Adeli A, Varco J J, Rowe D E
USDA-ARS, Waste Management and Forage Research Unit, Mississippi State, MS 39762, USA.
J Environ Qual. 2003 Mar-Apr;32(2):681-6. doi: 10.2134/jeq2003.6810.
Maximizing utilization of effluent nutrients by forage grasses requires a better understanding of irrigation rate and timing effects. This study was conducted in 1998 and 1999 on a Vaiden silty clay (very-fine, smectitic, thermic Aquic Dystrudert) soil to determine the effects of swine lagoon effluent irrigation rate and timing on bermudagrass [Cynodon dactylon (L.) Pers.] growth, nitrogen (N) and phosphorus (P) recovery, and postseason soil profile NO3(-)-N. Treatments consisted of swine effluent irrigation at the rates of 0, 5, 10, 15, and 20 ha-cm. Two additional treatments included 2.5 ha-cm applied on 1 September and 1 October in addition to a base summer rate of 10 ha-cm. In both years for early to mid-season irrigation, bermudagrass dry matter yield quadratically increased with increasing swine effluent irrigation rates. Averaged across years, effluent irrigation in October resulted in 30% less dry matter than in September. For late-season irrigation, apparent N recovery averaged 59% less and P recovery averaged 46% less with a delay in irrigation from 1 September to 1 October. The greatest quantity of soil NO3(-)-N was associated with both the greatest effluent rate and October irrigation treatments. Minimal yield benefit was obtained when effluent was applied at rates greater than 10 ha-cm during the summer months. Late-season irrigation, especially after 1 October for areas with similar climatic conditions, should be avoided to maximize synchronization of nutrient availability with maximum growth rates to minimize potential offsite movement of residual soil N and P.
要使饲草最大限度地利用污水中的养分，需要更好地了解灌溉速率和时间的影响。本研究于1998年和1999年在Vaiden粉质粘土（极细、蒙脱石、热性潮湿雏形土）土壤上进行，以确定猪 lagoon 污水灌溉速率和时间对狗牙根[Cynodon dactylon (L.) Pers.]生长、氮（N）和磷（P）回收以及季后土壤剖面NO3(-)-N的影响。处理包括以0、5、10、15和20公顷-厘米的速率进行猪污水灌溉。另外两个处理包括除了10公顷-厘米的夏季基本灌溉量外，在9月1日和10月1日分别额外施加2.5公顷-厘米的灌溉量。在这两年中，对于早季到中季灌溉，狗牙根干物质产量随着猪污水灌溉速率的增加呈二次方增加。多年平均来看，10月份的污水灌溉干物质产量比9月份少30%。对于晚季灌溉，从9月1日推迟到10月1日灌溉，表观氮回收率平均降低59%，磷回收率平均降低46%。土壤中NO3(-)-N含量最高的情况与最大污水灌溉速率和10月份灌溉处理相关。在夏季月份，当污水灌溉速率大于10公顷-厘米时，产量增加最少。应避免晚季灌溉，特别是在10月1日之后对气候条件相似的地区进行灌溉，以最大限度地使养分供应与最大生长速率同步，从而将残留土壤氮和磷的潜在场外迁移降至最低。
