Intercropping green manure crops—effects on rooting patterns

Abstract

Greater productivity under intercropping has been attributed to the complementary use of environmental resources. However, the rooting pattern of component species under intercropping, which is an important morphological feature considering the complementary uptake of nutrients, has been studied only rarely under field conditions because of inherent technical difficulties. We examined rooting patterns of three green manure species, both sole cropped and intercropped, using a newly developed multi-color staining technique. Species were chosen from different functional groups: sorghum (Sorghum bicolor (L.) Moench.), a C4 grass; crotalaria (Crotalaria juncea L.), a legume; and sunflower (Helianthus annuus L.), a C3 dicot. We also investigated these species' aboveground biomass and N uptake. Sorghum distributed roots deeper under intercropping than under sole cropping; it was the most important contributor to increased biomass under intercropping. Crotalaria had a deep rooting system under both sole cropping and intercropping. Sunflower, with a shallow rooting system, was suppressed extremely under intercropping, possibly because of water deficiency in late in the season. The rooting patterns of green manure species examined using multi-color staining were related closely to the aboveground performance of these species under intercropping.

Effect of Two Patterns of Intercropping Soybean with Maize on Yield and Its Components under Different Nitrogen Fertilizer Levels

“…Consequently, the yields of intercrops may exceed the yield sum of the corresponding sole crops. (Miyazawa et al, 2010). The majority of intercropping systems mostly involve legume/ cereal combinations due to its interspecific facilitation or complementarity (Loreau et al, 2001).…”

Dual and Triple Intercropping: Potential Benefits for Annual Green Manure Production

“…2, Table 5). In a previous study, we found that sorghum developed roots faster than the other two species, and it also developed deeper roots when intercropped than when sown alone (Miyazawa et al, 2010), which may have made sorghum the best contributor to intercropping productivity.…”

“…Sorghum and sunflower grew well across different climate and soil inorganic N conditions. Relatively low precipitation during the latter half of the experimental period in A07 may be the cause of low pRLO of sunflower in A07 (Table 5); sunflower has relatively shallow rooting pattern and may have been imposed greater water deficiency under intercropping (Miyazawa et al, 2010). The depression of sunflower biomass was well compensated by the increase of sorghum biomass.…”

“…Forb species also scavenge more N than C4 grass species because they require more N in their photosynthetic apparatuses. Sorghum and crotalaria have relatively deep root distributions compared with sunflower (Miyazawa et al, 2010), which may also facilitate their underground niche differentiation. We hypothesized that if the total seed amount and land area were fixed, intercropping would be advantageous in terms of biomass production, stability, and nutrient uptake compared with sole cropping.…”

Chrysoperla externa (Neuroptera: Chrysopidae) and Utetheisa ornatrix (Lepidoptera: Arctiidae) on organically grown Crotalaria juncea (Fabaceae)

“…Crotalaria juncea (Fabaceae) plants fix atmospheric nitrogen and are used as green manure, thereby suppressing weeds (Miyazawa et al, 2010;Queiroz et al, 2010). In addition, this plant presents antagonism to nematodes (Hooks et al, 2010) and to other harmful animals (Johnson et al, 1985;Ji et al, 2005), has the ability to grow in infertile soils, although it may not have good development (Monquero et al, 2009;Odhiambo, 2011), good resistance to drought (Meschede et al, 2007;Calonego & Rosolem, 2010), and its fibers are used in the paper industry due to their softness and resistance (Morris & Kays, 2005).…”