Fallow Plots Research Articles

Ecological features of the formation of fertility and productivity of biocenoses on chernozem soils of the Saratov region

An analysis of the species composition of vegetation on fallow plots of different duration and virgin lands made it possible to conclude that the fallow plots succession to the state of virgin lands with increasing age. Comparison of zootechnical parameters of hay from experimental agrocenoses made it possible to state that the average content of fat, ash and fiber for fallow variants is 17.0%, 9.8% and 7.7%, respectively, higher than in hay of the virgin variant. Analysis of the chemical composition of the hay of the experimental agrocenoses showed that the average concentrations of nitrogen, carbon, calcium and magnesium in the hay were lower than in the hay of the virgin agrocenosis by 11.4%, 2.6%, 44.0% and 51 .8% respectively. At the same time, a higher content of available phosphorus and potassium in the hay of fallow agrocenoses by 9.3% and 17.1%, respectively, was observed compared to virgin agrocenosis.

Effects of Previous Fall–Winter Crop on Spring–Summer Soybean Nutrition and Seed Yield under No-Till System

Interest in fall–winter species options for rotation with soybean (Glycine max (L.) Merr.) has arisen; however, little is known about how they can affect the performance of subsequent soybean under a no-tillage system in tropical environments. Our objective was to evaluate the leaf nutrient concentration, aboveground dry matter (DM) accumulation, macronutrient uptake, yield components, and seed yield of soybean cropped in succession to different crop species. Consequently, a field experiment was conducted during three consecutive growing seasons in Botucatu, São Paulo State, southeastern Brazil. The experiment was arranged in a randomized complete block design with four replicates. The treatments consisted of the cultivation of five crops (crambe (Crambe abyssinica Hochst. ex. R.E. Fries), maize (Zea mays L.), safflower (Carthamus tinctorius L.), sorghum (Sorghum bicolor (L.) Moench), and sunflower (Helianthus annuus L.)) in rotation with soybean, in addition to plots that lie fallow (spontaneous weeds) in the soybean off-season, totaling six treatments. Letting plots lie fallow during the off-season reduced the DM accumulation, nutrient uptake, and seed yield of the soybean crop in succession. Preceding cultivation of fall–winter crambe or sunflower favored the uptake of P, K, Ca, Mg, and S by the following soybean crop. The cultivation of sorghum, safflower, and crambe as fall–winter crops also increased the seed yield of subsequent soybean (from 12 to 18% on the average of three growing seasons) compared to fallow plots. The highest increases in soybean seed yield were found in succession to maize (37%) or sunflower (45%) in the second and third growing seasons, respectively.

Mapping the spatial and temporal patterns of fallow land in mountainous regions of China

ABSTRACT The rapid growth of the global population has resulted in a continuous increase in cropland intensity and a shortening of the fallow period as part of the cropland rotation cycle. Yet, there is a lack of systematic knowledge on the extent of fallow lands, particularly in complex landscapes, such as the mountainous regions of China. To fill this knowledge gap, taking Yuanyang County (YYC), Yunnan Province, China, as a case study, we tested a method to identify the spatial-temporal distribution of fallow land by mapping cropland with Landsat data. The overall accuracy of land cover classification, including cropland, ranged between 90.1% and 95.8% from 1998 to 2019. The average accuracy of fallow plots was 75.7% from 2001 to 2019. The annual fallow rate varied between 8.3% and 54.3%, with an average of 20.7%. Kernel density estimated with the probability density function showed that fallow varied between 5 and 13 blocks per km2, gradually decreasing from the central area to the periphery. Increasing elevation, the low value of regional domestic products, and the increased distance to rural settlements were closely related to the higher proportions of fallow land. The approach presented here can be applied to map fallow land in other regions.

