A laboratory study of the erodibilities of four agriculturally productive soils

Soil erosion by water is a serious problem throughout the world. It has been studied for most of this century, but much remains unknown and mis\mderstood. A study was conducted at The University of Tennessee to investigate relationships among soil properties and their possible uses as indicators of erodibility. Soil losses from four agriculturally productive East Tennessee soils were investigated under simulated rainfall. The effects of soil moisture, particle size distribution, organic matter, and other soil properties were studied, along with the effect of storm intensity. The largest difference between expected and observed erodibilities appeared to be due to the effect of a strong structure in a finer-textured (clay loam) soil. Subangular blocky structure was not expected to correspond to low erodibility. However, when the permeability of the underlying soil is sufficient and the aggregates are water stable, most of the water that strikes the surface enters the soil rather than becoming soil-carrying runoff. The findings of the study indicated that intensity and antecedent moisture do not affect all soils equally. Soil-loss tests used to compute a general erodibility value for a particular soil must include as much of a range of conditions as can be expected for that soil. The resulting value will be a good average, but probably a poor predictor for specific cases. Additional work is needed to be able to accurately predict soil loss from a particular site induced by a specific storm

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.While rice is produced in some parts of the world in an upland, rainfed culture, almost all US-produced rice is grown with flood irrigation. In the dry-seeding system commonly used in the midsouthern US, the crop is usually flooded at approximately the V-4 (early tillering) growth stage and a continuous flood is maintained until after heading. The total amount of water used in rice production is quite large, and soil, fertilizers, and pesticides can be carried in the runoff from agricultural fields. Flood depth affects most aspects of flooded rice production, and remote monitoring of the flood depth could be quite valuable to many producers. The objective of this research is to develop and test a system for monitoring water depths in rice fields and alerting the producer so that less labor and energy is required to efficiently manage flood-irrigated rice. A prototype monitoring station was designed to measure water depth in a flooded rice field and transmit the information over a wireless link. A similar sensor and circuit performed satisfactorily in a raingage in 2006. In 2007, prototype monitoring stations will be installed in production rice fields. Concurrently with sensor durability testing, tests will be conducted to determine the limits of the wireless communication system. With daily reports of the water status in each paddy, field visits can be reduced. Over-pumping should be minimized by allowing better scheduling of field visits to stop the pump, and future systems should work with automatic pump control systems to stop the pump before runoff occurs

Corn response to nitrogen is influenced by soil texture and weather

Citation: Tremblay, Nicolas, Yacine M. Bouroubi, Carl Bélec, Robert William Mullen, Newell R. Kitchen, Wade E. Thomason, Steve Ebelhar, et al. “Corn Response to Nitrogen Is Influenced by Soil Texture and Weather.” Agronomy Journal 104, no. 6 (2012): 1658–71. https://doi.org/10.2134/agronj2012.0184.Soil properties and weather conditions are known to affect soil nitrogen (N) availability and plant N uptake. However, studies examining N response as affected by soil and weather sometimes give conflicting results. Meta-analysis is a statistical method for estimating treatment effects in a series of experiments to explain the sources of heterogeneity. In this study, the technique was used to examine the influence of soil and weather parameters on N responses of corn (Zea mays L.) across 51 studies involving the same N rate treatments which were carried out in a diversity of North American locations between 2006 and 2009. Results showed that corn response to added N was significantly greater in fine-textured soils than in medium-textured soils. Abundant and well-distributed rainfall and, to a lesser extent, accumulated corn heat units enhanced N response. Corn yields increased by a factor of 1.6 (over the unfertilized control) in medium-textured soils and 2.7 in fine-textured soils at high N rates. Subgroup analyses were performed on the fine-textured soil class based on weather parameters. Rainfall patterns had an important effect on N response in this soil texture class, with yields being increased 4.5-fold by in-season N fertilization under conditions of “abundant and well-distributed rainfall.” These findings could be useful for developing N fertilization algorithms that would allow for N application at optimal rates taking into account rainfall pattern and soil texture, which would lead to improved crop profitability and reduced environmental impacts