Combined application of organic fertilizer and chemical fertilizer alleviates the kernel position effect in summer maize by promoting post-silking nitrogen uptake and dry matter accumulation

Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields.In order to clarify whether the combined application of organic fertilizer and chemical fertilizer(CAOFCF)can alleviate the kernel position effect of summer maize,field experiments were conducted during the 2019 and 2020 growing seasons,and five treatments were assessed:CF,100%chemical fertilizer;OFCF1,15%organic fertilizer+85%chemical fertilizer;OFCF2,30%organic fertilizer+70%chemical fertilizer;OFCF3,45%organic fertilizer+55%chemical fertilizer;and OFCF4,60%organic fertilizer+40%chemical fertilizer.Compared with the CF treatment,the OFCF1 and OFCF2 treatments significantly alleviated the kernel position effect by increasing the weight ratio of inferior kernels to superior kernels and reducing the weight gap between the superior and inferior kernels.These effects were largely due to the improved filling and starch accumulation of inferior kernels.However,there were no obvious differences in the kernel position effect among plants treated with CF,OFCF3,or OFCF4 in most cases.Leaf area indexes,post-silking photosynthetic rates,and net assimilation rates were higher in plants treated with OFCF1 or OFCF2 than in those treated with CF,reflecting an enhanced photosynthetic capacity and improved postsilking dry matter accumulation(DMA)in the plants treated with OFCF1 or OFCF2.Compared with the CF treatment,the OFCF1 and OFCF2 treatments increased post-silking N uptake by 66.3 and 75.5%,respectively,which was the major factor driving post-silking photosynthetic capacity and DMA.Moreover,the increases in root DMA and zeatin riboside content observed following the OFCF1 and OFCF2 treatments resulted in reduced root senescence,which is associated with an increased post-silking N uptake.Analyses showed that post-silking N uptake,DMA,and grain yield in summer maize were negatively correlated with the kernel position effect.In conclusion,the combined application of 15-30%organic fertilizer and 70-85%chemical fertilizer alleviated the kernel position effect in summer maize by improving post-silking N uptake and DMA.These results provide new insights into how CAOFCF can be used to improve maize productivity.

Improvement of Wolfberry(Lycium barbarum L.)Fruit Yield and Quality and Enhancement of Soil Fertility by Nitrogen Reduction Combined with Organic Fertilizers

Excessive amounts of nitrogen(N)fertilizers are applied during wolfberry production,resulting in some soil problems as well as potential environmental risks in the Qinghai-Tibet Plateau.In this study,organic fertilizers were used to replace part of the N fertilizer in wolfberry fields with different fertility levels.N fertilizer rates had 0,50,100,150,200,and 250 g N/plant.Organic fertilizer rates had 0,2,4,6,8,and 10 kg organic fertilizer/plant.The experimental treatments included 6 combinations of N0M10,N50M8,N100M6,N150M4,N200M2,and control was N250M0.The results showed that in the high-fertility soils,combinations of N150M4,N100M6 and N50M8 treatments were increased in yields,fruit shape index,flavonoid content,total phenol content,mineral nutrient content,and antioxidant activity of wolfberry fruits.Also they were improved in soil fertility and decreased in residual nitrate through the soil depth of 0-300 cm.In the soil with less fertility,fruit yield,amino acid contents,flavonoids,total phenols,mineral nutrients and antioxidant activity of fruits were increased by the N200M2,N150M4 and N100M6 treatments and soil fertility was improved as well.Also more residual nitrate was found in the depth of 0-100 cm of soil with both chemical and organic fertilizer compared with the control.Therefore,in the Qinghai-Tibet Plateau,combining decreased N fertilizer with organic fertilizer rather than chemical fertilizer alone could help farmers achieve satisfactory yields and quality of wolfberry fruits and reduce the risk of nitrate leaching.In conclusion,50-150 g/plant of N fertilizer combined with 4-8 kg/plant of organic fertilizer in high-fertility gardens and 100-200 g/plant of N fertilizer combined with 2-6 kg/plant of organic fertilizer in low-fertility gardens are recommended for wolfberry cultivation.

