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This research was conducted to assess the influence of long-term tillage system on soil organic carbon, microbial biomass carbon, root biomass and crop yield in spring wheat-field pea rotation fields in a rainfed semi-arid environment from 2013 through 2015. The treatments were; conventional tillage with stubble removed (T); no-till with stubble removed (NT); no-till with stubble retained (NTS) and conventional tillage with stubble incorporated (TS) arranged in a randomised complete block design with three replicates. The soil organic carbon in NTS increased by 16% and 14% over T and NT. Compared with the T and NT, NTS increased soil microbial biomass carbon by 42% and 38% in 0-30 cm depth, respectively. Root biomass was significantly increased in NTS by 47% and 54% over T and NT, respectively. Across the three years, NTS had an average grain yield of 53% and 41% higher than T and NT, respectively. Compared with NTS, T and NT decreased root biomass by 54% and 48%, respectively. In view of the limited and erratic biomass production in this region, integration of no-till with straw mulching is recommended for soil fertility improvement, environmental quality and sustainable crop production.

Balancing the use of maize (Zea mays L.) residues for soil amendment and forage is an important strategy for agricultural sustainability. Therefore, the study assessed the impacts of four proportions of maize residues to soil retention (S) and forage (F) on soil total organic carbon (TOC); total nitrogen (TN); carbon/nitrogen ratio (C/N); grain yield, economic benefits and nutritional contents of removed residues. The concentrations of TOC and TN increased when more residue returned, while the C/N ratios were S₁₀₀ + F₀ > S₃₄ + F₆₆ > S₆₆ + F₃₄. Also, crude protein, crude fat, and crude starch in the removed residues were F₃₄ > F₆₆ > F₁₀₀, while the crude fiber and ash contents exhibited the opposite trend. The crop yield improved with residue retention increased, but there were no differences on the economic benefits of the four residue-use systems. The S₃₄ + F₆₆ system maintained a TOC ranging from 11.51 to 13.37 g/kg, a TN from 1.12 to 1.16 g/kg, 92.93% of the annual yields of the S₁₀₀ + F₀ system, and 6.2 t/ha/year of forage. Therefore, the S₃₄ + F₆₆ system can balance the use of maize residues for soil amendments and forage to sustainably develop a household crop-livestock system.

The effect of organic, mineral and combined organic and mineral fertilization of soils on the winter wheat yields and nutrient contents in soils was evaluated in long-term field experiments. Two sites with different soil characteristics were evaluated - Lukavec u Pacova (cambisol) and Ivanovice na Hané (degraded chernozem). The type of fertilization influenced wheat yields. Nutrient uptake by winter wheat was higher under nitrogen (N) fertilization, which resulted in a negative balance of phosphorus (P) and potassium (K) and to a decrease of nutrient contents in the more fertile soils at Ivanovice na Hané. Two soil tests (Mehlich 3 method and NH₄-acetate method) were used to determine P and K availability. The mineral nitrogen fertilization negatively and significantly affected NH₄-acetate extractable concentrations of nutrients in the soils and these were lower in comparison with concentrations of P and K determined by Mehlich 3 method. Relative availability of P in alkaline soils from Ivanovice treated with mineral N increased while the soil pH decreased.

The 28-day incubation experiment was carried out to evaluate the impact of the application of digestate (Dig); digestate with straw (DigSt); pig slurry (Slu) and mineral fertilizer (NPK) on Cd, Cu, Mn and Zn availability, on K₂SO₄-extractable carbon content and on the soil pH value in long-term contaminated soil. At days three and seven of the experiment, the 0.01 mol/L CaCl₂-extractable fractions of Cd, Zn and Mn significantly decreased under organic treatments (Dig, DigSt and Slu) with the most pronounced effect under Dig treatment. The NPK treatment caused the increase of risky element concentrations since day 21 of incubation which was accompanied with pH decrease. The contents of 0.5 mol/L K₂SO₄-extractable carbon were the highest at day 3 and 7 of incubation in organic treatments. The significant correlations between 0.5 mol/L K₂SO₄-extractable carbon and CaCl₂-extractable metal concentrations showed a close relationship between fresh organic matter added in organic fertilizers and risky element availability, suggesting that newly added labile organic matter can form temporary ligands with risky elements and release them later following its decomposition.

