Carbon dioxide fertilization method for improving nitrogen fertilizer utilization rate of cucumber

Abstract

The application relates to a carbon dioxide fertilization method for improving nitrogen fertilizer utilization rate of cucumbers, which significantly improves the yield, photosynthesis efficiency, nitrogen absorption amount and nitrogen fertilizer utilization rate of cucumbers by regulating CO2 concentration, water content and nitrate-ammonium ratio. The specific technical scheme comprises the following steps: setting the CO2 fertilization concentration as 1200 mu mol.mol ‑1 , the water content as 70-80%, and the nitrate-ammonium ratio level as 13:1, and applying the soil by adopting a dropper. The photosynthetic rate, dry matter accumulation and nitrogen fertilizer utilization rate of the cucumbers are significantly improved. The application result of the method shows that, compared with the control treatment, when the CO2 fertilization is carried out, the water content is 70-80%, and the nitrate-ammonium ratio is 13:1, the yield of the cucumbers is increased by 69.4%-92.6%, the dry weight of the whole plant is increased by 52.0%-82.0%, the nitrogen absorption amount is increased by 67.0%-92.8%, and the nitrogen fertilizer utilization rate reaches 48.9%-51.4%. The application significantly improves the nitrogen fertilizer utilization efficiency of the facility cucumbers by optimizing the CO2 concentration, water content and nitrate-ammonium ratio, and has high popularization and application value.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, specifically to a method for improving the carbon dioxide fertilization of cucumbers. Background Technology

[0002] Currently, the atmospheric CO2 concentration has exceeded 420 μmol / mol. -1 According to global climate models, increased CO2 concentrations will have a significant impact on plant productivity in agro-ecosystems. While increased CO2 concentrations can promote photosynthesis and dry matter accumulation in vegetables, long-term CO2 fertilization will reduce plant nitrogen concentrations, limiting productivity. Ammonium nitrogen and nitrate nitrogen are the main nitrogen sources that plants can directly utilize, with ammonium nitrogen absorption being more efficient and energy-saving. Studies show that the combined application of ammonium and nitrate nitrogen can reduce energy consumption and, through the mutual restraint of rhizosphere acidification and alkalization, more effectively promote plant growth. In terms of environmental control, conventional CO2 fertilization concentrations do not reach the optimal photosynthetic efficiency threshold, and water management often adopts extensive irrigation patterns. Studies have shown that 70-80% soil moisture content can reduce nitrogen leaching by 34.7%, but in actual production, water fluctuations often lead to increased ammonium nitrogen volatilization. In addition, farmers' habitual nitrogen application rates have not significantly increased yields, but rather reduced nitrogen fertilizer utilization by 30%-50%, and CO2 concentrations are often controlled below 1000 μmol / mol. -1 The carbon-nitrogen synergistic effect was not fully utilized.

[0003] Applying nitrogen fertilizer according to plants' preferences for nitrogen forms has been suggested in some studies to increase nitrogen uptake and crop yield, while others indicate that this approach has little effect on yield increase and nitrogen uptake improvement. Therefore, researching the relationship between plant nitrogen form preferences (nitrate-to-ammonia ratio) and environmental regulation is crucial for increasing plant yield. Under CO2 fertilization, supplying nitrate nitrogen promotes nitrate reductase activity, while supplying ammonium nitrogen inhibits it. CO2 fertilization may inhibit nitrate reduction; when some nitrate nitrogen in the culture medium is replaced by ammonium nitrogen, wheat dry matter yield increases by 50%, with ammonium nitrogen showing a stronger promoting effect on CO2 fertilization during wheat growth. However, research on the effects of regulating soil moisture content and increasing the ammonium nitrogen supply ratio on photosynthesis and productivity in greenhouse vegetables under CO2 fertilization is limited. Studying CO2 fertilization, moisture content, and the nitrate-to-ammonia ratio can provide scientific fertilization guidance for greenhouse vegetable cultivation, effectively improving vegetable yield and quality, reducing fertilizer waste, lowering planting costs, and is of great significance for the sustainable development of the greenhouse vegetable industry. Summary of the Invention

