Changes in soil properties and soil solution nutrients due to conservation versus conventional tillage in Vertisols

Understanding of tillage effects on soil chemical properties and cations in soil solution dynamics is essential for making appropriate land-management decisions. Measurements were made after more than 25 years of different tillage treatments: conventional tillage (CT) and conservation tillage, which includes no-till (NT) and minimum tillage (MT). pH and bulk density did not show important changes but exchangeable cations and cations in soil solution were affected by depth and different tillage. The highest concentration of exchangeable Ca²⁺ and Mg²⁺ was found in NT, decreased in MT and the lowest concentration was found in CT (mean values were 26.0, 24.4 and 23.3 cmol_c kg^?1 for exchangeable Ca²⁺ and 4.2, 3.7 and 3.3 cmol_c kg^?1 for exchangeable Mg²⁺ in NT, MT and CT, respectively). In addition, the highest concentration of exchangeable Na⁺ was found in NT, decreased in CT and the lowest concentration was found in MT. However, the highest concentration of exchangeable K⁺ was found in MT. A significant depth effect was observed for cations in soil solution: Na⁺ increased with depth whereas K⁺ and Ca²⁺ decreased with depth. This study aims to demonstrate the effect of tillage on the distribution and concentration of certain chemical soil properties.     

Sulfur mineralization in two soils amended with organic manures,crop residues,and green manures

The mineralization of sulfur (S) was investigated in a Vertisol and an Inceptisol amended with organic manures, green manures, and crop residues. Field‐moist soils amended with 10 g kg^—1 of organic materials were mixed with glass beads, placed in pyrex leaching tubes, leached with 0.01 M CaCl₂ to remove the mineral S and incubated at 30 °C. The leachates were collected every fortnight for 16 weeks and analyzed for SO₄‐S. The amount of S mineralized in control and in manure‐amended soils was highest in the first week and decreased steadily thereafter. The total S mineralized in amended soils varied considerably depending on the type of organic materials incorporated and soil used. The cumulative amounts of S mineralized in amended soils ranged from 6.98 mg S (kg soil)^—1 in Inceptisol amended with wheat straw to 34.38 mg S (kg soil)^—1 in Vertisol amended with farmyard manure (FYM). Expressed as a percentage of the S added to soils, the S mineralized was higher in FYM treated soils (63.5 to 67.3 %) as compared to poultry manure amended soils (60.5 to 62.3 %). Similarly the percentage of S mineralization from subabul (Leucaena leucocephala) loppings was higher (53.6 to 55.5 %) than that from gliricidia (Gliricidia sepium) loppings (50.3 to 51.1 %). Regression analysis clearly indicated the dependence of S mineralization on the C : S ratio of the organic materials added to soil. The addition of organic amendments resulted in net immobilization of S when the C : S ratio was above 290:1 in Vertisol and 349:1 in Inceptisol. The mineralizable S pool (S_o) and first‐order rate constant (k) varied considerably among the different types of organic materials added and soil. The S_o values of FYM treated soils were higher than in subabul, gliricidia, and poultry manure treated soils.     

淮北变性土性状特点对其生产性能的影响及农业利用对策

本研究基于黄淮海平原多个变性土剖面分层土壤样品的土壤理化性状分析数据,对其肥力特征、生产性能以及培肥改良措施进行了系统研究。相关结果表明,机械组成中粘粒含量高、质地粘重、土壤结构和孔隙性差是变性土主要物理性状特征,受其影响,土壤表现出耕作性能差、蓄水能力弱、保水性能不强等特点;化学性状主要表现为有机质含量不高、质量差,土壤氮素水平仍较低,耕层土壤速效磷含量分异加大,土壤速效钾含量缓慢降低,土壤CEC含量较高,土壤保肥性能强,但供肥性能较差等特点。这些性状特点对土壤生产性能的影响主要表现在土壤适耕期短,易受旱、涝(渍)灾害的危害,土壤有效养分低、营养失调,钙质结核影响土壤蓄水能力和水分运行以及作物根系生长等方面。指出:(1)增加土壤有机质,改良土壤理化性质;(2)合理施肥,促进土壤养分平衡;(3)改进耕作、灌溉技术,调控土壤水分状况等是培育变性土肥力质量、提高土壤生产性能的关键性措施。     

A new method for studying clay soils using unaltered soil blocks

The purpose of this paper is to outline a procedure for soil block extraction, which is highly appropriate for clay soils. The method described here is rapid and cheap and has been used successfully by us in clay soils in southern Spain for the last six years. A wooden box is used to shape the soil block in situ and protect it during its transport from the field to the laboratory. Polyurethane foam was selected as the bonding agent, between the wooden framework and the soil block in order to avoid any possible alterations of the soil. This type of foam is used because it is strong, durable and non-toxic. The polyurethane foam is applied to the soil block as a permanent coating. This technique allows us to extract the clay soil solution in the laboratory.     