Influence of the nitrogen injection fertilization 'controlled uptake long term ammonium nutrition' (CULTAN) on winter rape yield and seed composition was studied in 2009 and 2010 at two sites with different soil-climatic conditions in the Czech Republic. Two conventional treatments consisted of fertilization using the system of divided doses applied on soil surface. Two CULTAN treatments used injection fertilization with the whole dose of nitrogen applied once in the vegetation period, in early spring at the BBCH 26 stage (6 side shoots detectable). The trial compared conventional and CULTAN treatments. The overall dose of nitrogen was 200 kg N/ha in each treatment. The seed yield in a two-year average was 4.83 t/ha at conventional and 4.80 t/ha at the CULTAN treatment. This difference was not statistically significant. The higher nitrogen content in seed was recorded mainly at CULTAN treatments at the Hněvčeves site in 2009. An inconclusively higher phosphorus content was recorded in winter rape seed fertilized with the CULTAN method at both sites in 2010. Content of K, Ca, Mg and S did not show statistically significant differences between the two treatments during both experimental years. In oiliness no differences between conventional and CULTAN methods were observed.

Cereal/legume intercropping may improve resource use efficiency in agroecosystems and increase yield per unit surface area and yield stability. Two field bean (Vicia faba L.) and four barley (Hordeum vulgare L.) cultivars were mono- and intercropped (additive design) in a 2-year lysimeter experiment on a sandy loam soil. The aim was to test the effect of the cropping system on dry matter and N yield of forage, the residual effect on the subsequent ryegrass crop (Lolium multiflorum Lam. westerwoldicum), and NO₃-N leaching in the rotation. Land equivalent ratios were 1.65 for dry matter and 1.67 for N yield, indicating a clear advantage of the intercrop over sole crops. Both species suffered from competition, especially in terms of N resources, but barley was less affected. Nitrate leaching was the lowest from intercrop. Preceding crop significantly affected dry matter, N content and NO₃-N leaching of ryegrass. Field bean sole crop gave the highest benefits to ryegrass in terms of forage dry matter and N content, but also the highest NO₃-N leaching, followed by the intercrop and the barley sole crop. Barley/field bean intercropping may be an effective strategy to reduce land requirements, N leaching losses and fertilizer inputs, thereby increasing the sustainability of farming systems.

The field experiment with different soil tillage treatments has been carried out in Prague-Ruzyně locality (Czech Republic) since 1995. Data of two growing cycles in the years 2007-2010 and 2011-2014 were evaluated. Tillage technique was decisive for changes in soil characteristics and crop yields. Bulk density, organic carbon (C_org) and microbial biomass C (C_mic) were more equilibrated throughout all tested soil layers (0-0.1; 0.1-0.2 and 0.2-0.3 m) in conventional tillage (CT). In reduced tillage (RT) and no-tillage (NT) treatments significant accumulation of C_org and increase of C_mic in the surface layer were found, compared to CT. No significant differences in C_org and C_mic between two growing cycles were determined; however, mostly higher values were obtained in the top layer of NT during the second growing period. Higher bulk density under conservation tillage techniques did not negatively affect soil characteristics and should be taken in consideration for data evaluation as it can alter interpretation of their changes in the soil profile. Crop yields were comparable in CT and RT. Yield decrease in NT was mostly observed for winter wheat and pea. Beneficial effects of RT and NT conserving soil moisture on crop yield were not observed in dry years.

The paper presents results of 3-year field studies carried out in a split-block design in four replications in the years 2012-2014 at the Agricultural Experiment Station in Mochełek (Poland). The effect of intensification of cultivation technologies on the yield of morphologically diversified cultivars of white (Lupinus albus), yellow (L. luteus) and narrow-leafed lupin (L. angustifolius) was examined. Traditional cultivars of white and yellow lupin gave significantly higher yields than the self-completing ones, as opposed to narrow-leafed lupin in which the self-completing cultivar had higher yields. Increasing expenses on industrial production means caused an increase in the yield of all the studied species. Seed yield of white and narrow-leafed lupin was significantly the highest in high-input technology, while that of yellow lupin in high- and medium-input technology. In all lupin species, insignificant diversification was observed in the number of pods per plant in medium- and high-input technologies as well as in low- and medium-input technologies. A significant increase in the seed yield along with an increasing intensity of the cultivation of traditional and self-completing cultivars of white and yellow lupin, as well as self-completing cultivars of narrow-leafed lupin, resulted mainly from developing a higher number of pods.

