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To evaluate the long-term effects of fertilisation on soil organic carbon (SOC) sequestration in rice-wheat cropping ecosystems, SOC dynamics, stocks and fractionation were determined. The treatments included no fertiliser, mineral N and P, mineral N, P and K, organic fertiliser (OF), OF plus NP and OF plus NPK. The results showed that the average carbon inputs that derived from crop stubble, root residues and organic fertilisers were between 1.47 and 4.33 t/ha/year over the past 34 years. The average SOC stocks measured in the samples collected in 2011-2013 ranged from 31.20 to 38.52 t/ha. The range of the SOC sequestration rate was 0.11-0.40 t/ha/year with a SOC sequestration efficiency of 6.3%. Overall, organic fertilisation significantly promoted C-input, SOC and the sequestration rate compared to mineral fertilisation. The "active pool" (very labile and labile fractions) and "passive pool" (less labile and recalcitrant fractions) accounted for about 71.0% and 29.0% of the SOC fractions, respectively. Significant positive relationships between C-inputs and SOC fractions indicated that SOC was not saturated in this typical rice-wheat cropping system, and fertilisation, especially organic amendment, is an effective SOC strategy sequestration.

Biochar plays a key role in nitrogen cycling, potentially affecting nitrogen adsorption and leaching when applied to soils. The laboratory experiments were conducted to investigate the adsorption characteristics of rice straw biochar (RSBC) to ammonium (NH₄⁺) and nitrate (NO₃^-) and the influence of RSBC on leaching characteristics of NH₄⁺ and NO₃^- at different soil depths using multi-layered soil columns. The results showed that the adsorption characteristics were significantly fitted with Freundlich and Langmuir adsorption isothermal curve models. The Freundlich isotherm model indicated that RSBC has relatively higher adsorption capacity and adsorption intensity to NH₄⁺ than NO₃^-. Moreover, the Langmuir isotherm model showed that the maximum adsorption capacity of RSBC to NH₄⁺ and NO₃^- were 31.25 and 10.00 mg/g, respectively. The leaching experiments showed that the contents of NH₄⁺ in the leachates from the soil columns showed significant differences at different depths depending on the application amount of RSBC. Compared with CK (0% RSBC amendment), the overall cumulative losses of NH₄⁺ via leaching were decreased by 23.3, 35.1 and 13.7% after adding 2, 4 and 6% RSBC, respectively. Correspondingly, the contents of residual soil NH₄⁺ in the soil column were increased significantly with the RSBC amendment at different depths. However, the losses of NO₃^- via leaching from the soil columns could not be retarded obviously by RSBC. Therefore, the application of an appropriate biochar rate is beneficial to retard the losses of soil NH₄⁺ from paddy soil.

Cultivar selection and crop systems are important factors for maximising soybean seed yield. The effect of row spacing (RS1 = 75 cm, RS2 = 25 cm) on the performance of 10 early maturity soybean cultivars grown in full-season and double-crop system for two consecutive years was studied. The agronomic traits measured were seed yield (SY), plant height (PH), pods per plant (PP), first pod height (FPH), crude protein. RS had a significant effect on SY, PH, PP and FPH. Higher SY (P < 0.01) was recorded in RS2 regardless of the crop system. The double-crop system yield reduction index of the tested cultivars ranged from 30.0% to 56.4% and from 21.5% to 57.2% for RS1 and RS2, respectively. Cultivars differed (P < 0.01) for all traits in both RS and crop systems. Maturity Group I cultivars showed the highest productivity; the cultivars PR92B63 and Atlantic were better adapted to the full-season crop system (SY > 5.67 t/ha); cv. Sphera was the most productive in the double-crop system (4.66 t/ha); cv. PR92M22 showed good adaptability to both cropping systems. In conclusion, the significant effect of RS and crop system on SY was observed, whereas different high yielding cultivars were identified as suitable for full-season and double-crop system.

