Effects Of Different Fertilization Practices Research Articles

Fertilizers and Manures Enhance the Bioavailability of Soil Phosphorus Fractions in Karst Grassland

Phosphorus is one of the major constraints to karst grassland productivity. Understanding the effects of different fertilization practices on soil phosphorus dynamics is essential for enhancing phosphorus bioavailability and rational management of soil phosphorus in karst grasslands. Here, we investigated the effects of fertilizers and manures on soil bioavailability of phosphorus fractions and explored the relationship between soil properties and soil phosphorus fractions. The four fertilizer application designs were as follows: control (CK; no fertilizer or manure); fertilization (F); manure application (M); fertilization and manure application (FM). The results showed that total phosphorus (TP) concentration was elevated by 23%, 1%, and 42% in F, M, and FM treatments, respectively, compared with CK. F and FM treatments enhanced the total inorganic phosphorus (Pi) concentration by 65% and 66%, respectively, while M and FM treatments enhanced the total organo-phosphorus (Po) concentration by 21% and 35%, respectively. FM treatment elevated bioavailable P, active Po, secondary mineral P, primary mineral P, and occluded P by 69%, 39%, 50%, 31%, and 41%, respectively. Fertilizers inhibited soil acid phosphatase activity, whereas alkaline phosphatase did not respond significantly to fertilizer management in low-latitude karst regions. SOM, TN, AP, and MBP are the key factors affecting the bioavailability of phosphorus fractions. The combined application of fertilizer and manure is the most beneficial measure for enhancing soil phosphorus bioavailability. This research helps deepen our understanding of soil phosphorus dynamics in the karst areas and provides a basis for further enhancement of nutrient availability and vegetation productivity of grassland ecosystems.

Effects of different fertilization practices on maize yield, soil nutrients, soil moisture, and water use efficiency in northern China based on a meta-analysis

The application of fertilizer to ensure the steady improvement of crop yield has become the main means of agricultural production. However, it remains to be determined whether fertilization practices with different combinations of nitrogen (N), phosphorus (P), potassium (K), and organic (O) fertilizers play a positive role in the sustainability of maize yield and the soil in which it is grown. Therefore,this meta-analysis extracted 2663 data points from 76 studies to systematically analyze and explore the effects of different fertilization measures on maize yield, soil nutrients, water content and water use efficiency (WUE) in northern China. Articles addressing this topic showed that fertilization effectively increased the soil nutrient content and maize yield. The soil organic matter (SOM) increased by 2.36 (N)–55.38% (NPO), total nitrogen content increased by 6.10 (N)–56.39% (NPO), available phosphorus content increased by 17.12 (N)–474.74% (NPO), and available potassium content changed by − 2.90 (NP)–64.40% (NPO). Soil moisture increased by 3.59% under a single organic fertilizer application and decreased by 4.27–13.40% under the other treatments. Compared with no fertilization, the yield increase of fertilized maize reached 11.65–220.42%. NP, NPK and NPKO contributed the most to increased yield in lithological, black and fluvo-aquic soils, respectively. The effects of different fertilization practices on maize yield varied in response to the same meteorological factors. The WUE increased from 9.51 to 160.72%. In conclusion, rational fertilization can improve the soil nutrient content and increase maize yield. The combined application of chemical and organic fertilizer showed the greatest increase in yield and WUE. Organic fertilizer application alone increased soil moisture. Our results provide a theoretical basis for fertilizer application and for improving the soil structure for maize cultivation in northern China.

Effects of different fertilization practices on CH4 and N2O emissions in various crop cultivation systems: A case study in Kazakhstan

The present study investigates the effects of different fertilization practices, including chemical and organic fertilizers, on CH4 and N2O emissions in various crop cultivation systems in Kazakhstan. The research focuses on three staple crops: wheat, barley, and corn, which are commonly grown in the region. A randomized complete block design field trial was conducted with three replications for each crop, totaling 27 plots. Gas sampling was carried out five times between June and September 2021, with cylindrical gas sampling chambers inserted into the soil at a depth of 10 cm. The concentrations of CH4 and N2O were analyzed using GS-MS. Results reveal that all three crops exhibited moderate to high CH4 and N2O emissions, with corn consistently displaying the highest emissions. Both chemical and organic fertilizers led to increased emissions of CH4 and N2O compared to control plots. The organic fertilizer treatment occasionally showed slightly higher emissions compared to chemical fertilizer treatment. However, the differences in CH4 and N2O concentrations between fertilized and unfertilized plots were not drastically significant. Notably, environmental factors, such as soil moisture and temperature, played a more prominent role in influencing CH4 and N2O production than the type of fertilizer applied. These findings underscore the significance of optimizing fertilization practices to minimize greenhouse gas emissions while maintaining crop productivity and promoting sustainable agriculture in Kazakhstan.

