Application Of Green Manure Research Articles

Long Term Manuring and Fertilization Effect on Soil Properties in Terrace Soil

The study was carried out the influence of long term manuring and fertilization on soil properties. Soil samples were collected in 2016 from a highly weathered terrace soil with rice-wheat cropping pattern at Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) experimental farm having five OM (control, cow dung, green manure, rice straw and compost) treatments combined with three mineral N fertilizer (control, 155 kg ha-1, 220 kg ha-1) levels. Long term (28 years) application of mineral fertilizers and manure resulted in significant differences in soil organic carbon, total N content, C:N ratio of soil and soil pHKCl between the treatments. The soil organic carbon content varied among the different treatments from 6.11 g OC kg-1 (application of rice straw and no N) to 9.43 g OC kg-1 (application of compost and 220 kg N ha-1 yr-1). The total soil N content varied among the different treatments from 0.41 g N kg-1 (application of rice straw and no N) to 0.73 g N kg-1 (application of compost and 220 kg N ha-1 yr-1). The C:N ratios of the soil varied among the different treatments from 13.3 (application of no exogenous OM and no N) to 15.1(application of green manure and no N). The soil pH varied among the different treatments from 4.42 (application of cow dung and 220 kg N ha-1 yr-) to 4.89 (application of compost/cow dung and no N). So, long term fertilization and manuring undoubtedly bring some changes in the physiochemical soil properties of terrace soil.

Application of several green manures to produce organic cabbage (Brassica oleracea var. Capitata) and their influence on soil biological properties

Green manure stands out in the organic vegetable production as complementary fertilizer alternative to organic compound incorporation, contributing to reduce production costs and improve soil physical, chemical and biological features. The aim of the current study is to assess green manure and spontaneous vegetation species in cropping systems focused on the organic cabbage production, as well as their influence on soil microbial community. The treatments consisted of green manures such as black velvet beans (Stizolobium aterrimum), Crotalaria spectabilis, jack beans (Canavalia ensiformis), pigeon peas (Cajanus cajan cv. Iapar 43) and spontaneous vegetation (fallow) in two cropping systems (with and without incorporation of green manure plants). Evaluations of green manure, cabbage crop and soil microbial activity were carried out. Green manure: fresh and dry mass, nitrogen and accumulated nitrogen content; Cabbage culture: horizontal and vertical diameter of the head, commercial and total mass; Microbial soil activity: soil microbial biomass carbon, soil basal respiration and metabolic quotient. For fresh and dry mass, jack beans and pigeons pea presented higher values, indicating good performance of these materials. For both, nitrogen content and accumulated nitrogen, the jack beans were stood. Regarding cabbage culture, the spontaneous vegetation decreased the horizontal diameter of the head when the incorporation did not occur. As for the commercial mass, for jack beans the cultivation with incorporation was superior. When the incorporation of the covering plants occurred, the crotalaria spectabilis produced less commercial mass and total head mass. Still in relation to total head mass, jack beans and spontaneous vegetation had lower mass when no incorporation occurred. As to soil microbial biomass carbon the spontaneous vegetation presented higher value, differing only from black velvet beans. The use of jack beans as a cover crop associated with the incorporation system was shown to be promising for the production of cabbage.

Long-term green manure application improves soil K availability in red paddy soil of subtropical China

