NITROGEN MANAGEMENT IN SOUTHEASTERN MINNESOTA

Crop Production/Industries,

Establishing a Baseline for Nitrogen Policy Assessment

nitrogen, nitrogen use efficiency, nitrogen management, Environmental Economics and Policy,

Nitrogen Management

Nitrogen is the plant nutrient most universally needed for high crop yields. The most abundant source of nitrogen is the inert gas N2, which constitutes approximately 78% of the earth\u27s atmosphere. This gas is unusable by plants; it must be converted, either by industrial processes or by natural soil microorganisms, to forms a plant can take up

Nitrogen management for corn

As pressure continues to reduce production costs, to manage risks, and to reduce loss of N to the environment, managing nitrogen remains a major challenge to Corn Belt corn producers. Major considerations include N rate, form of nitrogen, use of stabilizers, and method and timing of application

The NDICEA model: a supporting tool for nitrogen management in arable farming

Nitrogen use ef ficiency is an important item i n organic farmi ng. Modelling nitrogen dynamics can help to understand the impact of alter native agronomic practices and thus assist in decision making. In three exampl es in the Netherlands, the role of the NDICEA model is demonstrated. I t is concluded that NDICEA is an easy to use and helpful tool for optimizing nitrogen efficiency and mi nimizing losse

Nitrogen management of organic winter wheat Decision-making through model-based explorations

In organic wheat, nitrogen is one of the key limiting factors responsible for irregular productivity and low quality (David et al, 2005b), 5 to 50 % less than conventionally managed crops (Nieberg and Schulze Pals, 1996). On arable farms, the decreasing use of N-organic sources such as forage legumes, manures and composts relative to mixed-farms requires the development of suitable fertility strategies based on the use of off-farm organic fertilizers. Numerous mechanistic crop models simulating the dynamics of crop requirements and N supply in the soil (e.g. CERES, EPIC, APSIM, ARCWHEAT STICS) have previously been developed (Whisler et al, 1996). Although these models are highly used in research, their complexity and input requirements have limited their practical use for farmers and advisers. The aim of this study was to develop an engineering approach (Passioura, 1996) by the development of a decision-making tool for assessing N management of organic wheat on commercial farms. Azodyn-Org crop model was developed in organic agriculture to predict the influence of spring N fertilization strategies on grain yield, grain protein content, mineral N in the soil at harvest and gross margin (David et al., 2004). This simpler model requires little input data, which are easily measured in farmers’ fields (soil characteristics, climatic data, crop biomass and mineral N in the soil at the end of winter). The performance of Azodyn-Org was relevant for selecting appropriate strategies in a large range of environment and crop management conditions (David et al., 2005a). This paper focuses on the potential contribution of model-based explorations from Azodyn-Org for managing N fertilization in organic wheat crops at the regional scale

Nitrogen management in organic cauliflower

Consumers expect that the production of organic vegetables is less harmful to the environment compared to conventional vegetable cropping. However, vegetables with a high nitrogen demand such as cauliflower may cause intensive leaching of nitrate to natural waters in conventional as well as in organic production. In addition, organic growers face difficulties in providing adequate amounts of organic fertiliser in order to attain high yields due to the scarcity of organic livestock manure. In organic cropping systems, the use of an in-season living mulch may decrease the need for fertiliser and the risk of nitrate leaching. It may also improve nitrogen nutrition for next season’s crop. The aim of this study was to investigate the effect of growing an in-season living mulch of grass-clover on cauliflower yields, nitrate leaching over winter, and soil nitrogen availability the following spring. A field experiment was performed on a sandy loam soil using two varieties of cauliflower and with or without grass-clover as living mulch. The mulch consisted of an overwintering grass-clover that was incorporated in strips before the planting of cauliflower, and two levels of fertilisation (dried chicken manure) were applied. Plant samples were taken for evaluation of marketable and non-marketable yields, and for analysis of dry matter and nitrogen content. Evaluation of inorganic N-content in the soil was done at planting, at harvest, in late autumn and in spring by taking soil samples to a depth of 1.5 m. Results show that high yields of cauliflower can be maintained per meter plant row, whereas no effects on nitrate leaching could be observed in a cropping system with an in-season living mulch of grass-clover