The Effect of Natural Mulches on Crop Performance, Weed Suppression and Biochemical Constituents of Catnip and St. John's Wort

Abstract

Because of expanding markets for high-value niche crops, opportunities have increased for the production of medicinal herbs in the USA. An experiment was conducted in 2001 and 2002 near Gilbert, IA, to study crop performance, weed suppression, and environmental conditions associated with the use of several organic mulches in the production of two herbs, catnip (Nepeta cataria L.) and St. John's wort (Hypericum perforatum L. 'Helos'). Treatments were arranged in a completely randomized design and included a positive (hand-weeded) control, a negative (nonweeded) control, oat straw, a flax straw mat, and a nonwoven wool mat. Catnip plant height was significantly greater in the oat straw than the other treatments at 4 wk through 6 wk in 2001; at 4 to 8 wk in 2002, catnip plant height and width was significantly lower in the negative control compared with the other treatments. Catnip yield was significantly higher in the flax straw mat than all other treatments in 2001. In 2002, St. John's wort yields were not statistically different in any treatments. All weed management treatments had significantly fewer weeds than the non-weeded rows in 2002. Total weed density comparisons in each crop from 2 yr showed fewer weeds present in the flax straw and wool mat treatments compared with positive control plots. There was no significant weed management treatment effect on the concentration of the target compounds, nepetalactone in catnip and pseudohypericin-hypericin in St. John's wort, although there was a trend toward higher concentrations in the flax straw treatment.

Effect of Mulch and Mixed Cropping Grass - Legume at Saline Soil on Growth, Forage Yield and Nutritional Quality of Guinea Grass

“…Mulch application increased moisture content of soil by reducing soil evaporation. Duppong et al (2004) reported that higher soil moisture levels were retained under all mulches compared with non mulched treatment. Air temperature during experiment period was ranged 29-37 o C.…”

“…Mulch is being used for its beneficial effects on crop growth and yield such as reducing soil temperature (Duppong et al, 2004), conserving soil moisture content (Athy et al, 2006;Duppong et al, 2004), reducing weed growth (Duppong et al, 2004), reducing soil erosion (Dahiya et al, 2001), increasing nitrogen and potassium of plant (Wang et al, 2008), increasing leaf area index (Fahrurozzi et al, 2005), increasing carbon (Wang et al, 2009), and reducing evaporation (Taban and Naeini, 2006).…”

Experimental methods applicable in cultivation of medicinal plants

“…Za prekidanje mirovanja semena mogu se koristiti različite metode, kao što su: -držanje semena u suvim skladištima [15]; -izlaganje semena niskim temperaturama (3-6 o C) nekoliko dana, a potom optimalnim temperaturama za klijanje [16]; -izlaganje semena visokim temperaturama (30)(31)(32)(33)(34)(35) o C) u trajanju od nekoliko dana pre izlaganja delovanju optimalne temperature za klijanje [17,18]; -prekid mirovanja se postiže držanjem semena na svetlosti, pri čemu se obično kombinuje svetlost i temperatura u cilju prekida mirovanja semena [19]; -podvrgavanje semena uticaju različitih hemijskih sredstava kao što su: regulatori rasta, oksidanti, biljni produkti, azotna jedinjenja i druga hemijska sredstva [20,21]; -povređivanjem (skarifikacija) semena se može postići prekid mirovanja kod semena sa tvrdom, za vodu i gasove, nepropustljivom semenjačom (Daucus carota, Hibiscus trionum L., kao i mnoge leguminoze) [20,22]. Mnogi naučnici su radili na otkrivanju metoda za utvrđivanje vrste dormantnosti semena.Ukoliko semena ne klijaju pod optimalnimuslovima za klijanje date vrste, semena se smatraju dormantnim i sledeći korakje da se odredi vrsta mirovanja.…”

“…Ova metodologija je najčešće primenjivana u istraživanjima koja se odnose na korovsku floru, jer se mogu koristi za testiranje efikasnosti bilo koje vrste tretmana za suzbijanje korova.Ispitivani tretmani za suzbijanje korova mogu biti hemijske prirode, mehaničke mere suzbijanja, hemijske mere i biološke mere suzbijanja korova.Ogledima u poljskim uslovima se najčešće ispituju hemijske mere suzbijanja u vidu biološke aktivnosti novosintetisanih herbicida [33], upotreba malčeva kao mehanička mera suzbijanja korova [34,35], biološke mere suzbijanja u vidu alelopatskog delovanja različitih biljnih vrsta [36]. Ova vrsta ogleda je nezaobilazna u poljoprivredi, jer se pokazuje efikasnost ispitivanog tretmana u uslovima spoljašnje sredine koji su promenljivi.…”

“…Jedna od mogućih mera koja se koristi za suzbijanje korova je postavljanje malča, čiji se uticaj na korove takođe može ispitivati metodama za utvrđivanje efikasnosti [34]. Malčiranje je jedan od postupaka u zaštiti gajenih biljaka od negativnih spoljašnjih uticaja, koji podrazumeva prekrivanje zemljišta oko gajenih biljaka posebnim organskim ili sintetičkim materijalom, odnosno malčom.…”