Tobacco, a pivotal economic crop in China, faces the challenge of securing high-quality raw materials for its industry due to unbalanced and inefficient nitrogen (N) application. To assess the impact of fertilizer management and soil factors on the yield and quality of flue-cured tobacco (FCT), a meta-analysis was conducted across 82 peer-reviewed research studies. The findings demonstrated that both fertilizer management and soil properties exerted a significantly greater influence on yield (63.13% and 62.05%, respectively) than the proportion of superior and medium tobacco (PSMT) (23.57% and 23.83%, respectively). Multiple models were conducted to analyze the N application rate for maximum yield and PSMT, respectively, resulting in an optimum range from 90 to 100 kg N ha−1. The highest yield and PSMT increments were observed with fertilizer timing (FT) applied twice, a basal fertilizer ratio (BFR) exceeding 50%, and a soil pH below 6.5. The nicotine content escalated with increasing N application rates (NR) and soil nitrogen content, peaking at NR over 120 kg N ha−1 and soil total nitrogen (TN) above 2 g kg−1. Stepwise regression modeling indicated that nicotine content was positively influenced by fertilizer management factors (including NR, fertilizer timing, and BFR), as well as initial soil nitrogen content (AN and TN). However, it was negatively correlated with available potassium (AK). Therefore, the results of this meta-analysis suggest that effective fertilizer management, slightly acidic soils enriched with AK, and lower N supply capacity are crucial for enhancing leaf quality while reducing nicotine content. This approach promises improved economic and environmental returns for the tobacco industry in China.
Core Ideas We assessed the movement capacity of different P. Banding P fertilizer in suboptimal placement reduced wheat yield with monocalcium phosphate. Diammonium phosphate compensated for the reduction in wheat yield due to suboptimal placement. Banding of P can increase P availability to crops. Our objective was to determine if banding two forms of P fertilizer at multiple distances from the seed can improve wheat ( Triticum aestivum L.) growth and P uptake vs. broadcast P fertilizer application. Waters‐soluble and Ca 2 – P concentrations in soil was greater near the point of P placement when monocalcium phosphate was used compared to diammonium phosphate, while the opposite result was found when the P diffusion distance was greater than 2 cm from the P placement. Another field experiment with four application strategies (broadcasting P, banding P under the wheat row, and banding P 5 and 12 cm from the wheat row) and two P forms was conducted over 2 yr. Banding P under the wheat row increased wheat yield and P uptake regardless of the P form compared to broadcasting P. Banding 12 cm from the row resulted in a 6.0% reduction in wheat yield for monocalcium phosphate compared to broadcasting P. Banding diammonium phosphate 5 or 12 cm from the row provided yield compensations over monocalcium phosphate. Dry matter at regreening was significantly depressed for banding 5 or 12 cm from the row with monocalcium phosphate application relative to broadcasting P, while there was compensatory growth for banding 5 cm from the row after regreening. Root length proliferated with diammonium phosphate than with monocalcium phosphate regardless of band placement. Diammonium phosphate should not be placed more than 5 cm from the row to ensure maximum P uptake potential.
Influences of monocalcium phosphate monohydrate applying modes on the availability to rice and the distribution of available P in soil were studied through pot cultivation in greenhouse,and based on the results the desired applying mode of phosphate fertilizer in rice field was recommended.The results showed that the concentration of total P in surface water was the highest under broadcasting phosphate fertilizer on the soil surface,reaching up to 4.8 mg/L,while under other applying modes,the concentrations could meet the standard of Ⅲ in GB3838-2002;mixed applying mode could provide solid uptake room and highly available P for rice;in furrow application mode,most of P applied accumulated in a short range of less than 3 cm upper and lower the application band;in rice field,mixed applying phosphate fertilizer was a preferential considered mode for phosphate application;however,if available P in soil was relatively high,phosphate fertilizer should be applied in dry season.
The total K content,total non-exchangeable potassium(NEK) content and NEK release rate of five K-bearing minerals(phlogopite,biotite,vermiculite,muscovite and feldspar) were compared in current study.The results indicated that the total K,total NEK and NEK release rates of the minerals differed greatly,and the three parameters were not significant correlated.The total NEK content followed the order of phlogopite(5.19%) biotite(3.08%) vermiculite(2.01%) muscovite(1.18%) feldspar(0.24%),accounting for 58.4%,99.7%,62.5%,14.2% and 4.98% of the total K,respectively.The release characteristics of the NEK from five minerals was investigated during a 3 d extraction with NaBPh4 method with low K-extracting power,the amount of NEK released from minerals followed the sequence of biotite vermiculite phlogopite muscovite feldspar.The averaged NEK release rates from five minerals followed the same order and were 5.99,2.34,0.52,0.22 and 0.17 mg/(kg·min),respectively.How to evaluate the K availability in minerals according to the amount and the release rate of NEK was still a question need to be addressed in future.
Economic and bionomical benefit can be reached through using controlled-release fertilizers.The most important application of controlled-release of fertilizer is polymer-coated fertilizers.The current research and nutrients release model about polymer-coated controlled-release fertilizer are briefly introduced in this paper.The factors that influence the nutrients release behavior are as followings: membrane thickness,granule radius,diffusion coefficient,nutrients composition and nutrient dissolving property.The application of polymer-coated controlled-release fertilizer in our country is in the initial stage,and almost depends on importation,but shows strong application potential in future with the economic development.Some important progress about the research of polymer-coated controlled-release fertilizer has been made in our country.However,there are also some deficiencies in technological,cooperational and market aspects.Therefore,a commercial polymer-coated controlled-release fertilizer with Chinese-owned needs a long time study,especially in the theory research and market development.
Coating through polymer film to control nutrient release can reduce the nutrient losses and minimize environmental contamination. In this research, the waterborne acrylate latex and additive (cross-linker aziridine) were used to develop coated controlled-release fertilizers by Wurster-type fluidized bed, and the influences of different cross-linker percentage on the coating properties and the nutrient-release profiles were investigated. The results indicated that the waterborne coating coupled with the 2 wt % of cross-linker could effectively decrease the swelling capacity of the membrane to 5.54 ± 0.32% while obtaining a suitable Tg (6.13 °C); the cumulative nutrient-release percentage was significantly improved to around 40% in 9 days at 40 °C. This organic solvent-free coating provided a promising option for the development of coated controlled-release fertilizer.
A laboratory incubation experiment using soil columns was conducted to study the effects of monocalcium phosphate (MCP) and potassium chloride (KCl) on soil pH changes in fertilizer microsites with two Chinese soils. Mixtures of two fertilizers at two rates (0 and 0.26 g per column) were added to the surface of soil cylinders. The results shown that both fertilizers significantly decreased soil pH after 7 d and 28 d, which declined with time and distance from fertilizer site. Compared with KCl alone, the soil pH decrease close to the fertilizer site induced by applied KCl was slowed down in the acidic red soil by MCP addition but was promoted in the calcareous soil. Compared with MCP alone, the application of KCl with MCP had greater effects of reducing pH in both soils. The magnitude and extent of soil pH changes were mostly contributed by KCl in the KCl plus MCP treatment.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)