玉米单作及间作紫花苜蓿对产量性状及白浆土供肥特性的影响

Effects of Maize Monoculture and Intercropped with Medicago sativa L. on Yield of Maize and Nutrients of Albic Soil

以不施肥为对照,设4个不同施氮量,通过玉米单作及间作紫花苜蓿栽培模式,探索两种栽培模式对玉米产量性状及白浆土碱解氮/全氮、有效磷/全磷和速效钾/全钾等供肥特性的影响。结果表明,在供试4个施氮水平下,与玉米单作相比,间作紫花苜蓿均可显著提高玉米产量。225 kg/hm^2的施氮量在玉米单作及间作紫花苜蓿模式下均可极大促进作物对碱解氮的消耗,在降低白浆土碱解氮/全氮幅度上最具优势。施氮量为175和225 kg/hm^2时,与玉米单作相比,间作紫花苜蓿能极大减少全氮中碱解氮的损失。在低供氮水平下（140 kg/hm^2）,玉米间作紫花苜蓿能够使磷素活化系数（PAC）保持稳定;在较高施氮条件（225 kg/hm^2）,玉米间作紫花苜蓿能显著提升PAC。在玉米单作条件,200和225 kg/hm^2的施氮量更有助于玉米消耗白浆土中的有效磷,使PAC降至1.4%和1.2%,此时全磷各形态很难转化为有效磷。玉米间作紫花苜蓿可有效防止白浆土磷素有效性的降低,PAC处于3.2%～6.4%。无论间作与否,200 kg/hm^2施氮量均可使白浆土速效钾/全钾显著增加,将施氮量提升至225 kg/hm^2,两种栽培模式下白浆土的速效钾/全钾均显著降低。

In this study, four N applied levels, 140, 175, 200, and 225 kg/ha, were respectively conducted on two cultivation patterns of maize（Zea mays L.）, monoculture and intercropped with Medicago sativa L., on Albic soil.Also, a control of maize monoculture without additional N was set. And the effects of cultivation pattern on maize yield and nutrients（N, P, K） of Albic soil were studied. Results showed that maize yield was enhanced significantly when intercropped with M. sativa L. at any N levels. At N levels of 175 and 225 kg/ha, maize intercropped with Medicago sativa L. pattern was better for preventing available N of Albic soil loss than monoculture, and N level of 225 kg/ha in the two cultivation patterns was the best among all N levels for N assimilated by plants. Maize intercropped with M. sativa L. effectively kept the phosphorus activation coefficient（PAC） of Albic soil at relative stable value of3.2%-6.4%, while, maize monoculture, especially at N levels of 200 and 250 kg/ha, the available P in Albic soil was easily assimilated by plants, resulting in decreased PAC values of 1.4% at 200 kg/ha and 1.2% at 200 kg/ha,moreover, the other forms of P in the soil were difficult to be transferred into the available form. At N level of 200 kg/ha, both two cultivation patterns could significantly increase the total K and available K contents in Albic soil simultaneously, while at N level of 250 kg/ha, both the total K and available K contents were decreased significantly.