施磷对西北沿黄灌耕灰钙土玉米/鹰嘴豆间作产量及种间相互作用的影响

本试验在西北沿黄有效磷含量较低的灌耕灰钙土上研究了田间施磷水平对单作和间作玉米、鹰嘴豆的根际酸性磷酸酶活性、产量和土地资源利用效率的影响。结果表明,在不施磷(P0)和施磷量为40kg·hm-2(P40)时,玉米/鹰嘴豆间作系统的生物学产量或经济产量的土地当量比(LER)均小于1,间作系统未表现出土地资源利用的优势,主要原因是鹰嘴豆产量降低;当施磷量为80kg·hm-2(P80)时,LER1,间作系统表现出土地资源利用优势。P0、P40和P80处理间作玉米产量分别比相应单作增产3%、12%和19%;间作鹰嘴豆产量P0和P40处理显著低于单作。从玉米出苗到鹰嘴豆收获的间作作物共生期内,间作玉米相对于鹰嘴豆具有较强的水分和养分等资源的竞争力(Amc0),从鹰嘴豆生长动态曲线可以看出,P0、P40处理这种竞争在共生期明显,P80处理竞争不明显。各施磷水平下,间作玉米的收获指数高于单作,而间作鹰嘴豆的收获指数低于单作。鹰嘴豆通过分泌酸性磷酸酶促进玉米对有机磷利用的种间互惠作用未体现,两次取样中,不施磷时,间作鹰嘴豆根际土壤的酸性磷酸酶活性低于单作。基于本研究,西北沿黄灌耕灰钙土施磷量为0和40kg·hm-2时,玉米/鹰嘴豆间作系统无明显的间作优势,磷肥量为80kg·hm-2时表现出较为明显的间作优势。

Yield and inter-specific interactions in maize/chickpea intercrop under different application rates of P in irrigated sierozem along the Yellow River in Northwest China

The effects of application of different rates of phosphorous on rhizospheric soil processes and yield of maize and chickpea under mono-cropping and intercropping systems were studied in irrigated low Olsen-P sierozem along the Yellow River in Northwest China. The results show that zero (P0) or 40 kg·hm^-2 (P40) P application of maize/chickpea intercrop gives LER (land equivalent ratio) of biomass and grain yield less than 1.00. This implies intercropping disadvantage at P0 or P40, which is mainly due to reduction of chickpea yield. At P application rate of 80 kg·hm^-2 (P80), biomass and grain yield LERs are greater 1.00, implying intercropping advantage.Yield of intercropped maize is 3%, 12% and 19% higher than that of mono-cropped maize at P0, P40 and P80 respectively. Yield of intercropped chickpea at P0 and P40 are significantly lower than that of mono-cropped chickpea. Aggressivity of maize for water, nutrients and other resources is stronger than that of chickpea (A_mc>0) during the co-growth period of two crops. The dynamic curve of chickpea growth indicates that the aggressivity is more significant under P0 and P40 treatments. Harvest index (HI) of intercropped maize is higher than that of mono-cropped maize, and that of intercropped chickpea is less than that of mono-cropped at different P levels. There is no indication that intercropping chickpea enhances organic P utilization by maize. Acid phosphatase activity for intercropped chickpea at P0 is lower than that for the mono-cropped. No advantage is noted under intercropping at P0 and P40. However intercrop advantage is observed at P80.