Weed Pressure, Nutrient Content, and Seed Yield in Field Grown Sulfonylurea-Resistant Camelina sativa and Brassica napus

Camelina [(Camelina sativa (L.) Crantz], an oilseed species of Brassicaceae, does not have approved herbicides for weed control, which limits its expansion as a commercial crop. To evaluate agronomic traits and ecosystem services of non-transgenic cultivars of sulfonylurea-resistant camelina and canola (Brassica napus L.), a field study was conducted near Fargo, North Dakota. Two replicated locations (NDSU and NW22) were set up in a randomized complete block design including four blocks of camelina, canola, and fallow per location. Camelina and canola were seeded (18 May) at 4.9 and 2.9 kg ha−1, respectively, using 19-cm row spacing. Data was collected mid- and late-season (29 June and 22 July 2020 respectively) for crop and weed stem count (no. m−2), biomass dry matter (kg m−2), and nutrient (N, P, K, S) content (kg ha−1), as-well-as final season (7 August) seed yield (kg ha−1) for camelina and canola treated with and without sulfonylurea. Using Prefer 90 (NIS) at 0.25% v/v, camelina was treated with thifensulfuron at 6.3 g a.i. ha−1, and canola was treated with thifensulfuron at 10.5 g a.i. ha−1 and tribenuron at 5.3 g a.i. ha−1. Sulfonylurea-resistant camelina and canola reduced late-season dry weight biomass of weeds by >75% and ≥60%, respectively, compared with fallow plots. Application of sulfonylurea herbicides to camelina or canola prior to mid-season analyses was not a significant factor (p ≤ 0.05) for reducing weed pressure and generally had little impact on altering crop biomass, seed yield, and nutrient retention. However, in some cases, herbicide treatment had an additive effect of reducing weed pressure over that of camelina or canola alone. Depending on the rotational cropping system, sulfonylurea-resistant camelina and canola should provide additional options for integrated weed management approaches and reducing nutrient leaching in the upper Midwest and northern Great Plains of the USA.

Exclusion of plant input affects the temperature sensitivity of soil organic carbon decomposition

Plant residue input plays a vital role in cropland carbon (C) balance, which can be greatly affected by climate change. Our knowledge of the effect of plant residue on soil respiration is crucial for evaluating C exchange between the atmosphere and terrestrial ecosystems, but large uncertainties remain in the effect of plant input on the temperature sensitivity (Q10) of soil organic C (SOC) decomposition in cropland ecosystems. Here, soils were sampled from two bare fallow plots (including a Mollisol and an Alfisol with different climate and land-use history) and their adjacent old field plots, and were incubated at 10 °C and 20 °C for 815 days. The ‘equal-time’, ‘equal-C’, ‘one-pool model’ and ‘two-pool model’ methods were used to evaluate the Q10 of SOC decomposition. Results indicated that in the early stage of incubation, exclusion of plant input increased the Q10 (Alfisol) or had minor effect on the Q10 (Mollisol), which may be related to the interactions between substrate quality decrease (increase of chemical stability) and clay mineral suppression on microbial decomposition. However, in the later stage of incubation, plant residue removal decreased the Q10 values in both soils possibly due to the limitation of substrate availability on microbial decomposition. Overall, the role of plant input in the temperature sensitivity of SOC decomposition should be considered when predicting SOC stocks in a future warmer world.

Soil organic carbon accrual due to more efficient microbial utilization of plant inputs at greater long-term soil moisture

