One of the main goals of the 21st century’s developing society is to produce the necessary amount of food while protecting the environment. Globally, particularly in Lithuania and other northern regions with similar climatic and soil conditions, there is a lack of data on the long-term effects of crop rotation under the current conditions of intensive farming and climate change. It has long been recognized that monocultures cause soil degradation compared to crop rotation. Research hypothesis: the long-term implementation of crop rotation makes a positive influence on the soil environment. The aim of our investigation was to compare the effects of a 50-year-long application of different crop rotations and monocultures on soil CO2 emissions, earthworms, and productivity of winter rye. Long-term stationary field experiments were established in 1966 at Vytautas Magnus University Experimental Station (54°53′ N, 23°50′ E). The study was conducted using intensive field rotation with row crops, green manure crop rotations, three-course rotation, and rye monoculture. Pre-crop had the largest impact on soil CO2 emissions, and more intensive soil CO2 emissions occurred at the beginning of winter rye growing season. Rye appeared not to be demanding in terms of pre-crops. However, its productivity decreased when grown in monoculture, and the optimal mineral fertilization remained lower than with crop rotation, but productivity remained stable.

Nowadays the priority in agriculture is given to the soil tillage systems which enable reduction of organic matter decomposition. Our investigation was aimed to assess the long-term impact of reduced intensity tillage systems, straw and green manure combinations on soil organic matter quantity and quality. Since 1999, a long-term field experiment has been done at the Experimental Station of Aleksandras Stulginskis University (former Lithuanian University of Agriculture) at 54º52′50′′ N latitude and 23º49′41′′ E longitude. The results presented in this paper were obtained in the 12 th and 14 th years of investigations. The soil of the experimental site is Epieutric Endocalcaric Endogleyic Planosol. Continuous long-term (12 and 14 years) straw application increased soil organic carbon (SOC) content by 9.3% and 12.0% compared with the plots without straw. Reduced tillage systems without primary tillage (shallow rotovating before sowing, catch cropping for green manure with rotovating, no-tillage) were even more effective. Compared with conventional ploughing, SOC increased by 19.4% to 33.9%. These tillage systems increased soil quality too, since SOC stratification ratio between 0-10 and 10-20 cm layers increased by 1.14 till 1.21. Reduced tillage systems with primary tillage (shallow ploughing and shallow loosening) had no effect both on SOC and stratification process in the soil. SOC pools over the experimental years tended to increase by 9.3% and 11.6% in the treatments of long-term application of straw compared with the plots without straw. Notillage and catch cropping for green manure with rotovating compared with conventional ploughing significantly increased the pools of organic carbon by 31.7% to 33.3% in the plots without straw and by 28.9% to 32.7% in the plots with straw. Continuous straw application increased the quantity of mobile humus substances by 22.7% compared to the plots without straw. Straw in combination with catch crop for green manure incorporation and rotovating and no-tillage increased mobile humus substances by 53.2% and 58.8% compared with conventional ploughing. Only long-term application of straw increased the quantity of mobile humic acids by 40.6% compared with the plots without straw. The rate of mobile humic acids from total amount of mobile humus substances in the treatments without straw amounted to 39.8%, while with straw this content increased to 45.6%. Reduced tillage systems without primary tillage had no significant effect on mobile humic acids but tended to increase soil organic matter quality.

A long-term field experiment (since 1988) was carried out at the experimental station of the Aleksandras stulginskis university (Asu, 54º52′ N, 23º49′ e) in the conditions of transitional maritime-climate. Research data from the 2010-2012 experimental period are presented. the soil of the experimental site is silty light loam Endohypogleyic-Eutric Planosol (PLe-gln-w). Average annual temperature is 6.2°c. the aim of the experiment was to establish the influence of reduced primary autumn soil tillage on maize productivity. the treatments of the experiment were: 1) conventionally (22-25 cm) ploughed by a mouldboard plough, 2) shallowly (12-15 cm) ploughed by a mouldboard plough, 3) deeply (25-30 cm) tilled by a chisel cultivator, 4) shallowly (10-12 cm) tilled by a disc harrow, 5) no-till. the experimental results showed that all primary soil tillage methods (except for chiselling) normally had insignificant effect on maize biometric parameters. Deep chiselling had consistent negative influence on the biometric parameters of maize canopy, while no no-till effect was insignificantly positive. maize crop biometric parameters partially depended on weed infestation at the beginning and the end of maize vegetation. in two out of three experimental years, maize crop density at the beginning and end of vegetation did not differ significantly in differently tilled plots. A relationship was found between the number of annual as well as total number of weeds and crop density at the beginning of vegetation (r = −0.926** and −0.948**). crop density at the beginning of vegetation had significant positive effect on most maize productivity parameters. Reduced soil tillage from shallow ploughing to no-till had total positive effect on maize productivity in 2011 only because of the lower weed infestation. Relationships were established between weed infestation and maize crop productivity parameters (correlation coefficients from −0.394 to −0.965**). Productivity parameters were influenced by biometric parameters too (correlation coefficients from 0.713** to 0.920**).

