Crops shallow soil

Molinate is a selective pre- and postemergence soil herbicide mainly for the control of grass weeds and particularly for Echinocloa spp. (Smith and Fox, 1965). It is applied either before planting to water-seeded or shallow soil-seeded rice, or post flood on other types of rice culture. Applied at its recommended rate of 2-4 kg active ingredient/ha, its action lasts over the whole crop period (Swain, 1974). 

Habitat The tau zone. Shallow-soiled slopes and mountain brook valleys as a weed among unirrigated cereal crops. 

SNS indices for sequences of crops following grassland ate more complicated. Table 4.5 shows an example of indices for a medium soil or shallow soil (not over sandstone) in any rainfall area. 

Barley is an important crop, with the best quality grains sold for malting and the remainder used for feeding all classes of stock, especially pigs, dairy cows and intensively fed beef. Barley straw can be used for bedding and as a maintenance ration. Barley is a shallow-rooted crop which grows well on chalk and limestone soils, with a preferred pH of 6.5. Its place in the rotation can be when soil fertility is low, which means that it can follow a previous cereal crop such as wheat. 

Irrigated. Grown in levelled, bunded fields with good water control. Crop is fiansplanted or direct seeded in puddled soil, and a shallow floodwater is maintained on the soil surface so tiiat the soil is predominantly anoxic during crop growth. 

Despite the burning of crop residues in the productive, irrigated rice areas of tropical and subtropical Asia, and their removal for other purposes in the low-producing rainfed rice areas, soil carbon levels are largely constant (Bronson et al., 1998). In any case, the amount of carbon in the shallow puddled layer of ricefields amounts to only a few per cent of the amount in natural wetlands. 

Kouwenhoven, J.K., Perdok, U.D., Boer, J. and Oomen, G.J.M. 2002. Soil management by shallow mouldboard ploughing in The Netherlands. Soil and Tillage Research 65 125-139. Liebman, M. and Davis, A.S. 2000. Integration of soil, crop, and weed management in low-... 

Finally, certain triazine herbicides can be used selectively in orchards and in some horticultural crops. In this case, selectivity is not based only on physiological differences between species, but on physical selectivity associated with the location of the herbicide and the roots of the crop and weed species in the soil. Triazine herbicides such as simazine, which has very low solubility in water, remain close to the soil surface in most mineral soils. Careful application of simazine in horticultural or fruit crops can result in the herbicide being available to control shallow-rooted weed species without harming the deeper-rooted perennial species. The success of this use is dependent not only on the relative rooting depths of the tolerant and susceptible species, but also on soil conditions and other factors that may affect herbicide fate and movement. 

As mentioned earlier, high salt contents in water (e.g., Na, Ca, and Mg sulfates) in contact with soils produce salinization (i.e., excess salinity). Other causes of salinization include high water tables, high evaporation rates, and low annual rainfall. Excessive salinity makes it more difficult for plant roots to take in water, which considerably reduces crop yields and also degrades the quality of shallow groundwater and of surface water. 

The cause in some of the cases is of a physical character. Herbicidal compounds poorly soluble in water are located in the upper layer of the soil, and are thus absorbed by the shallow-rooted weeds, which are killed while they do not reach the roots of the deep-rooted crop plants, which can grow unhindered. Translocation proceeding at different rates in tolerant and sensitive plants and the detoxication of the translocating herbicide through deposition in parts of the plant, such as the cell... 

Deep plowing (8-12 inches with a moldboard plow), if properly done over a period of a few years, will gradually increase the depth of the topsoil. For most field crops, as stated above, this may have little effect but for certain special crops, such as vegetables, there is some evidence that this is beneficial on some soils. Crops, such as carrots, parsnips, and sweet potatoes, that prefer a loose soil, may grow better in a deep topsoil, well-supphed with humus, than in a shallow one. The importance of such deep soils in gardening is still uncertain because most deep plowing experiments have been conducted with field crops, and often in soils where root penetration was not an important factor Needless to say, there is a marked difference in the response of different kinds of plants to the soil environment. 

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