Soils Of Semi-arid Regions Research Articles

Trichoderma Rhizosphere Soil Improvement: Regulation of Nitrogen Fertilizer in Saline–Alkali Soil in Semi-Arid Region and Its Effect on the Microbial Community Structure of Maize Roots

In order to reduce the actual impact of a saline–alkali environment on maize production in semi-arid areas, it is particularly important to use the combined fertilization strategy of Trichoderma microbial fertilizer and nitrogen fertilizer. The purpose of this study was to investigate the effects of different concentrations of nitrogen fertilizer combined with Trichoderma on improving the structural characteristics and ecological functions of maize rhizosphere microbial community in semi-arid saline–alkali soil. Through the microbiome analysis of maize rhizosphere soil samples with 60 kg N·ha−1 (N1) and 300 kg N·ha−1 (N2) nitrogen fertilizer combined with Trichoderma (T1) and without Trichoderma (T0), we found that the combination of Trichoderma and different concentrations of nitrogen fertilizer significantly affected the structure of bacterial and fungal communities. The results of this study showed that the combination of Trichoderma and low-concentration nitrogen fertilizer (N1T1) could improve soil nutritional status and enhance its productivity potential, revealing the relationship between beneficial and harmful fungal genera, microbial diversity and abundance, and crop biomass, which is of great significance for improving agricultural production efficiency and sustainable development.

Canavanine Content Quantification in Processed Bitter Vetch (Vicia ervilia) and Its Application as Flour in Breads: An Analysis of Nutritional and Sensory Attributes.

Bitter vetch (Vicia ervilia Willd.) is a traditional Mediterranean-West Asian legume, mainly used as livestock feed because of its toxic non-proteinogenic amino acid, canavanine. However, historical sources suggest its past human consumption. Currently, bitter vetch is a minor crop confined to marginal soils in semi-arid regions, presenting a potential alternative protein source amid projected climate changes. This study evaluated the nutritional and sensory attributes of bitter vetch seeds processed through various household methods. Germination and cooking significantly reduced the canavanine content by 28% and 60%, respectively. Incorporating bitter vetch flour (BVF) into wheat bread enhanced protein and fiber contents without substantially altering carbohydrate and lipid levels, and the baking process reduced the canavanine content by 40%. Bitter vetch flour enriched the bread with iron and calcium, contributing significantly to their daily nutritional intakes. Sensory evaluations indicated positive reception for bread with 12% BVF, achieving a balance between nutritional enhancement and consumer acceptance. This study identifies bitter vetch seeds as a valuable resource for improving bread formulations with corrected gluten contents and enhanced protein quality, as measured using protein-digestibility-corrected amino acid score (PDCAAS) values. With strategic processing and formulation adjustments, bitter vetch has the potential to re-emerge as a feasible high-protein grain crop, promoting sustainable farming.

Sorption of ciprofloxacin and enrofloxacin on alkaline cropland soil in semiarid regions: Roles of pH, ionic strength, and ion type

Animals manure and chemical fertilizers are widely applied to agricultural soils to mitigate soil fertility decline resulting from intensive farming practices. However, the use of antibiotics such as ciprofloxacin (CIP) and enrofloxacin (ENR) in these manures introduces certain environmental risks. The sorption of CIP and ENR in soil is influenced by various factors. Soil cations (i.e., Na+, K+, Mg2+, and Ca2+) and artificially introduced ions (NH4+) can affect the sorption behavior of CIP and ENR in alkaline agricultural soils through mechanisms such as ion exchange and competitive sorption. To investigate the effects of ionic strength and ion type on the sorption of antibiotics in alkaline agricultural soil, batch equilibrium experiments were conducted in this study. The results showed that the affinity of alkaline farmland soil to CIP and ENR was poor, and Kd was only 159 L/kg and 89 L/kg, respectively. Increases in temperature and pH inhibited CIP and ENR sorption on soil. Mineral elements in the soil strongly inhibited CIP and ENR sorption. Conversely, NH4+ promoted the Kd values of CIP and ENR by 46% and 221%, respectively. Additionally, under different influencing factors, both the sorption affinity (Kd) and sorption amount of ENR were lower than those of CIP. These findings indicate that ENR has a greater migration potential and poses a greater environmental risk in agricultural soils. Alkaline soil and mineral elements increase the migration potential of CIP, ENR, but the introduction of NH4+ in agricultural production can weaken the migration potential of them.