[0004] This invention provides a carbon dioxide fertilization method to improve the nitrogen fertilizer utilization rate of cucumbers, which solves the problems of low nitrogen fertilizer utilization rate and insufficient synergistic effect of environmental control and nitrogen form ratio in existing technologies for greenhouse vegetables.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A carbon dioxide fertilization method for improving nitrogen fertilizer utilization in cucumbers includes the following steps:

[0007] (1) Sow cucumber seeds after germination, and transplant the seedlings when they have grown to two leaves and one heart.

[0008] (2) CO2 fertilization and nitrogen, phosphorus and potassium fertilization should be carried out starting on the 7th day after transplanting, and the CO2 concentration in the greenhouse should be stabilized at 1150-1250 μmol·mol⁻¹. -1 The ratio of nitrogen, phosphorus, and potassium fertilizers to ammonium nitrate is 12:1-14:1, and the soil moisture content is 70-80%.

[0009] Furthermore, preferably: the CO2 concentration inside the greenhouse is stabilized at 1200 μmol·mol⁻¹ -1 The ratio of ammonium nitrate to nitrogen, phosphorus, and potassium fertilizers is 13:1.

[0010] Furthermore, preferably, the application rate of nitrogen, phosphorus and potassium fertilizer is 210-215 kg of nitrogen, 30-35 kg of phosphorus and 245-255 kg of potassium per hectare.

[0011] Furthermore, preferably, the nitrogen, phosphorus, and potassium fertilizers used for fertilization are calcium nitrate, potassium nitrate, ammonium nitrate, ammonium sulfate, calcium dihydrogen phosphate, and potassium carbonate.

[0012] Furthermore, preferably: the nitrogen, phosphorus and potassium fertilizer has a nitrate-to-ammonia ratio of 13:1, and the fertilizers used for nitrogen, phosphorus and potassium fertilizer are calcium nitrate, potassium nitrate, ammonium nitrate and calcium dihydrogen phosphate, with a molar ratio of 3:6:1:0.5, and the fertilizer application rate is 211 kg of nitrogen, 33.3 kg of phosphorus and 252 kg of potassium per hectare.

[0013] The beneficial effects of this invention are:

[0014] This invention significantly improves cucumber yield, photosynthetic efficiency, nitrogen uptake, and nitrogen fertilizer utilization by controlling CO2 concentration, moisture content, and nitrate-ammonium ratio. Experimental results show that, compared to the control treatment, under CO2 fertilization with a nitrate-ammonium ratio of 13:1, cucumber yield increased by 69.4%-92.6%, total plant dry weight increased by 52.0%-82.0%, nitrogen uptake increased by 67.0%-92.8%, and nitrogen fertilizer utilization reached 48.9%-51.4%. This significantly improves the nitrogen fertilizer utilization efficiency of greenhouse cucumbers and has high potential for widespread application. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 The results show the effects of different methods in Example 1 on cucumber yield (a) and dry weight (b);

[0017] Figure 2 The results of different methods in Example 1 on the effect of nitrogen uptake in the whole cucumber plant;

[0018] Figure 3 The effect of different methods on nitrogen fertilizer utilization rate of cucumber plants in Example 1;

[0019] Figure 4 The results show the effects of different methods on cucumber yield (a) and dry weight (b) in Example 2;

[0020] Figure 5 The results of the effects of different methods on the nitrogen uptake of the whole cucumber plant in Example 2;

[0021] Figure 6 The effect of different methods on nitrogen fertilizer utilization rate of cucumber plants in Example 3.

[0022] Note: Different letters in the figure indicate significant differences between treatments (p<0.05). C: CO2 concentration; NA: nitrate-ammonium ratio; W: soil moisture content. An asterisk (*) indicates a significant difference (*p<0.05, **p<0.01, ***p<0.001), and ns indicates no significant difference (p≥0.05). Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are also possible.

