论文部分内容阅读
在下北岛七个试验点逐月采样分析,研究了牧草中总含氮量(N_t)、总含硫量(S_t)、氮/硫比率[(N/S)_t]、非蛋白质氮(N_(np))、总水溶性碳水化合物(TWSC)以及N_t/TWSC比率的季节性变化。虽然三叶草中总含氮量一般高于禾草,但在二者的化学成分中N_t的变化趋势相似。最高浓度出现在深秋至早春期间,最低浓度出现在夏季,而禾草的N_t在夏季的最低浓度又比三叶草的明显得多。考虑到放牧绵羊排回草场的尿可能的随机影响,禾草和三叶草的N_t随月分的波动是相似的。总含硫量的季节性变化不大,但禾草的含量通常高于同期的三叶草的含量,这是土壤中硫源丰富,禾草积累硫酸盐式硫较多的反映。然而,考虑到某些地方硫的供给极不适当,禾草的(N/S)_t比率在7至16的范围内,三叶草的(N/S)_t比率在14至21之间。N_(np)含量是用混合牧草测定的,其变化趋势与N_t一致。N_(np)占N_t的16—20％,各试验点之间的变化很小。TWSC含量在试验点之间和月与月之间的变化都显著,这对一个已知的表现出很大的周日和季节性波动的成分来说,是并不意外的。其平均值表明在夏末到秋季有最小值,在冬季有最大值的某些迹象。N_t/TWSC比率常常高于曾报道过的危险值0.3(美国西部半干旱草地春季禾草草场的数值),但在新西兰的情况下,将其作为“饲草性痉挛症”危害的一个指标的意义还不清楚。
The monthly nitrogen content (N_t), total sulfur (S_t), nitrogen / sulfur ratio [(N / S) _t] and non-protein nitrogen (N_ (np)), total water soluble carbohydrate (TWSC) and Nt / TWSC ratio. Although the content of total nitrogen in clover is generally higher than that of grass, the trend of N_t in the chemical composition of the two is similar. The highest concentration appeared in late autumn to early spring, the lowest concentration appeared in summer, and grass N_t lowest concentration in summer and clover significantly more. Considering the possible random effects of urine released from grazing sheep on pasture, the N_t of grasses and clovers is similar to that of the month. Seasonal changes in total sulfur content is not significant, but the grass content is usually higher than the clover content of the same period, which is rich in sulfur in the soil, the accumulation of sulfate-based grass reflects more sulfur. However, considering the extremely inappropriate supply of sulfur in some areas, the (N / S) _t ratio of grass is in the range of 7 to 16, and the (N / S) _t ratio of clover is between 14 and 21. The content of N_ (np) was determined by mixed forage, and the trend of N_ (np) was consistent with N_t. N_ (np) accounted for 16-20% of N_t, the change between the test points is small. The TWSC content varies significantly between test sites and between months and months, which is not surprising for a component known to exhibit significant sun and seasonal fluctuations. The average shows some signs of a minimum in late summer to autumn and a maximum in winter. The N_t / TWSC ratio is often higher than the previously reported hazard value of 0.3 (the value of the spring grassy pasture in western United States semi-arid grassland) but in New Zealand it is used as an indicator of the hazard of “fodder spasms” The meaning is not clear.