Catch crops

The drawback with late lambing is its dependence either on a buoyant store lamb market in September and October or else on the feasibility of growing a catch crop, such as stubble turnips or rape, on the farm, so that lambs can be fattened satisfactorily outdoors during the autumn and early winter. Again, intestinal parasites can be a problem, with the period of maximum risk, late July and August, occurring before the younger lambs have had a chance to build up their own immunity. 

Turnips are generally lower in dry matter content than swedes and are divided into two main groups white-fleshed varieties (8% dry matter), often called stubble turnips, which are frost susceptible and prone to bruising, but grow very fast and make valuable catch crops which can be grazed in situ and yellow-fleshed varieties (8-10% dry matter) which are whole season crops and produce higher yields. 

Stubble turnips were found to be almost the equal of white mustard as a catch crop and source of nitrogen to subsequent crops (Kotnik Kopke, 2000). 

Thorup-Kristensen, K, Magid, J and Jensen, L S (2003) Catch crops and green manures as biological tools in nitrogen management in temperate zones , Advances in Agronomy, 79, 227-302. 

Von Fragstein, P (1995) Manuring, manuring strategies, catch crops and N-fixation , Biological Agriculture and Horticulture, 11, 275-287. 

A chemical stimulant, a root exudate, is required to break seed dormancy of a parasitic weed and initiate seed germination. Upon receiving a signal for germination, a radicle emerges from the seed coat. However, an additional chemical signal is needed for the radicle to penetrate host roots and form a haustorium. Therefore several plants can serve as catch crops or trap crops for the reduction of the parasitic weed seed bank in infested soil. 

Catch crops are crops that are susceptible to the parasite and thus become infected. The parasite has the chance to set seed, therefore it is necessary to destroy the catch crop before seed formation of the parasite. 

Trap crops or so-called false hosts are crops able to stimulate parasite seed germination but are not themselves parasitized. Each trap crop control at least one species but not all genus species. (Abebe et al. 2005). Dodder (Cuscuta spp.) infestation can be effectively reduced by growing cereals or other grass crops (false hosts) continuously for several years (Dawson 1987). Other examples of suitable trap and catch crops are given in the Table 14.3. 

Intercropping with trap or catch crop against parasitic plants is often practiced in resource-poor regions but as parasitic plants it has considerable success. This approach is more effective than use of pesticides, cheap and environmentally... 

Sudan grass (Sorghum sudanense L.) Catch crop Oswald et al. 1999... 

Mung beans (Phaseolus aureus Roxb.) Catch crop Kleifeld et al. 1994... 

These days, allelopathic plants as catch crops or trap crops found utilization in plant protection of tropical regions against parasitic weeds. They do not eliminate the parasite completely but decrease the seed bank in the soil. Other applications of allelopathy for weed control include the use of plant residues as a natural herbicide agent, e.g., water extracts, pellets, flours, by-products of crop processing, etc. The strategies for use of volatile compounds as soil fumigants are developed. 

George T, Ladha IK, Garrity DP, Buresh RJ. 1994. Legumes as nitrate catch crops during the dry-to-wet transition in lowland rice cropping systems. Agronomy Journal 86 267-273. 

This family includes both leaf and root crops suitable for warm and cool climates. Spinach and red orache are fast-growing, leafy catch crops. Spinach is best sown in the cool temperatures of spring and fall, as it rapidly goes to seed in hot, dry weather. Sow little and often for a good supply. 

Stork, P.R. and Jerie, P.H. 2003. Initial studies of the growth, nitrogen sequestering, and dewatering potential of perennial grass selections for use as nitrogen catch crops in orchards. Australian Journal of Agricultural Research 54 17-37. 

Thorup-Kristensen, K. 2001. Are differences in root growth of nitrogen catch crops important... 

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