Effect of Biofertilizers on the Agromorphological Parameters of Three Okra Cultivars in Southern Côte d’Ivoire

Okra (Abelmoschus esculentus L.) is an herbaceous plant of the Malvaceae family. In Côte d’Ivoire, okra production is estimated to be over 193,000 tons. This low production is largely due to poor soils and hardly covers the needs of the population. To remedy this, growers systematically use mineral fertilizers. However, these fertilizers pollute the environment. To find an alternative to chemical fertilization and increase production, the effect of biofertilizers (Spaawet, Retone, Super Gro) compared with NPK mineral fertilizer was evaluated on Divo, Teriman, and Djonan F1 cultivars. The trial was set up in a factorial block design with three replications. Plant height, number of functional leaves, and crown diameter were assessed at 60 days after sowing (DAS). The time to 50% flowering, production time, and fruit yield were calculated. The results showed that the biofertilizer Retone induced the highest heights and number of functional leaves, with averages of 61.89 cm and 29.88 leaves, respectively. The diameter at the crown (17.77 mm) was highest with the NPK mineral fertilizer, and the shortest 50% flowering time, with an average of 47.61 days, was also obtained with the biofertilizer Retone. The NPK mineral fertilizer produced the longest production time, with an average of 35.25 days. The highest yields were obtained using Retone (11.07 t/ha) and NPK (9.52 t/ha) fertilizers. The “Divo*Retone” interaction produced the highest yield with an average of 12.19 t/ha. The biofertilizer Retone could therefore be used as an alternative fertilizer to chemical fertilization in okra crops, given its effect on the parameters assessed.

Coupling of reduced inorganic fertilizer with plant-based organic fertilizer as a promising fertilizer management strategy for colored rice in tropical regions

Colored rice is a type of high-quality,high-added-value rice that has attracted increasing attention in recent years.The use of large amounts of inorganic nitrogen fertilizer in rice fields results in low fertilizer use efficiency and high environmental pollution.Organic fertilizer is a promising way to improve soil quality and sustain high yields.However,most studies focus on the effect of animal-based organic fertilizers.The effects of different ratios of plantbased organic fertilizer and inorganic fertilizer on the grain yield and quality of colored rice have rarely been reported.Therefore,a two-year field experiment was conducted in 2020 and 2021 to study the effects of replacing inorganic N fertilizers with plant-based organic fertilizers on the yield,nitrogen use efficiency(NUE),and anthocyanin content of two colored rice varieties in a tropical region in China.The experimental treatments included no nitrogen fertilization(T1),100% inorganic nitrogen fertilizer(T2),30%inorganic nitrogen fertilizer substitution with plant-based organic fertilizer(T3),60%inorganic nitrogen fertilizer substitution with plant-based organic fertilizer(T4),and 100% plantbased organic fertilizer(T5).The total nitrogen provided to all the treatments except T1 was the same at 120 kg ha-1.Our results showed that the T3 treatment enhanced the grain yield and anthocyanin content of colored rice by increasing nitrogen use efficiency compared with T2.On average,grain yields were increased by 9 and 8%,while the anthocyanin content increased by 16 and 10% in the two colored rice varieties under T3 across the two years,respectively,as compared with T2.Further study of the residual effect of partial substitution of inorganic fertilizers showed that the substitution of inorganic fertilizer with plant-based organic fertilizer improved the soil physiochemical properties,and thus increased the rice grain yield,in the subsequent seasons.The highest grain yield of the subsequent rice crop was observed under the T5 treatment.Our results suggested that the application of plantbased organic fertilizers can sustain the production of colored rice with high anthocyanin content in tropical regions,which is beneficial in reconciling the relationship between rice production and environmental protection.

Repositioning fertilizer manufacturing subsidies for improving food security and reducing greenhouse gas emissions in China

China removed fertilizer manufacturing subsidies from 2015 to 2018 to bolster market-oriented reforms and foster environmentally sustainable practices.However,the impact of this policy reform on food security and the environment remains inadequately evaluated.Moreover,although green and low-carbon technologies offer environmental advantages,their widespread adoption is hindered by prohibitively high costs.This study analyzes the impact of removing fertilizer manufacturing subsidies and explores the potential feasibility of redirecting fertilizer manufacturing subsidies to invest in the diffusion of these technologies.Utilizing the China Agricultural University Agri-food Systems model,we analyzed the potential for achieving mutually beneficial outcomes regarding food security and environmental sustainability.The findings indicate that removing fertilizer manufacturing subsidies has reduced greenhouse gas(GHG)emissions from agricultural activities by 3.88 million metric tons,with minimal impact on food production.Redirecting fertilizer manufacturing subsidies to invest in green and low-carbon technologies,including slow and controlled-release fertilizer,organic-inorganic compound fertilizers,and machine deep placement of fertilizer,emerges as a strategy to concurrently curtail GHG emissions,ensure food security,and secure robust economic returns.Finally,we propose a comprehensive set of government interventions,including subsidies,field guidance,and improved extension systems,to promote the widespread adoption of these technologies.