Exploring stress-tolerant plant growth-promoting rhizobacteria from groundnut rhizosphere soil in semi-arid regions of Ethiopia

ABSTRACT The potential of rhizobacteria with plant growth promoting (PGP) traits in alleviating abiotic stresses, especially drought, is significant. However, their exploitation in the semi-arid regions of Ethiopian soils remains largely unexplored. This research aimed to isolate and evaluate the PGP potential of bacterial isolates collected from groundnut cultivation areas in Ethiopia. Multiple traits were assessed, including phosphate solubilization, indole-3-acetic acid (IAA) production, ammonia production, salt and heavy metal tolerance, drought tolerance, enzyme activities, hydrogen cyanide production, antibiotic resistance, and antagonistic activity against fungal pathogens. The identification of potent isolates was carried out using MALDI-TOF MS. Out of the 82 isolates, 63 were gram-negative and 19 were gram-positive. Among them, 19 isolates exhibited phosphate solubilization, with AAURB 34 demonstrating the highest efficiency, followed by AURB 12. Fifty-six isolates produce IAA in varying amounts and all isolates produce ammonia with AAURB12, AAURB19, and AAURB34 displaying strong production. Most isolates demonstrated tolerance to temperatures up to 40°C and salt concentrations up to 3%. Notably, AAURB12 and AAURB34 exhibited remarkable drought tolerance at an osmotic potential of −2.70 Mpa. When subjected to levels above 40%, the tested isolates moderately produced lytic enzymes and hydrogen cyanide. The isolates displayed resistance to antibiotics, except gentamicin, and all isolates demonstrated resistance to zinc, with 81–91% showing resistance to other heavy metals. AAURB34 and AAURB12 exhibited suppression against fungal pathogens, with percent inhibition of 38% and 46%, respectively. Using MALDI-TOF MS, the promising PGP isolates were identified as Bacillus megaterium, Bacillus pumilus, and Enterobacter asburiae. This study provides valuable insights into the potential of rhizobacteria as PGP agents for mitigating abiotic stresses and contribute to the understanding of sustainable agricultural practices in Ethiopia and similar regions facing comparable challenges.

The Effect of Remediation of Soil Co-Contaminated by Cu and Cd in a Semi-Arid Area with Sewage Sludge-Derived Biochar

In this study, biochar derived from sewage sludge was applied to remediate Cu and Cd co-polluted soil in semi-arid areas for the first time, in which the effects of biochar on the improvement of soil physicochemical and biological properties as well as the immobilization of Cu and Cd were investigated. Soil water holding capacity increased by 0.22–2.74%, soil CEC increased by 0.52–4.06 units, soil SOM content increased by 1.41–5.97 times, and urease and catalase activities increased by 0.012–0.032 mg·g−1·24 h−1, 0.18–2.95 mg H2O2·g−1, but soil pH increased only slightly by 0.69 units after biochar application. In addition, although the total content of these two metals in the soil increased with the use of biochar, the content of DTPA-Cu and Cd decreased by −0.128–0.291 mg/kg, 0–0.037 mg/kg, with the increase in biochar application, and the content of acid-soluble Cu in the soil decreased from 27.42 mg/kg to 3.76 mg/kg, the mobility and bioavailability of these two metals in the soil decreased. Finally, the complexation of organic functional groups with the soil dominates the immobilization process of metals, especially Cu. These findings suggest that biochar from sewage sludge can effectively improve soil quality and remediate heavy metal-contaminated soils in semi-arid regions. Meanwhile, the use of sludge-based biochar for the remediation of contaminated soils also provides a new method for the safe disposal of sewage sludge and a new way for sustainable development. In subsequent studies, methods such as modification are recommended to improve the efficiency of sludge-based biochar for the removal of Cu and Cd.

