香港有机高尔夫球场的草坪管理研究实施

OGC启德高尔夫球场为香港首个有机高尔夫球场,本文提出了有机高尔夫球场的管理标准,并以有机农业方式作出高尔夫球场草坪的水肥等栽培管理及病虫草害的综合生态防治方法,为今后有机高尔夫球场的发展提供参考。     

Effects of Quillaja saponaria extract alone or in combination with Yucca schidigera extract on ruminal fermentation and methanogenesis in vitro

The objective of the study was to evaluate effects of Quillaja saponaria (QS) with or without Yucca schidigera extract (YS) on in vitro ruminal fermentation and methanogenesis. The culture media consisted of 400 mL of strained rumen fluid collected from two non‐lactating Holstein cows and 400 mL of artificial saliva. The culture media was anaerobically incubated with 10 g of a mixture of concentrate and oat hay (1:1, w/w) at 39°C for 24 h. The treatments were arranged as 2 × 3 factorial design experiment consisting of three levels of QS (0, 2 or 4 mL/L) and two levels of YS (0 or 2 mL/L). Treatment interactions between QS and YS were observed for pH and ammonia N concentration. CH₄ production was not modified by addition of QS but decreased (P < 0.05) when added with YS. Addition of QS with YS increased (P < 0.05) propionate concentrations. Protozoa numbers were decreased (P < 0.05) by QS addition alone or with YS. Results show that QS and YS exhibited strong antiprotozoal effects and combinations of both plant extracts may have potential as safe manipulators of ruminal fermentation.     

Effect of Yucca schidigera with or without nisin on ruminal fermentation and microbial protein synthesis in sheep fed silage- and hay-based diets

A 4 × 6 Youden square design was used to study manipulating effect of Yucca schidigera with or without nisin on rumen fermentation characteristics and microbial protein synthesis in sheep fed silage‐ and hay‐based diets. Four ruminally canulated wethers were given isonitrogenous diets of timothy silage and concentrate (85:15) (S), and timothy hay and concentrate (60:40) (H), on DM basis. The six experimental diets were: (i) S; (ii) S + 240 ppm of Yucca schidigera (SY); (iii) S + 240 ppm of Yucca schidigera + 6 mg/kg bodyweight (BW)^0.75 of nisin (SYN); (iv) H; (v) H + 240 ppm of Yucca schidigera (HY); and (vi) H + 240 ppm of Yucca schidigera + 6 mg/kg BW^0.75 of nisin (HYN). Rumen pH was higher (P < 0.01) in sheep fed SYN diet than those fed S diet. Concentration of ammonia‐N (NH₃‐N) was significantly lower (P < 0.05) in sheep fed SY, SYN, HY, HYN than those of S and H. Total volatile fatty acids concentration was significantly lower (P < 0.05) in HYN than in H diet and tended to be higher in sheep fed H diets than those fed S diets. There was a significantly higher (P < 0.01) efficiency of microbial nitrogen synthesis in the rumen of sheep fed on HY diet than those fed on H diet.     

Effects of Rice Variety and Growth Location in Cambodia on Grain Composition and Starch Structure

The effects of variety and growth location on grain composition and starch structures were investigated using three rice （Oryza sativa L.） cultivars （Phka Romduol, Sen Pidao and IR66） with different amylose contents. All the three cultivars were planted in three different agro-climatic zones （Phnom Penh, Coastal and Plateau） of Cambodia. The protein content of polished grains increased when rice was planted at a location with higher average temperature, but their lipid content decreased. The amylose content and degree of branching were not greatly affected by the minor temperature differences among the growing locations. Starch fine structures characterized by the chain-length distribution were significantly different among the cultivars, but not significantly among different locations. The results suggested that protein and lipid biosyntheses were more sensitive to the environmental temperature than that of starch in rice grains.