A field experiment with an early rice-late rice rotation was carried out on a paddy soil derived from red soil in the southern part of Zhejiang Province to elucidate the effect of excess P application on some importan...A field experiment with an early rice-late rice rotation was carried out on a paddy soil derived from red soil in the southern part of Zhejiang Province to elucidate the effect of excess P application on some important characteristics of soil properies and its relation to nutrient status and grain yields of rice crops.The experimental results indicated that adequate fertilizer P (15 kg P hm-2) could increase the content of soil available P at the tillering stage of early rice, the contents of N, P and K in the shoots of early rice at primary growth stages, and the grain yield of early rice by increasing valid ears per hectare and weight per thousand grains, which was mainly related to the higher contents of reduced, non-reduced and total sugar in the shoots at the heading stage. And early rice supplied with excessive P could not yield more than that applied with adequate P, due to the reduction in the valid grain percentage and weight per thousand grains.In addition, onestime excess P supply at a rate as high as 90 kg P hm-2 could not improve the soil P fertility in case the soil available P content was lower than the initial (3.74 mg kg-1 soil) after an early rice-late rice rotation, and made a decline in the grain yield increased by per kilogram fertilizer P. Thus, one-time excess P supply should not be adopted for soils with a large P fixation capacity like the paddy soils derived from red soils.展开更多
The effects of different chemical fertilizer combinations (N, P and K) oncrop yield, N uptake and nitrate distribution and accumulation to a depth of 100 cm were studied ina cinnamon fluvo-aquic soil profile (Beijing)...The effects of different chemical fertilizer combinations (N, P and K) oncrop yield, N uptake and nitrate distribution and accumulation to a depth of 100 cm were studied ina cinnamon fluvo-aquic soil profile (Beijing) with a continuous winter wheat-summer maize croppingsystem for nine years. The experiment consisted of 7 treatments: no fertilizer control (CK); Nalone, N in combination with K (NK), P (NP), and P and K (NPK and N1PK); and P and K in combinationwithout N (PK). The rate of N was 150 kg ha^(-1) for the N treatments except Treatment N1PK withhigher N rate (195 kg ha^(-1)), and the rates of P (P_2O_5) and K (K2O) were 75 and 37.5 kg ha^(-1),respectively. The applications of N combined with P and K (NK, NP and NPK) resulted in higher cropyields than a single application of N. The yields followed the order: NPK > NP > N1PK > PK > NK > N> CK for winter wheat, and NPK > N1PK > NP > NK > N > PK > CK for summer maize. Supplement of N withP or K, or both P and K resulted in a higher average N uptake of the two crops, which was in adecreasing order NPK > NP > N1PK > NK > N > PK > CK. The combinations also increased apparent Nrecovery more than N alone and CK. The nitrate content in the profile was thus reduced more in thecombination treatments. The nitrate accumulation in the soil profiles followed the order: N > NK >N1PK > NPK > NP > CK > PK. Higher N uptake by the adequately fertilized crops (Treatment NPK)reduced nitrate accumulation in the profile and thus reduced nitrate leaching. The optimum N:P:Kratio was thus of paramount importance in increasing yields and N uptake of crops and reducingnitrate leaching losses.展开更多
文摘A field experiment with an early rice-late rice rotation was carried out on a paddy soil derived from red soil in the southern part of Zhejiang Province to elucidate the effect of excess P application on some important characteristics of soil properies and its relation to nutrient status and grain yields of rice crops.The experimental results indicated that adequate fertilizer P (15 kg P hm-2) could increase the content of soil available P at the tillering stage of early rice, the contents of N, P and K in the shoots of early rice at primary growth stages, and the grain yield of early rice by increasing valid ears per hectare and weight per thousand grains, which was mainly related to the higher contents of reduced, non-reduced and total sugar in the shoots at the heading stage. And early rice supplied with excessive P could not yield more than that applied with adequate P, due to the reduction in the valid grain percentage and weight per thousand grains.In addition, onestime excess P supply at a rate as high as 90 kg P hm-2 could not improve the soil P fertility in case the soil available P content was lower than the initial (3.74 mg kg-1 soil) after an early rice-late rice rotation, and made a decline in the grain yield increased by per kilogram fertilizer P. Thus, one-time excess P supply should not be adopted for soils with a large P fixation capacity like the paddy soils derived from red soils.
基金Project supported by the Ministry of Agriculture, China (No. 95-17-03-01).
文摘The effects of different chemical fertilizer combinations (N, P and K) oncrop yield, N uptake and nitrate distribution and accumulation to a depth of 100 cm were studied ina cinnamon fluvo-aquic soil profile (Beijing) with a continuous winter wheat-summer maize croppingsystem for nine years. The experiment consisted of 7 treatments: no fertilizer control (CK); Nalone, N in combination with K (NK), P (NP), and P and K (NPK and N1PK); and P and K in combinationwithout N (PK). The rate of N was 150 kg ha^(-1) for the N treatments except Treatment N1PK withhigher N rate (195 kg ha^(-1)), and the rates of P (P_2O_5) and K (K2O) were 75 and 37.5 kg ha^(-1),respectively. The applications of N combined with P and K (NK, NP and NPK) resulted in higher cropyields than a single application of N. The yields followed the order: NPK > NP > N1PK > PK > NK > N> CK for winter wheat, and NPK > N1PK > NP > NK > N > PK > CK for summer maize. Supplement of N withP or K, or both P and K resulted in a higher average N uptake of the two crops, which was in adecreasing order NPK > NP > N1PK > NK > N > PK > CK. The combinations also increased apparent Nrecovery more than N alone and CK. The nitrate content in the profile was thus reduced more in thecombination treatments. The nitrate accumulation in the soil profiles followed the order: N > NK >N1PK > NPK > NP > CK > PK. Higher N uptake by the adequately fertilized crops (Treatment NPK)reduced nitrate accumulation in the profile and thus reduced nitrate leaching. The optimum N:P:Kratio was thus of paramount importance in increasing yields and N uptake of crops and reducingnitrate leaching losses.