Organic-inorganic fertilization promotes paddy soil macroaggregate organic carbon accumulation associated with key bacterial populations in subtropical China

Macroaggregate organic carbon (Macro-OC) accumulation in paddy soils is of great significance in promoting multiple agroecosystem services. However, the effects of different fertilization practices on Macro-OC accumulation in paddy soils at the regional scale have not been comprehensively investigated. Here, we conducted long-term fertilization field experiments at four sites, Taoyuan, Wangcheng, Jinxian, and Suzhou, in the subtropical area of China to reveal the effects of inorganic and organic-inorganic (OIF) fertilization on Macro-OC accumulation and its relationships with important microbial traits (the abundance ratio of GH48:cbhI genes and the richness of keystone bacterial taxa) in paddy soils. The results showed that long-term fertilization (particularly OIF) significantly increased the content of Macro-OC, which mainly consisted of particulate organic carbon (C). Organic-inorganic fertilization decreased the percentage of O-alkyl C but increased the percentages of alkyl, aromatic, and phenolic C. Organic-inorganic fertilization promoted the abundance of the bacterial cellulose-degrading gene GH48 retrieved from macroaggregates. The orders Anaerolineales, Bacillales, and Clostridiales were identified as keystone bacterial taxa in macroaggregates and were significantly correlated with the physical fraction and chemical structure of Macro-OC. Structural equation modeling revealed that fertilization-induced changes in soil pH and C:N ratio affected the richness of Anaerolineales, Bacillales, and Clostridiales, which was strongly associated with the increase of percentages of aromatic and phenolic C and further facilitated Macro-OC accumulation. Together, these results suggested that OIF promoted Macro-OC accumulation associated with key bacterial populations in paddy soils. The results provide an important basis for boosting soil C accrual in the subtropical rice-growing areas.

Long-term continuous farmyard manure application increases soil carbon when combined with mineral fertilizers due to lower priming effects

Organic and synthetic fertilizers not only increase soil fertility and crop productivity but also enhance soil organic carbon (SOC). However, the priming effect (PE) leads to increased soil carbon (C) loss through native SOC mineralization. To date, the mechanisms by which long-term (>66 years) synthetic and/or organic fertilization alters net SOC sequestration remain a matter of debate. This study aimed to assess the effects of different fertilization practices on SOC decomposition and PE in agricultural systems subjected to long-term annual synthetic and/or organic fertilizer application. This aim was achieved by collecting topsoil samples (0–20 cm) from four long-term fertilization practices, i.e., unfertilized, synthetic supplemental (+s), cattle farmyard manure (+m, similar nutrient amount to +s), and synthetic fertilizer with farmyard manure (+s +m, the highest nutrient amount). The soil samples were incubated for 33 days with and without 13C-glucose addition, and a CO2 isotope analyzer combined with a modeling approach was used to establish a real-time method to monitor CO2 and 13CO2 production rates during the incubation period. Overall, +m increased the cumulative SOC-derived CO2 (SOC-CO2) by 107, 74, and 24 % compared to the unfertilized, +s and +s +m, respectively. The higher SOC-CO2 in +m treatment was associated with the greatest priming effect (PE, 390 ± 21 mg C kg soil−1), which corresponded to a 30 % increase compared to the average of the treatments that involved synthetic fertilizer (+s and +s +m) and a 137 % increase compared to the unfertilized control. The results were explained by the lower dissolved nitrogen (N), a proxy of available mineral N, in +m compared to +s +m, thus enhancing microbial mining for additional N via increasing SOC mineralization. However, the combined application of synthetic fertilizer and manure in the +s +m treatment provided enough easily accessible nutrients for microbial growth and activities from the applied synthetic fertilizer, leading to lower SOC mineralization than manure (+m) alone. Nevertheless, the treatments with manure application (i.e., +m and +s +m) significantly increased net SOC compared to the synthetically fertilized treatment and unfertilized control, suggesting greater C inputs than outputs and leading to high SOC accumulation over time. These results indicated that organic manure has a great potential to mitigate climate change by increasing SOC over time, which can be fostered by the addition of synthetic fertilizer; however, caution still needs to be taken regarding the quality and quantity of the added fertilizer.