[0024] Example 1

[0025] A carbon dioxide fertilization method for improving nitrogen fertilizer utilization in cucumbers includes the following steps:

[0026] 1. Test location and test varieties:

[0027] The experiment was conducted in four open-top (OTC) growth boxes in the greenhouse of the Nanjing Institute of Soil Science, Chinese Academy of Sciences. Cucumber seeds (variety Jinmei No. 3) were placed in constant temperature boxes (temperature 28℃, humidity 60%, no light) and germinated for 4 days. The seeds that showed signs of germination were then sown in seedling trays containing cultivation substrate.

[0028] 2. Test methods

[0029] The soil samples were taken from paddy soil in a vegetable field in Dianzhan Village, Taicang City, Jiangsu Province. The soil's physicochemical properties were: pH (H₂O) 6.92, electrical conductivity 496 μS / cm. -1 Organic matter 24.7g kg -1 Total nitrogen 0.95 g kg -1 Available nitrogen 153 mg / kg -1 .

[0030] Cultivation and Management: After germination, cucumber seeds are sown in seedling trays. When seedlings have grown to two leaves and a central bud, they are transplanted into flowerpots. CO2 fertilization should begin 7 days after transplanting, with each cucumber plant receiving 81.1 mg / kg of nitrogen, 12.8 mg / kg of phosphorus, and 96.8 mg / kg of potassium. -1 The calculated nitrogen, phosphorus, and potassium application rates per hectare are 211, 33.3, and 252 kg, respectively.

[0031] CO2 concentration control: In the greenhouse cultivation environment, the CO2 concentration in two OTC units is maintained at the atmospheric CO2 concentration (Cl), while the CO2 concentration in the other two OTC units is stabilized at 1200 μmol·mol⁻¹ using CO2 generators or gas cylinders. -1 (C2)

[0032] Soil moisture content control: Two soil moisture content levels were set, namely 30-40% (W1) and 70-80% (W2). The soil moisture content was adjusted and maintained constant at 30-40% and 70-80% daily using a weighing method with distilled water.

[0033] Nitrate-to-ammonium ratio control: According to the experimental design, nitrogen, phosphorus, and potassium nutrient solutions with different nitrate-to-ammonium ratios were prepared to ensure that the ratio of nitrate nitrogen to ammonium nitrogen was 5:9 (NA1), 9:5 (NA2), and 13:1 (NA3), respectively. The treatments without CO2 fertilization and those with nitrogen fertilizer were used as control treatments (CK). The specific raw materials and ratios of the nitrogen, phosphorus, and potassium nutrient solutions are shown in Table 1.

[0034] Table 1. Macro-elemental composition (mmol / L) of treatments with different ammonium nitrate ratios.

[0035] 5:9 2 0 1 4 0.5 3 9:5 3 2 1 2 0.5 2 13:1 3 6 1 0 0.5 0 12:2 2 6 2 0 0.5 0 11:3 2 6 1 1 0.5 0

[0036] 3. Data Measurement and Calculation

[0037] Photosynthesis measurement: The photosynthetic rate, stomatal conductance, and transpiration rate of the leaves were measured using a portable photosynthesis meter (Li-6400). During the measurement, the photosynthetic photon flux density, temperature, relative humidity, and air velocity in the leaf chamber were set to 1500 μmol·m⁻¹. -2 ·s -1 25.0℃, 50.0% and 500 μmol·s -1 .

[0038] Nitrogen uptake determination: After harvest, the plant is divided into four parts: roots, stems, leaves and fruits. The dry weight and nitrogen concentration of each part are measured, and the nitrogen uptake and nitrogen fertilizer utilization rate are calculated.

[0039] Nitrogen fertilizer utilization rate (%) = (Above-ground nitrogen uptake in nitrogen-applied areas - Above-ground nitrogen uptake in non-nitrogen-applied areas) / Nitrogen application rate × 100

[0040] 4. Experimental Results:

[0041] 4.1 The effects of different methods on increasing cucumber yield are shown in the figure. Figure 1 .