High long-term soil moisture may either stimulate or inhibit soil organic carbon (SOC) losses through changes to mineral and chemical composition, and resultant organo-mineral interactions. Yet, the trade-off between mineralization and accrual of SOC under long-term variation in unsaturated soil moisture remains uncertain. We tested the underexplored relationships between long-term soil moisture and organo-mineral chemical composition and its implications for SOC persistence in an experimental field in New York, USA, with differences in long-term mean soil volumetric water content (0–0.15 m depth) ranging from 0.40 to 0.63 (v/v) during the growing season. Long-term soil moisture across 20 subplots on four fallow plots were positively correlated with SOC (R2 = 0.23; P = 0.019, n = 20), mineral-associated organic matter (MAOM) content (g fraction/g soil) (R2 = 0.44; P = 0.001; n = 20) and occluded particulate organic matter (oPOM) content (R2 = 0.18; P = 0.033; n = 20). Higher long-term soil moisture was associated with a decrease in the relative content of sodium pyrophosphate extractable Fe (R2 = 0.33; P < 0.005; n = 20), an increase in sodium dithionite extractable Fe (R2 = 0.44; P < 0.001; n = 20), and an increase in SOC retention by non-crystalline Al pools (R2 = 0.51; P = 0.0002 for sodium pyrophosphate extracts, R2 = 0.41; P = 0.0014 for hydroxylamine hydrochloride extracts; n = 20 for both). Increasing long-term soil moisture was associated with a four-fold increase in microbial biomass C (per unit SOC) and lower metabolic quotient (R2 = 0.56, P < 0.001). MAOM fractions of high-moisture soils had lower C:N (from C:N 9.5 to 9.0, R2 = 0.27, P = 0.011, n = 20). Consistent with decreasing C:N, increasing decomposition with increasing moisture was reflected by a 15% and 10% greater proportion of oxidized carboxylic-C to aromatic-C and O-alkyl C, respectively, as measured with 13C NMR, and a more pronounced FTIR signature of N-containing proteinaceous compounds in high-moisture MAOM fractions, indicative of microbial metabolites and transformation products. A partial least squares regression showed that SOC content increased with greater long-term moisture (P = 0.019), pyrophosphate-extractable Al (P = 0.0001), and exchangeable Ca (P = 0.013). Taken together, our results show that higher long-term soil moisture resulted in SOC accrual by enhancing conversion of plant inputs into microbial biomass that interacts with reactive minerals.

PLANT-MICROBIAL INTERACTIONS IN THE ASSISTED BIOREMEDIATION OF A PETROLEUM HYDROCARBON-POLLUTED SOIL AFTER BIOAUGMENTATION WITH PLEUROTUS TUBERREGIUM

The plant-microbial interactions in the assisted bioremediation of a petroleum hydrocarbon-polluted soil after bioaugmentation with Pleurotus tuberregium were investigated. Top soils were collected from a fallow plot on the campus of the University of Benin, Nigeria. A list of all weeds growing on the plot was taken, with a bid to determine the soil seeds bank (Table 2). The soils were then polluted with different concentrations of waste engine oil (1.0, 2.5, 5.0 and 10.0% w/w oil in soil) on weight basis. The polluted soils were then left for five months (SPi). The unpolluted soil (0 %) was designated as control experiment. Result shows that concentration of Mn prior to augmentation of the control experiment (5MAP) was 28.5mg/kg as against 29.6mg/kg and 30.8 mg/kg in the weeded and unweeded bioaugmented treatments respectively. There were significant reductions in soil content of Zn at 10 MAA. Zn concentration in the weeded buckets ranged from 12.2 – 36.9 mg/kg compared to 10.6 – 30.8 mg/kg in the buckets with weeds. Concentration of Ni was 2.52 4.12mg/kg at 5 MAP compared to 0.72 – 1.15 mg/kg in the weeded buckets and 0.07 – 0.13mg/kg in the unweeded buckets 10 months after bioaugmentation. Hydrocarbon degrading bacteria count for SP0 were 1.81 x105 cfu/g in the presence of weed in soil (WW) and 1.65 x105 cfu/g in the absence of weeds in soil (NW) whereas SPA0 were 2.65 x105 cfu/g in the presence of weeds in soil (WW) and 2.04 x105 in the absence of weeds in soil (NW). The total fungi count for SP5 were 1.64 x105 weed presence in soil (WW) and 0.80 x105 cfu/g in no weed presence in soil (NW) for five months after pollution (5MAP) even as SPA5 were 2.08 x105 cfu/g for weed presence in soil (WW) and 1.22 x105 cfu/g for no weed presence in soil (NW) for ten month after bioaugmentation (10MAB) respectively. The most dominant bacteria were Clostridium sp. while the less dominant were Bacillus subtilis. For that of the fungi Aspergillus niger were dominant whereas Aspergillus flavus were the least.