We aimed to evaluate the extractability of different extractants for zinc (Zn) and copper (Cu) in soils of long-term field experiments covering different agro-ecological zones of India. The relationships between the amounts of Zn and Cu extracted by Mehlich 3, 0.1 mol/L HCl and AB-DTPA (ammonium bicarbonate-diethylenetriaminepentaacetic acid) with those extracted by DTPA, the conventional extraction method widely used in soil testing laboratories in India, were elucidated. The treatments of the long-term experiments included control (no fertilizer), 100% NPK, 50%NPK + 50% N through FYM (farm yard manure) and a fallow soil. Some important physico-chemical properties of soil like pH, organic carbon, textural class, CaCO₃ content, etc. were analyzed. The NPK + FYM treatment was found to be the most effective treatment in terms of increased content of Zn and Cu in soils. The results showed that the amount of Zn and Cu extracted by Mehlich 3 were significantly correlated with that extracted by 0.1 mol/L HCl (r = 0.970** for Zn and r = 0.914** for Cu). Accordingly, Mehlich 3 and 0.1 mol/L HCl could be used effectively for estimating Zn and Cu availability in soils of India. However, Mehlich 3 was superior to all the other extractants used for the study.

This study investigated the combined effects of drip irrigation and mulches on yield, water-use efficiency and economic return of tomato. The treatments of the study comprised different combinations of three drip irrigation levels (100, 75 and 50% of crop water requirement, ETc) and two mulches (black polyethylene sheet and paddy straw). The yield and yield-contributing characters in the mulched treatments for all levels of irrigation were significantly higher compared to those in the unmulched treatments. The yield of tomato increased with the increasing amount of irrigation water in unmulched treatment. The trend was reversed when drip irrigation was coupled with mulches. The highest yield for each mulch (81.12 t/ha for polyethylene and 79.49 t/ha for straw) was obtained when 50% of water requirement was applied. With 100% water application, polyethylene-mulched treatment produced lower yield than the straw-mulched treatment. The highest water use efficiency of 592 kg/ha/mm was obtained with 50% water application under polyethylene mulch. The highest net return (US$ 7098/ha), incremental net return (US$ 1556/ha), and incremental benefit-cost ratio (7.03) were found for 50% water application with straw mulch. The study thus reveals that drip irrigation with mulch has an explicit role in increasing the land and water productivity of tomato.

Based on a long-term fertilization experiment on a light soil, a study was conducted on the impact of varied fertilization on the levels of silicon forms available in the soil. It was shown that the exchangeable silicon content in the tested soil was very low, which can have a limiting effect on crop yields. Soil pH is a factor that significantly affects the exchangeable silicon content of the soil. Therefore, under the conditions of acidic soils, liming is a treatment that increases the level of silicon forms available to plants in the soil.

Low application of fertilizer potassium (K) in intensive agriculture leads to a gradual decrease and, afterwards, to a steady state of soil K determined by tests which are based on soil exchangeable K (K_exch) extraction. In this situation, non-exchangeable K (K_non-exch) is being released and therefore real plant availability does not necessarily correspond to soil test K. This incoherency was investigated in 14 agricultural soils with low K as determined by the Mehlich 3 method. Plant-available K released by exhaustive cropping of perennial ryegrass and K determined by the Neubauer seedling test were compared with 8 soil K extraction methods, with the total K content and with the relative content of soil K-bearing minerals. K determined by the ryegrass test (314 mg/kg on average) was more than 3-times higher than K based on K_exch extraction methods, but was from 2 to 3 times lower than K determined by K_non-exch extracting methods. The relative content of mixed-layer phyllosilicates was significantly related to K extracted by soil tests. The relative content of orthoclase correlated only with total K and mica-group minerals with none of the extractions. The best prediction of plant-available K in investigated soils was obtained with sodium tetraphenylboron and StepK methods.