Potassium (K) in soil minerals is an important factor affecting rice production in red paddy soil of subtropical China under intensive agricultural production. The long-term application of green manure might affect the soil K availability through accumulative effects of microbial activity on K-bearing minerals. This study aims to investigate the effect of green manure applications (GMs) on soil K availability in relation to soil minerals. The soil mineralogy under 36 years of GMs, including milk vetch application (MV), rape application (RA), and ryegrass application (RY), was studied by X-ray diffraction (XRD) measurement, with a winter fallow treatment (WF) as the control. Fast available K (FAK), non-exchangeable K (NEK), and structural K (SK) were extracted with NH4OAc, HNO3, and HF-HClO4 solution, respectively. All the extracted K was determined by flame photometry. The K release or retention was measured by a new method of potassium Q/I curve. The GMs significantly decreased the SK, which was associated with weakened diffraction intensity of feldspar and mica. However, the NEK under GMs increased from 90.9 to 100.1–104.8 mg kg−1 compared with that under WF, which was in line with the higher content of illite under GMs. The soil clays contained much kaolinite and illite, leading to easy leaching of K. The GMs obviously improved K retention in the soil, especially the MV and RY, which could be ascribed to the large amounts of illite with poorly crystallized structure under GMs. Long-term GMs, especially MV and RY, can improve the availability of SK and K retention capacity in the soil in relation to soil mineralogy, and thus can be an effective alternative to enhance soil K availability in red paddy soil.

Differential response of denitrifying community to the application of green manure and reduced chemical fertilizer in a paddy soil

Differential response of denitrifying community to the application of green manure and reduced chemical fertilizer in a paddy soil

Effect of Organic Amendments on the Productivity of Rainfed Lowland Rice in the Kilombero Floodplain of Tanzania

Organic amendments can reportedly sustain and increase lowland rice productivity in smallholder systems. Few studies have assessed locally-available substrates in hydrologically variable floodplain environments. We investigated the effects of green and farmyard manures on rice yields, and total soil C and N in the Kilombero floodplain, Tanzania. At both the fringe and the middle positions, five treatments were applied in 2016 and 2017, comprising (1) non-amended control, (2) farmyard manure, (3) pre-rice legumes, (4) post-rice legumes and (5) a combination of green and farmyard manures. Residual treatment effects were assessed in 2018 when rice plots were uniformly non-amended. Depending on the year and the position, organic amendments increased rice grain yields by 0.7–3.1 Mg ha–1 above the non-amended control. Sole green and farmyard manure applications had similar effects on grain yield, while a combination of green and farmyard manure led to a significant increase in grain yield above both the control and sole applications of organic amendments in both years. The contribution from biological N2 fixation by legumes ranged from 4 to 61 kg N ha–1. Despite partial N balances being mostly negative, we observed positive residual effects on the yield of the non-amended rice in the third year. Such effects reached up to 4 Mg ha−1 and were largest with post-rice legumes, sole or combined with farmyard manure. Irrespective of the position in the floodplain, manures significantly increased soil C and N contents after two years, hence enhancing soil fertility and resulting in increased rice grain yields. Comparable benefits may be obtained along the hydrological gradients of other large river floodplains of the region and beyond.

Egyptian Clover Green Manuring Improved Grain Nutritional Contents, Productivity and Soil Health of Spring Maize with Different Nitrogen Rates

ABSTRACT Application of green manures substitutes use of chemical fertilizers, improves soil health, prevents soil degradation also ensures food security. Two years’ field experiment was laid out to determine the impact of Egyptian clover green manuring (GM) under varying nitrogen (N) levels on soil properties and maize production. Maize was grown using six N levels, i.e., 0, 50, 100, 150, 200, and 250 kg ha−1 along with GM and without GM. The GM improved grain yield (+33%, +48%) due to substantial improvement in grains/cob, 1000-grain weight and grain nutritional contents during spring 2017 and 2018 respectively. Likewise, GM also improved organic matter (OM) (+40%, +88%), available N (+210%, +219%), and total phosphorus (P) (+112%, +128%) compared to no GM. Similarly, 250 kg N ha−1 produced more grains/cob, biological yield and grain yield compared to control and other levels. In interactive effect, GM with 150 kg N ha−1 outperformed in improving 1000-grain weight, maize productivity and agronomic N efficiency. In conclusion, GM improved soil OM and total soil N compared to no GM. Moreover, GM with 150 kg N ha−1 improved productivity, agronomic N efficiency and saved 40% N compared with no GM where 250 kg N ha−1 gave best results.

