The results of the greenhouse tests are shown in Table II and expressed as a percent of yield or uptake of nutrients from the standard sources. The response to nitrogen or phosphorus of the standard fertilizers was two to five times that of the no-nitrogen or no-phosphorus controls, thereby assuring valid comparison among the different nutrient sources. RESULTS AND DISCUSSIONThese experiments clearly show that long-chain crystalline ammonium and potassium ammonium polyphosphates are effective sources of N and P. As shown in Table II, all of the long-chain polyphosphates were good sources of N, although N uptake tended to be slightly lower than from ammonium nitrate. The long-chain polyphosphates prepared from furnace acid gave responses equivalent to or higher than that of monoammonium orthophosphate, but those products made from wet-process acid were slightly less effective.Most of the long-chain polyphosphates were low in available P (citrate + water soluble) and one sample contained only 27 % of its total P in an available form, as shown in Table II. Thus, the conventional availability test indicates that these polyphosphates could not be useful sources of P for growing plants. In spite of their low rating in the availability test all were effective fertilizers, and the results from fine and granular sources showed the usual granule size response obtained from water-soluble P sources in Mountview soil. Apparently, the rate of dis-solution in the soil was sufficient to give agronomic response typical of water-soluble sources. Therefore, the conventional availability test is not valid for these longchain polyphosphates.This investigation has shown that long-chain crystalline ammonium or potassium ammonium polyphosphates may be readily produced by thermal dehydration of orthophosphates or short-chain polyphosphates, and these highly condensed phosphates are effective sources of N and P.

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Applications of the substituted phthalimide growth regulators AC-94377 [1-(3-chlorophthalimido)cyclohexanecarboximide] and AC-99524 [1-tetrahydrophthalimido-cyclohexanecarboximide] to the soil surface stimulated germination and emergence of dormant wild mustard seed (Sinapsis arvensisL. ♯4SINAR) shallowly planted in soil in greenhouse experiments. Surface applications of AC-94377 enhanced the germination and emergence of dormant wild mustard seed planted 0.6 cm deep in soil from nine locations as the rates were raised from 0.4 to 3.7 kg ai/ha. Surface application of AC-94377 increased emergence rates and also extended the period of wild mustard emergence. Increasing quantities of wheat (Triticum aestivumL.) straw on the soil surface reduced the effect of surface-applied AC-94377 on shallowly buried dormant wild mustard seed. When dormant wild mustard seed were buried 1.3, 2.5, or 3.8 cm deep, surface applications of AC-94377 also stimulated greater emergence than the dormant controls from these depths, strongly suggesting that the compound moved from the surface to the depth of planting.

Summary: Wild oat (Avena fatua L.) plants sprayed at the 2‐or 3‐leaf stages of growth with diclotop‐methyl developed chlorosis over the entire leaf blade of all leaves. The leaves became necfrotic 7days after spraying Shool growth was inhibited. In wheat (Triticum aesicum L cv.Waldron) discrete chlorotic areas developed only where the herbicide convicted the 2nd or 3rd leaf with no visible injury so new growth uf'ter treutment. Growth inhibition of susceptible oat (Avena sativa L. cv. Garry) was sensitive to placement of diclutop‐methyl near the upica and meristematic sites of the plant. Chlorosis and necrosis were independent of herbicide placement. Selective herbicide placement induced chlorosis only or both chlorosis and growth inhibition Root growth in wild oat and barley (Hordeum rulgare L. cv. Dickson) was strongly inhibited by 1–0 μM diclofop‐methyl. Wild oat shoots were killed when seedlings were root‐treated with 10 μM diclofop‐melhyl. The 100 μM rool treatment killed barley shoots but only stunted the growth of wheat shoots by approximately 50%. In root‐ireated wheat plants the shoots were turgid and developed a light purple colour, whereas in foliar‐treated plants the shoots developed discrete chlorotic areas.