Effect of Biochar Application on the Improvement of Soil Properties and Buckwheat (Fagopyrum esculentum Moench) Yield on Two Contrasting Soil Types in a Semi-Arid Region of Inner Mongolia

Biochar application to soil is widely recognized as a promising agricultural management practice to increase crop production by enhancing the physical, chemical, and microbiological properties of the soil. Despite the fact that numerous studies have investigated biochar production and alterations in soil properties, the effects of biochar on contrasting soils within the same region remain poorly understood, especially for semi-arid regions. Therefore, a three-year field experiment was initiated in 2020 wherein biochar was applied once to a buckwheat field at rates of 0, 20, 40, and 60 Mg ha−1 (BC0: no biochar; BC1: 20 Mg ha−1; BC2: 40 Mg ha−1; BC3: 60 Mg ha−1) for two soil types (aeolian sandy and grey meadow soil) in the northeast of Inner Mongolia, China. The soil water storage (SWS), nutrient contents (organic matter, available nitrogen, phosphorus, and potassium), microbial biomass (carbon, nitrogen, and phosphorus), and enzyme activities (urease, invertase, and alkaline phosphatase) were assessed at a soil depth of 0–15 cm as part of the soil quality assessment, and the buckwheat grain yield was estimated for crop productivity evaluation. The results showed that biochar amendment improved selected soil physicochemical and microbiological properties and buckwheat yields for both soil types. Compared to BC0, the biochar addition increased buckwheat yields, on average, by 11.23% to 22.82% in aeolian sandy soil and by 7.36% to 14.87% in grey meadow soil across three years. The results of principal component analysis (PCA) and random forest analysis (RFA) indicate that soil available nutrients and microbiological properties were the most important factors influencing buckwheat yields in aeolian sandy soil and grey meadow soil, respectively. Based on RFA, the available potassium, phosphorus, and nitrogen were found to contribute at rates of 13.10%, 10.06%, and 8.12%, respectively, to buckwheat yields in aeolian sandy soil. In contrast, alkaline phosphatase, urease, and microbial biomass carbon contribute 20.26%, 8.48%, and 7.82%, respectively, to the buckwheat yields in grey meadow soil. Following biochar addition, there was greater improvement in soil health and buckwheat production for aeolian sandy soil than grey meadow soil. In conclusion, biochar addition is an effective practice for improving soil health and crop productivity in both aeolian sandy soil and grey meadow soil in semi-arid regions.

Método sobol para análise de sensibilidade do modelo hydrus na simulação de infiltração de água em depósito aluvionar no semiárido brasileiro

ABSTRACT Simulation of water flow in the soil in semiarid regions is fundamental for managing scarce water resources. Aiming for more accurate results, the sensitivity analysis (SA) of the hydrodynamic parameters involved in the simulations is very relevant. This study aims to evaluate the influence of hydrodynamic parameters on the hydrological response of an alluvial deposit in the dry bed of the Capibaribe River using the Hydrus-1D. A global sensitivity analysis method proposed by Sobol was chosen to evaluate the sensitivity of the soil water infiltration curve. A convergence analysis was carried out to investigate the evolution of the indices with increasing sample size. Values of the sensitivity indices showed gross variations at the beginning of the simulations for the different parameters, but they converged within the set of 10,000 samples. For parameters whose sensitivity indices are closer to 0, it is noted that 1,000 samples (14,000 simulations) were sufficient for the index to converge to their final value. The total and first-order sensitivity index calculated with 10,000 samples present the parameters n and Ks as the most important, being expressly more influential than the others.

The effect of different fertilisers and planting patterns on the fatty acid profile of safflower oil

The soils of semi-arid regions have serious nutrient deficiencies, and it seems that the qualitative aspects of crops are strongly influenced by fertiliser management and planting patterns. The current experiment was carried out to evaluate the fatty acid composition of safflower oil under the application of different fertilisers (control, farmyard manure at 10 and 20 t ha–1, NPK (nitrogen, phosphorus, potassium), nano Fe+Zn) and four different planting patterns (planting in-furrow or on-ridge with inter-row distances of 40 cm or 60 cm) in the semi-arid region of north-western Iran (Maragheh). Results showed that all oil compositions significantly responded to fertiliser treatments. Utilisation of farmyard manure (FYM) increased seed oil content, and the highest oil content was recorded in planting on-ridge, which was 18% higher than the control condition. The highest percentage of seed protein was obtained by application of NPK and planting on-ridge with wider inter-row distance. Evaluation of saturated fatty acids (palmitic, stearic, myristic, lauric) showed that the application of high levels of FYM significantly increased these compositions. However, the effect of FYM20 application on main unsaturated fatty acids (linoleic acid) was much more evident, and it increased iodine value. Taken together, the results of this study indicated a positive and significant effect of the application of high levels of FYM in on-ridge planting with wider row spacing on the qualitative and nutritional aspects of safflower oil.