Driving factors of soluble organic nitrogen dynamics in paddy soils: Structure equation modeling analysis

Soil soluble organic nitrogen (SON) is one of the most active components in soil nitrogen pools; however, limited information is available with regard to its driving factors, as well as their pathways and degrees of influence. In this study, structural equation modeling was used to analyze the driving factors, their significance, and pathways that affected SON dynamics in a waterlogged experiment of two typical paddy soils incubated for 80 d after green manure application. Soil pH, Eh, microbial biomass, enzyme activity, and SON dynamics were used to construct the structural equation model. Results showed that soil microbial biomass carbon (MBC), protease, glutamine, and initial organic matter (OM) directly and significantly affected soil SON with path coefficients corresponding to 0.405, 0.547, 0.523, and–0.623 (P < 0.01), respectively. Soil microbial biomass carbon and initial OM affected the SON dynamics indirectly through protease and glutamine activity. In addition, pH indirectly affected SON dynamics by glutamine activity. It is implied that soil MBC, protease, glutamine, and initial OM are the key factors affecting SON dynamics in the waterlogged paddy soils after green manure application. Our research indicated that structural equation modeling could provide an effective method to clearly recognize the impact, significance, and pathways of multiple factors on SON dynamics in paddy soils.

Co-incorporation of rice straw and leguminous green manure can increase soil available nitrogen (N) and reduce carbon and N losses: An incubation study

Returning rice straw and leguminous green manure alone or in combination to soil is effective in improving soil fertility in South China. Despite the popularity of this practice, our understanding of the underlying processes for straw and manure combined application is relatively poor. In this study, rice straw (carbon (C)/nitrogen (N) ratio of 63), green manure (hairy vetch, C/N ratio of 14), and their mixtures (C/N ratio of 25 and 35) were added into a paddy soil, and their effects on soil N availability and C or N loss under waterlogged conditions were evaluated in a 100-d incubation experiment. All plant residue treatments significantly enhanced CO2 and CH4 emissions, but decreased N2O emission. Dissolved organic C (DOC) and N (DON) and microbial biomass C in soil and water-soluble organic C and N and mineral N in the upper aqueous layer above soil were also enhanced by all the plant residue treatments except the rice straw treatment, and soil microbial biomass N and mineral N were lower in the rice straw treatment than in the other treatments. Changes in plant residue C/N ratio, DOC/DON ratio, and cellulose content significantly affected greenhouse gas emissions and active C and N concentrations in soil. Additionally, the treatment with green manure alone yielded the largest C and N losses, and incorporation of the plant residue mixture with a C/N ratio of 35 caused the largest net global warming potential (nGWP) among the amended treatments. In conclusion, the co-incorporation of rice straw and green manure can alleviate the limitation resulting from only applying rice straw (N immobilization) or the sole application of leguminous green manure (high C and N losses), and the residue mixture with a C/N ratio of 25 is a better option because of lower nGWP.

PENGARUH PEMBERIAN BAHAN ORGANIK KIRINYU ( Chromolaena Odorata )TERHADAP PERTUMBUHAN DAN HASIL SAWI (Brasica Juncea ) DI KAWASAN AGROECOTOURISM

This study aimed to explore the effect of Siam weed (Chromolaena odorata) green manure application on the growth and development of mustard (Brassica juncea) in Kelimutu National Park, Indonesia. The study was carried out between September and November 2010 in Ende district on the island of Flores, Indonesia, at an altitude of 1500 to 1730 meters above sea level. This study used a randomized block design with four treatments: K0: No Siam weed application, K1: 5 tons/ha Siam weed (2.8kg/plot), K2: 10 tons/ha Siam weed (5.6kg/plots), K3: 15 tons/ha Siam weed (8.4kg/plot), K4: 20 tons/ha Siam weed (11.2kg/plot). Researchers observed plant characteristics (plant height, leaf area, wet weight and number of leaves) and soil fertility indicators (Organic carbon). Plant organic matter was ground and subsequently analyzed for nutrients using a randomized block design along with lab analysis for soil fertility. The results of this study showed that the application of Siam weed organic matter had no significant effect on mustard plant height, leaf number, leaf area, or wet weight. However, it was found that organic matter application did have a significant effect on soil fertility indicators (organic carbon), and caused an increase in soil organic matter content.