[0042] Under CO2 fertilization conditions, with a moisture content of 70-80% and an ammonium nitrate ratio of 13:1, cucumber yield increased significantly, by 69.4%. Compared with the control treatment, CO2 fertilization significantly increased the total dry weight of cucumber plants at a moisture content of 70-80%, by 30.8%-52.0%.

[0043] 4.2 Effects of different methods on nitrogen uptake of whole melon plant, the results are shown in Table 2.

[0044] Compared with the control treatment, the net photosynthetic rate increased by 112% when the moisture content was 30-40% and the nitrate-to-ammonium ratio was 13:1 under atmospheric CO2. CO2 fertilization significantly improved the photosynthetic rate of cucumber leaves, with a net photosynthetic rate increasing by 263% when the moisture content was 70-80% and the nitrate-to-ammonium ratio was 13:1. At the same time, CO2 fertilization reduced the transpiration rate of leaves, thus reducing water consumption.

[0045] Table 2. Effects of different CO2 concentrations, moisture contents, and ammonium nitrate ratios on photosynthesis in cucumber leaves.

[0046]

[0047] Note: Different letters in the table indicate significant differences between treatments (p<0.05). C: CO2 concentration; NA: nitrate-ammonium ratio; W: soil moisture content. An asterisk (*) indicates a significant difference (*p<0.05, **p<0.01, ***p<0.001), and ns indicates no significant difference (p≥0.05).

[0048] 4.3 The effect of different methods on increasing nitrogen uptake is shown in the figure. Figure 2 .

[0049] Compared with the control (CK) treatment, under atmospheric CO2 concentration, a moisture content of 30-40% and a nitrate-ammonium ratio of 13:1 significantly increased the total nitrogen uptake of cucumber plants, with an increase of 69.6%. Under a moisture content of 70-80%, CO2 fertilization promoted nitrogen uptake in cucumbers even more with the increase of the nitrate nitrogen ratio.

[0050] 4.4 The effects of different methods on improving nitrogen fertilizer utilization rate are shown in the figure. Figure 3 Different letters in the figure indicate significant differences between treatments (p<0.05). C: CO2 concentration; NA: nitrate-ammonium ratio; W: soil moisture content. An asterisk (*) indicates a significant difference (*p<0.05, **p<0.01, ***p<0.001).

[0051] Under atmospheric CO2 conditions, the nitrogen use efficiency was 39.6% in the treatment with a moisture content of 30-40% and a nitrate-to-ammonium ratio of 13:1. Under CO2 fertilization, the nitrogen fertilizer use efficiency was 48.9% in the treatment with a moisture content of 70-80% and a nitrate-to-ammonium ratio of 13:1. CO2 fertilization and a soil moisture content of 70-80% significantly increased the nitrogen use efficiency in the treatment with a nitrate-to-ammonium ratio of 13:1.

[0052] Example 2

[0053] A carbon dioxide fertilization method for improving nitrogen fertilizer utilization in cucumbers includes the following steps:

[0054] 1. Test location and test varieties:

[0055] The experiment was conducted in four open-top (OTC) growth boxes in the greenhouse of the Nanjing Institute of Soil Science, Chinese Academy of Sciences. Cucumber seeds (variety Jinyou 38) were placed in constant temperature boxes (temperature 28℃, humidity 60%, no light) and germinated for 5 days. The seeds that showed signs of germination were then sown in seedling trays containing cultivation substrate.

[0056] 2. Test methods

[0057] The soil samples were taken from paddy soil in a vegetable field in Dianzhan Village, Taicang City, Jiangsu Province. The soil's physicochemical properties were: pH (H₂O) 6.92, electrical conductivity 496 μS / cm. -1 Organic matter 24.74 g kg -1 Total nitrogen 0.95 g kg -1 Available nitrogen 152.56 mg / kg -1 .

