The impact of reduced tillage and distance to field margin on predator functional diversity

Introduction Agricultural intensification results in biodiversity loss through land conversion and management practices which negatively impact arthropods. The abundance and diversity of ground-dwelling predators, e.g. ground beetles (Coleoptera: Carabidae) and spiders (Araneae), are negatively affected by soil disturbances such as tillage. Reducing soil disturbances can potentially conserve arthropod populations in the field and reduce the use of chemical pest controls. The present study investigated the ground-dwelling predatory community using pitfall traps in cereal fields with three different levels of soil disturbance: conventional tillage, reduced tillage and no tillage under Conservation Agriculture management, in 2018 and 2019. Pitfall traps were placed in transects from the field margins. Overall, the activity-density of ground-dwelling predators was higher in fields with minimum soil disturbance and generally declined with increased distance to semi-natural habitats. Functional diversity, expressed by the body size of ground beetles, was also affected by soil disturbances; large ground beetles more consistently occurred in CA, while few or none of the largest ground beetles were found in RT and CT. A higher sample-heterogeneity in less disturbed fields was indicated by a more variable median and higher skewness in the number of predators in those fields. In 2019 only, species diversity was higher along field edges bordering semi-natural habitats when compared to the cropped area. Our results show that reduced tillage supports predator arthropod communities at a local scale: It also bolsters agro-ecosystem resilience by promoting a higher activity-density and by increasing the heterogeneity and functional diversity of ground-dwelling predators. Implications for insect conservation The results obtained in the present study show that soil disturbances significantly influence arthropod abundance and diversity. Conservation of epigeic natural enemies in the agricultural landscape is improved by reducing soil-disturbing events such as tillage.

A Multivariate Approach to Evaluate Reduced Tillage Systems and Cover Crop Sustainability

The evaluation of the effects of conservation agriculture during the transition from conventional tillage to no-tillage requires numerous indicators to be considered. For this purpose, we monitored changes in a multi-parameter dataset during a three-year experiment that combined three tillage intensities (conventional tillage—CT; minimum tillage—MT; and no tillage—NT) with three soil covering managements (tillage radish cover crop, winter wheat cover crop and bare soil). Using a multivariate analysis, we developed a Relative Sustainability Index (RSI) based on 11 physical (e.g., bulk density and penetration resistance), chemical (e.g., soil organic carbon and pH) and biological soil properties (e.g., earthworm density) to evaluate cropping systems sustainability. The RSI was most affected by tillage intensity showing higher RSI values (i.e., better performances) in reduced tillage systems. Specifically, the RSI under NT was 42% greater than that of CT and 13% greater than that of MT. Soil covering had little impact on the RSI. Among the tested parameters, the RSI was increased most by saturated hydraulic conductivity (+193%) and earthworm density (+339%) across CT and NT treatments.to. Our results suggest that conservation agriculture and, particularly, reduced tillage systems, have the potential to increase farm environmental and agronomic sustainability.

Removal of Biomass and Nutrients by Weeds and Direct-Seeded Rice under Conservation Agriculture in Light-Textured Soils of North-Western India

The escalating scarcity of irrigation water, transplantation of rice on light-textured soils and labour cost acted as major drivers for the transition towards direct-seeded rice (DSR) cultivation from the conventionally flooded transplanting system. Despite these advantages, DSR is a challenge in light texture soil due to heavy weed infestation and a slight decline in crop yield. The weeds compete for nutrients and have an adverse effect on the growth and yield of crops. Hence, to assess the removal of macro and micronutrients by weeds and direct-seeded rice, a field experiment was carried out on sandy loam soil for two consecutive Kharif seasons (2018 and 2019). Three treatments from rice, namely: DSR under zero tillage (DSR-ZT), DSR under conventional tillage (DSR-CT) and DSR under reduced tillage (DSR-RT) were taken as main plots with three tillage treatments in wheat, namely: Conventional tillage without rice straw (CTW-R), Zero tillage without rice straw (ZTW-R) and Zero tillage with straw as mulch using Happy Seeder (ZTW+R) as subplots, replicated thrice. Among the rice establishment methods, DSR-RT showed an edge in terms of rice grain and straw yield (6.18 and 8.14 Mg ha−1, respectively) as well as macro- and micronutrient uptake by rice. Under management practices, ZTW+R proved as an efficient strategy in terms of yield and nutrient uptake by crops. The contribution of weeds towards biomass production was maximum under the ZTW-R (9.44%) treatment followed by DSR-ZT (7.72%). The nutrient budgeting showed that macro- and micronutrient removal by weeds was minimum under reduced tillage (24.51 and 50.35%, respectively), whereas it was 21.88 and 44.87% when wheat was grown under conventional tillage without rice straw. In overall, the research study concluded that weeds on an average remove 25.65 % macronutrients (N, P, K) and 51.47% of micronutrients (Zn, Cu, Fe and Mn) in DSR under rice-wheat cropping system.