Green manuring inhibits nitrification in a typical paddy soil by changing the contributions of ammonia-oxidizing archaea and bacteria

Rice–rice–green manure rotations in south China are characterized by high efficiency and good environmental performance, and the application of green manure plays an important role in N management. Nitrification is a key process in N cycling and is highly correlated with the N utilization of crops and with leaching losses. As a potential N loss pathway, the nitrification process and nitrifiers as affected by green manuring are of critical importance. A pot experiment covering green manure-double rice rotation was conducted to evaluate the effects of green manure and N fertilizer on soil nitrification and to achieve a mechanistic understanding of underlying processes in an alkaline paddy soil. Soil nitrification potential (NP) and the recovered nitrification potential (RNP) were measured. Relative contributions of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in soil nitrification were studied using specific bacterial inhibitors. In the alkaline paddy soil, soil NP and nitrate concentrations were significantly decreased by green manuring but increased with increasing N fertilization. Soil nitrification was dominated by AOB and that the relative contributions of AOB to RNP ranged from 65% to 79% at different sampling stages despite the larger abundance of AOA amoA gene numbers. RNP and the contribution of AOB to RNP were significantly increased by N fertilizer, whereas the contribution of AOA was decreased by green manuring. We concluded that the application of inorganic N enhanced NP while green manures reduced it, which is consistent with the variation of observed soil nitrate concentrations. These results indicate that the utilization of winter green manure is an effective practice to improve N management in paddy rice.

Evaluation of Farming Practices for Reduction of Greenhouse Gas Emission in Korean Agricultural Sector

This study was conducted to provide low carbon farming technique for greenhouse gases(GHGs) emission reduction in agriculture sector. It reviewed literatures on the characteristic of cultivation technique and its effects on carbon emission reduction. The effects of GHGs emission reduction were evaluated in agricultural land with several farming practices. In the rice cultivation technique, the irrigation water management showed good effect on GHGs emission reduction in paddy field. It also evaluated reduction efficiency of source of nitrogen supply and soil improvement. The intermittent irrigation showed 25.1% carbon reduction efficiency as compared to continuously flooded treatment. Slow release fertilizer and ammonium sulphate decreased carbon emission by 19.8% and 7.9% compared to urea, respectively. With soil amendments treatment, silicate fertilizer and zeolite reduced carbon emission 14.1% and 21.7% compared to rice straw treatment. In the upland crop cultivation technique, the efficiency of tillage management, green manure, livestock compost and nitrification inhibitor application were estimated. Substitution of 50% of nitrogen with hairy vetch showed 65.6% carbon reduction efficiency. It also showed 20.4% emission reduction with nitrification inhibitor treatment. However, GHGs emission were increased with livestock compost application. It provided basic data for reducing the GHGs emission in agriculture sector by accomplishing low carbon farming technique and policy project. Effect of farming practices on GHG emission reduction in paddy field.

Iron Enriched Green Manure Can Increase Wheat Fe Concentration in Pb-polluted Soil in the Presence of Piriformospora Indica (P.indica)