Salt acclimation can promote the tolerance of wheat plants to the subsequent salt stress, which may be related to the responses of the photosynthetic apparatus. The chlorophyl (Chl) b-deficient mutant wheat ANK 32B and its wild type (WT) were firstly saltly acclimated with 30 mmol NaCl for 12 days, then subsequently subjected to 6-day salt stress (500 mmol NaCl). The ANK 32B mutant plants had lower Chl b concentration, which was manifested in the lower total Chl concentration, higher ratio of Chl a/b and in reduced photosynthetic activity (P_n). The effect of salt acclimation was manifested mainly after salt stress. Compared to non-acclimated plants, the salt acclimation increased the leaf water potential, osmotic potential (Ψ_o) and K concentration, while decreased the amount of Na⁺ and H₂O₂ in WT and ANK 32B under salt stress, except for Ψ_o in ANK 32B. In addition, the salt acclimation enhanced the APX (ascorbate peroxidase) activity by 10.55% and 33.69% in WT and ANK 32B under salt stress, respectively. Compared to the genotypes, under salt stress, the Ψ_o, F_v/F_m, P_n and g_s of mutant plants were 5.60, 17.62, 46.73 and 26.41% lower than that of WT, respectively. These results indicated that although the salt acclimation could alleviate the negative consequences of salt stress, it is mainly manifested in the WT, and the ANK 32B plants had lower salt tolerance than WT plants, suggesting that lower Chl b concentration has a negative effect on the salt acclimation induced salt tolerance in wheat.

Zinc deficiency limits pecan nut production. The objective of this study was to evaluate changes in nutrient concentration and oxidative metabolism in pecan leaflets in response to the application at different doses of zinc. The foliar concentration of nutrients, leaflet area, total chlorophyll, dry weight (leaflets and root), superoxide dismutase (SOD), hydrogen peroxide, catalase (CAT), guaiacol peroxidase (GP) and antioxidant capacity were evaluated. Statistical analysis indicates that the application of 200 µmol Zn²⁺ affected the foliar concentration of N-total (24.50 ± 2.51 g/kg), P (10.34 ± 2.53 g/kg), Fe²⁺ (153.33 ± 6.27 mg/kg) and Zn²⁺ (42.00 ± 2.84 mg/kg), showing a greater area of the leaflet, total chlorophyll content and dry weight (leaflets and root). Plants treated with 50 µmol Zn²⁺ showed a higher level of SOD activity (1.38 ± 0.016 units/min/g), GP (5.56 ± 0.229 nmol glutathione/min/g), and the production of hydrogen peroxide, without exceeding the control. On the other hand, Zn treatments caused a significant decrease in CAT activity. Zn is an essential micronutrient for the growth and development of pecan, which promotes the accumulation of other nutrients. Therefore, its absence affects the generation of oxidative stress with the subsequent activation of the antioxidant defense enzyme system.

Plant growth regulators play crucial roles in modulating plant response to environmental stresses. In this experiment, the effect of different doses of paclobutrazol (PBZ) and putrescine (Put), i.e., 0, 50, 100 and 150 mg/L on mung bean in two conditions of water deficit (WD) and well-watered (WW) was investigated. The seed yield decreased due to water deficit stress, while the PBZ and Put application alleviated the damage of drought stress through increasing proline and leaf chlorophyll content and improving membrane stability, and thus increased plant yield compared to untreated control plants. According to regression equations, the high PBZ levels (150 mg/L or more) and moderate levels of Put (about 90 mg/L) were determined as the optimal concentrations to maximise mung bean yield in WD conditions. In WW conditions, the mung bean responses to PBZ were inconsistent, whereas Put application positively affected some physiological traits and seed yield. In conclusion, the physiological attributes and, subsequently, the seed yield of drought-stressed mung bean plants could be improved by foliar application of PBZ and Put.

Cinmethylin is a potential new pre-emergence herbicide in Europe inhibiting the fatty acid thioesterases in the plastid against Alopecurus myosuroides and other grass-weeds in winter cereals and oil-seed rape. Five field experiments were conducted in Southwestern Germany from 2018 until 2020 to assess the control efficacy of cinmethylin and other common pre-emergence herbicides alone and combined with post-emergence herbicides against A. myosuroides and yield response of winter wheat and winter triticale. In four experiments, the effect of early and late sowing of winter cereals was included as the second factor in the experiment to investigate if late sowing can reduce A. myosuroides density weed control efficacy. All fields were heavily infested with A. myosuroides with average densities of 110-730 plants/m². Late sowing reduced densities in three out of four experiments. Herbicides controlled 42-100% of the A. myosuroides plants. However, none of the treatments was consistently better than the other treatments over all experiments. In three out of 5 experiments, grain yields were significantly increased by the herbicide treatments. The results demonstrate that cinmethylin increases the options for controlling A. myosuroides in winter cereals. However, it needs to be combined with other control tactics.

