When we read Mr. Jun Zhu′s paper: a model of the age patterns of births by parity in natural fertility populations published in Mathematical Population Studies, Vol.4(3), pp.153～173, 1994, it really surprised us by ...When we read Mr. Jun Zhu′s paper: a model of the age patterns of births by parity in natural fertility populations published in Mathematical Population Studies, Vol.4(3), pp.153～173, 1994, it really surprised us by his creative ideas and perfect results. We studied the paper deliberately because it is a remarkable work, and could be a significant contribution to the modeling of fertility analysis. As some contents not perceivable to us, we would expect to discuss with Mr. Jun Zhu to make a clear comprehension of the models in the paper. Our aim is to lead the models and the theory more reliable and practical.展开更多
Natural organic fertilizers are receiving increased attention as a nutrient source for athletic turf fields. However, the performance of these fertilizers as an alternative to inorganic fertilizers is relatively untes...Natural organic fertilizers are receiving increased attention as a nutrient source for athletic turf fields. However, the performance of these fertilizers as an alternative to inorganic fertilizers is relatively untested. To address this issue, we initiated a study to evaluate turfgrass response to the use of pelletized poultry litter （PPL） as a nutrient source compared to inorganic fertilizer, and to compare core aeration and vibrating aeration. Four treatments were evaluated： synthetic fertilizer with vibrating aeration （VS）, synthetic fertilizer with core aeration （CS）, PPL with vibrating aeration （VP）, and PPL with core aeration （CP）. The PPL was applied at a nitrogen （N） rate equivalent to the synthetic fertilizer （assuming 50% availability of N）. Application of PPL did not produce significant changes in measured soil parameters during the 2.5 year study compared to the synthetic fertilizer. Minimal differences in tissue concentrations of Mn were observed. Remote sensing indicated that the CS treatment, which is the current management practice at the study site, produced the lowest turfgrass quality of all the treatments. Highest turf quality was achieved with the CP and VS treatments. Application of PPL resulted in greater turfgrass quality when compared to the same N rate of synthetic fertilizer, regardless of aeration method.展开更多
文摘When we read Mr. Jun Zhu′s paper: a model of the age patterns of births by parity in natural fertility populations published in Mathematical Population Studies, Vol.4(3), pp.153～173, 1994, it really surprised us by his creative ideas and perfect results. We studied the paper deliberately because it is a remarkable work, and could be a significant contribution to the modeling of fertility analysis. As some contents not perceivable to us, we would expect to discuss with Mr. Jun Zhu to make a clear comprehension of the models in the paper. Our aim is to lead the models and the theory more reliable and practical.
文摘Natural organic fertilizers are receiving increased attention as a nutrient source for athletic turf fields. However, the performance of these fertilizers as an alternative to inorganic fertilizers is relatively untested. To address this issue, we initiated a study to evaluate turfgrass response to the use of pelletized poultry litter （PPL） as a nutrient source compared to inorganic fertilizer, and to compare core aeration and vibrating aeration. Four treatments were evaluated： synthetic fertilizer with vibrating aeration （VS）, synthetic fertilizer with core aeration （CS）, PPL with vibrating aeration （VP）, and PPL with core aeration （CP）. The PPL was applied at a nitrogen （N） rate equivalent to the synthetic fertilizer （assuming 50% availability of N）. Application of PPL did not produce significant changes in measured soil parameters during the 2.5 year study compared to the synthetic fertilizer. Minimal differences in tissue concentrations of Mn were observed. Remote sensing indicated that the CS treatment, which is the current management practice at the study site, produced the lowest turfgrass quality of all the treatments. Highest turf quality was achieved with the CP and VS treatments. Application of PPL resulted in greater turfgrass quality when compared to the same N rate of synthetic fertilizer, regardless of aeration method.
