Fallow replacement using indianhead lentils: water use, yield and oil nitrogen

Because of increased costs of fertilizer and evidence of declining soil quality there has been renewed interest in crop rotations using legumes in the traditional spring wheat-fallow rotation areas of the semiarid northern Great Plains. Objectives were to test a "green fallow" method of farming as a system to build soil nitrogen and efficiently use water. We compared mechanical fallow using sweeps (N1F) and chemical fallow (CF) to green fallow. Fallow treatments MF and CF received 30 lb-N/acre. as N1-14NO3 broadcast prior to seeding wheat (Triticum aestivum L.). Lentils (Lens culinaris Medikus, cv. `Indianhead') were grown as a green manure crop in a green fallow-spring wheat rotation. The experiment was started in 1991 as a randomized complete block with four replications and MF as control. Soil was a Williams loam ( fine-loamy, mixed Typic Argiboroll) 7 miles north of Culbertson Montana. At full bloom, lentils were either killed by disking (GMMF) or chemical burn-down (GMCF). Average dry-weight of Indianhead lentils for 1991, 1992, and 1993 was 1500 lb/acre compared to an average of 4700 lb/acre for 1994 and 1995. Average water use by lentils in 1991, 1992, and 1993 was 10.6 inches. In contrast, MF and CF lost 9.9 inches. Average water use by lentils in 1994 and 1995 was 12.9 inches which was significantly more than the loss of 10.7 inches on MF and CF. At spring planting, there were no differences in soil water content among treatments. Wheat yield was 25% less on green fallow compared to MF and CF. Soil NO3 -N levels were 35 % lower on green fallow rotations than MF and CF rotations. There were no differences among treatments in nitrogen mineralization rates in 1993 following two cycles of green manure. Lack of available nitrogen, rather than lack of soil water, appears to have restricted wheat production on green fallow treatments

Water use and biomass production of oat-pea hay and lentil in a semiarid climate

Suitability of alternative crops in the northern Great Plains remains a question because of water limitations. Objectives were to compare water use of an oat (Avena sativa L.)—pea (Pisum sativum L.) mix grown for hay (OPH) to that of black lentil (Lens culinaris Medikus cv. Indianhead) grown as green manure (BL). Water use and plant biomass for OPH and BL were measured near Culbertson, MT (Site 1), during 4 yr. Soil water was measured by neutron attenuation. Precision-weighing lysimeters were used at Site 2, located 65 km southeast of Site 1, to measure water use. Soil was a Williams loam (fine-loamy, mixed, superactive, frigid Typic Argiustolls). Biomass of crops was measured biweekly. Relative feed value (RFV) based on measured neutral detergent fiber and acid detergent fiber was calculated. Biomass under OPH was 34 and 46% greater than with BL at Sites 1 and 2, respectively. At Site 1, biomass accumulated at a rate of 14 kg ha-1 mm-1 water used under BL and 23 kg ha -1 mm- 1 under OPH. Biomass accumulated at a rate of 21 kg ha- 1 mm-1 under BL and 29 kg ha -1 mm -1 under OPH at Site 2. Hay RFV, at full bloom in pea, averaged 116 (Number 2 hay), and this did not change appreciably as the crop matured to soft dough stage in oat. Oat—pea hay fits the growing conditions in the northern Great Plains and meets the needs of producers for high quality hay

Nuclear transparency from quasielastic A(e,e'p) reactions uo to Q^2=8.1 (GeV/c)^2

The quasielastic (e,e$^\prime$p) reaction was studied on targets of deuterium, carbon, and iron up to a value of momentum transfer $Q^2$ of 8.1 (GeV/c)$^2$. A nuclear transparency was determined by comparing the data to calculations in the Plane-Wave Impulse Approximation. The dependence of the nuclear transparency on $Q^2$ and the mass number $A$ was investigated in a search for the onset of the Color Transparency phenomenon. We find no evidence for the onset of Color Transparency within our range of $Q^2$. A fit to the world's nuclear transparency data reflects the energy dependence of the free proton-nucleon cross section.Comment: 11 pages, 6 figure

Model-independent measurement of t\boldsymbol{t}-channel single top quark production in ppˉ\boldsymbol{p\bar{p}} collisions at s=1.96\boldsymbol{\sqrt{s}=1.96} TeV

We present a model-independent measurement of $t$-channel electroweak production of single top quarks in \ppbar collisions at $\sqrt{s}=1.96\;\rm TeV$. Using $5.4\;\rm fb^{-1}$ of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider, and selecting events containing an isolated electron or muon, missing transverse energy and one or two jets originating from the fragmentation of $b$ quarks, we measure a cross section \sigma({\ppbar}{\rargap}tqb+X) = 2.90 \pm 0.59\;\rm (stat+syst)\; pb for a top quark mass of $172.5\;\rm GeV$. The probability of the background to fluctuate and produce a signal as large as the one observed is $1.6\times10^{-8}$, corresponding to a significance of 5.5 standard deviations.Comment: 8 pages, 4 figures, submitted to Phys. Lett.

Fallow replacement using indianhead lentils: water use, yield and oil nitrogen

Because of increased costs of fertilizer and evidence of declining soil quality there has been renewed interest in crop rotations using legumes in the traditional spring wheat-fallow rotation areas of the semiarid northern Great Plains. Objectives were to test a "green fallow" method of farming as a system to build soil nitrogen and efficiently use water. We compared mechanical fallow using sweeps (N1F) and chemical fallow (CF) to green fallow. Fallow treatments MF and CF received 30 lb-N/acre. as N1-14NO3 broadcast prior to seeding wheat (Triticum aestivum L.). Lentils (Lens culinaris Medikus, cv. `Indianhead') were grown as a green manure crop in a green fallow-spring wheat rotation. The experiment was started in 1991 as a randomized complete block with four replications and MF as control. Soil was a Williams loam ( fine-loamy, mixed Typic Argiboroll) 7 miles north of Culbertson Montana. At full bloom, lentils were either killed by disking (GMMF) or chemical burn-down (GMCF). Average dry-weight of Indianhead lentils for 1991, 1992, and 1993 was 1500 lb/acre compared to an average of 4700 lb/acre for 1994 and 1995. Average water use by lentils in 1991, 1992, and 1993 was 10.6 inches. In contrast, MF and CF lost 9.9 inches. Average water use by lentils in 1994 and 1995 was 12.9 inches which was significantly more than the loss of 10.7 inches on MF and CF. At spring planting, there were no differences in soil water content among treatments. Wheat yield was 25% less on green fallow compared to MF and CF. Soil NO3 -N levels were 35 % lower on green fallow rotations than MF and CF rotations. There were no differences among treatments in nitrogen mineralization rates in 1993 following two cycles of green manure. Lack of available nitrogen, rather than lack of soil water, appears to have restricted wheat production on green fallow treatments