Impact of Subsurface Application of Compound Mineral Fertilizer on Soil Enzymatic Activity under Reduced Tillage

Soil biochemical properties shaping soil fertility and agro-ecosystem productivity depend on the reduced tillage system and the dose and method of application of fertilizer; therefore, the research hypothesis put forward proposes that under reduced tillage system conditions, the subsurface application of a multi-component mineral fertilizer would increase soil enzymatic activity, thus favourably influencing the biodiversity of the soil environment. The objective of the three-year study was to evaluate the impact of subsurface application of varying mineral fertilizer rates on soil enzymatic activity under reduced tillage system conditions in soybean, winter wheat and maize rotations. The field experiment was set up as a split-plot design in four replicates. The first experimental factor included two methods of mineral fertilization application: fertilizer broadcast over the soil surface (S); fertilizer applied deep (subsurface placed) using a specially designed cultivator (Sub-S). The other factor was the rates of the mineral fertilizer (NPKS): 85 kg∙ha−1 (F85) and 170 kg∙ha−1 (F170). The method of application and rate of mineral fertilizer did not have a significant effect on the organic carbon and total nitrogen content in the soil of the plots with all rotational crops. Subsurface application of fertilizer significantly increased available phosphorus content in soil under soybean and winter wheat crops; however, it significantly decreased soil pHKCl values within sites with all crops in the rotation compared to surface application. At the same time, deep application of mineral fertilizer significantly stimulated dehydrogenase activity in the soil under the winter wheat crops and acid phosphatase activity in the soil under all rotation crops. The higher level of mineral fertilization contributed to reduction of soil pHKCl under winter wheat and maize, and promoted an increase in the soil P content. Additionally, significant increases of dehydrogenases and urease activity in the soil under winter wheat and maize crops, alkaline phosphatase activity in the soil under all the studied crops, and acid phosphatase activity in the soil under the soybean crops were found, compared to mineral fertilizer in the amount of 85 kg NPKS∙ha−1. The results of the present study have demonstrated a positive effect of subsurface application of compound mineral fertilizer on the soil biochemical parameters in reduced tillage. This may be a recommendation for the subsurface use of multicomponent mineral fertilizers in sustainable agriculture. However, a full objective characterization of the soil environment processes induced by in-depth application of mineral fertilizer in reduced tillage requires long-term monitoring.

Oat Cover Crop and No-tillage Can Provide Weed Suppression and Alter Weed Community Dynamics in Sweet Corn

Along with the many known benefits of cover crops, they may be an effective ecological weed management strategy in low-input agriculture. This research aimed to determine the effect of cover crops, combined with reduced-tillage and nitrogen inputs on sweet corn (Zea mays) yield and weed communities. During the 2-year study, the impact of the cover crop on yield varied. Yield within the no-till conventional treatment plots was not significantly different from the conventional treatment [6844 and 7721 lb/acre (P = 0.592)] in year 1 but differed in year 2 (P = 0.003). Weed density and experimental area covered by weeds were not significantly different between conventional and no-till conventional treatments. Multivariate analyses showed associations between specific weed species and management practices. Weeds were greatest in no-till organic treatments, and they had significantly lower yields, suggesting additional weed control beyond cover crops may be necessary for organic vegetable systems under reduced tillage.