Equally effective way to achieve sustainable farming and the challenge set by the European Commission on 20 May 2020: proper crop rotation and thus reduction of the quantity of on-farm chemicals. Long-term stationary field experiments were established in 1966 at Vytautas Magnus University Experimental Station (54°53′ N, 23°50′ E). The study was conducted with intensive, three-course, field rotation with row crops, for green manure crop rotations, and rye monoculture as well during the last 5-year period of a 50-year investigation to determine the effect of crop rotation combinations and rye monoculture on weed density and seed bank and grain yield. In cereal crops, weed counting was performed twice: weed density was determined before the application of herbicides, and weed counting was done before the harvest. Weed seedlings were counted, their botanical species were determined, annual and perennial weed number was estimated. Weed seed bank was established before primary tillage in soil. The results obtained confirmed the hypothesis that with climate change and intensive farming, long-term crop rotations are likely to increase crop productivity, reduce weeds and weed seed banks in the soil, and thus contribute to maintaining agroecosystem sustainability. The winter rye 1000 grain weight and yield decreases as weed mass increases showing strong negative correlations: y = 475.56 − 11.93x, r = −0.91, p ≤ 0.05; y = 82.97 −14.82x, r = −0.97, p ≤ 0.01. Reseeding of rye crops leads to a growing prevalence of weeds such as Equisetum arvense L. and Mentha arvensis. Crop structures these days are dominated by cereals, which inevitably increase the spread of weeds, and therefore, the importance of crop rotations increases in the context of intensive farming.

Please use the following format when citing the article: Bogužas V., Sinkevičienė A., Romaneckas K., Steponavičienė V., Skinulienė L., Butkevičienė L. M. 2018. The impact of tillage intensity and meteorological conditions on soil temperature, moisture content and CO 2 efflux in maize and spring barley cultivation. Zemdirbyste-Agriculture, 105 (4): 307-314. AbstractWith a worldwide increase in the use of sustainable tillage systems, it is important to ascertain their long-term effects on soil properties and greenhouse gas emissions. However, there are not many long-term experiments of this type, and they are conducted in very different climatic and soil conditions. To fill a knowledge gap in this field of study, a long-term, stationary field experiment was set up at Aleksandras Stulginskis University's Experimental Station (54°52ʹ57 N lat., 23°50ʹ51 E long.) in 1988. The current paper presents the experimental data from the 2015-2016 period. The soil of the experimental site is Epieutric Endocalcaric Endogleyic Planosol (PL.gln-can-eup) with a texture of loam on heavy loam. The topsoil layer's characteristics are as follows: pH KCL 6.6-7.0, available phosphorus (P 2 O 5 ) content 131.1-206.7 mg kg -1 , available potassium (K 2 O) content 72.0-126.9 mg kg -1 , humus content 1.68%. This study set out to investigate the effects of long-term application of different tillage systems and meteorological conditions on soil temperature, moisture content and soil surface carbon dioxide (CO 2 ) efflux in the stands of maize and spring barley. The experiment included the following primary tillage methods differing in intensity: 1) conventional ploughing (CP) at a 23-25 cm depth (control treatment), 2) shallow ploughing (SP) at a depth of 12-15 cm, 3) deep cultivation (DC) at a depth of 23-25 cm, 4) shallow cultivation (SC) at a depth of 12-15 cm and 5) no tillage (NT) (direct drilling). The findings of the study suggest that the soil surface CO 2 efflux depended on the amount of rainfall during the crop growing season. In a dry year 2016, the soil CO 2 efflux was lower than that in a wet year, the differences between the tillage treatments were more distinct, with the least flux being from the NT treatment. No significant differences among the tillage treatments were determined in a wet year 2015. The soil temperature depended on the tillage intensity and the weather conditions during the crop growing season. A lower soil temperature was recorded in the reduced tillage treatments compared with conventional tillage treatments. A negative strong correlation was established between the soil surface CO 2 efflux and soil temperature (y = 13.93867 + 0.303x; r = −0.96, P < 0.05). The tillage methods of different intensity did not have significant effect on the moisture content in the soil surface layer; however, in a dry year, the highest moisture content was determined in the no-tillage treatment, while in a wet year the differences were negligible.