淮北变性土区玉米施用硫·锌微肥的效果

试验结果表明 ,在淮北变性土区 ,施用硫、锌微肥能促进玉米植株的生长发育 ,增强玉米的抗旱能力 ,促进玉米果穗的生长发育和籽粒的灌浆 ,增加玉米籽粒产量     

Transformation of fertilizer P in a Vertisol amended with farmyard manure

Availability, fixation, and transformation of added P were studied in a 16-week incubation experiment with a Vertisol amended with farmyard manure in pots with 500 g soil each. P availability, as measured by Olsen P, decreased for up to 8 weeks with various rates of added P, when no manure was applied. In the presence of farmyard manure, P availability decreased during the first 6 weeks and then showed a considerable increase from the 8th week onwards. P fixation increased for up to 8 weeks with the rates of P in the absence of manure. With manure application, P fixation increased only during the first 6 weeks and thereafter decreased continuously. Thus the presence of farmyard manure shortened the period of P fixation and promoted its availability. After 16 weeks of incubation, when manure and fertilizer P were applied together, P was transformed into labile organic (NaHCO₃–P), moderately labile organic P (NaOH-P), and calcium-bound inorganic P (HCl-P). When manure was not applied. P accumulated predominantly as labile inorganic (NaHCO₃–P), moderately labile inorganic (NaOH-P), and inorganic HCl-P. The application of farmyard manure enriched long-term P fertility through NaHCO₃–P and NaOH–P and a shortterm P supply as HCl-P. All fractions except inorganic NaOH-P showed good relationships with Olsen P.     

Improved management of Vertisols in the semiarid tropics for increased productivity and soil carbon sequestration

Abstract. This study was undertaken to test the hypothesis that an improved system of catchment management in combination with appropriate cropping practices can sustain increased crop production and improve soil quality of Vertisols, compared with prevailing traditional farming practices. Initiated in 1976, the improved system consisted of integrated land management to conserve soil and water, with excess rainwater being removed in a controlled manner. This was combined with improved crop rotation (legume based) and integrated nutrient management. In the traditional system, sorghum or chickpea was grown in the post-rainy season with organic fertilizers, and in the rainy season the field was maintained as a cultivated fallow. The average grain yield of the improved system over 24 years was 4.7 t ha⁻¹ yr⁻¹, nearly a five-fold increase over the traditional system (about 1 t ha⁻¹ yr⁻¹). There was also evidence of increased organic C, total N and P, available N, P and K, microbial biomass C and N in the soil of the improved system. A positive relationship between soil available P and soil organic C suggested that application of P to Vertisols increased carbon sequestration by 7.4 t C ha⁻¹ and, in turn, the productivity of the legume-based system, thus ultimately enhancing soil quality.     

Land configuration and soil nutrient management options for sustainable crop production on Alfisols and Vertisols of southern peninsular India

Land configuration in combination with nutrient management has the potential to improve the productivity of Alfisols and Vertisols in the semi-arid tropics. A four year (1989–1990 and 1992–1993) field experiment was conducted at Coimbatore, India on Alfisols (Chromic Cambisol) to compare the effect of land configuration and nutrient management practices on yield of rainfed sorghum (Sorghum bicolor (L.) Moench). The land configuration treatments were flat bed (FB, the traditional practice), open ridging (OR, ridges, 45 cm apart and 30 cm high) and tied ridging (TR, same as OR plus ridges were tied randomly). The manure and fertilisers were farm yard manure (FYM, livestock excreta plus litter at 5 Mg ha⁻¹) and coir dust (CD, by-product after the extraction of coir from the coconut (Cocos nucifera L.) husk at 12.5 Mg ha⁻¹) in combination with nitrogen (N) and phosphorus (P) fertiliser levels. Tied ridges stored 14% more soil water and produced 14% and 11% more grain and straw yields of sorghum, respectively, than did flat bed. However, crop yield in TR was comparable with OR. Application of CD at 12.5 Mg ha⁻¹ combined with 40 kg N ha⁻¹ and 9 kg P ha⁻¹ was beneficial for more soil water storage and increased yield of sorghum by 7% over FYM at 5 Mg ha⁻¹ + 40 kg N ha⁻¹ and 9 kg P ha⁻¹. In Vertisols (Vertic Cambisols), experiments were conducted for two years (1991–1992 and 1992–1993) to evaluate land configuration practices. The treatments were broad bed furrow (BBF, 120 cm wide bed with 30 cm wide and 15 cm deep furrows on both sides), compartmental bunding (CB, bunds of 15 cm height formed in all the four sides to form a check basin of 6 m × 5 m size), ridging (RD, ridges were formed for each and every row of the crop manually at four weeks after sowing) and FB under sorghum + pigeonpea (Cajanus cajan (L.) Millsp) and pearl millet (Pennisetum glacum (L.) Stuntz) + cowpea (Vigna unguiculata (L.) Walp) intercropping separately. Compartmental bunding stored 22% more soil moisture and increased the yield of sorghum + pigeonpea intercropping than did FB in a low rainfall year. In a high rainfall year, BBF produced 34% and 33% more grain yield of sorghum and pearl millet base crops, respectively, over FB. However, BBF and CB were comparable. Pigeonpea intercrop under sorghum followed the same trend as its base crop, whereas, yield of cowpea differed compared to the pearl millet base crop. Tied ridging and application of manures (CD or FYM) in combination with inorganic N and P fertiliser can increase the soil water storage and yield of crops compared to traditional flat bed cultivation in rainfed Alfisol and related soils of semi-arid tropics. Similarly BBF and CB land configuration practices could be adopted on Vertisols for better water conservation to increase the soil fertility and productivity of intercropping systems.     