[0058] Cultivation and Management: After germination, cucumber seeds are sown in seedling trays. When seedlings have grown to two leaves and a central bud, they are transplanted into flowerpots. CO2 fertilization should begin 7 days after transplanting, with each cucumber plant receiving 81.1 mg / kg of nitrogen, 12.8 mg / kg of phosphorus, and 96.8 mg / kg of potassium. -1 The calculated nitrogen, phosphorus, and potassium application rates per hectare are 211, 33.3, and 252 kg, respectively.

[0059] CO2 concentration control: In the greenhouse cultivation environment, the CO2 concentration in two OTC units is maintained at the atmospheric CO2 concentration (Cl), while the CO2 concentration in the other two OTC units is stabilized at 1200 μmol·mol⁻¹ using CO2 generators or CO2 cylinders. -1 (C2)

[0060] Soil moisture content control: Two soil moisture content levels were set, namely 30-40% (W1) and 70-80% (W2). The soil moisture content was adjusted and maintained constant at 30-40% and 70-80% daily using a weighing method with distilled water.

[0061] Nitrate-to-ammonium ratio control: According to the experimental design, nutrient solutions with different nitrate-to-ammonium ratios were prepared to ensure that the ratio of nitrate nitrogen to ammonium nitrogen was 5:9 (NA1), 9:5 (NA2), and 13:1 (NA3), respectively. The treatments without CO2 fertilization and those with nitrogen fertilizer were used as control treatments (CK). The specific raw materials and ratios of the nitrogen, phosphorus, and potassium nutrient solutions are shown in Table 1.

[0062] 3. Data Measurement and Calculation

[0063] Photosynthesis measurement: The photosynthetic rate, stomatal conductance, and transpiration rate of cucumber leaves were measured using a portable photosynthesis meter.

[0064] Nitrogen uptake determination: After harvest, the plant is divided into four parts: roots, stems, leaves and fruits. The dry weight and nitrogen concentration of each part are measured, and the nitrogen uptake and nitrogen fertilizer utilization rate are calculated.

[0065] Nitrogen fertilizer utilization rate (%) = (Above-ground nitrogen uptake in nitrogen-applied areas - Above-ground nitrogen uptake in non-nitrogen-applied areas) / Nitrogen application rate × 100

[0066] Experimental results:

[0067] 4.1 The effects of different methods on increasing cucumber yield are shown in the figure. Figure 4 .

[0068] Under CO2 fertilization conditions, with a moisture content of 70-80% and an ammonium nitrate ratio of 13:1, cucumber yield increased significantly, by 92.6%. Compared with the control treatment, at a moisture content of 70-80%, CO2 fertilization significantly increased the total dry weight of cucumber plants, by 32.5%-82.0% (e.g., ...). Figure 4 (As shown).

[0069] 4.2 Effects of different methods on nitrogen uptake of whole melon plant, the results are shown in Table 3.

[0070] Compared with the control treatment, the net photosynthetic rate increased by 72.3% when the moisture content was 30-40% and the nitrate-to-ammonium ratio was 13:1 under atmospheric CO2. CO2 fertilization significantly improved the photosynthetic rate of cucumber leaves, with a net photosynthetic rate increasing by 147% when the moisture content was 70-80% and the nitrate-to-ammonium ratio was 13:1. At the same time, CO2 fertilization reduced the transpiration rate of leaves, thus reducing water consumption.

[0071] Table 3. Effects of different CO2 concentrations, moisture contents, and ammonium nitrate ratios on photosynthesis in cucumber leaves.

[0072]

[0073]

[0074] 4.3 The effect of different methods on increasing nitrogen uptake is shown in the figure. Figure 5 .

[0075] Compared with the control (CK) treatment, the treatment with atmospheric CO2 concentration, a moisture content of 30-40%, and a nitrate-to-ammonium ratio of 13:1 significantly increased the total nitrogen uptake of cucumber plants, with an increase of 58.1%. At a moisture content of 70-80%, the effect of CO2 fertilization on nitrogen uptake in cucumbers was even greater with increasing nitrate nitrogen content.

