缓释肥类型与运筹对不同穗型水稻产量的影响

以大穗型品种甬优2640和多穗型品种南粳9108为材料,270 kg hm–2纯氮条件下,选用树脂包衣(PCU)、硫包衣(SCU)和脲甲醛(UF)3种缓控释肥类型,设置了缓控释肥与尿素均基施、缓控释肥基施后分蘖期施尿素2种施肥方式,以常规尿素定量分施为对照(CK)。结果表明,缓控释肥的应用对甬优2640无增产效应。主要因为甬优2640穗大粒多,群体颖花量大。与CK比,相对集中在前中期的肥效难以满足植株全生育期生长,中后期叶面积指数下降快,氮素积累少,光合势弱,物质生产量不足,不能实现群体大库容的有效充实。而对南粳9108,脲甲醛基施+尿素分蘖期施处理比CK增产5.2%~5.9%,树脂包衣基施+尿素分蘖期施和脲甲醛+尿素均基施处理与CK平产的同时可减少施肥2~3次。2种运筹方式中,以缓控释肥基施后分蘖期施用尿素处理能有效增加植株茎蘖数,提高成穗率和最终穗数,扩大叶面积指数,增强光合势,增加干物质和氮素的积累,获得高产。3种肥料类型中,产量呈现UFPCUSCU。脲甲醛基施+分蘖期施尿素处理之所以能使南粳9108获得比CK更高的产量,是因为UF的肥效在中后期依然能相对稳定释放,配合尿素的分蘖期施用,既保证了前期分蘖的发生,又能保证高峰苗后稳定的茎蘖数和群体叶面积指数,植株在拔节后的光合势和物质积累量大,氮肥利用率高,增产显著。由此可见,针对不同穗型和产量特性的水稻品种,优选缓控释肥类型基施的同时,分蘖期配合速效肥料的施用,可获得既省工又增产的效果。

Effects of Slow/Controlled Release Fertilizer Types and Their Application Regime on Yield in Rice with Different Types of Panicle

Rice cultivars of Yongyou 2640 with big panicle and Nanjing 9108 with more panicles were adopted in this study. Three types of slow/controlled release fertilizer (polymer-coated urea, sulfur-coated urea, and urea formaldehyde) and two fertilization methods (both slow/controlled release fertilizer and conventional urea as basal fertilizer, slow/controlled release fertilizer as basal fertilizer with conventional urea as tillering fertilizer) were applied in field with conventional urea split fertilization as control (CK). The application of slow/controlled release fertilizer could not increase the yield of Yongyou 2640 that has big panicles and a large amount of spikelets. Compared with CK, most nitrogen of slow/controlled release fertilizers were released at early and middle stage of rice resulting in rapid decrease of LAI, fewer nitrogen accumulation and LAD, insufficient dry matter production and poor grain filling at middle and late stage. For Nanjing 9108, compared with CK, the yield in treatment with urea formaldehyde as basal fertilizer and conventional urea as tillering fertilizer was increased by 5.2% to 5.9%. And rice yield in treatment with polymer-coated urea as basal fertilizer and conventional urea as tillering fertilizer or treatment with both urea formaldehyde and conventional urea as basal fertilizer was similar to that of CK, while the fertilizer application frequency was decreased by 2 to 3 times. Rice yields in treatments with slow/controlled release fertilizer as basal fertilizer and conventional urea as tillering fertilizer were higher than those in treatments with both slow/controlled release fertilizer and conventional urea as basal fertilizer. Compared with the application of both slow/controlled release fertilizer and conventional urea as basal fertilizer, the application of slow/controlled release fertilizer as basal fertilizer and conventional urea as tillering fertilizer could increase the number of rice tillers effectively with a large number of panicles and a higher percentage of productive tillers. Meanwhile, the leaf area index and leaf area duration in treatment with both slow/controlled release fertilizer and conventional urea as basal fertilizer were large, which could enhance the accumulation of dry matter and nitrogen in rice. Rice yield by using different types of slow/controlled release fertilizer showed a tendency of urea formaldehyde > polymer-coated urea > sulfur-coated urea. In Nanjing 9108, the reason of high yield by using urea formaldehyde was that, nitrogen of urea formaldehyde could be steadily released at the late stage also, therefore, the application of urea formaldehyde as basal fertilizer and conventional urea as tillering fertilizer could not only promote tillering but also maintain a high level of productive tiller and leaf area index after peak seedling stage. And the highest leaf area duration, dry matter accumulation after elongating and the final nitrogen use efficiency were beneficial to obtain high yield. In conclusion, for rice cultivars with different types of panicle and various characteristics of yield, the application of optimal type of slow/controlled release fertilizer as basal fertilizer and conventional urea as tillering fertilizer can achieve labor saving and yield increasing simultaneously in rice production.