The Effects of Different Fertilization Practices in Combination with the Use of PGPR on the Sugar and Amino Acid Content of Asparagus officinalis

The present study examined the effects of different nitrogen (NH4NO3) and potassium (KNO3) fertilization levels in combination with a nitrogen-fixing, plant growth-promoting rhizobacteria (PGPR) inoculation on the carbohydrate (CHO), amino acid content, and nutrient concentrations (N, P, K) in the spears and the root system of asparagus plants. No significant differences were indicated between the different fertilization treatments regarding N, P, and K in the leaves and roots of asparagus. The inoculation of the asparagus fields with PGPR, no matter the type of the inorganic fertilizer, resulted in increased CHO and amino acid content of the foliage and roots of asparagus. The highest CHO content and amino acid content were recorded in the treatment that combined PGPR inoculation along with KNO3 fertilizer, indicating that higher K applications acted synergistically with the added PGPR.

Effects of different fertilization practices on anammox activity, abundance, and community compositions in a paddy soil

The return of crop residue and green manure into agricultural soil is known to be important agricultural management strategies, yet how they affect the anammox process remains poorly characterized. A field experiment containing four treatments: chemical fertilizer (F), F plus rice straw (FS), FS plus green manure (FSM), FSM with integrated management (FSMM), was performed to examine the effects of incorporation of rice straw and green manure residues on anammox. The results showed that the anammox activities in FS and FSM treatments (0.65 and 0.80 nmol N g−1 soil h−1, respectively) were significantly lower than those in F and FSMM treatments (1.60 and 1.28 nmol N g−1 soil h−1, respectively). Anammox contributed 4.07%–4.95% of total N loss in soil incorporated with residues, lower than soil treated with chemical fertilizer only (9.13%), the remaining being due to denitrification. However, the abundance of the hzsB gene (the hydrazine synthase β-subunit gene) in FS and FSM treatments (1.13 × 106 and 1.18 × 106 copies g−1 soil) were significantly higher than soil using chemical fertilizer only (7.49 × 105 copies g−1 soil) while showed no significant difference with FSMM treatment (8.81 × 105 copies g−1 soil). Illumina sequencing indicated that Brocadia was the dominant anammox genus, following by Scalindua and Kuenenia. Anammox bacterial diversity was altered after 4-year incorporation of rice straw and green manure, as shown by α-diversity indices. We concluded that rice straw and green manure incorporated with mineral fertilizer reduce N removal from paddy soil in terms of anammox in spite of stimulating anammox bacterial growth.

Effect of Different Fertilization Practices on Soil Microbial Community in a Wheat–Maize Rotation System

Little information is known about the effects of different fertilization practices on soil microbiome in intensively managed crop rotations. The objective of this research was to investigate the response of microbial community composition (phospholipid fatty acid, PLFA) and extracellular enzyme activity to fertilization treatments through a three-year experiment. Treatments were: Control (without fertilizer, CK), chemical fertilizer (NPK), NPK + pig manure (NPKM), NPK + straw (NPKS), and NPK + both manure and straw (NPKMS). We found that fertilization had no effect on the microbial abundance except arbuscular mycorrhizal fungi (AMF) PLFA. Soil microbial community composition was significantly affected by crop species and to a lesser extent by fertilization, with a greater influence on the wheat harvest. In addition, soil enzyme activities were enhanced by fertilization, especially in wheat season. Over three years, compared with NPK treatment, addition of organic manure or straw (NPKS and NPKMS) significantly increased the activities of the enzymes except invertase and urease, and the effect was greater at wheat harvest than the maize harvest. Our results indicate that the response of soil microbial community structure and enzyme activities to fertilization takes precedence than microbial biomass in the short term. The temporal variation in soil microbial community structure and enzyme activities in the crop rotation indicate that crop species may be carefully considered for sustainable agricultural intensification management.

Effect of long-term combined application of organic and inorganic fertilizers on soil nematode communities within aggregates.

