缓释肥料草酰胺合成工艺及其性能

为探究缓释肥料草酰胺的合成工艺及对作物生长的影响,并为作物生长期的合理施肥提供科学依据,利用煤制乙二醇的中间产物草酸二甲酯,在管式反应器中通过氨解反应连续化制备草酰胺。制备草酰胺最佳条件为:甲醇作溶剂,60℃常压下,氨气流速4 L/min,反应液循环回流4 h,最终转化率高达98.70%。对草酰胺肥料性能进行测试,通过测量土壤中铵态氮的含量以探究其缓释性能,最后将草酰胺施用于荞麦田地,通过测量荞麦株高及株粒质量的变化以探究草酰胺肥料对作物生长的影响。结果显示,前70 d施草酰胺的土壤铵态氮含量低于施传统肥料的土壤;70 d后施草酰胺的土壤铵态氮含量高于施传统肥料的土壤,施用草酰胺的荞麦株高及每株粒质量均高于施用传统氮肥。可见,与尿素、碳酸氢铵等传统氮肥相比,草酰胺具有肥效期长、经济效益好等优点,可作为一种优质缓释肥料。

Paddy Soil Stability and Mechanical Properties as Affected by Long-Term Application of Chemical Fertilizer and Animal Manure in Subtropical China

Wet stability, penetration resistance （PR）, and tensile strength （TS） of paddy soils under a fertilization experiment for 22 years were determined to elucidate the function of soil organic matter in paddy soil stabilization. The treatments included no fertilization （CK）, normal chemical fertilization （NPK）, double the NPK application rates （2NPK）, and NPK mixed with organic manure （NPK＋OM）. Compared with CK, Fertilization increased soil organic carbon （SOC） and soil porosity. The results of soil aggregate fragmentation degree （SAFD） showed that fast wetting by water was the key fragmentation mechanism. Among the treatments, the NPK＋OM treatment had the largest size of water-stable aggregates and greatest normal mean weight diameter （NMWD） （P ≤ 0.05）, but the lowest PR and TS in both cultivated horizon （Ap） and plow pan. The CK and 2NPK treatments were measured with PR 〉 2.0 MPa and friability index 〈 0.20, respectively, in the Ap horizon, suggesting that the soils was mechanically unfavourable to root growth and tillage. In the plow pan, the fertilization treatments had greater TS and PR than in CK. TS and PR of the tested soil aggregates were negatively correlated to SOC content and soil porosity. This study suggested that chemical fertilization could cause deterioration of mechanical properties while application of organic manure could improve soil stability and mechanical properties.

Potentials of NPK and Organic Fertilizers on Growth Performance of Cashew （Anacardium occidentale L,） Seedlings on Degraded Typic Alfisol Soils in Ibadan, Nigeria

Sequel to complaints by cashew farmers on poor establishment rate of cashew seedlings on rehabilitated moribund cashew plantations in south western Nigeria, a fertilizer trial involving the use of organic materials （cow-dung, poultry droppings, cocoa and kola pod husks） compared to NPK and control （no fertilizer） treatments was conducted on the growth performance of cashew seedlings at Ibadan, Nigeria. The fertilizers were applied to supply 15 g N seedlingl in 3 replications. Cashew seedling growth parameters and dry matter yield were determined. Fertilizers resulted to consistently general higher plant height, girth, number of leaves and leaf area compared to NPK and control. The differences in the mean values were however not significantly different for girth but it was significant （P 〈 0.5） for plant height, number of leaves and leaf area, while there was no particular regular trend for plant number of branches. Plant root lengths were significantly higher using the organic fertilizers than NPK and control. Similar trend was obtained in the dry weight values for plant leaf, stem, root and total dry matter yield. There was however no consistent significant effect on NPK usage over control for all the parameters. It was therefore deduced that optimal growth performance and better establishment of cashew seedlings could be obtained with the use of organic fertilizers rather than inorganic fertilizer. The use of cocoa pod husk followed by cow-dung and poultry droppings were outstanding in better growth and dry matter yield performance of cashew seedlings and were advised for this purpose.

Effect of Soil Strength and Soil Physical Properties on Performance of Tillage Machines

Soil parameters have significant influence on the performance of tillage machines for various kinds of tillage operations, such as soil movement by tillage tool, soil cutting, soil turning, soil pulverization, and manure injections, etc. This paper attempts to provide a clear overview of soil physical properties and soil strength, and their effects on the performance of tillage machines. Furthermore; it includes the descriptions and characteristics of these parameters, and last developed equipment and procedure for evaluating and assessing of these parameters.

Effect of Inorganic and Organic Based Fertilizers on Growth Performance of Tea and Cost Implications in Kusuku, Nigeria

A plot of 24 m × 10 m under fallow management after several years of cultivation to maize （Zea mays） was planted to tea （Camellia sinensis） cuttings at 1.0 m ×0.6 m and treated with or without fertilizer. The tea cuttings were applied NPK 25：5：5 （reference fertilizer）, cocoa husk, cow-dung, tea fluff and poultry droppings as manures, mixtures of the manures with urea in 3：1 ratio of N contents as organomineral and the control （no fertilizer）, monitored for growth performance for two years at Kusuku （6°50＇N; 11 °07＇E）, Nigeria. The organic based fertilizers generally outperformed NPK 25：5：5 and control in all the growth parameters. Organominerals resulted in an overall higher plant height, girth, number of leaves and branches compared to the manures in the first year of establishment, while the values were higher for manure treated plants in the second year. This trend was attributed to quicker release of nutrient by the organominerals in the first year, while the manures had undergone adequate decomposition for sufficient nutrient release to the advantage of the tea plants in the second year. However, comparative cost analysis showed that organominerals were more economical to achieve optimum tea production at minimum cost in the locality.