Chlorine, one of the most abundant elements in nature, undergoes a complex biogeochemical cycle in the environment, involved in the formation of volatile organochlorines (VOCls), which in turn can contribute to environmental problems, contaminate natural ecosystems, and are of public health concern. Several industrial and natural sources of VOCls have already been identified; however, data - particularly on the natural sources - are still scarce. The aim of this study was to investigate the diversity of emission of VOCls from soil and several undergrowth plants collected in temperate spruce forest ecosystem and the effect of salting on the VOCl emission of plants. Undergrowth plants were found to emit chloroform (CHCl₃) in the range of 2.2-201 pmol/day/g dry weight (DW), tetrachloromethane (CCl₄) 0-23.5 pmol/day/g DW, and tetrachloroethene (C₂Cl₄) 0-13.5 pmol/day/g DW; the average emission rates were about 10 times higher than that of soil (2.9-47.2; 0-5.8; 0-3.6 pmol/day/g DW of CHCl₃; CCl₄; C₂Cl₄ emission, respectively). Addition of sodium chloride solution in most cases caused an increase in the emission of CHCl₃ and caused a species specific - effect on the emissions of CCl₄ and C₂Cl₄. The results suggest that the emission of VOCls from spruce forest contribute to the atmospheric input of reactive chlorine; however, on a global scale it is only a minor net source.

The aim of this study was to determine the effect of sulphur (S) fertilization on macronutrient concentrations in the roots, straw and oil cake of white mustard and Indian mustard. The experiment was conducted in northeastern Poland (2006-2008). The highest content of N, P, K, Mg and S was noted in the oil cake of both mustard species. Sulphur fertilization increased S concentrations and had no effect on Mg concentrations in the roots of white mustard and Indian mustard. Sulphur fertilizers applied to soil significantly increased the content of N, K and Ca in the roots of Indian mustard, whereas they had no significant effect on the content of N, P and Ca, and decreased K concentrations in the roots of white mustard. Sulphur fertilization led to a significant decrease in N content, and an increase in the content of K and Ca in the straw of both mustard species. Sulphur fertilization significantly decreased P concentrations and increased S concentrations in the oil cake of both mustard species. In response to S fertilization, the content of N and K decreased in the oil cake of Indian mustard, but did not change significantly in the oil cake of white mustard. Therefore, S fertilization significantly differentiated the fertilizing value of post-harvest residues and the feeding value of white mustard and Indian mustard seeds.

This study compares the effect of application of digestate, straw, cattle slurry and inorganic fertilizers on crop yield and soil organic matter content. Total organic carbon (C), total organic nitrogen (N), hot water soluble C, microbial biomass C and hydrophobic soil components were evaluated in soil from the field experiment in Prague-Ruzyně (Orthic Luvisol, clay loam) with winter wheat. All fertilized treatments significantly increased grain yield above the level of non-fertilized control (5.68 t/ha), and the sequence was as follows: digestate (9.88 t/ha) > NPK(9.80 t/ha) > cattle slurry (9.73 t/ha) > digestate + straw (9.35 t/ha). Average organic C content in the soil ranged from 1.668-1.704% and the effect of different fertilization was not significant. The highest increase of microbial biomass C was recorded in digestate + straw (43.2% increase compared to control). Highly significant correlations were found between hydrophobic soil components and hot water soluble C (r = 0.988; P ≥ 0.05) and microbial biomass C (r = 0.964; P ≥ 0.05). Total organic N content ranged from 0.157-0.160% and differences among treatments were insignificant. Fertilization with digestate itself brings an effect in increasing crop yield, but does not improve the level of soil organic matter significantly.

This study was aimed to determine the impact of risk element content on the prevalence of the selected microbial groups in industrial soils of one of the steelworks in Poland. The concentration of heavy metals: Cd, Cr, Cu, Hg, Fe, Ni, Pb and Zn along with soil pH and the number of mesophilic bacteria, fungi, actinomycetes and Azotobacter was assessed in 20 soil samples. The limit concentrations of Cd, Pb and Zn were exceeded in five sites. However, even in these strongly contaminates sites, the studied microorganisms were abundant. The correlation between the concentration of heavy metals and microbial numbers was very weak and statistically insignificant. High numbers of fungi were observed in the contaminated sites, which was particularly interesting in one of the sites, strongly contaminated with Cd, Pb and Zn.

Long-term field experiments are important for assessing the yield response of crops to different tillage systems and pre-crops. An experiment was established in 1996 in Raasdorf (Austria) on a chernozem with four tillage treatments (mouldboard ploughing (MP), no-till (NT), deep conservation tillage and shallow conservation tillage) and two crop rotations. Winter wheat yields were generally at similar levels with all four tillage systems in most years between 1998 and 2012. Yields increased with higher amounts of rainfall during the vegetation period (from October until June) with the smallest increase among tillage treatments in NT. This indicates that MP can be superior to NT regarding yield at higher amounts of rainfall. Pre-crops considerably influenced winter wheat with higher yields after maize, soybean and winter wheat than after sugar beet. In one year with high rainfall, a tillage × pre-crop interaction showed that yields were lower after maize in NT than in other tillage systems whereas yields after sugar beet tended to be higher with NT in years with low rainfall.