The microbial community,nutrient supply and crop yields differ along a potassium fertilizer gradient under wheat-maize double-cropping systems

Soil microorganisms play critical roles in ecosystem function.However,the relative impact of the potassium(K)fertilizer gradient on the microbial community in wheat-maize double-cropping systems remains unclear.In this long-term field experiment(2008-2019),we researched bacterial and fungal diversity,composition,and community assemblage in the soil along a K fertilizer gradient in the wheat season(K0,no K fertilizer;K1,45 kg ha^(-1) K_(2)O;K_(2),90 kg ha^(-1)K_(2)O;K3,135 kg ha^(-1)K_(2)O)and in the maize season(K0,no K fertilizer;K_(1),150 kg ha^(-1) K_(2)O;K_(2),300 kg ha^(-1)K_(2)O;K_(3),450 kg ha^(-1)K_(2)O)using bacterial 16S rRNA and fungal internally transcribed spacer(ITS)data.We observed that environmental variables,such as mean annual soil temperature(MAT)and precipitation,available K,ammonium,nitrate,and organic matter,impacted the soil bacterial and fungal communities,and their impacts varied with fertilizer treatments and crop species.Furthermore,the relative abundance of bacteria involved in soil nutrient transformation(phylum Actinobacteria and class Alphaproteobacteria)in the wheat season was significantly increased compared to the maize season,and the optimal K fertilizer dosage(K2 treatment)boosted the relative bacterial abundance of soil nutrient transformation(genus Lactobacillus)and soil denitrification(phylum Proteobacteria)bacteria in the wheat season.The abundance of the soil bacterial community promoting root growth and nutrient absorption(genus Herbaspirillum)in the maize season was improved compared to the wheat season,and the K2 treatment enhanced the bacterial abundance of soil nutrient transformation(genus MND1)and soil nitrogen cycling(genus Nitrospira)genera in the maize season.The results indicated that the bacterial and fungal communities in the double-cropping system exhibited variable sensitivities and assembly mechanisms along a K fertilizer gradient,and microhabitats explained the largest amount of the variation in crop yields,and improved wheat?maize yields by 11.2-22.6 and 9.2-23.8%with K addition,respectively.These modes are shaped contemporaneously by the different meteorological factors and soil nutrient changes in the K fertilizer gradients.

Mitigation of N_(2)O emissions in water-saving paddy fields:Evaluating organic fertilizer substitution and microbial mechanisms

Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potential.However,the relationship linking soil N_(2)O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.Furthermore,the mitigation potential of organic fertilizer substitution on N_(2)O emissions and the microbial mechanism in rice fields must be further elucidated.Our study examined how soil N_(2)O emissions were affected by related functional microorganisms(ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),nirS,nirK and nosZ)to various fertilization treatments in a rice field in southeast China over two years.In this study,three fertilization regimes were applied to rice cultivation:a no nitrogen(N)(Control),an inorganic N(Ni),and an inorganic N with partial N substitution with organic manure(N_(i)+N_(o)).Over two rice-growing seasons,cumulative N_(2)O emissions averaged 0.47,4.62 and 4.08 kg ha^(−1)for the Control,Ni and N_(i)+N_(o)treatments,respectively.In comparison to the Ni treatment,the N_(i)+N_(o)fertilization regime considerably reduced soil N_(2)O emissions by 11.6%while maintaining rice yield,with a lower N_(2)O emission factor(EF)from fertilizer N of 0.95%.Nitrogen fertilization considerably raised the AOB,nirS,nirK and nosZ gene abundances,in comparison to the Control treatment.Moreover,the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.The AOB responded to N fertilization more sensitively than the AOA.Total N_(2)O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.In summary,we conclude that organic manure substitution for inorganic N fertilizer decreased soil N_(2)O emissions primarily by changing the soil NO_(3)^(−)-N,pH and DOC levels,thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification,and strengthening N_(2)O reduction in denitrification from water-saving rice paddies.

Application of organic fertilizer for improving soybean production under acidic stress

The presence of acidic soil in rural areas poses difficulties for agricultural production.One factor regulating soil pH is the overuse of inorganic fertilizer.The increased use of fertilizers in soybean production not only raises sustainability concerns but also contributes to soil acidity.Therefore,the use of organic fertilizer could offer a solution for addressing both issues related to soil acidity and sustainability.The purpose of this study was to investigate the manipulation of soil pH using organic fertilizer for soybean production under acidic stress.The planting medium,consisting of a mixture of topsoil,rice husk charcoal,and organic fertilizer(in a ratio of 2:1:1),was supplemented with 0.5 g of NPK fertilizer as a basal treatment in each planting medium.To regulate the soil acidity to pH 4,we added FeSO_(4) and allowed the mixture to incubate for 30 days.The results demonstrate that the application of three types of organic fertilizers chicken manure(P1),oil palm empty bunch fertilizer(P2),and vermicompost(P3)positively impacts the growth of three soybean varieties.The findings indicate that the application of P2 organic fertilizer can increase vegetative growth almost 50%in soybeans on acidic soil,including plant height,leaf count,and root length.Meanwhile,applying P3 organic fertilizer can boost reproductive growth responses in soybeans on acidic soil,such as pod number(from around 0-4 unit to 42-51 unit),grain number(from around 0-5 unit to 88-90 unit),and grain weight(from around 0-0.37 g to 12-25 g).Organic fertilizer has the potential to regulate soil pH,promoting higher yields of soybeans under acidic stress.