The associations among ion uptake, root development and biomass under salt stress have not been fully understood. To study this, a pot experiment was conducted with the objective to determine the concentrations of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn) and iron (Fe) and explore their associations with the biomass and root development by using eight wheat cultivars grown on control and salt stress treatments. About 6 folds increase Na⁺/K⁺ ratio in root, while 10 folds in the shoot were detected in salt stress compared to that for control. Ca, Mg, Zn concentrations in both root and shoot, and Fe concentration in the shoot were significantly changed by salt stress, except Fe concentration in the root. Principal component analysis revealed significant associations of these ions with the aboveground biomass and root traits. On salt stress treatment, the Na⁺/K⁺ ratio in shoot showed a significant negative correlation with root weight and aboveground biomass, while aboveground biomass correlated positively with lateral root length and root weight. A strategy towards manipulating the ion homeostasis, particularly Na⁺/K⁺, combined with selecting genotypes with better salt tolerance is of promise to alleviate the effects of salt stress.

High temperature decreases winter wheat grain yield by reducing the grain number and grain weight. The effect of heat stress on spike grain distribution and weight of individual grains within spike and spikelets was less studied. Our aim is to identify influence of high temperatures during different phenological stages on spike grain distribution and weight and to explore genotypic variation of the studied wheat cultivars. Within this study, a controlled experiment was conducted with 12 different winter wheat cultivars under heat stress at anthesis and mid-grain filling stage. The results showed that spike grain weight, thousand-grain weight and grain number per spike decreased moderately in treatments with individual heat stress at anthesis and mid-grain filling period, respectively, which decreased severely in the multiple heat stressed plants at both stages compared with the control treatment. Heat stress decreased number of spikelets with grains. Grain weight at the G1, G2 and G3 positions had a positive relationship with spike grain weight. Among the studied Serbian wheat cultivars Subotičanka and Renesansa were identified as the most heat tolerant and sensitive, respectively. Heat tolerance of the studied cultivars should be based on the cultivar capacity to retain higher grain weight, and to maintain production of distal spikelet grains.

Field experiments were conducted with two winter wheat cultivars that were primed with 6-benzylaminopurine (6-BA) or kinetin at the concentration 10 mg/L twice during the grain filling stage. After priming, wheat physiological parameters were measured in the field, and the analysis of yield was performed after harvest. Harvested seeds were subjected to low temperature storage for 12 months at -18 °C simulating conservation conditions in genebanks. In field experiments, treated plants exhibited up to 14% higher productivity, higher fresh and dry weight, and chlorophyll content index of flag leaves. Priming significantly improved germination, seedling vigour and growth parameters. In 5-days-old seedlings developed from low temperature stored seeds of field primed plants, the average accumulation of malondialdehyde and H₂O₂ was estimated 25% lower, which contributed to higher cell membrane stability. These results correlated positively with growth characteristics of 15-days-old seedlings. The stimulating action of cytokinin priming was more pronounced in the modern cv. Geya-1 compared to the older cv. Sadovo 772 and could be attributed to improved anti-aging mechanism connected with better protection against oxidative damage.

Three-year field trials were conducted to compare the effect of three tillage systems: strip-tillage (ST), strip-tillage after mouldboard ploughing (STmp) and conventional tillage (CT) on growth and yield of winter oilseed rape at the experimental station in Červený Újezd, Czech Republic. Compared to CT, the growth of roots and aboveground biomass was slower (significantly thinner root necks, shorter roots and leaves) under ST at the beginning of vegetation (BBCH 14-18). Plants under ST still had significantly thinner root necks, and a lower number of leaves than plants from CT before winter (BBCH 21) but the differences were no longer statistically significant in spring (BBCH 30). Despite a slower start, the ST variant with an average yield of 5.47 t/ha significantly exceeded the CT variant with the yield being 5.06 t/ha. Conversely, plants grown under STmp had significantly longer leaves than those under CT in BBCH 14-18 and with the highest values of all parameters, tended to faster growth of biomass, although the other differences were not statistically significant. No differences were observed between STmp and CT in BBCH 21 and 30. The STmp variant achieved the highest yield 5.53 t/ha, and significantly exceeded the CT variant.