The study evaluates the effect of liming materials application in combination with NPK fertilizer and borax on macronutrient contents (nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg)), in an extremely acid soil and raspberry leaves and fruits during a two-year period. Liming increased soil pH, N mineral content, P, Ca and Mg soil content, while K content either increased (dolomite and borax application), or decreased (lime application). The N and P contents in raspberry leaves after liming increased significantly, but P content remained below the optimal values. Some treatments with lime caused a decrease in K content in leaves, while dolomite and borax application increased K content. Initially optimal Ca content in leaves increased significantly in the treatments with lime, but decreased after dolomite application. The Mg content in leaves increased after dolomite and borax application, but mainly remained below optimal values. Liming either did not alter or only slightly altered macronutrient contents in raspberry fruits.

A field trial with four potato cultivars (Faluka, Manitou, Madeleine and Stirling) was conducted in two consecutive years (2012 and 2013) at a laboratory field of Biotechnical Faculty in Ljubljana. The aim of the study was to evaluate different requirements of the selected cultivars in regard to the ridge and tuber cluster. The following parameters were defined and monitored: area of the form surrounding the tubers (ellipse), cross-sectional area of the ridge, vertical and horizontal tuber span in the ridge, the length of semi-axes (a) and (b) of the ellipse, minimum distance of tubers and ellipse from the outer ridge side. The results of 2012 trial indicated that the minimal ellipse method defining the ellipse was not satisfactory as statistical significance was limited due to a large volume of vacant space in the ridge not occupied by potato tubers. Therefore, the mathematical model was upgraded in 2013 and a physical parameter (tuber mass) was incorporated in the equation to better depict the tuber cluster. The trials were designed as a randomized block with five repetitions. The largest ellipse, horizontal tuber span in the ridge and the longest semi-axis (a) were recorded for the cv. Manitou resulting in the highest yield. However, no statistical differences were recorded in the horizontal tuber span, the length of the semi-axis (a) or cross-sectional area of the ridge among cultivars analysed. It was determined that different cultivars require specific growth space in the potato ridge. Moreover, the newly developed method proved efficient for determining growth requirements of potato tubers in the ridge.

Paddy rice is important for Chinese agriculture and crop production, which largely depends on the leaf nitrogen (N) levels. The purpose of this study is to discuss the relationship between the fluorescence parameters and leaf N content of paddy rice and to test their performance in inversing N content of crops through back-propagation (B-P) neural network. In the correlative analysis of the fluorescence parameters and the N content, we found that the correlation between fluorescence ratios (F740/F685 and F685/F525 (F740, F685, F525 - intensity of fluorescence at 740, 685 and 525 nm, respectively)) and the N content (R² are 0.735 and 0.4342, respectively) is weaker than that between the intensity of fluorescence peaks (F685 and F740) and N content (R² are 0.9743 and 0.9686, respectively). Our studies show that the accuracy and precision of N content inversion which is acquired from the intensity of fluorescence peaks through the B-P neural network model are significantly improved (root mean square error (MSRE) = 0.1702, the residual changes between -0.1-0.1 mg/g) compared with the fluorescence ratio (MSRE = 0.3655, the residual changes from -0.3-0.3 mg/g). Results demonstrate that the intensity of fluorescence peaks can be as a characteristic parameter to estimate N content of crops leaf. The B-P neural network model will be serviceable approach in inversing N content of paddy leaf.

The experiment was carried out to observe the influence of the CULTAN method (controlled uptake long term ammonium nutrition) on grain yield and yield formation of spring barley cultivar Jersey. In four-year small-plot experiment under conditions of the Czech Republic, two methods of nitrogen fertilization were used: conventional surface fertilization and local fertilizer injection rich in ammonium into soil during vegetation at BBCH 29-30 stages. Furthermore, the impact of sulphur amendment in fertilizer and increased dose of fertilizer were observed. Basic dose of nitrogen was 80 kg N/ha, increased dose 130 kg N/ha. At CULTAN treatment, same or significantly higher grain yields were obtained compared to conventional nitrogen fertilization. Grain yield at CULTAN fertilization is formed mainly on the main stem because of reduced tillering; it has the impact on significantly higher percentage of grain retained on 2.5 mm sieve. A tendency to lower protein content in grain was recorded at local injection of fertilizer compared to conventional fertilization. CULTAN-treated plants showed a lesser dependency of qualitative parameters on fertilizer dose and sulphur amendment in fertilizer. A positive influence of the CULTAN method on yield and quality of grain was observed mainly at the less fertile site.