Impact of deeper groundwater depth on vegetation and soil in semi-arid region of eastern China.

Understanding the impact of deep groundwater depth on vegetation communities and soil in sand dunes with different underground water tables is essential for ecological restoration and the conservation of groundwater. Furthermore, this understanding is critical for determining the threshold value of groundwater depth that ensures the survival of vegetation. This paper was conducted in a semi-arid region in eastern China, and the effects of deep groundwater depth (6.25m, 10.61m, and 15.26m) on vegetation communities and soil properties (0-200 cm) across three dune types (mobile, semi-fixed, and fixed dunes) were evaluated in a sand ecosystem in the Horqin Sandy Land. For vegetation community, variations in the same species are more significant at different groundwater depths. For soil properties, groundwater depth negatively influences soil moisture, total carbon, total nitrogen, available nitrogen, available phosphorus concentrations, and soil pH. Besides, groundwater depth also significantly affected organic carbon and available potassium concentrations. In addition, herb species were mainly distributed in areas with lower groundwater depth, yet arbor and shrub species were sparsely distributed in places with deeper groundwater depth. As arbor and shrub species are key drivers of ecosystem sustainability, the adaptation of these dominant species to increasing groundwater depth may alleviate the negative effects of increasing groundwater depth; however, restrictions on this adaptation were exceeded at deeper groundwater depth.

Assessment of soil vulnerability to erosion in different land surface configurations and management practices under semi-arid monsoon climate

Soil erosion leads to reduction in land productivity. Concentrated rainfall under monsoon climate increases the erosion vulnerability of poor soils of semiarid regions. Soil vulnerability is the response to impact of slope and land management practices. Assessment of soil vulnerability to soil erosion is crucial for devising an effective soil conservation plan. Therefore, a 7-year long experiment has been initiated for assessing vulnerability to soil erosion for a sandy loam soil using Pearl millet (Pennisetum glaucum) as the test crop in a typical semiarid monsoon climate. In case of runoff, samples were collected and measured every 24 h. These samples were analyzed for sediment, clay, organic carbon (OC), and nitrogen content. A positive linear relation between rainfall and runoff at 2% slope (R2: 0.58–0.72), curvilinear relation at higher slope (R2: 0.81–0.86), and positive linear relationship between runoff and soil loss (R2: 0.47–0.64) were observed. An increase in slope length from 11 to 66 m increased runoff and soil loss by 1.62 times and 1.72 times, respectively. Similarly, an increase in slope steepness from 2% to 9% increased runoff and soil loss by 1.84 times and 3.84 times, respectively. In response to the 56.4% of the total rainfall received, the contribution of runoff and soil loss during the initial 30 days of the crop growing period to the total runoff and soil loss was 68–74% and 80–90% respectively. Sediments were enriched with organic carbon (1.62–3.12) and clay content (1.14–1.55), however, enrichment ratios reduced with the increase in slope. The total loss of nitrogen through erosion had a positive correlation with the sediment loss. Manure and mineral fertilizer application in pearl millet reduced the mean seasonal runoff by 14.4–24.8% and soil loss by 22.7–32.6%. Under bare soil conditions, application of manure and fertilizers reduced runoff by 6.4–8.7% and soil loss by 6.5–7.8%. The knowledge derived from this study can thus improve our understanding of hydrological responses and erosion process of both land configuration and land management practices. The data generated in the study is an important starting point to develop concepts for better management and effective mitigation of land degradation. The findings also suggest the need of initial soil cover, minimum soil disturbance at steeper slope (>3%) and need of conservation measures even on the milder slope (≤ 3%).