Quantification and mitigation of nitrogen leaching in a maize silage cropping system

Nitrogen (N) leaching is a major source of groundwater contamination. We used a series of lysimeters and suction cups to measure total N leaching losses in a high N maize crop system on a long-term maize paddock in the Waikato.&#x0D; The goal of the study was to 1) quantify N leaching losses under maize silage, 2) determine the effectiveness of a cut-and-carry annual ryegrass catch crop (RG) in mitigating N leaching losses and 3) determine an appropriate depth for measuring N leaching losses under maize.&#x0D; At least 200 kg/ha more fertiliser N than calculated plant requirements was applied to the maize crop to ensure surplus soil N after maize.&#x0D; Nitrogen leaching losses were measured in a maize-RG and maize-fallow rotation over two seasons (October 2018 - September 2020). Less than 10 % of N leaching losses occurred during the maize growing season. This is likely due to evapotranspiration exceeding rainfall in summer.&#x0D; The greatest leaching losses were observed in the maize-fallow rotation, averaging 60 kg N/ha and 88 kg N/ha for the 2018/19 and 2019/20 seasons. This was despite 2020 winter being drier than 2019. The greater 2019/20 leaching losses can be attributed to a greater soil N concentration (+15 mg N/L) in 2020.&#x0D; The importance of catch crops as a N leaching mitigation tool after maize was evident over the two years, resulting in leaching reductions &gt;85% in the maize-RG than the maize–fallow plots. The catch crop removed &gt;200 kg N/ha from the soil, significantly reducing the soil N concentration, which appear to be the main driver of leaching losses in our study. Additionally, RG also increased gravimetric soil water content by 7.3 % in the top 30 cm.&#x0D; When N leaching was measured at 70 cm, losses in fallow plots were almost three times higher than the 41.6 kg N/ha recorded at the 120 cm soil depth, our default maize rooting depth. &#x0D; A similar amount of isotopic 15N (1.2 %) was observed in maize grain at maturity when 15N was inserted to 60 cm or 120 cm soil depth. This was greater than the background values obtained when standard urea was applied to the plots (0.37 %), indicating 15N interception at depth. &#x0D; It is speculated that provided fertiliser rates match crop N demand and catch crops are used, N leaching losses in maize crops should be much lower than values reported here, irrespective of soil type and season.

Neue Pioniere in ostalpinen Peripherräumen: die Wiederbelebung von Geisterdörfern und partiellen Wüstungen in Friaul

Abstract. This study is based on amenity migration as theoretical concept and thus on the assumption that new in-migration improves the appearance, resilience and socioeconomic situation of remote alpine regions. Current revitalisation processes in Friulian alpine villages, having become sparsely inhabited or indeed real ghost villages, are particularly suitable for such studies. The research builds on the one hand on analysis of the current state of the art as well as on analyses of official statistical data. It is on the other hand derived from own surveys in the course of investigative visits to a large part of the Friulian ghost towns. In these remote areas locals and newcomers were interviewed personally. The results show that newcomers bring innovation and new impulses in agriculture, tourism, artistic and cultural sphere and play a key role in renovating existing buildings, reusing fallow plots of land and establishing a creative dynamic. Their activities increasingly enable the regeneration and maintenance of alpine cultural landscapes, resulting in new social and agrarian structures, which are emerging as „new farming“ in the study area. The village of Dordolla in Val Aupa has recently established itself as a centre of innovation in the Friulian mountains. The influx of new pioneers and their achievements are also evident in the rest of the valley. The regeneration processes analyzed in the study area could also be transferred to other remaining partially abandoned settlements in Friuli. The motivations, solutions and ways of thinking of new pioneers combined with the increasingly positive connotations of such areas make the regeneration of the cultural landscape and potential repopulation in other isolated areas by no means unrealistic.