Bacterial communities are key drivers of soil fertility and agriculture productivity. Understanding how soil bacterial communities change in response to different conditions is an important aspect in the development of sustainable agriculture. There is a desire to reduce the current reliance on high inputs of chemicals and fertilisers in agriculture, but limited data are available on how this might impact soil bacterial communities. This study investigated the bacterial communities in a spring barley monoculture site subjected to two different input regimes for over 12 years: a conventional chemical/fertiliser regime, and a reduced input regime. A culture independent approach was performed to compare the bacterial communities through 16S rRNA gene PCR-DGGE. PCO analysis revealed that the rhizosphere has a strong structuring effect on the bacterial community. Moreover, high inputs of agrichemicals lead to an increase of phosphorus level in the soil and a concomitant reduction of the bacterial diversity. These results may help to evaluate the environmental risks associated with agrichemical usage.

In long-term stationary experiments under different soil-climatic conditions, an influence of mineral and organic fertilization on yield of winter wheat, spring barley and potato tubers was evaluated. Statistically significantly lowest grain yields of winter wheat (4.00 t/ha) and spring barley (2.81 t/ha) were obtained in non-fertilized plots at all experimental sites. In the case of potatoes, the lowest yield of dry matter (5.71 t/ha) was recorded in the control plot, but the result was not statistically significant. The manure-fertilized plot gave the average yield of wheat higher by 30%, of barley by 22%. Application of sewage sludge resulted in wheat yield higher by 41% and barley yield higher by 26% over control. On average, application of sewage sludge and manure increased the yield of potatoes by 30% over control. The highest yield was obtained after application of mineral fertilizers; average yield increased by 59, 50 and 36% in winter wheat, spring barley and potatoes, respectively. No statistically significant differences among the plots with mineral fertilizers were observed. At different sites, the yield of studied crops varied; however, the effect of fertilization on yield increments was similar at all experimental sites except for Lukavec. It is the site with the lowest natural soil fertility, and it showed the highest effect of the applied fertilizers.

The aim of this work is to evaluate the changes of Mehlich 3 - P, K, Ca and Mg contents in soil during a long-term field experiments with sewage sludge, farmyard manure (FYM) and mineral NPK (NPK) application, compared to the control non-fertilized treatment. The experiment was established at the Humpolec and Suchdol sites (Czech Republic). Potatoes, wheat and barley were grown in crop rotation. Fertilizing system was based on the same nitrogen dose of 330 kg N/ha per one crop rotation. Archive soil samples from the beginning of the experiment (1996) and from the end of each year's crop rotation (1999, 2002, 2005, 2008 and 2011) were analyzed. In spite of the different soil-climatic conditions of the studied sites, very similar tendencies of P, K, Ca and Mg contents changes after the fertilizing systems used were observed in the soil. In case of the same nitrogen dose (330 kg N/ha), sewage sludge appeared to be better source of bioavailable soil phosphorus compared to the farmyard manure and NPK. On the contrary, FYM was a better source of bioavailable potassium and magnesium, despite the lower total magnesium content in FYM. The NPK treatment was the best long-term source of bioavailable potassium.

To investigate the effect of fertilization practice on dissolved organic nitrogen (DON) in aggregates, the study was conducted and involved four fertilization treatments: no fertilizer; mineral fertilizer (MF); pig manure matched with mineral fertilizer (MFP) and crop straw matched with mineral fertilizer (MFR). The results showed that DON content and storage were the highest in > 5 mm aggregates and were the lowest in < 0.25 mm aggregates. Compared with MF, MFP and MFR significantly increased DON contents in > 5 mm by 404.7% and 184.4%. In comparison with MFR, DON content and storage in > 5 mm aggregates for MFP were significantly enhanced by 77.5% and 75.0%. A significantly positive linear correlation relationship between DON content and microbial biomass carbon content was observed in aggregates (R² = 0.84; P < 0.01). The results suggest that pig manure matched with mineral fertilizer is a preferred strategy for retaining DON nutrient due to enhanced microbial biomass in aggregates on sloping upland of purple soil.