The use of high-quality seeds is essential to maintain high rates of production and productivity. The physiological quality of seeds obtained in the field is directly correlated to storage conditions and storage time. This study aimed to evaluate the physiological quality of soybean seeds in relation to different field environments (seed lots) and storage time. Commercial lots of seeds of the soybean cultivar M8349 IPRO were stored for three and six months. Seed moisture content was determined before and after accelerated aging, along with seed germination percentage and vigour evaluations performed before and after each storage period. The experiment was carried out as a completely randomised factorial design (10 × 3): with ten seed lots and three storage periods. The data were analysed by ANOVA, and the means of four independent replicates for each parameter evaluated were compared using the Scott-Knott test at 5% probability (P ≤ 0.05). Our results revealed that the low altitude regions where the seed samples were collected are suitable for soybean seed production with high physiological quality. Seed storage for six months does not cause a significant reduction in subsequent soybean seed field performance.

This article provides information on selected physico-chemical properties, including soil colour, texture, electrical conductivity, pH_H2O, pH_CaCl2, content of total carbon and Q_4/6 quotient, of the topsoil and subsoil of former flood sediments at three diverse vegetation plots in a floodplain and in two reference plots unaffected by floods, and changes of some soil properties caused by a new subsequent flood. Aggradation of flood sediments in the area was controlled both by local terrain morphology and vegetation type cover. Differences in the properties of sediments in the individual plot types were caused by the different production of litter, root biomass and carbon cycling before the new flood. Vertical distributions and inventories of ¹³⁷Cs in soils revealed the position and proportion of modern sediments in soil profiles, man-made filling of former erosion grooves and ploughing depths. The new flood of a lower hydrological power aggraded a thin layer of organo-clay sediment on the soil surface but showed minor effects on the investigated soil properties. The lowest dry bulk density and highest total porosity values were found in the topsoil of woody and grassy plots after the flood implying no substantial break down of soil aggregates by the flood. The highest dry bulk density values in the subsoil of fields indicated soil compaction from agricultural machinery. No increased soil salinity was found after the flood. The flood did not significantly affect the pH_H2O of the topsoil and subsoil; however, a significant increase in pH_CaCl2 was found for the topsoil of grassy plots and for all topsoil samples from the park. No significant increases in total carbon (C_tot) contents were found in topsoils of any plot types after the flood in spite of an accumulation of thin organo-clay material on the soil surface after the flood. However, significant increases in C_tot in subsoils of all plot types indicate the vertical migration of colloidal and dissolved organic carbon in soils during the flood. C_tot contents positively correlated with electrical conductivity values and negative correlated with pH values. The relatively minor changes in soil physico-chemical properties found after the flood can be explained by the short duration and small dynamic power of the flood, and the timing of sampling when the flood had receded and soil aeration was already being restored.

Biochar is considered as a universal conditioner to improve soil quality, but its effects of different addition rates on soil properties, bacterial community structure and plant growth are still unclear, particularly in the typical acid purple soil in the southwest of China. In this study, 110 days of rape growth pot experiment under the application rate of 0.0% rice husk biochar (CK), 0.8% (CT1), 2.0% (CT2) and 4.0% (CT3) to the acid purple soil. Results showed that all biochar additions improved soil pH, soil organic carbon (SOC), total phosphorus, available phosphorus, available potassium concentrations in the acid purple soil. The activity of both invertase and catalase, not urease, was significantly increased with the increasing of biochar addition rates. The 16s-gene sequencing results showed that the Chao1 index was increased only under CT3, and the Shannon index was increased after all biochar applications. Furthermore, biochar increased the relative abundance of bacteria that play important roles in soil carbon and nitrogen cycles, SOC decomposition, plant diseases control and growth. The plant height and biomass production of rapes were increased under the low biochar level (CT1), but not under the higher rates of CT2 and CT3. These results demonstrated that biochar, as a soil conditioner to the acid purple soil, could increase soil pH value, SOC, available phosphorus and potassium and affect carbon and nitrogen cycles related to bacterial communities for promoting plant performance under low application rate.

