Takatsugu Horiuchi

EFFECTS OF SILICATE MATERIALS ON GROWTH AND GRAIN YIELD OF RICE PLANTS GROWN IN CLAY LOAM AND SANDY LOAM SOILS

The usefulness of silicate materials in rice cultivation has been reported by a number of authors. However, very little has been done to study recycling of silicon (Si)-rich plant residues, such as the use of rice chaffs as soil amendments. Pot experiments were conducted in a green-house at Gifu University in 1997. In this investigation, powdered rice chaff (Cp) and normal rice chaff (Ch) were mixed in a fertile clay loam soil and an infertile sandy loam soil, with or without a biodecomposer (Wara soil). Calcium silicate was also applied to the soils for comparison. For both types of soils, six treatments were replicated four times giving 48 pots (24 × 2) in total with a randomized complete block design. Rice plants (Oryza sativa L. cv. Hatsushimo) were grown in pots filled with the soils as treated above, and the growth and Si and nitrogen (N) contents in the plants and grain yield were determined. Application of rice chaffs had little effect on plant height, but slightly increased the number of tillers per pot. The total N content of the plants was decreased in the clay loam soil but not in the sandy loam soil, but the Si content in the plants, grown in both soils, was increased. The effect of Cp and Ch on the Si content of plants was significantly enhanced by the addition of the biodecomposer. Both organic and inorganic silicate materials increased the number of grains and the dry weights of grains. The application of Cp together with the biodecomposer was the most effective. Cp could be used instead of inorganic Si fertilizer, providing a sustainable Si recycle system in rice cultivation.

Evaluation of the SPAD Value in Faba Bean (Vicia faba L.) Leaves in Relation to Different Fertilizer Applications

Abstract The correlations of the reading of a portable chlorophyll meter (SPAD-502) with the chlorophyll and N contents of leaves of two faba bean (Vicia fabaL.) cultivars, Japanese (Ryousai-issun) and Egyptian (Cairo 241), were examined. The SPAD readings positively correlated (ρ<0.01) with the chlorophyll contents and the r2 values were 0.99 and 1.00 for Ryousai-issun and Cairo 241, respectively. A close linear relationship (ρ0.001) was observed between SPAD reading and total leaf N content at the pod development stage of faba bean plants with r2 = 0.88 and 0.99 for Ryousai-issun and Cairo 241, respectively. The SPAD reading was the highest in the 2nd to 4th leaves counted from the top (the youngest fully expanded leaves). The changes in leaf chlorophyll content of both cultivars from 3 weeks after transplanting to the ripening stage showed an incomplete “M” type curve. SPAD readings were significant¬ly higher in Ryousai-issun than in Cairo 241 throughout the growth season. Organic fertilizers application improved faba bean plant growth. These results suggest that the SPAD-502 chlorophyll meter can be used to measure chlorophyll and nitrogen contents of faba bean leaves for quick screening faba bean genotypes.

Effect of Chinese Milk Vetch (Astragalus sinicus L.) as a Cover Crop on Weed Control, Growth and Yield of Wheat under Different Tillage Systems

Abstract Reduced tillage systems are gaining popularity but weed control is often a limiting factor in the adoption of such systems. Cover crops have become a viable option for sustainable agriculture because of its contribution to soil fertility and improved crop performance. However, the contribution of cover crops to weed management is not clearly defined. We compared minimum tillage (MT) and no-tillage (NT) with conventional tillage (CT) for their effects on wheat growth in an original paddy land clay soil in the presence of Chinese milk vetch as a cover crop. Cover crop biomass, weed emergence, main crop growth and yield and soil penetration resistance were examined. Chinese milk vetch was successfully established under MT and CT but not under NT, which retarded its growth resulting in a significantly large biomass of all weed species. Weed suppression was more effective when the cover crop was broadcasted than row seeded. The presence of milk vetch as a cover crop significantly suppressed weed growth under MT especially at the late stage of growth and resulted in a comparable grain yield to that under CT. Although soil penetration resistance under MT remained high throughout the period of wheat growth, milk vetch could be effectively utilized as a cover crop under MT and wheat grain yield under MT was comparable to that under CT without mulch treatment.

