Wheat/maize or wheat/soybean strip intercropping II. Recovery or compensation of maize and soybean after wheat harvesting

While early-maturing crops benefit from intercropping, late-maturing crops usually suffer growth penalties during the intercropping phase. It is possible, however, that recovery or compensation of the late-maturing crops occurs after the harvest of the early-maturing crops. Three field experiments were conducted at Baiyun in 1997 and at Jingtan in 1997 and 1998 to test the hypothesis in wheat/maize and wheat/soybean intercropping. The biomass and nutrient accumulation in intercropped soybean were significantly smaller than in sole soybean before wheat harvest but thereafter increased sharply at Jingtan site in 1997. The rates of dry matter accumulation in the intercropped maize (10.0-20.1 g/m(2) per day) were significantly lower than those in the sole maize (17.1-34.8 g/m(2) per day) during the early stage from 7 May to 3 August, while mostly intercropped with wheat. After 3 August, however, the rates of intercropped maize, increasing to 58.969.9 g/m(2) per day, was significantly greater than in sole maize (22.7-51.8 g/m(2) per day) at Baiyun site in 1997 and nutrient acquisition showed the same trends as growth. At Jingtan site in 1998, the disadvantage of the border row of intercropped maize resulted from interspecific competition diminished after wheat harvest and disappeared at maize maturity. It was concluded that then was indeed recovery of growth after wheat harvesting in wheat/maize and wheat/soybean intercropping. However, the recovery was limited under N0P0 treatment. The interspecific competition, facilitation and recovery are together contributed to yield advantage of intercropping. (C) 2001 Elsevier Science B.V. All rights reserved.