Browse on keywords: weed fertility
Search results on 05/18/13
2181. Gill, G.S. and W.M. Blacklow. 1984. Effect of Great Brome (Bromus diandrus Roth.) on the growth of wheat.. Aust. J. Agric. Res., 35:1-8.
Studied competition between wheat and great brome. Competition with great brome reduced the concentration of nitrogen and phosphorous in wheat shoots. The reduction suggested that great brome competed with wheat for absorption of nitrogen and phosphorous. Competition with great brome also resulted in significant reduction in the grain yield. Reduction in mass per grain was probably due to competition with great brome for water during grain-filling.
2221. Goldstein, Walter A.. 1986. Alternative crops, rotations, and management systems for dryland farming.. Ph.D. dissertation, Agronomy and Soils, WSU.
This work covers a number of research areas, including the use of edible white lupine as an alternative crop, the use of black medic in rotation with spring peas and winter wheat (the PALS concept), performance of winter wheat as influenced by rotations, fertilization, and fumigation; rotational effects of medics; wheat interference with weeds; costs and returns of alternative systems; comparison of agronomic effects of conventional, organic, and biodynamic management. The PALS (perpetuating alternative legume system) concept was field-tested using a pea + medic - medic GM - winter wheat rotation with limited inputs of agrichemicals and tillage. This system was more economic using market prices of commodities at both a low and high yield level. With government support prices, the PALS system was competitive in the low yield situation, but not the high. Rotational effects appeared to suppress weeds in wheat with the medic compared to a continuous cereal system.
2809. Hume, L.. 1982. The long-term effects of fertilizer application and three rotations on weed communities in wheat.. Can. J. Plant Sci., 62:741-750.
The effect of fertilizer application and three rotations (continuous cropping, fallow-wheat, and fallow-wheat-wheat rotations)on the species composition of the weed community was examined using rotations that had been running for 21-22 yrs. Fertilizer application tended to reduce community differences between continuous cropping and short-term wheat-fallow rotations. With the use of 2- or 3-yr wheat-fallow rotations and herbicide application, weed problems can be minimized in southeastern Saskatchewan.
2862. Hurd-Karrer, A.M.. 1946. Relation of soil reaction to toxicity and persistence of some herbicides in greenhouse plots. USDA Technical Bulletin 911.
Deals with herbicides used prior to 2,4-D, such as sodium chlorate, sodium thiocyanate, ammonium sulfamate, borax. Initially, all herbicides were most toxic in acid soils, and least toxic in alkaline soils, and persisitence was similar. Borax was the most persistent. Nitrogen fertilizer did not reduce chlorate toxicity in a practical manner.
2889. Idaho Agr. Expt. Sta.. 1947. Annual report. ID Agr. Expt. Sta. Bull. #269.
Weed response to 2,4-D - perennials; alfalfa by fertilizer experiments - hay yield over 4 T/ac, responded to P,S; wheat yields after 7 yr alfalfa responded to S and ammonium sulfate; yields up to 68 bu/ac. T: weed response to 2,4-D.
3945. Mahler, R.L.. 1981. Implications of acidification of farmland in northern Idaho.. ID Agr. Expt. Sta. CIS #629.
Loss of Ca and Mg is primarily by crop removal in northern Idaho; wheat crop removes 20-50 lb/ac/yr of each cation; ammonium-based fertilizers have been main acidifying factor; had been a big change in past 25 yrs; large % of soils now below pH 6.0; current wheat varieties in Idaho acid intolerant; soil acidity may favor certain weeds and diseases.
5735. Rasmussen, P.E. and C.R. Rohde. 1988. Stubble burning effects on winter wheat yield and N utilization under semiarid conditions.. Agronomy J. 80:940-942.
Burning vs. not burning was examined at 3 nitrogen levels over 6 years (3 crops). Burning had no effect on grain yield or grain N uptake. Burning increased straw yield when wheat was fertilized by N, but had no effect on straw N uptake. Burning did not decrease foot rot incidence or severity, but did reduce downy brome density. T: Effects of stubble burning and N fertilization on grain and straw of winter wheat 1980-85. Effect of stubble burning on foot rot infection. Effect of stubble burning on downybrome infestation.
6276. Singh, H. and J.P. Agarwal. 1983. Studies on nitrogen fertilization and weed management in wheat.. Indian J. Agron., 28(1):23-29.
About 40-45 kg N/ha could be saved by pre-emergence application of tribunil over the conventional method of weeding.
6293. Singh, H.P. and J.P. Agerwal. 1982. Studies on nitrogen fertilization and weed management in wheat.. Indian J. Agron., 27(1):71-77.
Nitrogen fertilization did not affect composition, density and dry matter accumulation in weeds. The concentration of N in weeds tended to increase with nitrogen application. Tribunil for weed control. Liberal doses of fertilizers and frequent irrigation have been adopted to realize maximum yields in Mexican dwarf wheats, and have stimulated the rank growth of weeds. The weed flora of wheat has greatly changed in the recent past and some new obnoxious non-legume weeds like Phalaris minor and Avena fatua have come into prominence. Similarity to wheat plant in early stages.
6301. Singh, R.A., O.P. Singh and M. Singh. 1976. Effect of soil compaction and nitrogen placement on weed populations.. Plant and Soil, 44:87-96.
Field experiements showed that soil compaction did not affect wheat yield significantly under rainfed conditions. Weed population was significantly reduced due to soil compaction. Compaction decreased total moisture use and increased water use efficiency. Weed population was not affected due to nitrogen placement. Under rainfed conditions, deep placement of nitrogen was important for increasing the efficiency of fertilizer as well as water utilization by wheat crop.