A long-term fertilization experiment was conducted to examine the effects of different fertilization practices on nematode community composition within aggregates in a wheat-maize rotation system. The study was a randomized complete block design with three replicates. The experiment involved the following four treatments: no fertilizer, inorganic N, P and K fertilizer (NPK), NPK plus manure (NPKM) and NPK plus maize straw (NPKS). Soil samples were taken at 0–20 cm depth during the wheat harvest stage. Based on our results, NPKS contributed to soil aggregation and moisture retention, with a positive effect on soil total nitrogen accumulation, particularly within small macroaggregates (0.25–1 mm) and microaggregates (<0.25 mm). The C/N ratio was correlated to the distribution of the soil nematode community. Both manure application and straw incorporation increased the nematode functional metabolic footprints within all aggregates. Additionally, the functional metabolic footprints decreased with a decline in aggregate size. The accumulation of total nitrogen within <1 mm aggregates under NPKS might play a key role in maintaining the survival of soil nematodes. In our study, both crop straw incorporation and inorganic fertilizer application effectively improved soil physicochemical properties and were also beneficial for nematode survival within small aggregate size fractions.

Effects of different fertilization practices on the incidence of rice pests and diseases: A three-year case study in Shanghai, in subtropical southeastern China

To implement organic rice farming around a drinking water source in the western suburbs of Shanghai, pioneering field experiments on the relationships between fertilizer applications and occurrences of rice pests and diseases were performed without the use of pesticides and fungicides from 2012 to 2014. The rice plants treated with chemical fertilizers (CF) accumulated higher content of available nitrogen (NH4++NO3−) and grew higher and more luxuriantly, but they were more susceptible to pests and diseases. Comparatively, the plants treated with organic manure demonstrated higher resistance to rice pests and diseases and grew more healthily. However, excessive application of organic manure also increased the risks of pests and diseases. The unfertilized plants were highly deficient in nutrients, but they maintained the lowest rates of pests and diseases. This suggests that rice pests and diseases were easily triggered by a high content of N-related nutrients in plant tissues and inhibited by nutrient deficiency. Annual climatic conditions also deeply affected the occurrences of rice pests and diseases. Long-term warm and humid weather in the growing areas favored the development of herbivorous pests and fungal diseases. The incidence of migratory pests in Shanghai is also linked to violent summer storms. Frequent rain storms in southern or southwestern China increased the chance of infestations of migratory pests in Shanghai. Rice yield was primarily determined by the infestations of pests and diseases. In the pest-infested year of 2012, the grain yield for the different fertilizers was only 40%–44% of that under conventional farming practices, and the yield in CF was even significantly lower than that in the unfertilized CK. In 2013, with lower infestation rates, the grain yield of the different fertilizers was more than 80% of the conventional yield. The application of a lower amount of organic manure, 2100kgha−1 of cake manure, was recommended for the implementation of organic rice farming in the water source areas in Shanghai.

Effect of wheat cultivars, fertilizers, and fungicides on Fusarium foot rot disease of wheat

Fusarium culmorum is a principal causal agent of root, crown, and foot rot disease in the wheat-growing areas of Turkey. The effects of different fertilization practices, fungicide sprays, and cultivar reactions of 12 wheat varieties were investigated for disease development in greenhouse conditions in 2006-2007. The fertilizers used in the experiments significantly reduced disease by 27.5%-54.7% compared to the nonfertilized control. The plants fertilized with calcium ammonium nitrate (26% N) or composite NPK (15%, 15%, 15%) showed fewer disease symptoms than those fertilized with NPK (20%, 20%, 0%) in the presowing applications. On the other hand, foot rot severity was lower with ammonium nitrate (33% N) than urea (46% N) when applied as a supplement in the 25th and 45th growth stages of the Zadoks scale. Furthermore, fungicide sprays and seed dressing treatments also decreased foot rot symptoms. Seed treatment with tebuconazole lowered disease severity in the subcrown internode compared to the control and it was overall the most effective fungicide with 47.8% efficacy. When plants were sprayed with fluquinconazole, tebuconazole, or epoxyconazole + carbendazim (two times at Zadoks growth stages 31 and 45), disease severity decreased by 96.3%, 93.9%, and 91.0%, respectively. In the cultivar reaction tests, no stable or considerable tolerance was observed in the 12 wheat varieties against foot rot. It may be concluded from this study that fertilizer forms and fungicide preference can play an important role where Fusarium foot rot is the main problem in wheat-growing areas.

Compost Amendment Enhances Natural Revegetation of a Mediterranean Degraded Agricultural Soil.

