Weeds hand weeding

Recycling weeds Hand-weeding may seem like a chore compared to the application of sprays, but when those weeds are composted, all the energy and nutrients they have taken from the soil can be returned to the garden without any taint of chemicals. 

Perennial weeds should be controlled prior to mulching and planting. Polythene mulching of raised beds can help to control weeds. Hand weeding of weeds from planting holes may be needed dming crop production. 

Selective toxicity is also important in relation to the development of resistance or tolerance to pollutants from two distinct points of view. On the one hand, there is interest among scientists concerned with crop protection and disease control in mechanisms by which crop pests, vectors of disease, plant pathogens, and weeds develop resistance to pesticides. Understanding the mechanism should point to ways of overcoming resistance, for example, other compounds not affected by resistance mechanisms or synergists to inhibit enzymes that provide a resistance mechanism. On the other hand, the development of resistance can be a useful indication of the environmental impact of pollutants. 

In organic systems the number of hours of hand weeding needs to be reduced, as labour, particularly in the developed countries, is expensive. This can be achieved by competition, the timing of cultivations, adaptation of the rotation nutrient management system and by crop density (Kropff, et al., 2000). Barberi, et al. (2002) experimented with a system of soil disinfection using hot steam to sterilise weed seeds. 

Weed control Sterile substrate 1 x hoeing, 1 X hand weeding... 

Weed competition for water and nutrients can have similar effects on fruit quality as described above for fertilisation. For example, if weed competition is completely prevented by chemosynthetic herbicides in conventional production, this can lead to excess supply of certain mineral nutrients, in particular nitrogen and potassium, which in turn results in reduced sensory quality and shelf-life (Section 16.2.2). On the other hand, excessive weed competition, in particular, during the pre-bloom phase and the end of the first shoot growth period (Gut and Weibel, 2005), can induce nutrient and/or water deficiency and a risk of quality loss. 

In many crops where weed killers are used, applications must be made with care or the crop being weeded may suffer. This takes some attention. Coffee showed characteristic injuries (22, 51) from applications of the weed killers 2,4-D, TCA, and CMU [3-(p-chlorophenyl)-l,l-dimethylurea]. On the other hand, as in other tree crops, further work on coffee proved that, if properly handled, weed sprays did not result in important permanent harm to the trees. Some of the most recent work has shown (22) that amine salts and butoxyethanol esters of 2,4-D caused less... 

II period emphasize hand weeding and immediate reseeding of all areas of weed growth. 

Left) Hand-weeding If you hand-weed regularly, and the soil is moist, you can develop a quick "nipping" action that makes weeding almost pleasurable. Weeds that have only gained a superficial foothold in a loose mulch are particularly satisfying to remove. 

Paths and patios can aiso be hand-weeded. There are toois speciaiiy designed to heip pry weeds from cracks between paving siabs. 

Remove individual weeds like daisies, plantains, and dandelions by hand, using an old kitchen knife or special tool, such as an asparagus fork. 

Control of weeds in fruit is just as important as for vegetables—except where fruit trees are growing on vigorous rootstocks. A full-sized fruit tree surrounded by a wildflower meadow gains many benefits from it, and together this association forms a valuable wildlife habitat. But in the case of small trees and all soft fruits, weeds compete with the crop plants for light, water, and nutrients if very profuse, they can reduce air flow and increase the likelihood of fungal attack. Do not let weeds get out of hand. 

Plant diseases, nematodes, weed seed and even insects can be carried from place to place on eqnip-ment, introduced into the garden with transplants or moved by insects and hnman hands. Keep eqnipment clean. Remove soil from tillers and garden equipment after using them. This is especially important if they are to be moved between farms, fields or even parts of the yard. 

The uracils with herbicidal activity do not necessarily contain 5-halo substituents. 3-Cyclohexyl-5-methyluracil [354] (XLIV), l,3-di-isopropyl-6-methyl-uracil [352] (XLV) and 3-s-butyl-5-thiocyanato-6-methyluracil [353] (XLVI), for example, are cited as having this type of activity. 3-Butyl-6-methyluracil (XLlllc) possesses interesting selective activities. For instance, this pyrimidine kills many annual weed species without damage to peas and peanuts, even when applied at twice the concentration needed to kill the weeds [346]. On the other hand, the related 5-bromo derivatives, such as (XLlIlb), are useful as industrial herbicides where it is desirable to kill all plants [346]. 

Table II summarizes these results. Most noticable is the good activity of the m-toluate against wild oats and black grass but poor activity against mustard. On the other hand, mustard is very sensitive to the -toluate, whereas wild oats and black grass are quite tolerant. Careful studies with the more active enantiomer of AC 222,293 showed it to be approximately twice as active as AC 222,293. It should be noted that the selectivity shown by AC 222,293 is dependent on the presence of the methyl ester function. The acids are not selective but studies (2) indicate that it is, in fact, the acid which is the toxicant and this is liberated at different rates from the ester in the sensitive weeds and the crops.

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