Effectiveness of biofertilizers foliar application on yield and quality traits of flax(Linum usitatissimum L.)

Flax is considered to be one of the most significant dual-purpose crops for oil and fiber production in Egypt and worldwide.Biofertilizers have a substantial impact on various metabolic processes,including increased photo-synthesis,endogenous hormone levels,ion absorption,nucleic acid synthesis,and protein synthesis.These factors collectively contribute to the growth and development of plants.Therefore,this study aims to investigate how three biofertilizers(Algae extract,CMS as a by-product of yeast,and Metalosate multi minerals as amino acids)can enhance both the quantity and quality of flax seed yield under sandy soil conditions.Two field experiments were conducted at the Experimental Station of National Research Centre in Nubaria District,Behira Governorate,Egypt during two seasons(2021/2022)using a randomized complete block design(RCBD).The results revealed significant differences among all tested biofertilizers in terms of various characteristics studied in flax.Foliar application of algae extract at a rate of 1.50 mL/L resulted in an increase in seed yield(ton/ha)by 26.69%&19.89%,straw yield(ton/ha)by 8.08%&17.12%,and oil yield(kg/ha)by 47.72%&33.69%compared to the control group during both seasons respectively.Foliar applications of algae extract at a rate of 1.50 mL/L along with CMS at a rate of 5 m L/L and amino acids at a rate of 1.50 mL/L demonstrated significantly higher macronutrient contents(N,P,K),micronutrient contents(Fe,Zn,Mn),seed oil content,and protein content in flax seeds during both seasons.The highest values for seed oil content and protein content%were obtained through foliar application of amino acids at a rate of 1.50 mL/L.It can be concluded that foliar sprays with these bio-fertilizers effectively improved flax performance by increasing seed straw and oil yields,nutrients oil,protein and fatty acids seeds contents.

Microbial Fertilizer: A Sustainable Strategy for Medicinal Plants Production

Medicinal plants have aroused considerable interest as an alternative to chemical drugs due to the beneficial effects of their active secondary metabolites.However,the extensive use of chemical fertilizers and pesticides in pursuit of yield has caused serious pollution to the environment,which is not conducive to sustainable devel-opment in thefield of medicinal plants.Microbial fertilizers are a type of“green fertilizer”containing specific microorganisms that can improve the soil microbial structure,enhance plant resistance to biological and abiotic stresses,and increase the yield of medicinal plants.The root exudates of medicinal plants attract different micro-organisms to the rhizosphere,which then migrate further to the plant tissues.These microbes can increase the levels of soil nutrients,and improve the physical and chemical properties of soil through nitrogenfixation,and phosphorus and potassium solubilization.In addition,soil microbes can promote the synthesis of hormones that increase plant growth and the accumulation of active compounds,eventually improving the quality of med-icinal plants.In 2022,the total value of the global microbial fertilizer market was$4.6 billion and is estimated to reach$10.36 billion by 2030.In this review,we have summarized the types of microbial fertilizers,the coloniza-tion and migration of microorganisms to plant tissues,and the beneficial effects of microbial fertilizers.In addi-tion,the prospects of developing microbial fertilizers and their application for medicinal plants have also been discussed.It aims to provide a reference for the rational application of microbial fertilizers in thefield of med-icinal plants and the green and sustainable development of medicinal plant resources.

Analysis on Demonstration Application of Silicon Fertilizer in Field Cultivation of Rice

[Objectives]This study was conducted to investigate the scientific application of silicon fertilizer in rice cultivation,one of the staple crops.[Methods]In 2022,Yandu District carried out a special experiment and field demonstration study on the effects of foliar application of Zhengda water-soluble silicon fertilizer on rice production.[Results]The preliminary results showed that①Zhengda water-soluble silicon fertilizer could effectively improve the growth and development of rice and improve the population quality.The peak number of tillers,productive tiller percentage,number of effective panicles and number of effective grains per panicle increased by 6.7%,5.8%,5.5%,and 1.2%,respectively.②The yield and processing quality were improved.After applying silicon fertilizer,the yield per unit area increased by about 6.8%,and the unpolished rice yield,milled rice yield and head rice yield increased by 0.7%,1.94%and 2.15%respectively.[Conclusions]The demonstration application of silicon fertilizer in field cultivation of rice in Yandu District further proves previous research conclusions and has important practical significance.