A vegetation analysis was carried out on a degraded agricultural soil of the Mediterranean area (Campania region, southern Italy) in order to study the effects of different fertilization practices (quality compost, mineral fertilizers, mixed fertilization, and no fertilization) on the whole spontaneous vegetation community. The study was performed for two consecutive years at three different scales (species level, community structure, and community properties), using three different units of abundance (number of individuals, biomass, and cover of each species). The observations were carried out in spring, after 5 and 6 years of soil treatments, on a total area of 4 m(2) for each soil treatment and in each year. The different fertilization practices did not determine changes in species composition; however, the relative abundance of dominant species increased in compost and mixed fertilized soils, particularly in the second year of observation. Although the dominance and diversity were unaffected by the different fertilization practices, the total biomass and total number of individuals increased in compost-amended soils. These results indicate the effectiveness of soil quality compost amendments to enhance natural revegetation, a key step in the recovery of degraded areas.

Simulating the effects of chemical and non-chemical fertilization practices on carbon sequestration and nitrogen loss in subtropical paddy soils using the DNDC model

Understanding the long-term and quantitative effects of different fertilization practices on carbon sequestration and nitrogen loss is important when establishing the best fertilization regime. In this study, the DeNitrification–DeComposition (DNDC) model was validated first for the change of soil organic carbon (SOC) at the site mode and at the regional mode, and then it was used to simulate the effects of three fertilization practices including rice straw (RS) returning, chemical fertilizer application (CF), and green manure planting (GM) on C and N dynamics in paddy soils from a subtropical area of China. The prevailing fertilization practices in the study area were set as the baseline scenario, and alternative scenarios were assigned by varying only one of the three fertilization practices. All three fertilization practices increased SOC content but had different effects on rice yield, N2O emission, and nitrate leaching loss. Compared with a baseline RS rate of 15 %, the SOC contents less than RS rates of 30, 50, and 80 % were increased on average by 12.84, 29.48, and 53.50 %, respectively. SOC content also increased as the CF rate rose from 70 to 130 % of the baseline scenario and then leveled off from 130 to 160 %. SOC contents under GM were higher than that without GM by 35.74 %. Both the N2O emissions and the nitrate leaching were increased with the increasing CF rate, while they decreased under GM treatment. However, RS increased the N2O emissions but decreased the nitrate leaching. The polygon-based modeling method with the DNDC could accurately evaluate the general trend of SOC dynamics and nitrogen loss from paddy soils.

不同培肥茶园土壤微生物量碳氮及相关参数的变化与敏感性分析

Soil microbial biomass as an important active component in global carbon and nitrogen cycle,and its relative parameters can function as sensitive indicators of changes in soil quality.Our objective was to investigate effects of different fertilization practices on soil microbial biomass Carbon(SMBC),Nitrogen(SMBN),the microbial quotient(MQ) and the ratio of SMBC to dissolved organic carbon(DOC),and to analyze the correlations of these biological indices with other soil parameters,the physicochemical properties in tea leaves,respectively,through the long-term fertilizer experiment of the tea garden in east Fujian(119°23′—119°51′E,26°41′—27°24′N).Six fertilization treatments were designed in this study: chemical fertilizers(C),half-organic manure plus half-chemical fertilizers((CO)1/2),organic manure fertilizers(O),leguminous green manure plus chemical fertilizers(CL),half-organic manure,leguminous green manure plus half-chemical fertilizers((CO)1/2L),and without fertilizers(CK).Results indicated that in comparison with CK,SMBC concentrations in(CO)1/2L,CL and O treatments increased by 1.87,1.26,1.49 times,SMBN increased by 2.18,1.32 and 1.70 times,respectively,whereas SMBC and SMBN concentrations in the C treatment decreased by 46%,59%,individually.In terms of the ratio of SMBC to DOC,different fertilization treatments followed the orders of O(CO)1/2LCL(CO)1/2CKC.Thus the fertilizing effect on soil fertility improvement in the O and(CO)1/2L treatments was better than those in other treaments.A correlation analysis revealed that the concentration of SMBC and the ratio of SMBC to DOC were significantly and positively correlated with soil urease activity,the contents of soil organic matter,total N and P,hydrolysable N,available P and K,soil water,CEC(P0.05),respectively,further suggesting the concentration of SMBC and the ratio of SMBC to DOC are closely related with soil fertility,and can be used as the sensitive indices of soil fertility in the tea garden with long-term fertilizer application.