Effects of carbonized chicken manure on the growth, nodulation, yield, nitrogen and phosphorus contents of four grain legumes

The effects of carbonized chicken manure (CCM) on the growth, nodulation, yield, nitrogen (N) and phosphorus (P) contents of four grain legumes (soybean, cowpea, common bean and adzuki bean) were evaluated in a greenhouse experiment. Carbonized chicken manure produced from chicken manure dried in a furnace at 450°C was used in this experiment. The manure was incorporated into the sandy loam soil of each grain legume at two rates (0 kg N ha−1 and 100 kg N ha−1) three weeks before sowing. Growth, nodulation and total biomass N and P were evaluated at peak flowering stage of growth. The CCM showed positive effects on nodule number and weight of soybean and cowpea while it depressed nodule number in adzuki bean. Biomass total N content of soybean and cowpea increased with CCM supply while it decreased in adzuki bean. Biomass and seed total P content of soybean, cowpea and adzuki bean all increased in response to CCM application. Soybean and cowpea seed yields increased by 27% and 43% respectively in response to CCM supply. There was a strong positive correlation between seed P content and seed yield of soybean which indicates the importance of elemental P to soybean seed yield. No such phenomenon was observed in adzuki bean. A strong positive correlation was also observed between seed total N content and seed yield of the grain legumes. The results indicate that although common bean had the highest biomass total P content at peak flowering stage both vegetative and reproductive growth were poor due to the unsuitably high day/night temperatures in the greenhouse. Application of CCM slightly depressed yield of adzuki bean due to the reduction in the number of pods per pot and the 100 seed weight. This study shows that CCM is a good source of N and P for the growth, nodulation and yield of some grain legumes particularly soybean and cowpea.

Residual Effects of Compost and Green Manure of Pea with Other Organic Wastes on Nutrient-Use Efficiency of Successive Rice after Wheat

Adoption of legumes in cereal-based cropping systems and improvement of organic fertilizers are important to reduce chemical fertilizer use. We supplied compost and green manure (GM) of green pea plant residue (GP), without supplementation or supplemented with dried chicken manure (CM) and/or rapeseed oil residue (RR), for wheat and examined the effects of compost and GM (remaining fertilizer) on the rice of pea–wheat–rice system in two factorial pot experiments. Additions of pea residue resulted in an increase of 30% grains of rice compared to without addition, and compost increased 25% grains against GM. Supplementation increased 63–70% of rice grains as compared to the control. Nitrogen (N) and potassium (K) recovery efficiencies were correlated with yield, which suggested that composting and supplementation enabled effective nutrients accumulation in plant, resulting in better yield. Therefore, it is recommended that composting of GP with CM plus RR improves effectiveness of pea on rice of a pea–wheat–rice system.

Bio-active compost from pea plant enriched with chicken manure and oilseed rape cake and its effect on yields and nutrient recovery efficiencies of wheat and rice

Two factorial pot experiments were conducted to evaluate the effect of biodecomposer (BD) and nutrient supplemented compost of pea residue on wheat and rice. Compost was prepared with green pea plant residue (PP), in the presence or absence of BD, without or with dried chicken manure (CM) and/or oilseed rape cake (RC). We assessed the effect of compost on yields and nutrient recovery efficiencies of both crops. Results revealed that BD reduced composting duration and enriched compost with N, P and K. Composts with CM and CM plus RC increased grain yields of wheat and rice. The composts increased grains of wheat and rice nearly 5 and 1.6 times, respectively, above the control. Nitrogen, P and K recovery efficiencies were positively correlated with yields, suggesting that supplementation in composting with CM or CM plus RC enabled effective accumulation of the nutrients, resulting in higher yield. Moreover, BD increased 9.4% of wheat and 6.9% of rice grains. So, composting of PP, in the presence of BD, with CM or CM plus RC is recommend for a pea-wheat-rice cropping system to improve soil fertility and effectiveness of pea on the system.