Effects of Tillage Systems on the Physical Properties of Soils in a Semi-Arid Region of Morocco

Climate change, drought, erosion, water contamination resources, desertification, and loss of soil quality represent major environmental risks worldwide. Facing these risks is the most important issue for sustainable development. Conventional tillage (CT) practices seem to expose the soils of semi-arid regions, which are initially fragile, to degradation that is accentuated by the overuse of the environment. The benefits of conservation agriculture (CA) could mitigate the degradation of natural resources, particularly soils. The adaptation and transfer of the no-till (NT) system with mulch open new perspectives for the development of agriculture in semi-arid regions. The main objective of this study is to assess the impact of conservation agriculture, especially no-till (NT) system, on the physical properties of soil (structural stability (SS), bulk density (BD), gravimetric water content (θg), and soil organic matter (SOM)) compared to conventional tillage (CT). The main changes associated with the transition from a CT system to an NT system were evaluated at the experimental site, Merchouch (M13), which is typified by vertisol soil, and at the Ain Sbit (AS7) site, which is characterized by isohumic soil. Under a no-till system, most of the physical properties of the soil were improved in both sites, with a clear difference in the M13 site. Structural stability under NT showed a significant increase in both sites (fast wetting (FW), slow wetting (SW), and wet stirring (WS) improved by 88, 43, and 83% at the M13 site, respectively, against, 16, 23, and 7%, respectively, at the AS7 site). On the other hand, the SOM increased from 2.0 to 2.6% (an improvement of 28%) at AS7 and from 1.2% to 1.9% (an improvement of 52%) at M13. This research demonstrated that conservation agriculture, especially NT, improves the soil physical quality in both medium and long terms, confirming its suitability for the climatic and edaphic constraints of semi-arid areas in Morocco as well as in other parts of the world.

Clean application of pistachio residues-based vermicompost with γ-aminobutyric acid can alleviate the negative effects of high soil pH on P uptake in saffron (Crocus sativus L.)

In semiarid areas dominated by calcareous soils, a large portion of available P may be deformed into insoluble structures due to the chemical activity of carbonate compounds. This phenomenon, known as P deficiency stress, is considered one of the most important limiting factors for saffron (Crocus sativus L.) production. To avoid P limitation, the application of clean and practical techniques has been emphasized to improve saffron adaptability grown in P-deficient calcareous soils. Hence, field experiments were conducted based on a factorial randomized complete block design with three replicates during 2017–2018 and 2018–2019 (farm 1) and repeated during 2018–2019 and 2019–2020 growing seasons (farm 2). Four levels of γ-aminobutyric acid (GABA) (0, 0.5, 1, and 2 mg L−1) and soil amendments (control, pistachio residues-based vermicompost (VP: 10 t ha−1; 50% in each growing season), sulfur (S: 100 kg ha−1; 50% in each growing season), and VP +S) were considered as experimental factors. From the results, application of VP, S, and VP+S decreased soil pH and increased Olsen-P, microbial biomass, and microbial respiration. Furthermore, the increase was observed for flower number, proline content and corm growth. Following GABA foliar application, flower number, proline content and P availability improved. Compared to control treatment, P concentration in large-sized daughter corms increased by 23.6, 16.8%, and 30.8%, following VP, S, and VP +S, respectively. Among the treatments, the highest P acquisition efficiency (39.2%) were recorded by applying VP +S along with 2 mg L−1. Overall, the results recommend the co-application of VP with GABA foliar spray to improve saffron production grown in calcareous soils of semiarid regions.

Risk of Salinization in the Agricultural Soils of Semi-Arid Regions: A Case Study from Moldavian Plain (NE Romania)

In the present study, the salinization trends of different soil types from a small hydrographic basin situated in NE Romania (Roșior basin) are investigated. The climatic conditions are favorable for long dry summers and intensive evaporation. The soils are developed on immature evolved clay sediments, as revealed by geochemical analysis. The salinity varies among soil types, attaining maximum values for Solonetz with total dissolved salts (TDS) between 1165.75 to 1881.25 mg/L. The aqueous solutions are represented by natural water and soil solution. The hydrogeochemical facies of the natural waters change from HCO3−—Mg2+ in the upper basin to SO42−—Na+ in the middle or lower basin. The soil solution is moderately or strongly salinized and shows anionic variations from HCO3− to SO42− in the studied profiles, whereas Na+ is always the main cation. The concentrations of Na+ and SO42− evolve simultaneously. Raman spectroscopic exploration of the white efflorescences, which occur on topsoil, reveals the presence of thenardite as the dominant phase. The composition of soil solution results from both the ionic exchange and evaporation processes. The nature of soil solution mineralization and summer temperatures are two main factors that interact and promote the thenardite precipitation. The soil salinization induces negative effects on crop nutrition, impacting further the crop yields. The results of this study can be extrapolated to larger areas formed on Sarmatian sedimentary deposits affected by salinization processes.