[0076] 4.4 The effects of different methods on improving nitrogen fertilizer utilization rate are shown in the figure. Figure 6 .

[0077] Under atmospheric CO2 conditions, the nitrogen use efficiency was 43.2% in the treatment with a moisture content of 30-40% and a nitrate-to-ammonium ratio of 13:1. Under CO2 fertilization, the nitrogen fertilizer use efficiency was 51.4% in the treatment with a moisture content of 70-80% and a nitrate-to-ammonium ratio of 13:1. CO2 fertilization and a soil moisture content of 70-80% significantly increased the nitrogen use efficiency in the nitrate-to-ammonium ratio treatment of 13:1.

[0078] Example 3

[0079] This is essentially the same as Example 2, except that the ammonium nitrate ratio is 12:2 and 11:3, and the specific raw material ratios are shown in Table 1. The CO2 concentration was stabilized at 1150 μmol·mol⁻¹. -1 When the moisture content is 70-80% and the nitrate-ammonium ratio of nitrogen, phosphorus, and potassium fertilizer is 12:2, the cucumber yield increases by 84.3%; when the nitrate-ammonium ratio of nitrogen, phosphorus, and potassium fertilizer is 11:3, the cucumber yield increases by 78.4%, showing a significant increase in cucumber yield.

[0080] When the CO2 concentration is stable at 1250 μmol·mol -1 When the moisture content is 70-80% and the nitrate-ammonium ratio of nitrogen, phosphorus, and potassium fertilizer is 12:2, the cucumber yield increases by 88.2%; when the nitrate-ammonium ratio of nitrogen, phosphorus, and potassium fertilizer is 11:3, the cucumber yield increases by 79.1%, showing a significant increase in cucumber yield.

[0081] in conclusion

[0082] This invention significantly improves the yield, photosynthetic rate, and nitrogen fertilizer utilization rate of greenhouse cucumbers by optimizing CO2 concentration, moisture content, and ammonium nitrate ratio. This method is applicable to the cultivation of greenhouse vegetables, especially cucumbers, and has high potential for widespread application.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for applying carbon dioxide to improve nitrogen fertilizer utilization in cucumbers, characterized in that, Includes the following steps: (1) After the cucumber seeds have been germinated, they are sown and transplanted when the seedlings have grown to two leaves and one heart. (2) CO2 fertilization and nitrogen, phosphorus and potassium fertilization should be carried out on the 7th day after transplanting. The CO2 concentration in the greenhouse should be stable at 1150-1250 μmol·mol-1. The nitrate-ammonium ratio of nitrogen, phosphorus and potassium fertilization should be 12:1-14:

1. The soil moisture content should be 70-80%. The amount of nitrogen, phosphorus and potassium fertilization is 210-215 kg of nitrogen, 30-35 kg of phosphorus and 245-255 kg of potassium per hectare. The fertilizers for nitrogen, phosphorus and potassium fertilization are calcium nitrate, potassium nitrate, ammonium nitrate, ammonium sulfate, calcium dihydrogen phosphate and potassium carbonate.

2. The carbon dioxide fertilization method according to claim 1, characterized in that: The CO2 concentration in the greenhouse was kept stable at 1200 μmol·mol⁻¹, and the nitrate-ammonium ratio of nitrogen, phosphorus, and potassium fertilizer was 13:

1.

3. The carbon dioxide fertilization method according to claim 1, characterized in that: The nitrogen, phosphorus, and potassium fertilizer has a nitrate-to-ammonia ratio of 13:

1. The fertilizers used in the nitrogen, phosphorus, and potassium fertilizer application are calcium nitrate, potassium nitrate, ammonium nitrate, and calcium dihydrogen phosphate, with a molar ratio of 3:6:1:0.

5. The fertilizer application rates are 211 kg of nitrogen, 33.3 kg of phosphorus, and 252 kg of potassium per hectare.

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