Effects of Different Organic Fertilization Practices and Mineral Fertilization on Potato Quality

ABSTRACT The short-term effects of different fertilization practices were the target of the three year series of experiments. The effects of organic fertilizers and a mineral fertilizer were investigated on selected quality characteristics of potato (Solanum tuberosum cv. Matilda). Chemical composition, new contemporary quality parameters, ‘change of electrical conductivity’ and ‘darkening of potato extract’, and a parameter of environmental quality were analysed to discover the qualitative effects of increasing rates of fertilizers (fresh and composted farmyard manure, aerated slurry and mineral fertilization). In contrast to farmyard manure, the high application rate of the mineral fertilizer raised the concentration of nitrogenous compounds (nitrate and free amino acids) in potato. The slurry fertilization caused a similar but smaller reaction. The potato dry matter content differed more strongly than starch between the organic and the mineral fertilizer and between the application rates. The minerally-fertilized potatoes showed a lower dry matter content than the organically-fertilized. Thus, the dry matter and starch yield showed no significant difference between the mineral and organic treatments, even though the fresh matter yield was higher with the mineral fertilization. The ‘change of electrical conductivity of potato extract’ was highest with the mineral fertilization and the difference between organic fertilizers widened with increasing fertilization levels. The concentrations of mineral compounds and vitamin C, and the ‘darkening of potato extract’, due to a strong variation between replications, showed only a few statistically significant differences between the treatments.

Effects of different fertilization practices on the N03-N, N, P, K, Ca, Mg, ash and dietary fibre contents of carrot

The effects of different fertilization practices on the NO3-N, N, P, K, Ca, Mg, ash and dietary fibre contents of carrots were studied in field experiments in southern Finland. Unirrigated and irrigated placement and broadcast fertilization, NPK fertirrigations without basic fertilization, NPK fertirrigations with NPK basic fertilization and PK placement with N fertirrigations were compared. Further, single application was compared with split applications. The results of 1986 were analysed by contrast analysis. Fertilization practices affected the NO3-N content in carrot, and irrigation increased the NO3-N content. Highest NO3-N contents were observed with NPK fertirrigations treatments. Fertilization increased the N content of roots, and nitrogen content was higher with PK placement with N fertirrigations as compared to NPK fertirrigations without basic fertilization, or to NPK fertirrigations. Placement fertilization increased P content as compared to broadcast fertilization, NPK fertirrigations without basic fertilization, NPK fertirrigations or split application. Irrigation decreased P content. Fertilization increased the K contents of carrot roots as compared to unfertilized treatments, but there were no significant differences between fertilization practices. Fertilization had no effect on the Ca or Mg contents of carrot roots. Fertilization increased the ash content. Placement fertilization, single application and unirrigated single application yielded higher ash contents than did split application, NPK fertirrigations or PK placement with N fertirrigations. Fertilization and irrigation increased the dietary fibre content as compared to unfertilized and unirrigated treatments, respectively. Irrigated single application increased dietary fibre content as compared to split application and PK placement with N fertirrigations. Besides the fertilization experiment, samples from two organically cultivated fields were collected in order to obtain data concerning organically cultivated carrots.

Effects of different fertilization practices on the quality of stored carrot

The effects of different fertilization practices on quality constituents of stored carrots were studied. The field experiments were carried out in southern Finland, and the carrots were stored in refrigerated storage for six months in 1985 and four months in 1986. After storage period the marketable yield and weight loss were measured, carotene content was analyzed and a sensory evaluation for taste and texture was performed in both years. In 1986, also NO3-N, N, P, K, Ca, Mg, ash, glucose, fructose and sucrose were analysed. In 1985, after storage, NPK fertirrigations without basic fertilization showed a tendency to produce a lower marketable yield than single application and placement fertilization. In 1986, after storage, split application and NPK fertirrigations showed a tendency to produce a lower marketable yield than unirrigated single application. The supraoptimal N amount showed a tendency to have a higher carotene content than optimal N amount, and NPK fertirrigations lower NO3-N content than irrigated single application. The irrigated placement and broadcast treatments yielded high K contents. The unfertilized treatments yielded higher marketable yield, lower NO3-N, N and K contents than fertilized treatments as an average.