Paddy management on different soil types does not promote lignin accumulation

Paddy soil management is generally thought to promote the accumulation of soil organic matter (SOM) and specifically lignin. Lignin is considered particularly susceptible to accumulation under these circumstances because of the recalcitrance of its aromatic structure to biodegradation under anaerobic conditions (i.e ., during inundation of paddy fields). The present study investigates the effect of paddy soil management on SOM composition in comparison to nearby agricultural soils that are not used for rice production (non‐paddy soils). Soil types typically used for rice cultivation were selected, including Alisol, Andosol and Vertisol sites in Indonesia (humid tropical climate of Java) and an Alisol site in China (humid subtropical climate, Jiangxi province). These soil types represent a range of soil properties to be expected in Asian paddy fields. All upper‐most A horizons were analysed for their SOM composition by solid‐state ¹³C nuclear magnetic resonance (NMR) spectroscopy and for lignin‐derived phenols by the CuO oxidation method. The SOM composition was similar for all of the above named parent soil types (non‐paddy soils) and was also not affected by paddy soil management. A substantial proportion (up to 23%) of the total aryl‐carbon in some paddy and non‐paddy soils was found to originate from condensed aromatic‐carbon (e.g ., charcoal). This may be attributed to the burning of crop residues. On average, the proportion of lignin was low and made up 20% of the total SOM, and showed no differences between straw, particulate organic matter (POM), and the bulk soil material. The results from CuO oxidation are consistent with the data obtained from solid‐state ¹³C NMR spectroscopy. The extraction of lignin‐derived phenols revealed low VSC (vanillyl, syringyl, cinnamyl) values for all investigated soils in a range (4 to 12 g kg⁻¹ OC) that was typical for agricultural soils. In comparison to adjacent non‐paddy soils, the data do not provide evidence for a substantial accumulation of phenolic lignin‐derived structures in the paddy soils, even for those characterized by higher organic carbon (OC) contents (e.g ., Andosol‐ and Alisol (China)‐derived paddy soils). We conclude that the properties of the parent soil types are more important for the lignin content of the soils than the effect of paddy management itself.     

Assessment of the limiting nutrients for wheat (Triticum aestivum L.) growth using Diagnosis and Recommendation Integrated System (DRIS)

ABSTRACT

The Diagnosis and Recommendation Integrated System (DRIS) was used as a tool to assess the limiting nutrients for wheat growth. To this effect, two separate greenhouse experiments were conducted to assess the limiting nutrients for wheat growth using soil samples collected from Wolmera district, Ethiopia. The experiments consisted of eight fertilizer treatments, optimum (Opt.), optimum-N (Opt-N), optimum-P (Opt-P), optimum-K (Opt-K), optimum-S (Opt-S), optimum-B (Opt-B), optimum-Zn (Opt-Zn) and control on Nitisols and six fertilizer treatments (Opt, Opt-N, Opt-P, Opt-S, Opt-B, and control) on Vertisols. In Nitisols, dry shoot weight yields were reduced by 93%, 70%, and 50% in the control, Opt-N, and Opt-P treatments, respectively. Whereas the corresponding reductions were 85%, 78%, and 42%, respectively, in Vertisols as compared to the optimum treatment. DRIS results indicated that N is the most limiting nutrient, followed by S, B, and P, while Zn was the least limiting nutrient for wheat production in the two study soils.