Transition to conservation agriculture: how tillage intensity and covering affect soil physical parameters

Conservation agriculture (CA) relies on two key practices to improve agricultural sustainability—reduced tillage and cover crop usage. Despite known soil physics benefits (reduced soil compaction and strength, enhanced soil porosity and permeability), inconsistent reports on short-term CA results have limited its adoption in European agroecosystems. To elucidate the short-term effects, a three-year experiment in the low-lying Venetian plain (Northern Italy) was undertaken. Bulk density, penetration resistance, and soil hydraulic measures were used to evaluate results obtained by combining three tillage intensities (conventional tillage (CT), minimum tillage (MT), no tillage (NT)) with three winter soil coverages (bare soil (BS), tillage radish cover crop (TR), winter wheat cover crop (WW)). Among the tillage methods and soil layers, CT, on average, reduced BD (1.42 g cm−3) and PR (1.64 MPa) better in the 0–30 cm tilled layer. Other treatments yielded higher values (+4 % BD and +3.1 % PR) in the same layer. Across the soil profile, reduced tillage coupled with WW improved soil physics even below the tilled layer, as evidenced by root growth-limiting threshold declines (−11 % in BD values > 1.55 g cm−3 and −7 % in PR values > 2.5 MPa). Soil hydraulic measures confirmed this positive behaviour; NT combined with either BS or WW produced a soil saturated conductivity of 2.12 × 10−4 m s−1 (four-fold that of all other treatments). Likewise, sorptivity increased in NT combined with BS versus other treatments (3.64 × 10−4 m s−1 vs an all-treatment average of 7.98 × 10−5 m s−1). Our results suggest that despite some measure declines due to reduced tillage, the strategy enhances soil physics. In the short term, cover crop WW moderately increased physical soil parameters, whereas TR had negligible effects. This study demonstrates that CA effects require monitoring several soil physical parameters.

Influence of tillage systems and herbicides on weed control and yield of cotton in wheat-cotton system

Wheat–cotton system is a major production system in Pakistan, however, cotton yield is declining in the system most likely due to weeds infestation and intensive tillage practices. Conservation tillage such as reduced and zero tillage in combination with appropriate herbicide may have the potential to enhance cotton yield on sustainable basis. The objective of this study was to determine the effect of herbicides under different tillage systems on weed control and cotton yield in wheat-cotton system. A field experiment was conducted at Cotton Research Station, Ratta Kulachi, Dera Ismail Khan, Pakistan, during 2017 and 2018. In the experiment, post-emergence herbicides, i.e. floxyfop-R-methyl 10.8 EC (108 g a.i. ha-1), lactofen 24 EC (168 g a.i. ha-1), floxyfop 10.8 EC + lactofen 24 EC, hand weeding, weedy check and three tillage systems (zero tillage, reduced tillage and conventional tillage) were evaluated in randomized compete block design (RCBD), with split plot arrangements, replicated 4 times. Tillage was allotted to main plots while herbicides were applied to subplots. The results revealed that hand weeding and floxyfop as post emergence alone or in combination with lactofen reduced weed density to the minimum irrespective of the tillage systems. Maximum dry weed biomass was recorded in control. Interaction effects revealed that reduced tillage in combination with broad spectrum herbicides had maximum weed population reduction percentage. Reduced tillage with broad spectrum herbicides had seed cotton yield compared to zero and conventional tillage. In conclusion, broad-spectrum herbicides under reduced tillage were more productive in wheat based cropping system on silty clay soil of D.I.Khan.

The effect of different tillage systems upon some microorganisms

The aim of this research was to establish the influence of two tillage systems: one without ploughing, and one with conventional tillage, upon soil microorganisms. The experiment was carried out on the farm of Brezovo, in two variants - control, with applied conventional tillage and a second variant – without ploughing, on an area of 200 dk for each variant. The soil type of the field is sandy - clay, with medium to high cation exchange capacity. The nitrate nitrogen content was determined colometrically and spectrophotometrically for phosphorus and potassium. The ratio of carbon to nitrogen was measured twice - before sowing and during harvest time. The amount of total bacterial and fungal microflora, as well as the ratio of active bacteria and fungi was monitored. Based on the obtained results, it was found that the numbers of the total bacteria and fungi is higher in the variant without ploughing, compared to the control sample. The same trend is maintained in the quantitative ratio of active fungi and bacteria. Reduced tillage systems create better conditions for the development of the studied groups of microorganisms, compared to conventional cultivation technologies.