Effects of different fertilization practices on the glucose, fructose, sucrose, taste and texture of carrot

The effects of different fertilization practices on the glucose, fructose, sucrose, taste and texture of carrot cv. Nantes Duke Notabene 370 Sv were studied in field experiments carried out in southern Finland in 1985 and 1986. The effects of unirrigated and irrigated placement and broadcast fertilization, NPK fertirrigations without basic fertilization, NPK fertirrigations with NPK basic fertilization, and PK placement with N fertirrigations were compared. Further, the effects of single application were compared with those of split applications. Sugar analyses were made by high performance liquid chromatography, and sensory evaluations were performed for taste and texture. The results were analysed by contrast analysis. In 1985, fertilization and fertilization practices had no effects on sugar contents. In 1986, the unfertilized treatments had a tendency to yield higher glucose and fructose, and thus also total sugar contents than did the fertilized treatments on the average. Placement fertilization had a tendency to increase the glucose content as compared to NPK fertirrigations. No significant differences or tendencies were found in sucrose content. The glucose and fructose contents were higher in 1985 than in 1986. The sucrose content was mainly opposite, being higher in 1986.Weather conditions were more favourable for photosynthesis in 1986 than in 1985. The mean total sugar content in fresh weight was 7.8 % in 1985 and 6.7 % in 1986. Indicative results of taste and texture are presented. The sugar content in organically cultivated carrots did not differ from that of conventionally grown carrots, but the taste was worse.

Effects of different fertilization practices on the carotene content of carrot

The effects of different fertilization practices on the carotene content of carrot cv. Nantes Duke Notabene 370 Sv were studied in field experiments in southern Finland. Unirrigated and irrigated placement and broadcast fertilization, NPK fertirrigations without basic fertilization, NPK fertirrigations with NPK basic fertilization, and PK placement with N fertirrigations were compared. Further, single application was compared to split applications. Carotene determinations were done at harvest in 1985 and 66, 88 and 121 (at harvest) days from sowing in 1986. The results were studied by contrast analysis. Weather conditions had a strong effect on the carotene content and in both years the carotene content increased with the length of the growing season. At harvest in 1985, PK placement with N fertirrigations had a tendency to yield a higher carotene content than did broadcast fertilization, irrigated single application, and NPK fertirrigations. The carotene content was higher when P and K were placement fertilized as compared to treatments where P and K were broadcast fertilized or fertirrigated (p = 0.1). At the first sampling date in 1986, fertilization increased the carotene content (p = 0.1). PK placement with N fertirrigations had a tendency to increase the carotene content as compared to placement fertilization, single application and irrigated single application. At the second sampling date and at harvest in 1986 no statistically significant differences could be found. The results indicate that the placement of PK-fertilizer or NPK-fertilizer was favourable to carotene production. Besides the fertilization experiment, samples from two organically cultivated fields were collected to obtain data concerning organically cultivated carrots.

Effects of different fertilization practices on the growth, yield and dry matter content of carrot

The effects of different fertilization practices on the carrot root and shoot dry weights, yield, dry matter contents and root/shoot ratio were studied in field experiments. Unirrigated and irrigated placement and broadcast fertilization, fertirrigations without basic fertilization, fertirrigations with basic fertilization, and PK placement with N fertirrigations were compared. In addition, split application was compared to single application of nutrients. The soil nutrient levels were studied by soil analysis. The carrot root and shoot samples were collected three times during the growing period. Cv. Nantes Duke Notabene 370 was grown. The carrot shoots reached their maximum weight already by three months, whereas roots grew slowly during the first two months but grew considerably during both the third and fourth month. The root and shoot dry weights were positively correlated at all sampling dates in both years ( r ≥0.77***), The big photosynthetizing apparatus caused the production of high root yield. The placement fertilization of granular NPK fertilizer increased the yield as compared to broadcast of granular NPK fertilizer (p = 0.009**). The yield was also increased by the placement of P and K as compared to treatments without placement fertilization of P and K (p = 0.03*). There was no difference in yields between single application and split application. Irrigation decreased the yield in 1985 (p = 0.03*). In 1986the yield was significantly higher than in 1985 (p = 0.000***). At harvest the fertilization did not affect the dry matter content of carrot roots when compared with unfertilized treatments. The difference in dry matter content was greater between years (p = 0.000***) than between fertilization practices (p = 0.05*). The treatment PK placement with N fertirrigations yielded carrots with a higher dry matter content than did the NPK fertirrigations treatments. Besides the fertilization experiment samples from two organically cultivated fields were collected to obtain data concerning organically cultivated carrots and soils.