ABSTRACT Soil pollution with heavy metals and iron (Fe) malnutrition is big concern of industrial areas in arid and semi-arid regions. We studied the potential of Fe-enriched green manures application and Piriformospora indica (P.indica) to increase grain Fe concentration of two bread wheat genotypes differing in Fe efficiency (Triticum aestivum L. cvs. Falat, and Durum) in a Pb-polluted soil. To prepare Fe-enriched green manures sunflower, corn, and canola were cultivated in the soils treated with 0%, 0.5%, 1% and 1.5% (W/W) of iron slag, converter slag, and elemental sulfur. After 70 days, the plants were harvested and the Fe concentration in their biomass was measured. The plants grown in 1.5% elemental sulfur were selected as green manures due to their higher Fe concentration than those grown in soils treated with other industrial byproducts studied. Application of sunflower residues and presence of P. indica in Pb-polluted soil increased the grain Fe concentration of Falat and Durum wheat genotypes from 48.8 to 132.7 and 40.2 to 118.8 mg kg−1, respectively. The response of wheat plants to the presence of P. indica and green manure application was significantly affected by the wheat genotype. Application of sunflower residues increased soil microbial respiration and dissolved organic carbon which was consistently magnified by the presence of P. indica. This study showed that agricultural management, including the use of Fe-enriched green manure, could be asuitable method to increase Fe concentration and reduce Pb concentration in wheat grains grown in Pb-polluted soils of arid and semi-arid regions.

Contributions of ammonia-oxidising bacteria and archaea to nitrification under long-term application of green manure in alkaline paddy soil

Rice–rice–green manure rotation is a cropping system that effectively maintains high yields and improves soil fertility. Nitrification, a critical process in N cycling, is affected by different fertilisation regimes, but the roles of ammonia-oxidising bacteria (AOB) and ammonia-oxidising archaea (AOA) in nitrification and their shift in abundance and diversity in response to long-term green manure application in alkaline paddy soil is poorly understood. In the present work, nitrification potential (NP), the contributions of AOA and AOB to nitrification, abundances, and communities of AOA and AOB were studied to mechanistically understand the effects of green manuring and fertilisation regimes on nitrification and ammonia oxidisers. Results showed that the combination of green manure and reduced chemical fertiliser increased grain yields. Soil NP increased with increasing amount of chemical fertiliser. The combination of green manure and different rates of chemical fertiliser promoted the soil recovered nitrification potential (RNP) and the contribution of AOB to nitrification (RNPAOB). Differences in AOA and AOB communities revealed that an increase in the abundance of Nitrosopumilus in AOA and a decrease in the abundance of Nirosomonas in AOB were observed in green manure treatment compared with those of chemical fertiliser treatments. Partial least squares path modelling showed that chemical fertilisation exerts direct effects on NP whereas green manuring markedly influenced RNP. For the relative contributions of AOA (RNPAOA) and AOB, RNPAOB were correlated with chemical fertilisation, whereas green manuring directly affected RNPAOA. In conclusion, green manuring changed the nitrification process by affecting RNP, whereas chemical fertiliser directly influenced NP. Changes in AOA composition and their impact on nitrification might reflect a mechanism worthy of further research.

ПРОДУКТИВНОСТЬ ЗЕРНОТРАВЯНОГО СЕВООБОРОТА В ЗАВИСИМОСТИ ОТ ЗАДЕЛКИ НАВОЗА, СОЛОМЫ И ПРОМЕЖУТОЧНОГО СИДЕРАТА

The article presents the results of studies on the introduction of manure, straw and intermediate green manure in a grain-grass crop rotation against the background of the introduction of calculated doses of mineral fertilizers on the gray forest soil of the Republic of Tatarstan. The results of studies showed that options with the introduction of manure and plant biomass reduced the soil density in the 0-10 cm layer by 0.02-0.04 g/cm3, in the 10-20 cm layer by 0.03-0.04 g/cm3. The total content of structural aggregates in the variants with the introduction of manure and the joint incorporation of straw and green manure increased to 46.7-72.9%, the structural coefficient was 0.87-2.69, against 44.3-63.9% and 0.79 -1.77 on the mineral background. The amount of crop and root residues that came into the soil after harvesting perennial grasses more accumulated in the backgrounds with the addition of manure, straw and green manure and amounted to 10.8-12.1 tons per hectare, while the mineral background made up only 10, 11 tons per hectare. Against the same background, an increase in the content of humus in the soil by 0.12-0.16% occurred. Improving the soil fertility of the soil, manure, straw and green manure contributed to an increase in crop yields in crop rotation compared with the mineral background: winter rye by 0.2-5.0 centner, spring wheat by 1.2-6.8 centner, perennial grasses by 1.2-7.3 grain units, spring wheat – 2.5-5.4 centner, oats - 2.4-5.3 center per hectare. Crop cultivation in a grain-grass crop rotation on the background of the combined application of straw and crop green manure made it possible to get a maximum profit of 22,835.6 rubles per ha with a profitability level of 162.8%, against 15540.0 rubles per ha and a profitability of 96.4% against a mineral background.

