| The double cropping rice region in southern Hunan plays an important role in ensuring national food security.In order to provide suitable soil conditioning methods for double cropping rice area in southern Hunan,field experiments were carried out in Hengyang county with early rice varieties Zhuliangyou 819 and Lulianyou 996 and late rice varieties Yuzhixiang and Xiangwanxian No.13 from 2020 to 2021.The effects of three soil conditioners(lime,biochar and xiangrunbang conditioner)on yield components,rice quality and nutrient utilization of double cropping rice were compared.The main results are as follows:(1)Different soil conditioners had significant effects on the yield and yield components of double cropping rice.The application of biochar could improve the yield of rice,especially early rice,which was significantly increased by 7.01%-8.96%compared with the control.The main reason for yield increasing was to increase the number of grains per panicle.Lime and xiangrunbang conditioner had no significant effect on the yield of double cropping rice.(2)Except that there was no significant difference among the treatments of Xiangwanxian No.13,biochar could increase the aboveground dry matter weight of all varieties,and the performance of early rice varieties was significantly higher than that of late rice varieties.Lime and xiangrunbang conditioner had no obvious effect on dry matter weight.(3)Soil conditioner had no significant effect on grain type of rice,but had a certain effect on appearance quality,eating quality and cooking quality,while there were differences among varieties.Among three soil conditioners,biochar had a better effect on improving rice quality,mainly in increasing milled rice rate,whole milled rice rate,gel consistency,peak viscosity and disintegration value,and reducing chalky grain rate,chalkiness and absolute value of setback value.(4)Biochar increased the nitrogen accumulation and nitrogen dry matter production efficiency of rice,which increased bu 8.13-47.00 kg/hm~2and 0.48-16.7 kg/kg respectively compared with the control.In the experiment in the second year,biochar significantly improved the nitrogen harvest index.Lime and xiangrunbang conditioner had no significant effects on nitrogen dry matter production efficiency and nitrogen use efficiency of rice,and the effect on nitrogen accumulation was different between years and varieties.(5)Biochar treatment could improve the phosphorus accumulation,phosphorus dry matter production efficiency and phosphorus utilization efficiency of rice,which was stable between years,in which the phosphorus accumulation increased by 1.59-13.43 kg/hm~2.The effects of lime and xiangrunbang conditioner on phosphorus accumulation and utilization efficiency varied from year to year,which improved the phosphorus dry matter production efficiency in the first year,and significantly increased the phosphorus accumulation in the second year.All regulators had no significant effect on phosphorus harvest index of early and late rice.(6)Biochar could improve the total potassium accumulation,potassium dry matter production efficiency,potassium utilization efficiency and potassium harvest index of rice,but the difference was significant between years and varieties.The first two were 5.48-51.20kg/hm~2and 1.12-11.31 kg/kg higher than the control respectively.Lime and xiangrunbang conditioner treatment had no significant effect on the total potassium accumulation of double cropping rice,but significantly improved the potassium dry matter production efficiency of rice in the second year.In conclusion,biochar has the better effect on improving the yield,quality and nitrogen,phosphorus and potassium utilization efficiency of double cropping rice in southern Hunan,which is an ideal soil conditioner in double cropping rice area in southern Hunan. |
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