The focus of this study is on the soil physicochemical, biological, and microbiological processes altered by biochar application to heavy metal (HM) contaminated soils. The aim is to highlight agronomical and environmental issues by which the restorative capacity of biochar might be developed. Literature shows biochar can induce soil remediation, however, it is unclear how soil processes are linked mechanistically to biochar production and if these processes can be manipulated to enhance soil remediation. The literature often fails to contribute to an improved understanding of the mechanisms by which biochar alters soil function. It is clear that factors such as biochar feedstock, pyrolysis conditions, application rate, and soil type are determinants in biochar soil functionality. These factors are developed to enhance our insight into production routes and the benefits of biochar in HM soil remediation. Despite a large number of studies of biochar in soils, there is little understanding of long-term effects, this is particularly true with respect to the use and need for reapplication in soil remediation.

Soybean plants grown under NaCl were foliar sprayed twice with melatonin (MLT). Results revealed that salt stress reduced growth, biomass accumulation, photosynthesis, mineral uptake, the content of δ-aminolevulinic acid, chlorophylls, carotenoids and PSII efficiency. However, MLT application enhanced pigment synthesis and PSII activity. MLT up-regulated the antioxidant system and glyoxalase function resulting in reduced accumulation of reactive oxygen species (ROS). Reduced ROS in MLT-treated plants protected membrane functioning by reducing lipid peroxidation, electrolyte leakage and lipoxygenase activity. Nevertheless, MLT application reduced methylglyoxal accumulation while increased the content of reduced glutathione and ascorbic acid. It could be concluded that exogenous MLT mitigated the salt stress damage in soybean plants by improving photosynthesis, antioxidant systems, controlling ion homeostasis and minimising excessive ROS accumulation.

Soil nitrogen (N) deficiency is a common phenomenon that plagues both naturally growing plants as well as agricultural crops, ultimately affecting their growth and productivity. The aim of our study is to determine the effect of short-term N deprivation on secondary metabolites production in developing and mature leaves of flax (Linum usitatissimum L.). Two weeks under low-N conditions decrease plant growth, N concentration, and soluble proteins content in leaves. Reduction in photosynthesis intensity was also observed. A decrease of cyanogenic glycoside content under N-deficient conditions was most visible in mature leaves. However, the content of linamarin and lotaustralin was about 10-fold higher in younger than in mature leaves, in which play probably protective role due to the possibility of toxic HCN release. Despite the N deficit, flax plants accumulated nitrogen in cyanoglycosides. N from cyanoglycosides can be used to synthesise amino acids; this possibility is supported by the high activity of β-cyanoalanine synthase, especially in N-deficient leaves. On the other hand, the content of different types of phenolic compounds increased in N-deficient plants, especially in young leaves, possibly replacing cyanoglucosides in protective functions. Our results indicated that cyanogenic glycosides could be an important nitrogen source for flax plants grown under temporary N-deficient conditions.

Quinones, redox-active functional groups in soil organic matter, can act as electron shuttles for microbial anaerobic transformation. Here, we used ¹³CH₄ to trace ¹³C conversion (¹³C-CO₂ + ¹³C-SOC) to investigate the influence of an artificial electron shuttle (anthraquinone-2,6-disulfonate, AQDS) on denitrifying anaerobic methane oxidation (DAMO) in paddy soil. The results showed that AQDS could act as the terminal electron acceptor for the anaerobic oxidation of methane (AOM) in the paddy field. Moreover, AQDS significantly enhanced nitrate-dependent AOM rates and the amount of ¹³C-CH₄ assimilation to soil organic carbon (SOC), whereas it was remarkably reduced nitrite-dependent AOM rates and ¹³C assimilation. Ultimately, AQDS notably increased the total DAMO rates and ¹³C assimilation to SOC. However, the electron shuttle did not change the percentage of ¹³C-SOC in total ¹³C-CH₄ conversion. These results suggest that electron shuttles in the natural organic matter might be able to offset methane emission by facilitating AOM coupled with the denitrification process.