Effects of Slow-release Nitrogen Fertilizer on Yield and Nitrogen Accumulation of Summer Maize in Shajiang Black Soil Area

[Objectives] This study was conducted to verify the field application effect of slow-release nitrogen fertilizer on summer maize in Shajiang black soil area by simultaneous sowing and fertilization, and explore the application scope and nitrogen metabolism mechanism, so as to lay a foundation for fertilizer reduction and efficiency improvement. [Methods] With maize variety Beiqing 340 and sulfur-coated urea as experimental materials, five nitrogen application levels were set, namely, control (C0), slow-release nitrogen 70 kg/hm^(2) (C70), slow-release nitrogen 140 kg/hm^(2) (C140), slow-release nitrogen 210 kg/hm^(2) (C210) and slow-release nitrogen 280 kg/hm^(2) (C280). The phosphorus and potassium fertilizers were all in accordance with the unified standard. [Results] With the application rate of slow-release nitrogen increasing, the nitrogen accumulation in organs increased first and then decreased after tasseling stage of maize. In order to reduce the fertilizing amount and increase efficiency, 210 kg/hm^(2) of slow-release nitrogen fertilizer was the best fertilizing amount for summer maize in Shajiang black soil area. [Conclusions] This study provides reference for fertilizer reduction, efficiency improvement and sustainable development of summer maize in Shajiang black soil area.

Effect of K Fertilizer on Absorption of Mineral Elements in Greenhouse-grown Strawberry Fruits

[Objectives]The paper was to explore the effect of K fertilizer on the absorption of mineral elements in greenhouse-grown strawberry fruits.[Methods]A systematic investigation was conducted on the effects of K fertilizer dosage levels on the absorption of mineral elements in Fengxiang strawberries,an excellent variety suitable for cultivation in Anhui Province.The investigation was carried out under medium N and P conditions in a greenhouse.[Results]The N content of strawberry fruits increased as the K_(2)O dosage increased within the range of 0-250 kg/hm^(2).Similarly,the P content of strawberry fruits increased gradually with the increase of K_(2)O dosage within the range of 0-125 kg/hm^(2).[Conclusions]This study presents a basis for enhancing the absorption of mineral elements in strawberry fruit by applying K appropriately.

Determination of Egg Shell Structure and Mineral Composition Using SEM-EDS and Identification the Possibility to Produce Fertilizer

Throwing out egg shells without using them depreciates a vital source of calcium. As an egg shell contains twice the amount of calcium a person needs a day, it is considered as the richest source of calcium of natural origin. Egg shells have been traditionally and widely used in medicine, beauty science and food production for decades. In spite of that, there is a lack of new solutions that profoundly study mineral elements and beneficial components contained in egg shells for further usage as a product. Assuming we consume 2 eggs a day, the yearly consumption for a person is 730 eggs. As beneficial component, the egg shell structure and mineral elements, were determined in 3 types of samples (Mongolian eggs, Russian eggs, and iodized eggs) by SEM-EDS (Scanning electron microscopy with energy dispersive spectroscopy), a state-of-the-art research method. Consequently, it was established that egg shells consists of Ca (72.6% - 85.7%), Mg (2.7% - 4.5%), Si (0.3% - 0.6%), P (7.0% - 18.1%), S (0.5% - 2.0%), K (0.4% - 0.9%), I (2.6% - 3.0%), respectively. Additionally, the D3.8 × 120, 250, 500, and 1000 times zoomed images of shell structure (SEM) of each sample were examined, and the results were compared and evaluated. The reverse titration method examination has demonstrated that the calcium carbonate (CaCO3) content in egg shells is 91% - 92.5%, and pH is 8.41 - 8.75. Ultimately, fertilizer containing 97.7% Ca without chemical additives has been extracted by grounding the eggshells to 4.4 μm, then preparing the mixture at the rate of 20:0.5 (shell: mix, enriched with mandarin and lemon peel) and adjusting its pH to 7.5 - 8.0. Further research on the impact of fertilizer on growing process of indoor flowers has been commenced.

