施钾量对水稻干物质积累及吸钾规律的影响

Effects of Potassium Application Levels on the Characteristics of Dry Matter Accumulation and Potassium Uptake in Rice

在长江中游水稻种植主产区,采用田间裂区试验,以湖北省主推水稻品种丰两优香1号和两优6326为试验材料,研究施钾量对水稻干物质积累及吸收规律的影响。结果表明:施钾(K_2O)(60～180 kg/hm^2)显著提高了水稻干物质积累量及稻谷产量;与不施钾处理相比,品种丰两优香1号和两优6326分别增产3.7%～12.8%和10.3%～16.9%;随施钾量增加,不同品种水稻产量均呈先升高后平台的趋势。水稻干物质积累量和钾素吸收均符合Logistic曲线增长规律(P<0.01)。随施钾量增加,干物质快速积累始期(T1)、末期(T2)以及最大积累速率出现时间(T_(max))均有所提前、快速积累持续时间缩短(ΔT),最大积累速率显著提高(V_(max));相同施钾量条件下,不同水稻品种间T_1、T_2、T_(max)和ΔT均存在一定差异。钾素快速积累始期(T_1')、末期(T_2')及最大积累速率出现天数(T_(max)')以及快速积累持续时间(ΔT')均随施钾量增加呈先增加后降低的趋势,当施钾量(K_2O)在60～120 kg/hm2时达到最大。施钾也显著提高了水稻钾素吸收量,且随施钾量的增加呈逐渐升高趋势;生产100 kg稻谷的吸钾量随施钾量增加同样呈逐渐升高的趋势。综上所述,施用钾肥(K_2O)(120～180 kg/hm^2)可明显提高水稻干物质积累量和稻谷产量,缩短干物质和钾素快速积累持续时间和最大积累速率出现时间;在分蘖盛期至孕穗期之间补充钾肥有利于中后期养分供应及产量形成。

Split plot field trial was conducted to test the effects of potassium(K)fertilizer amounts on the dynamic changes of dry matter and K accumulations of two main cultivars(FLYX1 and LY6326)in the main production area of the middle reaches of the Yangtze River.The results showed that K application increased dry matter and grain yield compared with the treatment without K;the increases of grain yield of reached 3.7%~12.8%and 10.3~16.9%respectively due to K application the varieties of FLYX1 and LY6326.The grain yield of the two varieties first increased and then came to a platform.The accumulations of dry matter and K in rice aboveground parts exhibited a Logistic curve(P<0.01).The dates of the parameter of T1,T2 and Tmax advanced obviously,ΔT shortened obviously,and Vmax obviously increased with K application rates.Under the same K rate,there were some differences in T1,T2,Tmax andΔT between the two varieties.The days of T1′,T2′,Tmax′andΔT′showed the trend of increasing first and decreasing later,and they all reached the maximum under the treatment of 60-120 kg/hm2.K application could significantly increase the K uptake of aboveground parts,and the K uptake increased gradually with the increase of K input.Meanwhile,the K uptake per 100 kg of grain also increased gradually with the increase of K input.In conclusion,K(K2O)fertilizer application(120-180 kg/hm^2)could significantly increase dry matter and grain yield of rice,shorten the duration of rapidest accumulation and the days needed for reaching the rapidest rate for dry matter and potassium.Supplement of potassium nutrition is beneficial to the yield formation between the tillering and booting stages of rice.