Agronomic, nutritional, and environmental aspects are integrated to promote sustainable tropical grassland production. Biological nitrification inhibition (BNI) is a plant-based strategy to improve nitrogen use efficiency by grasses in which they suppress the pace of soil nitrification via exudation of inhibitory compounds. To evaluate the effect of BNI on the productive performance of Megathyrsus maximus under field conditions, we evaluated a collection of 27 germplasm accessions and commercial cultivars of the forage grass in the dry tropics of Colombia. We measured plant yield dry matter, nutrition quality parameters, and nitrification rates of soil at 22 months after pasture establishment. Our results highlighted germplasm accessions of superior agronomic performance (for dry matter production and nutrition quality) and high capacity to decrease nitrification. Although no relation was observed between agronomic aspects, nutritional aspects, and nitrification rates, we conclude that there is no agronomic or nutritional penalty on environmentally friendly grasses, and BNI could be adopted as a target trait in plant breeding programs toward the development of eco-efficient forages and contribute to the sustainable intensification of livestock systems.

Returning straw to the soil is an effective way to improve the soil quality. As genetically modified (GM) crops experience expanded growing scales, returning straw to the soil could also be necessary. However, the impact of GM crop straws on soil safety remains unclear. The environment (including soil types, humidity and temperature) can result in a significant difference in the diversity of soil bacterial communities. Here, we compared the impacts of the straw from Bt maize IE09S034 (IE) and near-isogenic non-Bt maize Zong31 (CK) on soil bacterial community and microbial metabolic activity in three different environments. Sampling was carried out following 6-10 months of decomposition (May, June, July, and August) in three localities in Chinese cities (Changchun, Jinan, and Beijing). Our results showed that Bt maize residues posed no direct impact on soil bacterial communities in contrast to the environment and decomposed time. The microbial functional diversity and metabolic activity showed no significant difference between IE and CK. The results could be a reference for further assessing the effect of Bt maize residues on the soil that promotes the commercialisation of Bt maize IE09S034.

Quantifying carbon in root exudates and exploring their influencing factors are essential to understand soil organic carbon dynamics in cropland. A pot experiment was carried out to explore quantitative relations between root exuded carbon and root traits in wheat and rapeseed. The result showed that rapeseed had a similar pattern in root carbon exudation intensity (EI) as the wheat, but its EI per plant was obviously higher than that in wheat. Rapeseed plants had higher EI per root biomass than wheat plants in the early growth period but lower in the late growth period. EI per root biomass in both crops had significant exponential relationships with the specific root length (RL), surface area (RSA), volume (RV), root C/N ratio and root soluble sugar content. However, EI per plant of both crops had a markedly quadratic relationship with RL, RSA, RV and root biomass. During the whole growth period, the rapeseed had cumulative root carbon exudation of 14.09 g/plant, which was almost twice of that in the wheat plant. Root traits had close relations to root carbon exudation in both crops. Quantitative regression models between them could be referred to estimate root C exudation in rapeseed and wheat farmland.

Long-term impacts of straw incorporation on soil fertility, and maize production and nitrogen (N) use status had not been thoroughly investigated in Northeast China, the most vital agricultural base across the nation. We conducted a consecutive 6-year field experiment, including straw amendment at 4 000, 8 000 and 12 000 kg/ha, and no straw incorporation was set as the control. Our experiment confirmed that the grain yield and crop N uptake in straw treatments were raised due to consistently improved soil fertility indices (associated with soil N cycling), and larger straw addition generally exerted more profound influences. Boosted nitrogen harvest index (NHI) indicated that nitrogen use efficiency (NUE) was gradually enhanced if applying more straw. More specifically, greater straw amendment caused higher N recovery efficiency from straw N, even though the N recovery efficiency of accumulated N addition declined accordingly (considering fertiliser N besides straw N). Thus, these trends suggested that more efficient utilisation of straw N by crop was the probable reason for elevated NUE over multi-year time series. Our research offered helpful insight to optimally employ straw incorporation and N fertilisation for coordinating agricultural sustainability and environmental protection.

