Effects Of Different Fertilization Types And Alfalfa Additions On Substrate Nutrients And Seedling Growth Of Rice Seedlings

The current double-season rice seedlings mostly use rice field soil as the seedling substrate,which has the problem of unbalanced nutrients and insufficient organic matter.Alfalfa has a high yield and strong regeneration,and its stems contain a large amount of nitrogen,phosphorus and potassium,making it an excellent leguminous forage grass.In recent years alfalfa has been increasingly used as a winter forage and green manure in southern rice fields,but there are relatively few studies on alfalfa as a green manure to improve the nutrients in the seedling substrate.Therefore,in this experiment,a two-factor pot experiment with different fertilizer application patterns and different alfalfa additions was set up to investigate the effects of different amounts of alfalfa green manure additions and different fertilizer application patterns on the growth of rice seedlings and substrate nutrients,with the aim of providing scientific reference for the improvement of rice seedling substrate.Four levels of alfalfa addition were set: 0g(A0,no addition),6g(A1,low amount),18g(A2,medium amount)and 36g(A3,high amount)of alfalfa per kg of soil,with three fertilizer application patterns: no fertilizer(NF),compound fertilizer(CF)and chicken manure(CM);12 treatments in total.The main study findings were.1.When compound fertiliser was added with high amounts of alfalfa,total substrate N reached 1.99g/kg,a significant increase compared to the control.Total substrate phosphorus was 1.50g/kg when compound fertiliser was applied alone,significantly higher than the control treatment.There was no significant effect of different fertiliser treatments and alfalfa additions on the total potassium content of the substrate.Compound fertiliser alone significantly increased the substrate fast-acting phosphorus content(29.47mg/kg),while the substrate fast-acting potassium content and organic matter increased with the amount of alfalfa added.2.The high amount of alfalfa alone significantly reduced the dry matter weight of the roots and the seedling strength index was 0.0121,significantly lower than the control,while the remaining treatments had no significant effect on the seedling strength index.The leaf age of the seedlings raised with the low amount of alfalfa supplementation was 3,which significantly increased the leaf age of the seedlings.This indicates that the high amount of alfalfa supplementation inhibited the root growth of rice seedlings and reduced seedling quality,while the low amount of alfalfa supplementation with compound fertilizer promoted seedling growth.3.N accumulation was increased by 106.3% and 105.1% for compound fertilizer alone and compound fertilizer with low amount of alfalfa addition,respectively,compared with the control treatment.The highest phosphorus accumulation in seedlings was achieved when compound fertilizer was applied alone,reaching 2.81 mg/100 plants,a significant increase compared to the control.Potassium accumulation in seedlings was 34.63 mg/100 plants when compound fertiliser was added with low amounts of alfalfa,which was significantly higher than the control treatment.This indicates that the application of compound fertiliser with low levels of alfalfa addition had the best effect in promoting nutrient accumulation in seedlings.4.When compound fertilizer was applied with low and high alfalfa additions,seedling leaf POD enzyme activity exceeded 450 U/g/min,SOD enzyme activity exceeded 510U/g/min and CAT enzyme activity exceeded 420 U/g/min,a significant increase compared to the control treatment.The highest POD,SOD and CAT enzyme activities in the roots of seedlings were achieved with 273.93 U/g/min,353.40 U/g/min and 232.76 U/g/min respectively when compound fertilizer was applied alone,which was a significant increase.This indicates that the application of compound fertilizer with low and high amounts of alfalfa addition can improve the stress-resistant enzyme activities of seedlings.5.The overall score of seedlings increased with the addition of alfalfa in the no-fertilizer treatment,decreased with the addition of alfalfa in the chicken manure treatment,and decreased with the addition of alfalfa in the compound fertilizer treatment.In all treatments,the highest overall seedling scores were found in the four treatments with compound fertilizer,and the highest overall seedling scores were found when compound fertilizer was applied alone.In conclusion,compound fertiliser alone and compound fertiliser with low levels of alfalfa additions improved substrate nutrients and increased seedling nutrient accumulation and antioxidant enzyme activity in seedling leaves and roots,but did not have a significant effect on seedling strength index.In conclusion,compound fertiliser alone and compound fertiliser with low levels of alfalfa addition improved the substrate nutrients and increased the accumulation of nutrients and antioxidant enzyme activity in seedling leaves and roots,but had no significant effect on the seedling strength index.