Nutrition management in conversion-to-organic citrus orchard in the Indonesian citrus and subtropical fruits research institute

One of the main challenges in organic citrus cultivation is how to manage land and nutrients so that plant needs can be met all the time while maintaining soil quality. This paper provides information on applied nutrition management, evaluation of changes in soil characters, and production in the conversion-to-organic citrus orchard in the Indonesian Citrus and Subtropical Fruits Research Institute. The citrus used are 5-year-old Siam citrus (Citrus nobilis Lour.) grafted on Japansche Citroen rootstock. The initial stage in the conversion to organic farming is the creation of ecosystems that support organic agriculture and improvement of soil fertility through the cultivation of gliricidia (Gliricidia sepium) and marigold (Tagetes erecta L.) as living hedges around the garden, planting citronella grass (Cymbopogon nardus) and marigold (Tagetes erecta L.) in the embankment, and planting land cover crop. Nutrition management in the orchard includes the application of green manure sourced from biomass of the living hedges, soybeans (Glycine max (L.) Merill) and wild plants obtained from the orchard; application of compost from dolomite enriched goat manure; and application of liquid organic fertilizer from fermented goat manure with local microorganisms. Nutrition management applied in the organic conversion orchard in the first year was followed by improvement in some soil characters, namely pH, organic matter content, cation exchange capacity, total N and exchangeable Ca but vice versa for available P, exchangeable K, and Mg. Citrus production in the first year fell by about 11% from the previous year and was followed by a decrease in the other quality parameters of fruits, except for the levels of vitamin C and total acid.

Ecosystem service function of green manure and its application in dryland agriculture of China

Dryland agriculture, with wide distribution and high yield potential, plays an important role in ensuring food security in China. It is currently limited by water scarcity, soil depletion, water and soil loss, and low non-renewable resource-use efficiency. Green manure has the potential to improve growth environment of crops and promote sustainable high-yield crops by increasing soil quality, balancing soil nutrients, and enhancing soil water-storage capacity. In addition, green manure has ecological benefits, including enhancing agroecosystem biodiversity, increasing soil surface cover degree, reducing ineffective nutrient loss to environment, improving air balance of farmland systems, and biological control of diseases, insect pests, and weeds. Under current scenario of intensified global climate change, environmental deterioration, and agricultural product demand changes, the traditional agronomic techniques of using green manure as a fertilizer cannot satisfy the requirements of agricultural development. Thus, it is necessary to strengthen the selection and bree-ding of green manure genetic resources for dryland agriculture, to develop a new regionalization of green manure, and to establish a cropping pattern based on green manure suitable for different regions. Furthermore, it is important to study and optimize the tillage and cultivation techniques to satisfy modern production and to establish an evaluation system for the comprehensive benefits of green manure. It is needed to establish a green manure application pattern that enables resource and ecological protection for improving ecological environment and economic efficiency of dryland agriculture and provides theoretical basis and technical support for exploiting green manure benefits.