Enrichment Factors, Health Risk, and Source Identification of Heavy Metals in Agricultural Soils in Semi-arid Region of Hainan Island

To understand the enrichment factors and pollution levels of heavy metals in agricultural soils in the semi-arid region of Hainan island, 1818 surface soil samples were collected in Gancheng Town and analyzed for their heavy metal contents and physicochemical composition. Correlation analysis was used to determine the heavy metal enrichment factors. The geo-accumulation index (Igeo), comprehensive ecological risk index (RI), and hazard index (HI), as well as carcinogenic risk (CR), were used to assess the degree of pollution and health risk. Positive matrix factorization (PMF) was used to determine the primary sources of pollution and priority sources. The average values of heavy metal contents in the topsoil were 22.7, 0.128, 33.4, 14.5, 0.032, 9.32, 32.5, and 43.3 mg·kg-1 for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively. With the exception of Zn, the concentrations of other heavy metals in the topsoil were higher than the soil background values of Hainan, showing different degrees of heavy metal accumulation effect. The Igeo revealed that the major pollutant element in soils was As, followed by Cd and Cu. The RI showed that the proportion of soil samples that were high-risk level or worse was 29.4% of the total number of samples, among which As was the major source of risk. The health risk assessment results indicated that As, Cr, and Ni exposure presented carcinogenic risk for children with high CR values. Based on PMF, four major sources of heavy metals were identified in the study area. Hg was derived mainly from industrial sources, and As was closely associated with agricultural activities. Ni, Cu, Cr, and Zn were related to soil parent materials. Pb and Cd were associated with agricultural activities and traffic emissions. The PMF models combined with correlation analysis were useful for estimating the source apportionment of heavy metals in soils.

Nitrogen enriched chemically produced carbon supplementary impacts on maize growth under saline soil conditions

Poor organic matter and nitrogen (N) deficiency along with salinity in arid and semiarid region soils are major hurdles to optimization of cereal's yield. In different cereals, maize productivity is significantly decreased due to less availability of N in low organic matter soils. Scientists suggest the incorporation of organic fertilizers to overcome this issue. That’s why the current study was conducted to explore the effectiveness of chemically produced nitrate blended acidified carbon (NBC). There were 3 levels of NBC i.e., 0, 0.50 and 1.00% applied under naturally normal and saline soils having EC 2.75 and 6.19 dS/m respectively. Results showed that the addition of 1.00NBC was significantly better compared to 0NBC for improvement in maize growth attributes i.e., root (32.86 and 77.84%) and shoot (74.17 and 67.57%) length, shoot fresh (53.98 and 97.42%) and dry weight (53.20and 84.20%), root dry (45.97 and 53.66%) and fresh weight (45.62 and 25.14%) in normal and saline conditions respectively. A significant enhancement in chlorophyll a, b, total and carotenoids of maize leaves also validated the imperative role of 1.00NBC than 0NBC in saline and normal soil. Application of 1.00BC also significantly decreases leaves electrolyte leakage and Na concentration in root and leaves over 0NBC in saline soils. In conclusion, 1.00NBC is an effective amendment to improve maize growth in saline soil. More investigations are suggested on different cereal crops under variable agroclimatic zones to declare 1.00NBC as the most effective amendment for alleviation of salinity stress.

Phosphorus in alkaline soils of the semiarid region, Brazil: inorganic fractions, capacity factor, and availability

The study was designed to quantify the contents of Pi fractions and correlate them with the P capacity factor of soils in the Brazilian semiarid region. We also evaluated the effect of soil P doses contact time and P availability for maize plants in alkaline soils of the Brazilian semiarid region. Soil samples were collected between the Piranhas-Açu (RN) and Jaguaribe (CE) rivers valleys. The maximum phosphate sorption capacity was highly correlated with the values of remaining P, indicating that it can be used as a measure to estimate the P capacity factor of these soils. Maximum P sorption capacity correlated with Fe2O3 and Ca2+ contents and pH values. These results demonstrate that P sorption is explained by P adsorption on the surface of iron oxides and by its precipitation with Ca2+ in alkaline soils. The contact time increases promote plant P contents decreased substantially in the first 30 to 60 days after fertilization and decreased until 120 days of incubation but then tended to stabilize at the longest soil P contact times.

