不同氮、钾肥施用量对甜瓜养分吸收、分配及产量的影响

Effects of Different Nitrogen and Potassium Fertilizing Amount on Nutrition Absorption, Nutrition Distribution and Yield of Muskmelon

【目的】通过研究中等肥力土壤条件下不同氮、钾肥施用量对大棚甜瓜养分吸收、分配及产量的影响,为连栋棚加地膜覆盖高产栽培条件下合理施用氮、钾肥提供理论依据。【方法】采用连栋棚加地膜覆盖栽培,试验设重氮重钾(N2K2)、重氮轻钾(N2K1)、轻氮重钾(N1K2)、轻氮轻钾(N1K1)、中氮中钾(NK)5个处理。以早熟厚皮甜瓜品种‘RX8’(TC620-8-56×TA11-1)为试验材料,在孕穗期、坐果期及成熟期测定不同器官干物质积累量及氮、磷、钾养分累积吸收量,并结合成熟期产量,分析不同氮、钾肥施用量对甜瓜养分吸收、分配及产量的影响。【结果】不同氮、钾肥施用量对甜瓜干物质积累量及氮、磷、钾养分累积吸收量的变化趋势相似,均表现为随生育期的推进而呈上升趋势,不同氮、钾肥施用量只改变不同生育时期干物质积累量及氮、磷、钾累积吸收量,并不改变其累积趋势。从干物质积累及分配特性看,伸蔓期,甜瓜以营养生长为主,NK处理根、茎、叶干物质积累量一直呈较高水平,且茎、叶干物质积累量显著高于其他处理(P<0.05),平均分别增加17.8%、16.0%。随着果实发育,干物质积累逐渐转向果实,不同氮钾处理下果实干物质积累分配系数增加,至成熟期果实干物质积累分配系数高达0.62—0.66,NK处理果实干物质积累量及分配系数均显著高于其他处理(P<0.05),平均分别增加31.9%、4.27%。从养分积累及分配特性看,甜瓜对钾需求量最大,氮次之,磷最少,成熟期甜瓜氮、磷、钾累积吸收量分别高达4 160.4、1 394.8、7 874.2 mg/株。NK处理氮、磷、钾累积吸收量在伸蔓期、坐果期、成熟期一直呈较高水平,与其他处理相比,NK处理氮、磷、钾累积吸收量均显著增加(P<0.05)。NK处理坐果期、成熟期果实氮、磷、钾分配系数也一直呈较高水平,且成熟期果实氮、钾分配系数显著高于其他处理(P<0.05),分别平均增加9.10%、9.81%。从产量及产量构成因素看,同一供氮水平下,高钾、低钾处理间甜瓜纵径、横径、果形指数、单瓜重及产量差异均未达5%显著水平;同一供钾水平下,高氮处理甜瓜纵径、横径、单瓜重及产量均高于低氮处理,平均分别增加4.81%、6.04%、19.8%及20.5%,且除纵径外,上述指标差异均达5%显著水平;从整体看,NK处理甜瓜纵径、横径、单瓜重、产量均最高,且单瓜重和产量显著高于其他处理(P<0.05),平均分别增加21.6%和22.1%。【结论】土壤中等肥力水平及连栋棚加地膜覆盖高产栽培条件下,氮、钾施肥量分别以200kg·hm^(-2)、300 kg·hm^(-2)较为适宜,有利于甜瓜最大限度的提高养分的吸收利用能力,促进养分吸收及营养物质向果实的分配转移,从而得到高产。

【Objective】To provide a theoretical basis for the rational application of nitrogen and potassium fertilizers with plastic film mulching in high yield cultivation environment, the effects of different nitrogen and potassium fertilizers in the condition of the medium fertile soil on nutrient absorption, distribution and yield of muskmelon were studied.【Method】An early maturing and thick-skinned muskmelon variety ‘RX8＇（TC620-8-56×TA11-1） with plastic film mulching cultivation in greenhouse was used for our study. Five treatments（N2 K2, N2 K1, N1 K2, N1 K1 and NK） were performed to investigate the influence of different fertilizing amount of nitrogen and potassium on nutrient absorption, distribution and yield of muskmelon. The accumulation of dry matter and nitrogen, phosphorus and potassium were measured in different organs at the vining, fruit-set and mature stages. Furthermore, we also measured the production of muskmelon at maturity. 【Result】The results indicated application of different nitrogen and potassium fertilizers on the accumulation of dry matter and nitrogen, phosphorus and potassium in muskmelon posed a similar variation trend, and had an increasing level with the growth. Applied different amount of nitrogen and potassium fertilizers changed the accumulation amount of dry matter and nitrogen, phosphorus and potassium at different growth stages, but did not change the accumulation trend. From the characteristics of dry matter accumulation and distribution, the muskmelon was mainly vegetative growth at the vining stage, and the dry matter accumulation in root, stem and leaf had a high level under NK treatment in this stage. The accumulation of dry matter in stem and leaf under NK treatment increased averagely by 17.8% and 16.0% respectively, which was significantly higher than that under other treatments（P〈0.05）. The accumulation of dry matter increased under different nitrogen and potassium fertilizers during fruit development stage, the distribution coefficient was about 0.62 to 0.66 at mature stage. The dry matter accumulation and its distribution coefficients in fruit increased averagely by 31.9% and 4.27% under NK treatment, respectively, which was significantly higher than that of other treatments（P〈0.05）. As for the characteristics of the nutrient accumulation and distribution, potassium was the top demand of muskmelon, followed by nitrogen and phosphorus. The uptake amounts of nitrogen, phosphorus and potassium of muskmelon were 4 160.4 mg, 1 394.8 mg, 7 874.2 mg/plant at mature stage, respectively. The amounts of nitrogen, phosphorus and potassium uptake had a relatively higher level under NK treatment than that of other treatments at the vining, fruit-set and mature stages all the time（P〈0.05）. The distribution coefficients of nitrogen, phosphorus and potassium in fruit at mature stage under NK treatment had a relative high level, of which increased by 9.10% and 9.81% respectively and was higher than other treatments in maturity fruit（P〈0.05）. The yield and yield components, including the difference of the fruit vertical and transverse diameter, shape index, average weight and yield of high potassium and low potassium treatments did not reach 5% significant level under the same nitrogen level condition. The fruit vertical and transverse diameter, average weight and yield of high nitrogen-treated were higher than those of low-nitrogen treatment, with an average increase of 4.81%, 6.04%, 19.8% and 20.5% respectively under the same potassium supply. And the differences of these indexes except for vertical diameter reached a significant level of 5%. On the whole, the fruit vertical and transverse diameter, average weight and yield of muskmelon treated with NK were the highest, and average weight and yield were significantly higher than those of other treatments（P〈0.05）, with an average increase of 21.6% and 22.1%, respectively.【Conclusion】This study demonstrated that the optimum fertilizing amount of nitrogen and potassium with plastic film mulching for muskmelon growth in the condition of the medium fertile soil was 200 kg·hm^-2 and 300 kg·hm^-2, respectively, which was beneficial to improve the ability of nutrient absorption and promote the absorption and distribution of the nutrient to the fruits.