The paper examines the effect of the long-term (10 years) low-intensity sprinkler irrigation on the properties of leached chernozem soils covered with Bromopsis inermis Leyss. (BIL) stands in the Southern Cis-Ural forest-steppe. The study analysed changes in the soil's agrophysical and chemical properties. As a result of long-term irrigation, the humus horizon (A + AB) thickness increased by 16 ± 3 cm; the organic carbon (Corg) content and nutrients decreased in this rooting zone, in particular, Corg by 0.3%, available phosphorus by 24.8 mg/kg, exchangeable potassium by 18.4 mg/kg and the stock of Corg by 16 t/ha. The particle size distribution of irrigated soil did not significantly changed; some changes were observed for the soil's aggregate composition. The soil's hydrophysical properties, water and air regime worsened.

The main aim is to find out the influence of using coloured plastic mulches (blue, white, green, red, black and white on black) compared with a mulch-free treatment on the root zone temperature, growth and productivity of broccoli. The results indicated that the highest and lowest mean root zone temperatures were recorded the in the dark-coloured mulches (blue, green, red and white on black) and in the light-coloured mulches (white), respectively, in both the winter and spring seasons. The average shoot length, leaf number and root volume of the broccoli for all the treatments was higher in the spring season compared with those of the winter season. The highest marketable head fresh weight values were 449.6 and 451.0 g found in the black mulch, while the lowest values were 391.4 and 397.5 g found in the winter and spring seasons for the red mulch, respectively. The N, P, K, Ca and Mg concentrations in the broccoli heads ranged from 2.0 to 2.8%, 0.9 to 1.0%, 2.7 to 3.6%, 1.9 to 5.9% and 0.5 to 0.89%, respectively, for all the treatments.

One of the qualitative characteristics of both green and dried hops is the content of hop essential oils which are contained in a quantity of 0.5 to 3.5%, depending on the hop variety. These essential oils are heat labile substances because the temperature has an influence on their content. Hop cones, dried either in belt or chamber dryers, are exposed to a drying medium temperature of 55 °C to 60 °C for the entire duration of drying, i.e. for 6-8 hours. Under current drying conditions there is a loss of approx. 15 to 25% of the total content of essential oils present in hops before drying. In case of special aroma hop varieties, such losses lead to a decline in the product quality. Comparative measurements have been carried out with a laboratory equipment to find out whether more aromatic essential oils are retained in hop cones at a drying temperature of 40 °C compared to a drying temperature of 60 °C. The measurement carried out with the most common variety of Saaz hop concluded that the essential oil losses were lower by 33.4% at a drying temperature of 40 °C, and with other seven mostly hybrid varieties the losses were lower on average by 13.9% than at a drying temperature of 60 °C. The measurements proved that each of the varieties retained, to a significant extent, its content of essential oils in the dried hop cones at a drying temperature of 40 °C.

A forced convection automatic cabinet dryer integrated with a data logger was designed and fabricated. The okra samples were dried in the dryer at drying temperatures of 50, 60, and 70 °C and at three different load densities of 200, 300, and 400 g at a continuous air velocity of 0.7 m.s^-1. Energy and exergy analyses of the drying process were performed. The obtained results showed that the energy efficiency, energy utilisation, and utilisation ratio increased from 26.59 to 68.24%, 5.47 to 114.36 W, and 0.36 to 0.71 as the temperature increased to 70 °C, respectively. The inflow, outflow, and exergy losses were in the range of 7.02 to 26.14 W, 4.43 to 14.16 W, and 2.59 to 11.98 W, respectively, while exergy efficiency varied from 49.15 to 63.47%. The findings show that exergy efficiencies decrease with an increase in the drying temperature, but increase with a lower load rate. The index of sustainability varies from 2.14 to 2.77, the value increases as the load density decreases while it decreases with a temperature increment.