The objective of the present study was to evaluate the effect of P, Ca, S, and/or K and/or Mg application at different rates on the botanical composition, herbage yield and its nutritive value in dehesas developed on calcareous soils. In two growing seasons, 2009/10 and 2010/11, five surface-broadcast fertiliser treatments were applied once in autumn. Two grazing periods were simulated by cutting the pasture in mid-spring and late-spring. Treatment K1, with the highest amount of Ca and without K in its composition, provided higher crude protein values in the herbage than controls in 2009/10. When the effect of each nutrient was analysed separately, a strong and highly positive response of Mg application on herbage production was recorded. A surface application of fertilisers containing 25 kg Mg/ha in autumn could increase herbage yield by 40% under the studied conditions. However, Mg was not applied alone, and thus this increase could be due to an effect of Mg by itself or to a synergistic effect between Mg and other nutrients applied. The application of Ca, P and Mg may also favour the production of high-quality forage by yielding a greater cover of legumes and digestible protein.

A study was conducted to investigate the influence of sodicity induced changes in soil physical properties on paddy root growth in the normal agriculture, semi-reclaimed and sodic soils. The root growth (length, length density, biomass and distribution pattern) were unfavourably affected by the soil physical properties (bulk density, soil aggregate stability, available water content, hydraulic conductivity and soil water retention potential) in the case of sodic soil. The microbial biomass carbon, bacterial, fungal population and dehydrogenase activity showed the lower values in the case of sodosol compared to the normal soil. These soil biological properties tend to sustain paddy root growth in normal and semi-reclaimed soils. Principal component analysis revealed that soil physical properties accounted for 98.2% of total variance in root growth. The study revealed that salt stress induces changes in soil physical properties limiting paddy root growth in the salt affected soils. It is important to reclaim sodosols to alleviate salt induced physical stress for optimum paddy root growth.

A long-term experiment was used to evaluate the effects of different nutrient management practices on the distribution of soil organic N fractions and their contribution to N nutrition of a rice-wheat system. Continuous rice-wheat cultivation for 13 years without any fertilization was unable to maintain total soil nitrogen level to its original level and resulted in a decrease at 8.3 mg N/kg/year. Likewise, amino acid N, amino sugar N, ammonia N, hydrolysable unknown N, total hydrolysable N and non-hydrolysable N decreased by 37.2, 29.6, 33.7, 10.4, 26.6 and 20.4%, respectively over their initial status. However, application of inorganic fertilizers alone or in combination with organic manures led to a marked increase in total N and its fractions. The increase in total N with the application of farmyard manure, press mud and green manure along with inorganic fertilizer over treatment with inorganic fertilizer alone was 23.1, 34.4 and 7.0%, respectively. These results imply that integrated use of inorganic fertilizers with organic manures represent a sound practice for sustaining N reserves in soil. On average, amino acid-N, amino sugar-N, ammonia-N and hydrolysable unknown-N constituted about 27.9, 10.7, 28.7 and 32.7% of the total hydrolysable-N, respectively.

We measured the long-term (28 years) sustainability of rice-wheat cropping system under integrated nutrient management practices emphasizing the trends in grain yields, sustainable yield index (SYI) and nutrient budgeting. The data of long-term experiment revealed that grain yield of both rice and wheat declined under control and sub-optimal fertilizer inputs (50% or 75% recommended fertilizer NPK). Negative yield trend (slope) was observed in control plots for rice (-0.0296) and wheat (-0.0070); whereas positive yield trend was observed under treatments receiving organic supplements. The SYI values indicate that rice yields are more sustainable than wheat. Data on apparent nutrient balance showed a deficit of N (-42.2 kg/ha/year), P (-9.1 kg/ha/year) and K (-52.2 kg/ha/year) under control plots. Surprisingly, there was net depletion of K under the organic supplemented plots. Correlation study revealed that apparent balance of K was negatively correlated with SYI (r = -0.921 for rice; r = -0.914 for wheat) and yield slope (r = -0.870 for rice; r = -0.896 for wheat). If the trend of K imbalance is not reversed, the potential to improve N and P fertilizer use efficiency and crop yields will be limited.