In order to understand the effect of different interplantation models on the soil and water losses of young tea oil plantations(Camellia oleifera),the soil and water losses of pure tea oil plantation;tea oil + big gre...In order to understand the effect of different interplantation models on the soil and water losses of young tea oil plantations(Camellia oleifera),the soil and water losses of pure tea oil plantation;tea oil + big green bean(Phaseolus aureua);tea oil + peanut(Arachis hypogaea)were investigated for a whole year in Xinyu,located in the central Jiangxi province.The results showed that the surfaced runoff ranged from 102.03～157.29 t·hm-2a-1 with the average of 136.16 t ·hm-2a-1.The less value was observed in the inter-cropped plantation with peanut,and the runoff values from the pure plantation was very similar to that from the inter-cropped plantation with big green bean,and both were greater by 46.21% and 54.17%,respectively,compared with the inter-cropped stand with peanut.The soil erosion was 139.9～341.3 t·km-2a-1 with the average of 239.9 t·km-2a-1,and the values from the inter-cropped plantations with big green bean and peanut increased by 143.96% and 70.40%,respectively,compared with the pure oil stand.The soil erosion in the 3 type stands was all mild.The nutrient loss ranked from great to small value as the following:Ca 4.645 3 kg·hm-2a-1,K 1.402 6 kg·hm-2a-1,Mg 0.265 1 kg·hm-2a-1,P 0.042 6 kg·hm-2a-1,N 0.039 1 kg·hm-2a-1.The loss in the first half year was significantly greater than that in the second half year,regardless inter-cropped or not.The peak value appeared between March and June.The losses of N,P,and K in the inter-cropped plantation with the big green bean were less than those in the inter-cropped stand with peanut.The loss of K in the inter-cropped stand with peanut was almost the same as the pure plantation,however,the losses of N and P in the inter-cropped stand with peanut were less by 50 percent than that in the pure plantation.展开更多
Understanding the relationship between landscape pattems and ecological processes has been a central yet challenging research theme in landscape ecology. Over the past decades, many landscape metrics have been propose...Understanding the relationship between landscape pattems and ecological processes has been a central yet challenging research theme in landscape ecology. Over the past decades, many landscape metrics have been proposed but few directly incorporated ecological processes. In this paper, we developed a landscape index, namely, location-weighted landscape index （LWLI） to highlight the role of landscape type in ecological processes, such as nutrient losses and soil erosion. Within the framework of the Lorenz curve theory, we develop this index by integrating land- scape pattern and point-based measurements at a watershed scale. The index can be used to characterize the contribution of landscape pattern to ecological processes （e.g. nutrient losses） with respect to a specific monitoring point in a watershed. Through a case study on nutrient losses in an agricultural area in northeastern China, we found that nutrient losses tended to be higher for a watershed with a higher LWLI value, and vice versa. It implied that LWLI can be used to evaluate the potential risk of nutrient losses or soil erosion by comparing their values across watersheds. In addition, this index can be extended to characterize ecological processes, such as the effect of landscape pattern on wildlife inhabitation and urban heat island effect. Finally, we discuss several problems that should be paid attention to when applying this index to a heterogeneous landscape site.展开更多
文摘In order to understand the effect of different interplantation models on the soil and water losses of young tea oil plantations(Camellia oleifera),the soil and water losses of pure tea oil plantation;tea oil + big green bean(Phaseolus aureua);tea oil + peanut(Arachis hypogaea)were investigated for a whole year in Xinyu,located in the central Jiangxi province.The results showed that the surfaced runoff ranged from 102.03～157.29 t·hm-2a-1 with the average of 136.16 t ·hm-2a-1.The less value was observed in the inter-cropped plantation with peanut,and the runoff values from the pure plantation was very similar to that from the inter-cropped plantation with big green bean,and both were greater by 46.21% and 54.17%,respectively,compared with the inter-cropped stand with peanut.The soil erosion was 139.9～341.3 t·km-2a-1 with the average of 239.9 t·km-2a-1,and the values from the inter-cropped plantations with big green bean and peanut increased by 143.96% and 70.40%,respectively,compared with the pure oil stand.The soil erosion in the 3 type stands was all mild.The nutrient loss ranked from great to small value as the following:Ca 4.645 3 kg·hm-2a-1,K 1.402 6 kg·hm-2a-1,Mg 0.265 1 kg·hm-2a-1,P 0.042 6 kg·hm-2a-1,N 0.039 1 kg·hm-2a-1.The loss in the first half year was significantly greater than that in the second half year,regardless inter-cropped or not.The peak value appeared between March and June.The losses of N,P,and K in the inter-cropped plantation with the big green bean were less than those in the inter-cropped stand with peanut.The loss of K in the inter-cropped stand with peanut was almost the same as the pure plantation,however,the losses of N and P in the inter-cropped stand with peanut were less by 50 percent than that in the pure plantation.
基金Under the auspices of Chinese Academy of Sciences (No. KZCX2-YW-421)National Natural Science Foundation of China (No. 40621061, 30570319)
文摘Understanding the relationship between landscape pattems and ecological processes has been a central yet challenging research theme in landscape ecology. Over the past decades, many landscape metrics have been proposed but few directly incorporated ecological processes. In this paper, we developed a landscape index, namely, location-weighted landscape index （LWLI） to highlight the role of landscape type in ecological processes, such as nutrient losses and soil erosion. Within the framework of the Lorenz curve theory, we develop this index by integrating land- scape pattern and point-based measurements at a watershed scale. The index can be used to characterize the contribution of landscape pattern to ecological processes （e.g. nutrient losses） with respect to a specific monitoring point in a watershed. Through a case study on nutrient losses in an agricultural area in northeastern China, we found that nutrient losses tended to be higher for a watershed with a higher LWLI value, and vice versa. It implied that LWLI can be used to evaluate the potential risk of nutrient losses or soil erosion by comparing their values across watersheds. In addition, this index can be extended to characterize ecological processes, such as the effect of landscape pattern on wildlife inhabitation and urban heat island effect. Finally, we discuss several problems that should be paid attention to when applying this index to a heterogeneous landscape site.