This study was devoted to verifying the performance of various configurations of a winged chisel plough (WCP) in a soil bin. The performance of the new tool was assessed at three wing depths (5, 10 and 15 cm), three bend angles (10, 20 and 30 °), and three rake angles (7.5, 15 and 22.5 °) with three replications using a completely randomised design at a constant depth and speed of 30 cm and 1 m.s-1, respectively. The draught and vertical forces, soil disturbed and upheaved areas plus the efficiency of the soil loosening were measured during the tests. The results revealed that the draught and vertical forces were significantly increased by increasing the wing depth, bend and rake angles. The soil disturbance area increased with an increase in the wing depth, bend and rake angles. While the soil upheaving was decreased by increasing the wing depth and bend angle, the effect of the rake angle on the soil upheaving area was not significant. The maximum efficiency of the soil loosening of 268.1 cm2.kN-1 was achieved for a wing depth of 10 cm, a bend angle of 20 °, and a rake angle of 15 °. A significant improvement in the efficiency of the soil loosening along with maintaining a considerable portion of the residue on the soil surface suggest that the WCP should be adopted for conservation tillage.

The friction properties of ackee apple (Blighia sapida) seeds at an 11.9, 17, 22, 27, and 32% (w.b.) seed moisture were determined, which are vital for designing their processing techniques and equipment to replace the present manual methods. The ackee apple grows in many West African countries, especially Nigeria. The ackee seeds were harvested at Lanlate, Oyo State, Nigeria, where ackee trees are predominant. Standard experimental methods were adopted to determine the properties. The data were analysed using an ANOVA and the least significant difference (LSD) at P ≤ 0.05. As the moisture increased, the static coefficient of friction on glass (27.6-36.40), aluminium (27.0-30.2), polyvinyl chloride (PVC; 27.9-32.8) surfaces and normal stress at 200 g (8.73-8.93 g×cm-2), 300 g (11.65-11.79 g×cm^-2) and 400 g (14.37-14.65) loads increased significantly and linearly. The shear stress linearly decreased at a 200 g load (1.62-1.25 g×cm^-2), but was non-significant at the 300 and 400 g loads. The coefficient of internal friction linearly decreased (0.744-0.588) implying that the wet seeds flow more easily than the dry ones, which should be considered in designing conveyors. The relationships between the ackee seeds' moisture and friction properties were expressed with regression models. Data for designing the handling techniques and machines for the ackee seeds were obtained.

The physical properties of agricultural products are essential in designing machines, equipment, and systems for efficient processing operations. Two periwinkle varieties, viz Tympanotonus fuscatus (Linnaeus, 1758) and Pachymelania aurita O. F. Müller, 1774, were utilised in this study to investigate and determine their physical properties relevant to the design of efficient processing equipment. The geometric (axial dimensions, mean diameters, surface area, sphericity, aspect ratio) and gravimetric (bulk and true densities, mass, and porosity) properties were measured. The averages for the major diameter, arithmetic mean diameter, geometrical mean diameter, and surface area were highest in the T. fuscatus variety. In contrast, the minor diameter, sphericity, and aspect ratio were highest in the P. aurita variety. The average bulk and true densities, porosity, and average periwinkle weight for T. fuscatus were higher than the P. aurita variety. Tukey's pairwise comparison analysis carried out on all the physical properties of the T. fuscatus, and P. aurita varieties of the periwinkle shells revealed a statistically significant difference at P < 5%.

This paper reports the design, fabrication and testing of a low-cost PVC-based manual fertiliser applicator (MFA) for the placement of granular and powdery fertilisers (organic and inorganic) at a required soil depth and plant spacing. The MFA consists of a spring-loaded trigger mechanism, a connecting tube and a knapsack plastic tank for the fertiliser storage, holding between 8.0-12.0 kg of fertiliser depending on the fertiliser's characteristics. The MFA was tested using four common fertilisers (NPK, SSP, Urea and organic manure) at different fertiliser moisture contents (3, 4, 5 and 6% w.b.). The results reveals that the MFA performed effectively in the fertiliser's discharges although it was significantly affected by the moisture content and fertiliser type. However, the MFA performed optimally when the moisture content was not above 4% (w.b.) giving optimal discharge values of 3.82, 3.45, 1.88 and 1.70 g per application for the NPK, SSP, urea, and pulverised organic fertilisers, respectively, at 4-7 cm application depths. Operators can, however, effectively determine the depth of placement and the number of applications during use based on agronomic recommendations.