Integrated Nutrient Management Fostered Economic Yield and Bioactive Principle of Medicinal Herb (Cassia angustifolia Vahl.) in Saline Soil of Semi-Arid Region of Western India

ABSTRACT In this investigation, cultivation of an economically important medicinal plant (Senna, Cassia angustifolia Vahl.) was explored in saline soil for improving productivity and quality through effective nutrient management practices. Field experiments were conducted in two consecutive growing seasons in saline soils of semi-arid region, where recommended dose fertilizer (RDF) supplied through organic (vermicompost) and inorganic (chemical) source alone or in combination with local microbial consortia (MC). Plant growth and nutrition significantly improved due to integration of organic and inorganic fertilizer alone or in combination with MC. The results also reflected in economic yield (leaf + pod) of senna where 29–37% increase in leaf and 57–76% increase in pod yield was recorded over control. The results revealed that integration of organic and chemical fertilizer along with MC recorded significant higher leaf (1682 kg ha−1) and pod (488 kg ha−1) yield as compared to the other treatment. Sennocide content in leaf and pod was significantly improved by organic as well as integrated application of organic and inorganic fertilizer. However, the highest sennocide content in leaf (2.81%) and pod (3.11%) was recorded in integrated application of organic fertilizer and MC. Additionally, integrated application of organic and chemical fertilizer was found effective in restoring organic carbon, increasing the amount of available nutrients (N, P, and K), and enhancing the biological activity of the saline soil. Therefore, integration of organic and chemical fertilizer as well as MC has potential to improve yield and quality of senna through enhanced soil fertility and biological function.

Effects of irrigation water quality and NPK-fertigation levels on plant growth, yield and tuber size of potatoes in a sandy loam alluvial soil of semi-arid region of Indian Punjab

Management of saline water through desalination or blending with low salinity canal water may be a viable strategy for potato irrigation in semi-arid regions having saline ground water and scarce canal water. A 4-year study was conducted to investigate the effects of four water qualities [canal water (CW), desalinated water (DSW), saline ground water (GW) and mixed water (MW) (CW + GW)], three N-P-K-fertigation levels [F100 = 100% NPK (190, 28.4 and 53.9 kg ha−1 of N, P and K, respectively), F80 = 80% NPK and F60 = 60% NPK] and their interaction on the performance of two potato varieties grown in a sandy loam alluvial soil of semi-arid region. The electrical conductivity (EC) of CW, DSW, GW and MW ranged from 0.3 to 0.4, 0.2–0.3, 3.2–4.2 and 1.8–2.2 dS m−1, respectively. Drip irrigation with GW resulted in 21–44% reduction in total tuber yield compared with CW, however, the maximum reduction (54%) was observed in grade-A tuber yield that was accompanied by a considerable increase in grade-C tuber yield. Irrigation with MW increased total tuber yield by 9–37% compared with GW. Irrigation with DSW manifested a 41% and 14% increase in total tuber yield as compared with GW and MW, respectively. The tuber yield obtained with MW was comparable with DSW up to soil EC1:2 of 0.65 dS m−1, and beyond that level, DSW was observed to be superior. The variety ‘Kufri Surya’ had slight yield advantage over ‘Kufri Pukhraj’ when CW, DSW and MW were used, however, yields of both varieties were statistically at par under GW irrigation. The variety ‘Kufri Jyoti’ exhibited a 13–22% yield advantage over ‘Kufri Surya’ for all irrigation water qualities. Plant growth and yield attributing parameters were the highest at F100 which declined progressively with a decrease in fertigation level for all water qualities. However, these differences were narrow between GW and MW and moderate between CW and DSW. Therefore, in drip fertigated potatoes using saline or mixed water in a sandy loam soil, it is advocated to use 80% of recommended NPK without any loss in tuber yield and to reduce cost of cultivation & environmental pollution.

Controlled nitrogen transformation in chemo-amended urea improves nitrogen use efficiency and productivity of wheat grown on alkaline calcareous soil.

