| Phosphorus is one of the essential nutrients for plants.It is involved in the synthesis and metabolism of many important compounds in plants,which is essential for the growth and development of crops.The rational application of phosphate fertilizer is the key to ensuring the high yield and high nutrient efficiency of the crops in the rice-rapeseed rotation system.At present,the research on the phosphorus fertilizer in the rice-rapeseed rotation system mainly focuses on the amount of phosphate fertilizer,but there is a lack of systematic research on the suitable phosphate fertilizer form and ratio.In order to clarify the suitable type and ratio of phosphorus fertilizer in rice-rapeseed rotation,the field experiment of two seasons was conducted to study the effects of four forms of phosphorus fertilizer and different rations of superphosphate and calcium magnesium phosphate on the yield,nutrient absorption and fertilizer utilization rate of rice and rapeseed.And combined with the indoor cultivation experiment,the effect of soil p H on the transformation of different forms of phosphate fertilizer was analyzed,in order to provide theoretical support for the rational application of phosphate fertilizer in rice-rapeseed rotation system.The main results show:1. The application of phosphate fertilizer can increase the yield of rice and rapeseed significantly.The application effect of different phosphate fertilizer is slightly different.Compared with the non-phosphorus treatment,the average yield e of rice and rapeseed increase 790-2132 kg/hm~2 and 687-1032 kg/hm~2 respectively;with an average increase rate of 11.5%-31.0%and 36.5%-55.6%.In the rice season,the application of calcium magnesium phosphate has the lowest yield,which is significantly lower than the other three forms of phosphate fertilizers.Compared with the application of diammonium phosphate treatment,the average yield is reduced by14.9%.The yield of rapeseed treated with calcium magnesium phosphate was the highest.Phosphorus application can significantly increase phosphorus accumulation in rice and rapeseed shoots.Compared with no phosphorus application,phosphorus accumulation in rice and rape shoots increased by an average of 6.09-9.00 kg/hm~2 and5.90-10.68 kg/hm~2 respectively.The average growth rates were 21.4%-31.6%and49.6%-89.7%.In the rice season,diammonium phosphate applied aboveground had the highest phosphorus accumulation,and compared with the treatment of calcium superphosphate,monoammonium phosphate and diammonium phosphate,the accumulation of phosphorus in rape shoots was the highest when calcium magnesium phosphate was applied.The average increase was 2.63,4.24 and 4.78 kg/hm~2,and the average increase was 13.2%,23.1%and 26.8%.Different types of phosphate fertilizer showed different utilization rates of phosphorus fertilizer on rice and rape.The application of diammonium phosphate in rice had the highest apparent utilization rate and agronomic efficiency of phosphate fertilizer,and it was the lowest when calcium magnesium magnesium phosphate fertilizer was applied.The agronomic efficiency reached the maximum,and the phosphate fertilizer utilization rate was the lowest when diammonium phosphate was applied.After the 2nd anniversary of rice-rapeseed rotation,the total phosphorus and available phosphorus contents in the non-phosphorus application soil decreased by 0.25 g/kg and 1.97 mg/kg respectively;while the total phosphorus in the soil decreased slightly after phosphorus application and the available phosphorus content increased by 7.18-8.57mg/kg,the soil phosphorus activation coefficient increased by 0.01%-0.44%,and soil available phosphorus content increases the highest with the application of calcium magnesium phosphate fertilizer.The phosphorus in the soil is mainly inorganic phosphorus.After applying phosphorus,the content of active phosphorus and stable phosphorus in the soil increases,while the phosphorus content in the medium and stable states decreases,and there is no significant difference in soil phosphorus composition between different forms of phosphorus fertilizer.2. The application of different ratios of superphosphate and calcium magnesium phosphate fertilizer can significantly increase the yield of rice and rape.Compared with no phosphorus application,the yield of rice and rape increased by 790-1845kg/hm~2 and 807-1032 kg/hm~2 respectively,with an average increase in yield11.5%-26.8%and 43.5%-55.6%.Different ratios of superphosphate and calcium magnesium phosphate fertilizers have different effects on rice and rapeseed.When the superphosphate and calcium magnesium phosphate fertilizers are applied in a 1:1ratio in the rice season,the yield is the highest,and the average yield is 8733 kg/hm~2.However,the yield of rapeseed reaches the highest with an average yield of 2887kg/hm~2when the calcium magnesium phosphate is applied completely.Different rations of superphosphate and calcium magnesium phosphate fertilizers can significantly increase the phosphorus accumulation in the shoots of rice and rapeseed.Compared with no phosphorus application,phosphorus accumulation in the shoots of rice and rapeseed increased by 6.09-10.55 kg/hm~2 and 7.69-10.68 kg/hm~2,with average growth rates of 21.4%-37.0%and 64.7%-89.7%respectively.When superphosphate and calcium magnesium phosphate fertilizers are applied in different proportions,the utilization rates of phosphorus fertilizer in rice and rape are different.In the rice season,the agronomic efficiency of phosphorus fertilizers is the highest when superphosphate and calcium magnesium phosphate are applied at a ratio of 1:1;the agronomic efficiency of phosphorus fertilizer reaches the maximum when the calcium magnesium phosphate is completely applied in the rapeseed season.After the 2 nd anniversary of rice-rapeseed rotation,the soil total and available phosphorus content of the no phosphorus fertilizer treatment decreased by 0.25 g/kg and 1.97mg/kg respectively compared with the basic soil.While there are no significant change in soil total phosphorus content when superphosphate and calcium magnesium fertilizer are applied in different proportions,and the soil available phosphorus content in the soil increased by 7.56-8.78 mg/kg,and the soil phosphorus activation coefficient increased significantly by 0.50%-0.57%.3. In acidic soil,the soil p H increased with the extension of the cultivation time in the simulated flooded soil and simulated dryland soil;when cultivated for 30 days,soil p H are maximum with the monoammonium phosphate treatment in simulated flooded and dryland soils.In alkaline soil,under simulated flooding and dryland conditions,the soil p H changes slightly after adding different forms of phosphorus fertilizers.Among them,the soil p H treated with calcium magnesium phosphate fertilizers is the highest under flooded conditions,and the soil is treated with diammonium phosphate under simulated dryland conditions reaches the highest p H.The soil p H is the lowest when treated with monoammonium phosphate under both conditions.Compared with the non-phosphorus treatment,the addition of phosphate fertilizer can significantly increase the effective phosphorus content in the soil.Under simulated flooding conditions in acid soil,the soil available phosphorus increase 8.35mg/kg within 0-30 d which treated with diammonium phosphate,and the increase in calcium magnesium phosphate fertilizer was at least 3.98 mg/kg.However the soil available phosphorus with calcium magnesium phosphate fertilizer increases by 5.02mg/kg insimulated dryland soil.The soil available phosphorus with monoammonium phosphate within 0-30 d showed the largest increase in alkaline soil under both simulated flooding and dryland soil,increasing by 5.43 mg/kg and 5.09 mg/kg respectively.When the acid soil is flooded,the effect of diammonium phosphate is higher.When the acid soil is about to be drought,the calcium magnesium magnesium phosphate fertilizer is more effective;while in the alkaline soil,under the flooding and drought conditions,monoammonium phosphate shows the highest fertilization.In summary,in the acidic soil rice-rapeseed rotation in southern China,the yield and utilization rate of phosphate fertilizers were the highest in the rice season with diammonium phosphate and the rapeseed season with calcium magnesium phosphate fertilizers.Superphosphate and calcium magnesium phosphate fertilizers can also be used as 1:1 coordinated application ration. |
PDF Full Text Request