Optimized NPK fertilizer recommendations based on topsoil available nutrient criteria for wheat in drylands of China

The optimized management of crop fertilization is very important for improving crop yield and reducing the consumption of chemical fertilizers.Critical nutrient values can be used for evaluating the nutritional status of a crop,and they reflect the nutrient concentrations above which the plant is sufficiently supplied for achieving the maximum potential yield.Based on on-farm surveys of 504 farmers and 60 field experimental sites in the drylands of China,we proposed a recommended fertilization method to determine nitrogen(N),phosphorus(P),and potassium(K)fertilizer input rates for wheat production,and then validated the method by a field experiment at 66 different sites in northern China.The results showed that wheat grain yield varied from 1.1 to 9.2 t ha^(-1),averaging 4.6 t ha^(-1),and it had a quadratic relationship with the topsoil(0-20 cm)nitrate N and soil available P contents at harvest.However,yield was not correlated with the inputs of N,P,and K fertilizers.Based on the relationship(exponential decay model)between 95–105%of the relative yield and topsoil nitrate N,available P,and available K contents at wheat harvest from 60 field experiments,the topsoil critical nutrient values were determined as 34.6,15.6,and 150 mg kg^(-1)for soil nitrate N,available P,and available K,respectively.Then,based on five groups of relative yield(>125%,115–125%,105–115%,95–105%,and<95%)and the model,the five groups of topsoil critical nutrient levels and fertilization coefficients(Fc)were determined.Finally,we proposed a new method for calculating the recommended fertilizer input rate as:Fr=Gy×Nr×Fc,where Fr is the recommended fertilizer(N/P/K)input rate;Gy is the potential grain yield;Nr is the N(N_(rN)),P(N_(rP)),and K(N_(rK))nutrient requirements for wheat to produce 1,000 kg of grain;and Fc is a coefficient for N(N_c)/P(P_c)/K(K_c)fertilizer.A 2-year validated experiment confirmed that the new method reduced N fertilizer input by 17.5%(38.5 kg N ha^(-1))and P fertilizer input by 43.5%(57.5 kg P_(2)O_(5) ha^(-1))in northern China and did not reduce the wheat yield.This outcome can significantly increase the farmers’benefits(by 7.58%,or 139 US$ha^(-1)).Therefore,this new recommended fertilization method can be used as a tool to guide N,P,and K fertilizer application rates for dryland wheat production.

Coupling Aquaculture—Crop Productions and Using of Water Drained from Ponds Rearing Clarias gariepinus as Fertilizer for Okra Production (Abelmoschus esculentus var. Clemson spineless, L. Moench)

The present study concerns the revalorization of drained water from aquaculture ponds rearing Clarias gariepinus on okra crops. The rearing was carried out at the farm of Gaston Berger University in 100 m2 ponds. In each pond, the individuals of C. garipinus with an average weight of 6 ± 0.3 g were stocked at a density of 11 per m2. The water temperature and pH were measured during the experiment. The control fishing is carried out every month to monitor variations in the weight and size of reared individuals. The plant production is carried out in elementary plots measuring 3 m × 1.5 m. Each plot was fertilized with either: drained water from C. gariepinus rearing (DWC), poultry droppings (PD), cow dung (CD) and mineral fertilizer (NPK). Treatments are carried out in tripliqua with either river water (RW), RW + the recommended dose of NPK (RD-NPK), RW + RD-PD, RW + RD-CD, DWC, DWC + 25% RD-NPK, DWC + 50% RD-NPK, DWC + 75% RD-NPK, DWC + 25% RD-PD, DWC + 50% RD-PD, DWC + 75% RD-PD, DWC + 25% RD-CD, DWC + 50% RD-CD, DWC + 75% RD-CD. Growth parameters and yield of okra were determined. The average temperature in the rearing environment was 27.6 ± 1.5˚C and pH 7.9 ± 1.1. After six (06) months of rearing, C. gariepinus individuals reached an average weight of 850.12 ± 1.3 g and an average height of 52.44 ± 1.1 cm. The daily weight gain and specific growth rates over this period were 3.9 g per day and 2.8% per day, respectively. The treatment T1 (RW + DR-NPK) gave the highest mean collar diameter and mean plant height with 2.3 ± 0.9 cm and 61.6 ± 32 cm, respectively. In T4 (DWC), the mean height of plants was 38.8 ± 23.5 cm and mean collar diameter 1.4 ± 0.8 cm. The growth performance in T4 was comparable to that of RD-CD (T3), but different from RD-NPK (T1) and RD-PD (T2). The highest average number, average weight, average length and average diameter of fruits were noted in treatments T13 (RW + RD-75%CD) and T7 (DWC + 75% RD-NPK). The best yields were noted in T1 (RW + RD-NPK) = 10.8 ± 5.4 t·ha−1, T5 (DWC + 25% RD-NPK) = 9.2 ± 4.6 t·ha−1 and T4 (DWC) = 8.6 ± 4.3 t·ha−1 which are comparable and higher than those obtained in T2 = 5.7 ± 2.8 t·ha−1 and T3 = 7.5 ± 3.8 t·ha−1.

