A field experiment was carried out at the Joniškėlis Experimental Station of Lithuanian Research Centre for Agriculture and Forestry in 2016-2018 to ascertain the effects of reduced tillage and the combinations of reduced tillage with soil improvement practices on soil organic carbon (SOC) and quantity and quality of humus in a clay loam. The following tillage systems were investigated: 1) deep ploughing (DP) at 21-23 cm depth (control), 2) shallow ploughing at 15-17 cm depth (SP), 3) ploughless tillage (at 10-12 cm depth) (PT), 4) ploughless tillage and aftereffect of lime sludge last incorporated in 2014 (PT + aLS), 5) ploughless tillage with cover crops for green manure (PT + GM) and 6) no-tillage with cover crop for winter mulch (NT + WM). The reduction of tillage intensity increased the contents of SOC and C in humic substances (HS) in the upper (0-10 cm) soil layer. The incorporation of organic sources in the form of green manure and winter mulch promoted microbiological activity and the mineralization of the soil organic matter (SOM) already present in it. However, the SOC and total nitrogen (N tot) content did not increase in proportion to the fresh organic matter incorporated. The tillage systems applied had influence on the changes in the humus fractional composition. The increased content of plant residues under PT + GM and NT + WM treatments resulted in higher amounts of mobile HS in the upper soil layer, meanwhile the PT + aLS treatment increased the amount of agronomically most valuable Ca-bound HS. Higher amounts of HS bound with clay minerals were found under PT + aLS treatment, as calcium (Ca) is an important factor for SOC sequestration in a clay. The humification degree increased in 0-30 cm soil layer under all reduced tillage systems investigated compared to the DP (control). The use of soil improvers had a more significant effect than just reduction of tillage. However, due to the complexity of SOM a clear relationship between SOM qualitative characteristics and tillage practices applied was not identified.
It is widely believed that soil disturbance by tillage is a primary cause of the loss of soil organic carbon (SOC) and that substantial SOC sequestration can be accomplished by conversion from conventional ploughing to reduced tillage. The objective of our study was to find alterations of the organic C content in soil humic and granulodensimetric fractions depending on soil tillage and crop rotation. The field experiment was carried out at the Joniskelis Experimental Station of the Lithuanian Institute of Agriculture on a drained clay loam Endocalcari-Endohypogleyic Cambisol (CMg-n-w-can). Two technologies -reduced tillage (RT) and conventional tillage (CT) -were compared in crop rotations with different proportions of overwintering and spring crops (0%, 25%, 50%, 75%, and 100% overwintering crops). The results of 2004-2006 are presented. Tillage had a greater influence than crop rotation on all soil C fractions. RT promoted the formation of all fractions of humic acids and FA1 and FA3 fractions of fulvic acids in the entire plough layer. Increasing the proportion of overwintering crops in the rotation to 100% tended to strengthen this effect. The C content in particulate organic matter (POM), light fraction (LF), and both clay-sized sub-fractions, expressed per unit mass of soil, significantly increased under RT in the top 15 cm of soil. The introduction of overwintering crops into the rotation and increasing their proportion had a significant positive influence on C content in POM and LF in the whole plough layer.
The paper presents the research conducted at the Joniškėlis Experimental Station of the Lithuanian Research Centre for Agriculture and Forestry on a clay loam Gleyic Cambisol during the period of 2006–2010. The research investigated the changes of mineral nitrogen in soil growing catch crops during the winter wheat post-harvest period and incorporating their biomass into the soil for green manure. Green manure implications for environmental sustainability were assessed. The studies were carried out in the soil with a low (1.90–2.00%) and moderate (2.10–2.40%) humus content in organic and sustainable cropping systems. The crop rotation, expanded in time and space, consisted of red clover (Trifolium pretense L.) → winter wheat (Triticum aestivum L.) → field pea (Pisum sativum L.) → spring barley (Hordeum vulgare L.) with undersown red clover. Investigations of mineral nitrogen migration were assessed in the crop rotation sequence: winter wheat + catch crops → field pea. Higher organic matter and nitrogen content in the biomass of catch crops were accumulated when Brassisaceae (white mustard, Sinapis alba L.) was grown in a mixture with buckwheat (Fagopyrum esculentum Moench.) or as a sole crop, compared with oilseed radish (Raphanus sativus var. Oleiferus Metzg.) grown with the long-day legume plants blue lupine (Lupinus angustifolius L.). Mineral nitrogen concentration in soil depended on soil humus status, cropping system and catch crop characteristics. In late autumn there was significantly higher mineral nitrogen concentration in the soil with moderate humus content, compared with soil with low humus content. The lowest mineral nitrogen concentration in late autumn in the 0–40 cm soil layer and lower risk of leaching into deeper layers was measured using organic cropping systems with catch crops. The highest mineral nitrogen concentration was recorded in the sustainable cropping system when mineral nitrogen fertilizer (N30) was applied for winter wheat straw decomposition. In the organic cropping system, the incorporation of catch crop biomass into soil resulted in higher mineral nitrogen reserves in soil in spring than in the sustainable cropping system, (mineral nitrogen fertilizer (N30) applied for straw decomposition in autumn and no catch crop grown). Applying organic cropping systems with catch crops is an efficient tool to promote environmental sustainability.
Please use the following format when citing the article:
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.