Peanut-maize intercropping is known to alleviate iron deficiency in peanut on calcareous soils by belowground interspecific interactions. However, the underlying mechanisms of these interactions are not fully understood. A two-year field experiment with two nitrogen fertilizer levels was performed on a calcareous soil, to study Fe and N nutrition and yield of a peanut-maize intercrop (IC). In order to identify belowground interspecific interactions, root barriers were employed between adjacent peanut and maize rows. Chlorophyll (measured by SPAD) and active iron concentration in peanut leaves, total Fe and N concentrations, acquisitions, and grain yield were determined. IC increased SPAD values and active iron concentrations in young peanut leaves and alleviated peanut Fe deficiency chlorosis compared with sole-crop (SC) peanut. Total Fe and N concentrations in IC peanut were higher than those in SC peanut, and Fe and N accumulations per plant were also higher than in SC peanut without N fertilizer. IC did not significantly influence Fe concentration in IC maize, but improved N concentration. IC significantly decreased Fe and N acquisition per ha and grain yield of peanut and maize components compared with the respective SC. However, the combined Fe and Ne acquisition per ha in the IC was significantly higher than the weighted mean of the SC systems. The land equivalent ratios (LER_Fe, LER_N and LER_grain) were greater than 1, but decreased to close to 1 with root barriers. Supplying N fertilizer increased grain yield and Fe and N acquisition in the IC, but significantly decreased LER_Fe, LER_N, and LER_grain, confirming that N availability and use are important for determining intercrop advantages. The effect of physical root barriers between rows of peanut and maize indicates that belowground mutual interspecific interactions regarding Fe and N acquisition plays a major role for determining the advantages of peanut-maize IC on calcareous soils.

众所周知，花生-玉米间作可通过地下种间相互作用减轻钙质土壤上花生中的铁缺乏症。但是，这些相互作用的潜在机制尚未完全了解。在钙质土壤上进行了为期两年的采用两个氮肥水平的田间试验，以研究铁和氮的营养状况以及花生玉米间作作物（IC）的产量。为了鉴定地下种间相互作用，在相邻的花生行和玉米行之间采用了根系屏障。确定了花生叶中的叶绿素（通过SPAD测量）和活性铁浓度，总铁和氮浓度，获取量和谷物产量。与单作（SC）花生相比，IC增加了年轻花生叶片中的SPAD值和活性铁浓度，并减轻了花生铁缺乏症的中毒。IC花生中的总Fe和N含量高于SC花生，每株植物中的Fe和N积累也高于不含氮肥的SC花生。IC对IC玉米中的Fe浓度没有显着影响，但改善了N浓度。与相应的SC相比，IC显着降低了每公顷的铁和氮获取量以及花生和玉米成分的谷物产量。但是，IC中每公顷的Fe和Ne的总采集量显着高于SC系统的加权平均值。土地当量比（LER 与相应的SC相比，IC显着降低了每公顷的铁和氮获取量以及花生和玉米成分的籽粒产量。但是，IC中每公顷的Fe和Ne的总采集量显着高于SC系统的加权平均值。土地当量比（LER 与相应的SC相比，IC显着降低了每公顷的铁和氮获取量以及花生和玉米成分的籽粒产量。但是，IC中每公顷的Fe和Ne的总采集量显着高于SC系统的加权平均值。土地当量比（LER_Fe，LER _N和LER_晶粒）大于1，但因根障而降低至接近1。供应氮肥增加了IC中的谷物产量以及铁和氮的吸收，但显着降低了LER _Fe，LER _N和LER_谷物，这证实了氮的有效性和使用对于确定间作优势非常重要。行花生和玉米之间的物理根屏障的影响表明，关于铁和氮获取的地下相互种间相互作用在决定钙质土壤上花生玉米IC的优势方面起着重要作用。