Effects of mixed fertilizers formed by the compounding of two targeted controlled-release nitrogen fertilizers on yield,nitrogen use efficiency,and ammonia volatilization in double-cropping rice

One-time application of mixed fertilizer formed by the compounding of two controlled-release nitrogen fertilizers(CRUs)with targeted N supply during the periods from transplantation(TS)to panicle initiation(PI)and from PI to heading(HS)is expected to synchronize the double-peak N demand of rice.However,its effects on the yield and N use efficiency(NUE)of labor-intensive double-cropping rice were unknown.Two targeted CRU(CRU_(A)and CRU_(B))were compounded in five ratios(CRU_(A):CRU_(B)=10:0,7:3,5:5,3:7,and 0:10)to form five mixed fertilizers(BBFs):BBF1-5.A field experiment was performed to investigate the characteristics of N supply in early and late seasons under different BBFs and their effects on N uptake,yield,and ammonia volatilization(AV)loss from paddy fields of double-cropping rice.Conventional high-yield fertilization(CK,three split applications of urea)and zero-N treatments were established as controls.The N supply dropped significantly with the increased compound ratio of CRU_(B)during the period from TS to PI,but increased during the period from PI to HS.With the exception of the period from TS to PI in the late rice season,the N uptake of early and late rice maintained close synchronicity with the N supply of BBFs during the double-peak periods.Excessive N supply(BBF1 and BBF2)in the late rice season during the period from TS to PI increased N loss by AV.The effect of BBF on grain yield increase varied widely between seasons,irrespective of year.Among the BBFs,the BBF2 treatment of early rice not only stabilized the spikelets per panicle but also ensured a high number of effective panicles by promoting N uptake during the period from TS to PI and a high grain-filling percentage by appropriately reducing the N supply at the later PI stage,resulting in the highest rice yield.While stabilizing the effective panicle number,the BBF4 treatment of late rice increased the number of spikelets per panicle by promoting N uptake during the period from PI to HS,resulting in the highest rice yield.The two-year average yield and apparent N recovery efficiency of the BBF2 treatment during the early rice season were 9.6 t ha 1 and 45.3%,while those of late rice in BBF4 were 9.6 t ha 1 and 43.0%,respectively.The yield and NUE indexes of BBF2 in early rice and BBF4 in late rice showed no significant difference from those of CK.The AVs of BBF2 during the early rice season and of BBF4 during the late rice season were 50.0%and 76.8%lower,respectively,than those of CK.BBF2 and BBF4 could effectively replace conventional urea split fertilization in early and late rice seasons,ensuring rice yield and NUE and reducing AV loss in paddy fields.

Effects of different ration of NPK fertilizer on the grain yield and protein content in forage rice

Different ratios of NPK were adopted in this research to study its effects on the objective traits of 2 early forage-rice varieties, and to obtain the optimum ratio to further improve the application technique in theory. At the same time, the possibility of increasing yield and protein content in the grain through cultivation technique was also studied. The conclusions were：

Effects of water and fertilizer deficit regulation with drip irrigation at different growth stages on fruit quality improvement of kiwifruit in seasonal arid areas of Southwest China

