of 6.2 Mg ha−1 eucalyptus biochar could become a potential practice to enhance not only the nutrient status of crops and soils, but also crop productivity within an upland rice–sugarcane rotation system established on tropical low fertility sandy soils.

Effect of different application rates of metamitron as fruitlet chemical thinner on thinning efficacy and fluorescence inhibition in Gala and Fuji apple

Crop thinning is an important and difficult agricultural practice. Knowing the effect of the application dose of a product is a crucial element of any thinning program. The aims of this study were to investigate the effect of different metamitron doses on Gala and Fuji apples applied at fruit king diameters of between 8 and 10 mm and to determine fluorescence inhibition at the different application rates. Trials were conducted over two seasons from 2015 to 2016 in apple orchards in Lleida (Spain). Photosynthesis inhibition caused by metamitron was also analysed and measured, using chlorophyll fluorescence and biexponential pharmacokinetic models. Under the trial conditions, the application of metamitron reduced final fruit set, number of fruits per tree and crop load depending on the application rate. A dose effect was observed in all yield parameters. Moreover, when metamitron showed high efficacy, there was an improvement in fruit weight, coloration and diameter. The estimated parameters A, α and B using a biexponential equation were related with final fruit set, however the period of inhibition has to be finished before prediction can be made of metamitron efficacy in the year. The fluorescence analysis showed a dose effect, with metamitron dose increasing inhibition. Additionally, the same result was also observed in the area under curve analysis, with metamitron dose reducing the area and inhibition increasing. In all yield parameters, the fluorescence and area under curve analyses showed differences between cultivars, with the inhibition caused by metamitron higher in Gala than in Fuji. Moreover, differences between years were observed. 2015 was warmer than 2016, and the higher temperatures increased the thinning efficacy of metamitron.

Effects of vermiculite, nanoclay and zeolite on ammonium transport through saturated sandy loam soil: Column experiments and modeling approaches

Economic and nature-friendly amendments are needed to increase fertilizer efficiency and crop yield for sustainable agriculture in coarse-textured soil. In this investigation, the effects of different application rates (2%, 4% and 8%) of vermiculite, nanoclay and zeolite amendments on adsorption and transport of ammonium (NH4-N) in sandy loam soil were studied using batch and column experiments. The results of batch experiment indicated that the maximum distribution coefficient (Kd) was obtained in soil amended with zeolite 8%, while minimum Kd was achieved in the control soil. Column experiments revealed that the application of inorganic amendments decreased the leaching of NH4-N from 89.4% in control soil to 77.6%, 70.2%, 52.5%, 85.3%, 60.8%, 38.5%, 12.6% and 2.1% in soil columns amended with vermiculite 2%, 4%, 8%, nanoclay 2%, 4% and zeolite 2%, 4%, 8%, respectively. On the basis of the application rate of inorganic amendments required to retain 40% of injected NH4-N, the effectiveness of zeolite is about 2 and 4 times that of nanoclay and vermiculite, respectively. The HYDRUS-1D program was used to simulate the leaching of NH4-N using the advection–dispersion equation model (ADE) along with batch and fitted Kd. The simulation results indicated that the ADE model with fitted Kd described the behavior of NH4-N transport more suitable than the ADE model using batch Kd (root-mean-square error, RMSE < 0.06 and RMSE < 0.13, respectively). Results of our study indicated that amending sandy loam soil with inorganic amendments can be an effective technique for decreasing NH4-N transport and improving the efficiency of N fertilizer in sustainable agriculture systems.

Biofortification of Spring Barley Grain with Microelements through Sulfur Fertilization

One means of enriching plants with microelements is agronomic biofortification, whereby the mineral composition of plants is stimulated through appropriate fertilization. A fertilizer component which has received much attention in recent years is sulphur. Due to the significant reduction in SO2 emissions from industrial sources to the atmosphere, a progressive deficiency of this nutrient has been observed in soils in Poland and other parts of the world. Therefore, a study was undertaken to assess the effect of different application rates (20 and 40 kg·ha−1) and forms (elemental and ionic) of sulphur on the content of selected micronutrients (Mn, Fe, Zn, and Cu) and their proportions (Fe : Mn) in the grain of the Antek variety of spring barley. In a three-year single-factor field experiment setup on luvisols with low content of sulphur, the following fertilizers were tested: ammonium sulphate, potassium sulphate, and Wigor S (80% elemental sulphur and 20% bentonite). It was demonstrated that, in the fertilization of spring barley, supplementation of NPK with sulphur can be regarded as an agronobmic method of biofortification of grain with micronutrients because it beneficially affects the content of manganese, iron, zinc, and copper in the grain. An increase in the content of these micronutrients was found in the grain of plants fertilized with sulphur in comparison to plants that were not fertilized with this nutrient in each of the growing seasons. Ammonium sulphate, compared to the other fertilizers tested, had the greatest impact on the content and uptake of all micronutrients, with the exception of zinc. Marked differences in the effect of the application rates of 20 and 40 kg·S·ha−1 were observed only for fertilizers containing the ionic form of sulphur. The beneficial effect of sulphur on the biofortification of microelements in spring barley grain indicates the need to include this nutrient in cultivation of this species.