Effects of powdered rice chaff on growth and yield of rice under different soil pH conditions

Abstract A recent rapid reduction in soil pH has been attributed to fertilizer mismanagement. The decomposition and consequent nutrient release from silicate rich organic material such as powdered rice chaff (Cp) could be affected by such reductions in pH. In the present study, rice plants were grown in either Cp or calcium silicate (Si-Ca) under various soil pH ranging from 5.5 to 7.5. The results show that the pH of soils gradually decreased at different growth stages in the case of pH 6.5 with Cp treatment. On the other hand, pH gradually increased at different growth stages of the rice plants when soil pH was initially 5.5, both with Cp and with calcium silicate. Nitrogen (N) and silicon (Si) contents of the plants decreased gradually with growth stage after the maximum tillering stage. The relationship between Si and N content in the plant at maximum tillering stage showed contradictory results. Si content was higher at pH 6.5 and at pH 5.5 with both Cp and calcium silicate treatments. On the other hand, N content was higher at pH 6.5 and at pH 7.5. Yield and yield components were significantly higher at pH 7.5 with Cp. These results suggest that Cp can be used as an alternative source of inorganic Si fertilizer. The mechanism by which the Cp acts under different pH nutritional conditions is unclear.

Association of grain shedding habit with polyploidy in tartary buckwheat (Fagopyrum tataricum) strains

Abstract Sixty tartary buckwheat (Fagopyrum tataricum) strains were investigated for grain shedding habit, plant height, grain yield, dry weight of plant, weight of grain, days to flowering after sowing and DNA content of nuclei. The grain shedding habit was evaluated from the breaking strength of pedicel and the percentage of the grains dropped by threshing. DNA content of nuclei was detected by flow cytometry to classify the polyploidy level. The fluorescence intensity of the flow cytometry demonstrated no difference between common buckwheat (F. esculentum) and tartary buckwheat, but a clear difference was detected between the diploid and the autotetraploid strains. The survey of DNA content of the 60 tartary buckwheat strains revealed that most of the strains were diploids, but one strain was autotetraploid. The autotetraploid strain exhibited less grain shedding, and produced the largest grains among the strains tested. However, the other characters of the autotetraploid strain, such as plant height, grain yield, dry weight of a plant, and days to flowering, were similar to the mode of the traits of the diploid strains.

Nitrogen Uptake by Faba Bean from 15N-Labelled Oilseed-Rape Residue and Chicken Manure with Ryegrass as a Reference Crop

Abstract The effects of soil amendment with oilseed-rape residue (OSRR) and chicken manure (CM) on the growth and nitrogen (N) uptake of faba bean (Vicia faba L.) were assessed in a pot experiments with Italian ryegrass (Lolium multiflorum Lam.) as a reference crop. A 15N isotope dilution method was used to estimate the amount of N derived from the residue (OSRR and CM) and from atmosphere through N2 fixation in the plants. Dry weights (DW) of shoots and whole plants were heaviest in the plants grown on the soil amended with CM (CM plants) followed by the plants grown on the soil amended with OSRR (OSRR plants) and control plants in this order. There were significant differences (p<0.05) in dry weight between CM, OSRR and control plants. DW of roots was also increased by amendment with either CM or OSRR in faba bean, but it was decreased in ryegrass. The amount of total N in both roots and shoots were increased by application of either CM or OSRR in both faba bean and ryegrass. The amount of N2 fixed by faba bean cultured on 1.2 kg soil amended with 10g residue (CM or OSRR) was 85.9 mg pot-1 but total N in faba bean derived from OSRR and CM was 192 and 374 mg pot-1, respectively. The percentage of N derived from atmosphere to total N in faba bean plants ranged from 15.9 to 26.5%. The amount of N taken up by faba bean and ryegrass plants from CM were larger than those from OSRR by 81.0 and 54.3%, respectively. Soil N balance was calculated as the difference between the amount of N applied (including fixed) and taken up by the plants. The N balance of soil amended with OSRR after cultivation of faba bean was 72.2% higher than that of the soil amended with CM, and that after cultivation of ryegrass was 89.9% higher.