钙镁肥对水稻和小龙虾产量、品质及土壤养分状况的影响

  目的  探讨施用钙镁肥对稻田综合种养的稻虾品质及土壤养分的影响，以期为稻虾综合种养专用肥研发和高效种养技术模式提供支撑。  方法  共设5个处理，常规施肥（FP）、添加不同用量钙镁肥处理（OPT1, OPT2, OPT3）和控释肥处理（OPT4），其中OPT1 ~ OPT3钙镁总用量参考普通稻田钙镁的用量，分别为50.4，45.0和54.9 kg hm?2。  结果  与FP相比，在常规施肥中添加适量钙镁肥不能显著提高稻虾产量，不同处理条件下，水稻和小龙虾的产量分别为4176.11 ~ 4567.38 kg hm?2和1740 ~ 2055 kg hm?2。施用钙镁肥能显著提高稻米和小龙虾品质，其中OPT3稻米垩白度和垩白粒率分别降低了71.43%，50.74%（P < 0.05），胶稠度和蛋白质分别显著增加了9.21%和11.6%（P < 0.05）；同时，小龙虾镁、蛋白质和氨基酸含量分别显著增加了11.63%、15.42%和8.57%（P < 0.05）。另外，施用钙镁肥能显著提高土壤交换性钙含量，以OPT3最高，可达3.19 cmol kg?1，比FP提高29.15%。  结论  施用适量钙镁肥不能显著提高稻虾产量，但对稻虾的品质有显著影响，以OPT3效果最佳，其钙镁总用量为54.9 kg hm?2。

Effects of Calcium and Magnesium Fertilizer Application on Yield Quality of Rice and Shrimp and Soil Nutrients

  Objective  The effects of applying calcium (Ca) and magnesium (Mg) fertilizers on the quality and soil nutrients of integrative rice and shrimp system in paddy field were assessed, aiming to provide supports for the research of special fertilizer and high-efficiency management technology models on integrative rice and shrimp systems.   Method  This experiment consisted of five treatments, namely conventional fertilization (Farmer Practice, FP), different dosages of Ca and Mg fertilizers (Optimized Treatments, OPT1, OPT2, OPT3), and controlled-release fertilizer treatment (OPT4). The total amount of Ca and Mg in OPT1-OPT3 were 50.4, 45.0 and 54.9 kg hm?2, respectively, with reference to conventional application rates in paddy field.  Result  The results indicated that adding appropriate fertilizer rates of Ca and Mg could not significantly improve the rice yield and shrimp yield compared with FP. Under different management conditions, the yields of rice and crayfish were 4176.11-4567.38 kg hm?2 and 1740-2055 kg hm?2, respectively. However, the application of Ca and Mg fertilizer could significantly improve the quality of rice and crayfish. The chalkiness and chalkiness rate of OPT3 rice decreased significantly (P < 0.05) by 71.43% and 50.74%. The gel consistency and protein increased significantly (P < 0.05) by 9.21% and 11.6%. Meanwhile, the Mg, protein and amino acid contents of crayfish increased significantly (P < 0.05) by 11.63%, 15.42%, and 8.57% compared with FP, respectively. In addition, this study found that the application of Ca and Mg fertilizers could significantly increase the soil exchangeable Ca content (P < 0.05), the OPT3 was the highest, reaching 3.19 cmol kg?1, 29.15% higher than FP.   Conclusion  In conclusion, it can be seen that the application of an appropriate amount of Ca and Mg fertilizer has an obvious effect on improving the quality of rice and shrimp, especially in OPT3 treatment, with 54.9 kg hm?2 of Ca and Mg fertilizer application rates.