Wheat Production Alters Soil Microbial Profiles and Enhances Beneficial Microbes in Double-Cropping Soybean

Plant-parasitic nematodes represent a substantial constraint on global food security by reducing the yield potential of all major crops. The soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is widely distributed across important soybean production areas of the U.S., being the major soybean yield-limiting factor, especially in the Midwestern U.S. Double cropped (DC) soybean is commonly planted following winter wheat. We previously reported double-cropping soybean fields with reduced SCN counts compared to fallow at both R1 growth stage (beginning of flowering) (−31.8%) and after soybean harvest (−32.7%). To test if higher counts of beneficial and SCN antagonistic microorganisms could be correlated with the suppression of SCN in fields previously planted with wheat, three field locations with noted SCN suppression were selected for a metagenomics study. Ten subplots were selected (5 wheat and 5 fallow pre-soybean) from each location. A total of 90 soil samples were selected: 3 fields ×2 treatments × 3 timepoints × 5 replications. Three DNA markers targeted distinct microbial groups: bacteria (16S V4-V5), fungi (ITS2), and Fusarium (tef1). Amplicons were sequenced using an Illumina MiSeq platform (300 bp paired-end). Sequencing datasets were processed in R using the DADA2 pipeline. Fungal populations were affected by location in all sampling periods and differed significantly between DC and fallow plots at soybean planting and after harvest (P &amp;lt; 0.001). Several enriched fungal and bacterial taxa in wheat plots, including Mortierella, Exophiala, Conocybe, Rhizobacter spp., and others, were previously reported to parasitize SCN and other plant-parasitic nematodes, suggesting a potential role of beneficial microbes in suppression of SCN in soybean fields double-cropped with wheat.

Performance of Pigeon Pea (Cajanus cajan) Varieties under Different Soil Amendments in Ndokwa, Delta State, Nigeria

Background: Pigeon pea is an important legume worldwide that is not cultivated by the farmers in Ndokwa, Delta State. Hence, the study looked at the possibility of evaluating the potential of pigeon pea in Ogume, a community in Ndokwa. Methods: Top soils were collected from a fallowed land mixed thoroughly and filled into 4 kg bags and were divided into 3. The 1st was amended with poultry manure, 2nd was NPK 15:15:15 amended and 3rd was without amendment, tested with two varieties of Cajanus cajan. The experiment was a 2 by 3 factorial, in a completely randomized design with 3 replicates. Residual effects of the amendments were evaluated in 2020. Soil samples were taken to establish the fertility status before amendment and at harvest. Data were taken on the agronomic and yield parameters and were analyzed using ANOVA while means were separated using LSD at P≤0.05. Result: Result obtained showed that the tallest plants (9.83±0.51) were observed in the poultry manure in 2019 while the fallowed plots had the tallest plants (11.17±0.49) in 2020, while in both years, the number of pods and dry pod weight was insignificant among the treatments and varieties. This shows that farmers do not need to spend much finance in amending the soil for pigeon pea cultivation in Ndokwa community, Delta State.

Features of water regime changes of steppe chernozem in the South-East of Central Chernozem zone in modern conditions

The article presents an analysis of the elements of the water regime of the steppe chernozems of the Stone Steppe of the Central Chernozem Region in the conditions of the dry period from the end of 2019 to the autumn of 2020. The objects of the study were: the mowed fallow land plowing in 1882, the old-growth forest strip of 1903 planting and arable land adjacent to fallow plots. The soil-hydrological constants were calculated (total water capacity, lowest field capacity, permanent wilting point) both in the time interval and down the soil profile to a depth of 2 m. The reserves of productive moisture during the growing season were also studied. The maximum values of productive moisture content was reached on the mowed fallow sites by the beginning of February, the minimum in the forest belt areas, the arable land plots had an intermediate value. By the middle of the growing season (June), 2020, the moisture reserves in the soils of the forest strip, fallow and arable land were 127, 123 and 109 mm, respectively, in the meter thickness. The highest amount of productive moisture in the upper soil horizon (0-20 cm) is observed under the forest belt – 39 mm. However, moisture content under the fallow land in the upper horizon had decreased to rate of the dead moisture reserve by early August. Similar values were found in soil under the forest belt and arable land. Otherwise, moisture profile was formed in underlying carbonate horizons. The forest belt soils in insufficient atmospheric moisture conditions in 2020 were more dried out than soil of fallow and arable land. The estimation was given for nature of soil profile changes of soil moisture profile due to influence of forest belt. The data of productive moisture reserves in soil at different distances from the forest belt were presented. In the meter layer at the edge of the forest belt, moisture reserves were at the level of 94.0 mm, sharply decreasing to 60.3 mm at a distance of 25 m from the forest strip, with a gradual decrease to 34 mm at a distance of 125 m. The results of observations showed a clear downward trend of productive moisture content due to distance from the old-growth forest belt.