Low wheat production is linked to soil degradation, low organic matter, temperature variation, and nutrient depletion in soils of semiarid regions. Nitrogen is mostly applied as urea to meet crop requirements; however, excessive N application may pollute the environment and contaminate groundwater. The current studies explored possible ways for decreasing N losses (NH3 volatilization and NO3 leaching) and improving N availability for wheat production in alkaline soil. The ZnO was coated on urea (1% Zn coating) to get zinc-coated urea (ZnU), and both urea and ZnU were incubated in laboratory at recommended rate (RR), i.e., 150kgNha-1 and 80% (N of RR), after further coating with inhibitors [N-(n-butyl) thiophosphoric triamide (NBPT) at 1% of urea and 4-amino-1,2,4-triazole (ATC) at 2% of urea], thus creating six treatments. The results showed higher NH3-N loss at day 4 and thereafter a decreasing trend reaching to minimum at day 14. The cumulative NH3-N volatilization from urea alone was found higher (28.99%), except ATC treatments producing statistically similar losses due to restriction in nitrification process. In greenhouse, the treatments were tested in wheat cultivars (Faisalabad 2008 and Lasani) for crop growth, nutrient (N, P, K, and Zn) uptake, and yield parameters, where 80% of RR treatment, i.e., NBPT + ZnU80, was found at par with full RR as commercial products, especially comparable to ZnU (at RR) that produced the highest chlorophyll (53.65unit value), net leaf photosynthetic rate (19.64μmol CO2 m-2s-1), plant biomass (208.13g/pot), grain yield (63.65g/pot), and nutrient (NPK and Zn) accumulation in grain of Fsd-2008 cultivar. In field trial, NBPT + ZnU80 also outperformed and produced the highest physiological efficiency (PE), agronomic efficiency (AE), and nitrogen recovery efficiency (REN); the treatment also found statistically similar with ZnU (at RR) that produced the maximum plant height (95.4cm), plant biomass (11.58 t/ha), grain yield (4.69 t/ha), and 1000-grain weight (42.55g). The relative NO3 leaching was found lower in 80% N treatments, yet leaching was not significant from either treatment at the three stages of crop growth. Overall, current studies revealed the effectiveness of NBPT-amended urea (followed by ZnU) with 20% saving of N inputs through higher N availability for plant uptake that could benefit growers as well as conserve environment.

Biochemical phosphorus transformations in a calcareous soil as affected by earthworm, cow manure and its biochar additions

Application of raw or char material may modify the influence of earthworm activity on soil phosphorus (P) transformation. The purpose of this study was to investigate the effect of cow manure or cow manure biochar addition and its interaction with earthworm on organic (Po) and inorganic (Pi) P fractions, alkaline phosphatase activity and P-solubilizing bacteria (PSB) in a calcareous soil of semi-arid region. For this purpose, the soil was amended with cow manure and its biochar in 4 levels (0, 1, 2 and 5%) in the absence and presence of earthworm (Eisenia fetida). The treatments were then incubated for 90 days. The monitoring of earthworms was also carried out after 30 and 90 days incubation. The results showed an increase in weight of earthworms in control and cow manure amended soils at both incubation times. However, application of cow manure biochar resulted in mortality and an initial weight loss of earthworms (36–85%) at 30 days incubation. This negative effect decreased over time, so that the earthworms recovered in 1% biochar amended soil. Amendment additions increased proportion of NaHCO3-Pi and NaOH-Pi but decreased proportion of HCl-Pi, residual-P, NaOH-Po and HCl-Po, making P more available in soil. The impact of cow manure biochar on the NaHCO3-Pi and NaOH-Pi fractions was stronger than that of cow manure. Earthworm decreased the proportion of Pi fractions but increased the proportion of Po fractions, indicating a transformation of P from Pi to Po forms. Alkaline phosphatase activity and PSB number were also increased as affected by earthworm and amendment (especially cow manure) additions. No significant interaction between earthworm and amendment additions was observed (p < 0.05), indicating that the influence of earthworm on P transformations was not dependent on amendment additions. Overall, we concluded that biochar can be useful for the amendment of semi-arid calcareous soil in terms of P availability, but the negative response of earthworms to biochar and its effect on other soil processes should be taken into consideration.