For a long time,seasonal drought occurs frequently in Southwest China,and the management of water and fertilizer in kiwifruit orchards has no quantitative standards,which seriously affects the yield and quality of kiwifruit.Therefore,the effects of water and fertilizer deficit regulation with drip irrigation(WFDRDI)on the quality of kiwifruit at different growth stages were explored to achieve water and fertilizer saving,and green and efficient production of kiwifruit.We select‘Jin Yan'kiwifruit and set two water deficit levels(W_(D20%)and W_(D40%))and three fertilizer deficit levels(F_(D15%),F_(D30%)and F_(D45%))at bud burst to leafing stage(stageⅠ),flowering to fruit set stage(stageⅡ),fruit expansion stage(stageⅢ)and fruit maturation stage(stageⅣ),respectively,with a full irrigation and fertilization as the control treatment(CK)in 2017and 2018.Results showed that the WFDRDI at stageⅡandⅢhad significant effect on fruit physical quality of kiwifruit,specifically,theⅢ-WD40%F_(D30%)andⅢ-W_(D20%)F_(D45%)treatments significantly increased fruit firmness by 13.62 and 15.59%(P<0.05),respectively;theⅡ-W_(D40%)F_(D15%)andⅢ-W_(D40%)F_(D15%)treatments significantly increased dry matter by 8.19 and 6.47%(P<0.05),respectively;theⅢ-W_(D20%)F_(D15%)treatment significantly increased single fruit weight and fruit volume by 9.33 and 12.65%(P<0.05),respectively;theⅡ-W_(D20%)F_(D15%)treatment significantly increased fruit water content by 1.99%(P<0.05).The WFDRDI had an obvious effect on fruit chemical quality of kiwifruit.TheⅢ-W_(D20%)F_(D45%),Ⅳ-W_(D40%)F_(D15%)andⅣ-W_(D20%)F_(D30%)treatments significantly increased vitamin C(Vc)content by 69.96,36.96 and 34.31%(P<0.05),respectively;theⅢ-W_(D40%)F_(D15%)andⅣ-W_(D40%)F_(D15%)treatments significantly increased total soluble solid(TSS)content by 3.79 and 17.05%(P<0.05),respectively,and significantly increased soluble sugar content by 28.61 and 34.79%(P<0.05),respectively;the contents of fructose,glucose and sucrose also had a significantly increasing trend,which was increased significantly by 5.58–19.63%,40.55–60.36%and 54.03–54.92%in theⅢ-WD40%F_(D15%)andⅣ-W_(D40%)F_(D15%)treatments(P<0.05),respectively;sugar–acid ratio was increased significantly in theⅣ-W_(D40%)F_(D15%)treatment by 64.65%(P<0.05).The degree and duration of water and fertilizer deficit had a comprehensive effect on fruit quality of kiwifruit.The WFDRDI at stageⅡandⅢcontribute to improving fruit physical quality,and the threshold of water and fertilizer deficit were 20 and 15%,respectively;stageⅢandⅣare the critical periods for improving fruit chemical quality by water and fertilizer coupling effect,and the threshold of water and fertilizer deficit were 40 and 15%,respectively.Therefore,aiming at precise water and fertilizer saving,theⅠ-W_(D20%)F_(D30%),Ⅱ-W_(D40%)F_(D15%),Ⅲ-W_(D40%)F_(D15%)andⅣ-W_(D40%)F_(D15%)treatments under WFDRDI during the whole growth period of kiwifruit were the best mode to improve quality and production of kiwifruit.

Effects of Combined Application of Biochar-based Organic Fertilizer and Reduced Nitrogen Fertilizer on Soil Enzyme Activity and Yield of Purple Cabbage(Brassica oleracea var.capita rubra)in Yuanmou County

[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity,and yield of purple cabbage(Brassica oleracea var.capita rubra)were investigated in the field base of Institute of Thermal Zone Ecological Agriculture,Yunnan Academy of Agricultural Sciences in Yuanmou County.[Methods]A total of 13 treatments were set up by applying biochar-based organic fertilizer at three levels of 15,30 and 45 t/hm^(2)(T_(1),T_(2),T_(3)),combined with top application of nitrogen fertilizer(urea)at four levels:375(N_1),300(N_(2)),225(N_(3))and 0 kg/hm^(2),with non-fertilizing treatment as control check(CK),in order to explore the optimal ratio for the combined application of biochar-based organic fertilizer with nitrogen fertilizer.[Results]The application of biochar-based organic fertilizer could significantly improve soil nutrients,enzyme activity,and purple cabbage yield.The improvement effect of combined application with nitrogen fertilizer was higher than that of single application of biochar-based organic fertilizer,and the improvement effect was enhanced with the application amount of biochar-based organic fertilizer increasing.The contents of organic matter and total nitrogen were the highest in treatment T_(3)N_(3),of which the values increased by 81.39%and 56.09%compared with the CK,respectively.The contents of soil hydrolyzable nitrogen,available phosphorus,and available potassium were all the highest under treatment T_(3)N_(2),with increases of 92.76%,171.01%and 235.50%,respectively.There was a significant positive correlation between the activity of soil catalase,urease,and sucrase and organic matter,total nitrogen,and available nutrients.The overall soil enzyme activity was relatively higher in treatment T_(3)N_(2).The yield of purple cabbage treated with biochar-based organic fertilizer combined with nitrogen fertilizer could reach 85750 kg/hm^(2),which was 94.78%higher than that treated with biochar-based organic fertilizer alone.Based on comprehensive analysis,the optimal combination ratio was 45 t/hm^(2)of biochar-based organic fertilizer and 300 kg/hm^(2)of urea(T_(3)N_(2)).[Conclusions]This study provides data support for the promotion of biochar-based organic fertilizers and reduced fertilizer in agricultural soil in the Dam area of Yuanmou County.