The role of fallowing in the restoration of woody species in the Woodlands of Northern Uganda

AbstractThe study sought to determine the extent to which fallowing can lead to recovery towards an historic woody vegetation of Sudanian woodlands in northern Uganda. Fallow sites of three distinct ages were assessed. Plots were established in crop fields that had been under cultivation for over 10 years, sites that had been under fallow for 3–6 years (young fallow) and fallow sites of at least 9 years (old fallow) in three districts. In each plot, all woody plants were enumerated and species composition, diversity and richness assessed. Young fallow plots were dominated by pioneer species such as Piliostigma thonningii and Annona senegalensis, while old fallow by a mix of late and early successional species such as Vachellia hockii (formerly Acacia hockii) and Combretum collinum. Vitellaria paradoxa (Shea butter tree) was the most abundant in all fallow categories. Species composition in crop field was different from young and old fallow. Species richness increased significantly from abandoned Crop field to Young fallow and then to Old fallow. Simpson's Diversity Index showed similar trends. V. paradoxa contributed most to overall similarity among the fallow categories. Fallowing can facilitate restoration of characteristic species of Sudanian woodlands.

Plant inputs mediate the linkage between soil carbon and net nitrogen mineralization

Plant residue inputs play a crucial role in regulating soil carbon (C) stock and nitrogen (N) availability in cropland. However, little is known regarding how plant inputs mediate the relationships between soil C and net N mineralization, causing additional uncertainty in predicting ecosystem C and N dynamics. This study investigated the influences of long-term deprivation of plant inputs, short-term addition of maize straw and experimental warming on soil C and net N mineralization and their relationships. We conducted an 815-day laboratory incubation experiment under 10 and 20 °C using soils from a long-term bare fallow plot (without plant inputs for 23 years) and its adjacent old field plot (with continuous plant inputs). Our results showed that long-term deprivation of plant inputs decreased soil net N mineralization (per unit total N or TN) by 56% on average, but had minor effect on soil C mineralization (per unit soil organic C). Soil C and net N mineralization rates were positively correlated in the old field soil under 20 °C. However, soil C and net N mineralization rates were not correlated in the bare fallow soil, mainly due to the low level of net N mineralization. Moreover, soil C and net N mineralization rates were significantly increased by the addition of maize straw in both land-use types. When net N mineralization was <162 (or 159) μg N g−1 TN d−1, soil C and net N mineralization rates were negatively correlated due to an increase of microbial N demand during plant litter mineralization. When net N mineralization was >162 (or 159) μg N g−1 TN d−1, soil C and net N mineralization rates were positively correlated owing to a greater microbial mining of N from soil organic matter (SOM). Further, elevated temperature increased soil C and net N mineralization rates, and changed the relationships between soil C and net N mineralization. Taken together, this study provides evidence that plant inputs mediate the relationships between soil C and net N mineralization, and is thus critical in controlling ecosystem C and N cycling.

Ammonia-oxidizing archaea are integral to nitrogen cycling in a highly fertile agricultural soil

Nitrification is a central process in the global nitrogen cycle, carried out by a complex network of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), complete ammonia-oxidizing (comammox) bacteria, and nitrite-oxidizing bacteria (NOB). Nitrification is responsible for significant nitrogen leaching and N2O emissions and thought to impede plant nitrogen use efficiency in agricultural systems. However, the actual contribution of each nitrifier group to net rates and N2O emissions remain poorly understood. We hypothesized that highly fertile agricultural soils with high organic matter mineralization rates could allow a detailed characterization of N cycling in these soils. Using a combination of molecular and activity measurements, we show that in a mixed AOA, AOB, and comammox community, AOA outnumbered low diversity assemblages of AOB and comammox 50- to 430-fold, and strongly dominated net nitrification activities with low N2O yields between 0.18 and 0.41 ng N2O–N per µg NOx–N in cropped, fallow, as well as native soil. Nitrification rates were not significantly different in plant-covered and fallow plots. Mass balance calculations indicated that plants relied heavily on nitrate, and not ammonium as primary nitrogen source in these soils. Together, these results imply AOA as integral part of the nitrogen cycle in a highly fertile agricultural soil.

