Effect of Brassicaceae as cover crops

Abstract

In addition to true cereals (Poaceae) and legumes (Fabaceae), which are most commonly used as cover crops, plant species from the mustard family (Brassicaceae) are increasingly used due to their biological and agronomic characteristics. Crucifers grow fast, develop high biomass, achieve great land coverage ( gt 80%) and possess high nutrient uptake. These are the reasons that their use as cover crops has a beneficial effect on soil fertility, erosion prevention, weed suppression and groundwater quality protection. Majority of crucifers contain glucosinolates, the enzymatic conversion of which releases biologically active compounds into the soil, which are toxic to soil pathogens, nematodes and some weeds. In this way, crucifers act as soil biofumigants, and this effect is used in the control of harmful organisms within the cover crops technology. Due to different production systems and agroecological conditions, the release of these compounds in the soil is not constant, so the efficiency is not always the same. In this regard, biofumigation as a biological measure should be seen as a part of an integrated pest management strategy. With its flowers, crucifers attract a large number of insects: pollinators, predators and parasitoids, thus positively affecting the biodiversity of beneficial insects and the biocontrol of harmful ones. The most commonly used multipurpose cover crops are: rapeseed (Brassica napus L.), white mustard (Sinapis alba L.), brown mustard (Brassica juncea (L.) Czern.), charcoal turnip (Brassica rapa rapifera), fodder radish (Raphanus sativus L.), oil radish (Raphanus sativus var. oleifera) and others.

Osim pravih žita (Poaceae) i leptirnjača (Fabaceae) koje se najčešće koriste u pokrovnim usevima, zbog svojih bioloških i agronomskih osobina sve više se koriste biljne vrste iz porodice kupusnjača (Brassicaceae). Kupusnjače brzo rastu, imaju veliku produkciju biomase, ostvaruju veliku pokrivenost zemljišta (>80%), a usvajanju i velike količine hranljivih materija. Zbog svega toga, primenom u pokrovnim usevima, povoljno utiču na plodnost zemljišta, sprečavaju njegovu eroziju, guše korove i štite kvalitet podzemnih voda. Većina kupusnjača sadrži glukozinolate, čijom enzimskom konverzijom se u zemljištu oslobađaju biološki aktivna jedinjenja, koja su toksična za zemljišne patogene, nematode i neke korove. Time kupusnjače u zemljištu deluju kao biofumiganti, a ovaj efekat u okviru tehnologije pokrovnih useva koristi se u kontroli štetnih organizama. Zbog različitih sistema proizvodnje i agroekoloških uslova, oslobađanje tih jedinjenja u zemljištu nije konstantno, pa efikasnost nije uvek ista. U tom smislu biofumigaciju kao biološku meru, treba posmatrati kao deo integrisanog pristupa kontrole štetnih organizama. Svojim cvetovima biljne vrste kupusnjača privlače veliki broj insekata: polinatora, predatora i parazitoida, pa tako pozitivno utičući na biodiverzitet korisnih insekata i biokontrolu štetnih. U pokrovnim usevima za različite namene najčešće se koriste: uljana repica (Brassica napus L.), bela slačica (Sinapis alba L.), smeđa slačica (Brassica juncea (L.) Czern.), repa ugarnjača (Brassica rapa rapifera), stočna rotkva (Raphanus sativus L.), uljana rotkva (Raphanus sativus var. oleifera) i druge.