The Effects of Farmyard Manure and Green Manure Applications on Some Soil Physical Properties

In this research was carried out to determine the effects of farmyard manure and green manure applications on some physical soil properties in an organic vegetable cultivation field. The effects of control (C), farmyard manure (FYM) (35 t ha-1) and green manure (GM) applications on some soil physical properties (Soil water characteristics (0.001, 0.1, 0.33, 1, 5, 10 and 15 bar), available water capacity, porosity and bulk density) were investigated for soil depths of 0-10 and 10-20 cm and for two years. In the study at all tension values, the highest volumetric soil water content was obtained for FYM application and the lowest volumetric soil water content for C application. The highest total porosity with macro and micro porosity were found in the FYM application and the lowest total porosity with macro and micro porosity were found in the application C. The available water capacity was the highest in the GM application and the lowest in the C application. In addition, the highest bulk density was found in C application and the lowest bulk density was found in FYM application. These results showed that the effects of different organic material applications on soil physical properties are important.

English

In rainfed tract, the success of agriculture depends on conservation and efficient use of soil moisture and nutrients availability that directly linked with the presence of moisture in soil. The moisture can be conserved through several means including green manures and gypsum addition. The experiment was conducted to investigate the integrated effect of green manures and gypsum for moisture conservation and their impact on wheat production under rainfed conditions. The experiment was planned at six sites with five treatments including gypsum at 1 t ha-1, green manure (Guar 40 days old) and gypsum+green manuring were compared with control (untreated) and farmer practice (traditional). Results showed a significant increase (up to 38 to 76%) in wheat grain yield with the application of gypsum and green manure while soil moisture contents were enhanced up to 34 to 65% compared to control. It was also noticed that the treatments altered the soil properties (pH, Electrical conductivity (Ece), Organic Matter, Available Phosphorous and Extractable Potash) positively by improving soil water relationship over the control. Key words: Gypsum, green manure, moisture contents, soil properties, conservation, wheat yield.

The role of contract type in soil-improving investments: evidence from rice-planting large-scale production units in China

AbstractThe emerging large-scale production units (LSPUs) have become increasingly important in Chinese agricultural production and rural transformation due to rapid industrialization and urbanization. Based on household and plot-level data from Jiangsu and Jiangxi Provinces in China, this study provides insights into the farming systems of these LSPUs and examines how contract type, as a proxy for land tenure security, impacts on the production unit's soil-improving investments. Results from the two-stage control function approach show that the written nature of contracts positively affects the application of organic fertilizer and green manure on rented-in plots. Descriptive analysis also confirms the collateralization effect of contract type by showing that plots that are used as collateral for credit are characterized by written contracts. Policies facilitating LSPUs' access to farmland with more formal contracts may therefore play an important role in improving soil quality and land productivity.

Effect of green manure and plant density on correlation between rhizospheric bio-chemical properties and rice (Oryza sativa) yield

The present investigation was carried out to evaluate the effect of application of green manure along with varying plant density on microbial population and soil enzymatic activities of rhizospheric soil as well as on yield of rice (Oryza sativa L.)during year 2013–14. Application of green manures @15 t/ha and increased plant density up to 44 plants/m2 positively enhanced microbial population in the soil. Correlation among different microbial population, soil enzymatic activities and soil nutrient status in different treatments irrespective of the time intervals showed that the treatments with higher plant density along with green manure showed a significant positive correlation between dehydrogenase enzyme and bacterial as well as with fungal population. On contrary, treatment having sole application of inorganic fertilizer with 22 plants/m2; actinomycetes and bacterial population had significant positive correlation with dehydrogenase activity whereas fungal population showed a negative relationship. The soil urease and alkaline phosphatase activity had positive correlation with bacterial and fungal population in all treatments except the treatment with 22 plants/ m2 + recommended inorganic fertilizers. There was significant negative correlation between fungal population and diazotrophic population in all treatments. The plant height and various yield attributes were significantly higher in treatment having green manure (15 t/ha) + 44 plants/m2+ recommended NPK. Thus, above finding revealed that the agronomic practices (green manure and increased plant density) significantly improved the interaction of microbial population and soil enzymatic activities in rhizospheric soil which in turn affect the soil fertility as well as rice yield.