Integrating broccoli rotation, mustard meal, and anaerobic soil disinfestation to manage verticillium wilt in strawberry

Verticillium wilt, a disease caused by the fungus Verticillium dahliae, affects a vast range of crops, including strawberries. A field trial was established to evaluate the effect of broccoli in rotation prior to strawberries, anaerobic soil disinfestation (ASD), and mustard cake (MC) alone and in combination at suppressing V. dahliae. Broccoli, cauliflower and fallow plots were established in year 1, followed by strawberry, winter cover crop, and lettuce across all plots over the next two years. ASD and ASD + MC improved strawberry yields compared to the untreated control (UTC). At the end of the harvest season, V. dahliae infection rates in strawberry crowns were lower in the ASD and ASD + MC treatments compared to the UTC. After harvest of the lettuce crop, the number of V. dahliae microsclerotia in soil treated previously with ASD was lower than in the UTC. Broccoli residue incorporation had no effect and MC alone a limited effect on strawberry yields, V. dahliae in strawberry crowns, and soil microsclerotia levels at lettuce harvest. All rotations treated with ASD showed higher total net returns despite the higher cost of treatments. The ability of ASD to control V. dahliae and its persistent suppressive effect on soil microsclerotia levels have important economic implications for growers.

Soil productivity improvement under different fallow types on Alfisol of a derived savanna ecology of Nigeria

Fallowing is considered an important management strategy for the restoration of soil productivity. Therefore, a three-year fallow of pigeon pea (Cajanus cajan), mexican sunflower (Tithonia diversifolia) and elephant grass (Pennisetum purpureum) was established at Landmark University, Nigeria between 2016 – 2019. Leaf nutrient concentrations of maize (Zea mays) planted with soils taken from each fallowed plots after three years were also determined. The experimental design was a randomized complete block design with three replications. Soil samples were collected from each fallow plots for physical and chemical analysis (bulk density, porosity, moisture content, particle size, dispersion ratio, soil erosion loss, soil organic matter (SOM), total N, available P, exchangeables K, Ca, Mg, CEC and pH.) before and at the end of the experiment. Means of data collected were separated using Tukey's HSD test at p = 0.05. Tithonia fallow improved soil properties and leaf nutrient concentration of maize compared with Pennisetum and Cajanus fallows. The order was Tithonia >Pennisetum >Cajanus. This was adduced to the regular return of plant residues to the soil in Tithonia fallow which resulted in high SOM (Tithonia increased SOM by about 23%, 7.5%, and 20%, respectively, compared with the initial soil, Pennisetum and Cajanus fallows) and increases soil N, P, K, Ca, Mg, CEC and pH and also stabilized soil structure by increasing porosity, moisture content and reducing bulk density, dispersion ratio, and soil loss. Therefore, plant species of high nutrient contents and high return of biomass to the soil are necessary for quick restoration of soil productivity in a derived savanna ecology.

Impact Assessment of the Long-Term Fallowed Land on Agricultural Soils and the Possibility of Their Return to Agriculture

Agricultural land abandonment is a process observed in most European countries. In Poland and other countries of Central and Eastern Europe, it was initiated with the political transformation of the 1990s. Currently, in Poland, it concerns over 2 million ha of arable land. Such a large acreage constitutes a resource of land that can be directly restored to agricultural production or perform environmental functions. A new concept for management of fallow/abandoned areas is to start producing biomass for the bioeconomy purposes. Production of perennial crops, especially on poorer soils, requires an appropriate assessment of soil conditions. Therefore, it has become crucial to answer the question: What is the real impact of the fallowing process on soil, and is it possible to return it to production at all? For this purpose, on the selected fallowed land that met the marginality criteria defined under the project, physicochemical tests of soil properties were carried out, and subsequently, the results were compared with those of the neighboring agricultural land and with the soil valuation of the fallow land, which was conducted during its past agricultural use. The work was mainly aimed at analyzing the impact of long-term fallowing on soil pH, carbon sequestration and nutrient content, e.g., phosphorus and potassium. The result of the work is a positive assessment of the possibility of restoring fallowed land for agricultural production, including the production of biomass for non-agricultural purposes. Among the studied types of fallow plots, the fields where goldenrod (Solidago L.—invasive species) appeared were indicated as the areas most affected by soil degradation.

Long‐term manure application for crop yield stability and carbon sequestration in subtropical region

AbstractYield stability and carbon sequestration of agricultural systems are impacted by nutrient management strategies. Major objectives of this study were to understand the effects of long‐term (43 years) manure application on a) environmental parameters such as soil organic carbon (SOC) sequestration, enzyme activities in surface and subsurface layers, and b) yield, and yield stability under a soybean–wheat cropping system in a Vertisol. For this, 100% recommended dose of nitrogen (N), N and phosphorus (NP), N, P and potassium (NPK), NPK + farmyard manure (NPKM) was compared with an unfertilized control (UC) and a fallow land. After 43 years, NPKM and NPK plots had ∼63 and 30% higher total SOC stock than UC, and 45 and 17% higher total SOC stock than fallow plots, respectively in the 0–30 cm layer. Acid hydrolysable C was ~ 42 and 57% higher for NPKM plots in those layers respectively than fallow land. The proportion of macroaggregates was less than 30% in both soil layers of cultivated plots. NPKM had 44 and 28% greater humic and fulvic acid‐associated C than fallow land in top layer. Enzyme activities improved in NPKM by ~ 60 and 61% as compared with fallow land. A steady decline in soybean productivity over the years might be due to residue effect. However, wheat yield increased steadily with manuring. Higher SOC accumulation (p &lt; .001), greater enzyme activities (p &lt; .05), improved structure (p &lt; .05) could enhance wheat yield under NPKM. Thus, manure application could lead to yield stability and enhance SOC sequestration in subtropical region simultaneously.

Tillage Impacts on Initial Soil Erosion in Wheat and Sainfoin Fields under Simulated Extreme Rainfall Treatments

The main aim of this research was to determine the potential effects of different tillage systems (TT: traditional tillage and RT: reduced tillage) on runoff and erosion at two different locations (Kahramanmaras and Tarsus, Southern Turkey) under (i) fallow, (ii) wheat (Triticumaestivum L.), and (iii) sainfoin (Onobrychissativa L.) crops. Rainfall simulations with intensity of 120 mm h−1 and 30-min duration, representing a typical extreme thunderstorm in this area, were used. We quantified the elapsed time to runoff generation (ET), total runoff volume (R), soil loss (SL), sediment concentration (SC), and runoff coefficient (RC). At both locations, the fallow plots indicated the first runoff response ranging between 1.2 and 3.1 min, while the range was between 9.4 and 8.9 min for the sainfoin plots. The highest runoff coefficient was recorded for the fallow parcel in Tarsus (57.7%), and the lowest runoff coefficient was recorded for the sainfoin parcel in Kahramanmaras (4%). For both study sites, the fallow plots showed higher soil erosion rates (871 and 29.21 g m−2) compared with the wheat plots (307 and 11.25 g m−2), while sainfoin recorded the lowest soil losses (93.68 and 3.45 g m−2), for Tarsus and Kahramanmaras, respectively. Runoff and sediment yield generated from sainfoin and wheat parcels under the RT system were less than under the TT system at the Kahramanmaras location. At the Tarsus location, the effect of soil tillage on soil and water losses was insignificant on the sainfoin planted plots. The reduced tillage system was successful in reducing sediment yield and runoff generated from parcels growing wheat and sainfoin compared to traditional tillage in Tarsus location, but runoff and soil loss were found to be very high compared to parcels constructed in the Kahramanmaras location.